Mobile Commerce And Wireless Computing Systems 0201752409, 1011031051, 9780201752403

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Elliott_ppr 9/19/07 3:46 PM Page 1

As content delivery over wireless devices becomes faster and more secure, it is thought that mobile commerce M-commerce) will overtake tethered E-commerce as the medium of choice for digital commerce transactions. As well as the obvious effect on financial services (mobile banking), telecommunications, and retail and information services (such as video delivery of sports results) it is also likely to have a profound effect on the way a wide variety of businesses arrange for people to meet and interact. This book explores the theory and practice of both the technical and business domains of M-commerce, particularly wireless networking and mobile commerce applications, as well as discussing the 'what, why and how' of M-commerce. The book starts by covering the theoretical underpinning of the subject, before going on to put the theory into practice, covering the technologies, approaches, applications and design issues. Features • Explains the fundamentals of mobile commerce and wireless systems design, and implementation

• Balances enthusiasm for the technological capabilities with wider social and political implications through discussion of security and ethical issues

Geoffrey Elliott is Head of Division for Information Systems at London South Bank University. Nigel Phillips worked in the computer industry for 10 years before joining London South Bank University, consulting on the application of complexity theory.

www.pearson-books.com

and

• Tutorial approach, with exercises, student activities, short case studies and technical reports to enhance learning.

About the authors

Geoffrey Elliott Nigel Phillips

• Applications oriented, showing how good systems design leads to efficient and effective M-commerce systems

This book is intended for anyone wishing to find out more about the theory and practice of commercially exploiting these exciting and ground-breaking new technologies.

Mobile Commerce and Wireless Computing Systems

Mobile Commerce and Wireless Computing Systems

Geoffrey Elliott

and

Nigel Phillips

Mobile Commerce and Wireless Computing Systems

Mobile Commerce and Wireless Computing Systems

We work with leading authors to develop the strongest educational materials in mobile computing, bringing cutting-edge thinking and best learning practice to a global market. Under a range of well-known imprints, including Addison Wesley, we craft high quality print and electronic publications which help readers to understand and apply their content, whether studying or at work. To find out more about the complete range of our publishing, please visit us on the World Wide Web at: www.pearsoned.com

Mobile Commerce and Wireless Computing Systems Geoffrey Elliott and Nigel Phillips

Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies around the world Visit us on the World Wide Web at: www.pearsoned-ema.com

First published 2004 © Pearson Education Limited 2004 The rights of Geoffrey Elliott and Nigel Phillips to be identified as authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved; no part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without either the prior written permission of the Publishers or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP. All trademarks used herein are the property of their respective owners. The use of any trademark in this text does not vest in the author or publisher any trademark ownership rights in such trademarks, nor does the use of such trademarks imply any affiliation with or endorsement of this book by such, owners. ISBN 0 201 75240 9 British Library Cataloguing-in-Publication Data A catalogue record for this book can be obtained from the British Library. Library of Congress Cataloging-in-Publication Data Elliott, Geoffrey. 1964Mobile commerce and wireless computing systems / Geoffrey Elliot and Nigel Phillips. p. cm. Includes bibliographical references and index. ISBN 0-201-75240-9 (alk. paper) 1. Mobile computing. 2. Mobile commerce. 3. Wireless communication systems. I. Phillips, Nigel, 1956- II. Title. QA76.59.E45 2003 004.165--dc21 2003051276 10 9 8 7 6 5 4 3 2 1 08 07 06 05 04 Typeset by 30 in 10/12 pt Caslon Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset

Contents

Preface Acknowledgements

1

Mobile commerce (M-commerce): definitions and context 1.1 1.2

1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12

1.13 1.14 1.15 1.16 1.17

1.18

Defining M-commerce A short history of wireless computing 1.2.1 First generation wireless communication 1.2.2 Second generation wireless communication 1.2.3 Third generation wireless communication Diffusion of M-commerce innovation Obstacles to M-commerce The Mobile Internet and mobile information assets The untethered Mobile Internet M-commerce versus E-commerce The wireless world Pervasive computing systems, theory and practice Trends in mobile and pervasive computing Applications of M-commerce The trend towards mobile working 1.12.1 Wireless telemetry and wireless telematics 1.12.2 Tracking and monitoring the mobile workforce 1.12.3 Customer-focused products and services Effectiveness and efficiency in mobile domains The M-commerce value chain Networked wireless business systems Bluetooth technology Factors determining M-commerce innovation and adoption in the 21st century 1.17.1 Five characteristics of innovation 1.17.2 The socio-technical perspective of technology innovation and adoption Conclusions Short self-assessment questions and Group activity References and Bibliography

xv xvii

1 3 4 4 5 7 10 11 12 15 20 21 23 24 26 27 28 29 30 32 33 37 37 38 40 41 44 45 47

vi

Contents

2

Commercial communications and networks

49

2.1 2.2 2.3 2.4

51 54 55 58 60 60 62

2.5 2.6 2.7

2.8 2.9

2.10

2.11 2.12

2.13

2.14

Introduction The nature of commercial communication Communication and language complexity Information and meaning 2.4.1 Information as channel capacity 2.4.2 Information as a measure of variety 2.4.3 Information as a means of reducing uncertainty 2.4.4 Information as a measure of an agent’s ability to estimate a parameter Data and knowledge Shared meaning Communication and information theory 2.7.1 Source 2.7.2 Transmitter 2.7.3 Channel 2.7.4 Noise 2.7.5 Receiver 2.7.6 Destination 2.7.7 Channels and transportation Telecommunications and networks Media types in telecommunications 2.9.1 Bound media 2.9.2 Unbound media Modulation and digitization 2.10.1 Modulation 2.10.2 Digitization Communication network infrastructures Types of channel 2.12.1 Circuit switching 2.12.2 Packet switching 2.12.3 Protocols and protocol stacks The International Standards Organization reference Model 2.13.1 Application Layer 2.13.2 Presentation Layer 2.13.3 Session Layer 2.13.4 Transport Layer 2.13.5 Network Layer 2.13.6 Data Link Layer 2.13.7 Physical Layer Transport Control Protocol/Internet Protocol (TCP/IP)

62 63 64 66 66 66 67 67 67 67 68 69 72 72 73 75 75 75 76 79 79 79 80 81 83 84 84 85 86 86 87 87

Contents

2.15 Communications network devices 2.15.1 Transceivers 2.15.2 Repeaters 2.15.3 Bridges 2.15.4 Hubs 2.15.5 Routers 2.15.6 Switches 2.15.7 Gateways 2.15.8 Wireless access points 2.15.9 Mobile terminal 2.16 Network topologies 2.16.1 Mesh topology 2.16.2 Bus topology 2.16.3 Star topology 2.16.4 Star bus 2.16.5 Hierarchical star 2.16.6 Ring 2.16.7 Ad hoc wireless 2.16.8 Infrastructure wireless 2.16.9 Piconet 2.16.10 Network addresses 2.17 Conclusions Short self-assessment questions and Group activity References and Bibliography

3

vii

89 89 89 90 90 90 90 90 90 91 91 91 92 92 92 93 93 94 94 94 95 96 97 98

Wireless protocols: context and usage

101

3.1 3.2

103 105

3.3 3.4

Introduction Wireless cellular phone networks 3.2.1 History and development of cellular radio networks 3.2.2 Current and future cellular communication networks 3.2.3 Cellular radio networks 3.2.4 Cellular mobility management 3.2.5 Wireless operational features The Wireless Applications Protocol (WAP) WAP architecture layers 3.4.1 The Wireless Application Environment (WAE) layer 3.4.2 The Wireless Session Protocol (WSP) layer 3.4.3 The Wireless Transaction Protocol (WTP) layer 3.4.4 The Wireless Transport Layer Security (WTLS) 3.4.5 The Wireless Datagram Protocol (WDP) layer

106 109 113 115 116 117 122 124 124 125 126 126

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Contents

3.5 3.6 3.7 3.8 3.9

3.10 3.11 3.12

3.13 3.14 3.15

4

WAP functionality and adaptation Service bearer adaptation Comparison of wireless and wired network Internet protocols The integration of WAP and TCP/IP within the OSI architecture model The Mobile Internet 3.9.1 Mobile Internet network operators 3.9.2 Wireless Internet portal providers The Mobile Internet – services and products Other wireless Internet providers A case study of iMode 3.12.1 iMode service operation 3.12.2 Characteristics of iMode A comparison of WAP and iMode WAP and iMode billing models Conclusions Short self-assessment questions and Group activity References and Bibliography

Wireless programming for mobile devices: context and usage 4.1 4.2 4.3 4.4 4.5

4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15

Introduction The development and use of the xHTML WML and xHTML convergence A comparison of WML and xHTML transmission protocols Creating an Internet WAP site 4.5.1 Step 1 – Downloading an emulator 4.5.2 Step 2 – Creating and building the WAP or xHTML site 4.5.3 Step 3 – Registering and publishing a WAP site Developing a basic WAP site using WML WML and WML Script The WML language basics – elements and attributes WML deck navigation – event and task handling Push and pull browsing WML option menus and variables Passwords and security in WML Handling text formatting, tables and images in WML Capturing and sending information within the WAP environment Application and web server access security

127 129 130 132 135 135 136 139 142 143 145 147 148 149 151 152 154

157 159 161 162 164 165 165 168 169 170 172 173 177 182 183 190 192 194 196

Contents

5

ix

4.16 WML Scripting within the WAP environment 4.16.1 Variables 4.16.2 Functions 4.16.3 Pragmas 4.17 WML Script libraries 4.18 WML Script statements 4.19 WAP site usability issues 4.20 Hosting WAP sites 4.21 Conclusions Short self-assessment questions and Group activities References and Bibliography Appendix 4.1 Commonly used WML tags Appendix 4.2 Commonly used HTML tags

196 197 199 199 201 202 205 206 207 208 210 211 215

Operating systems: micro and macro devices

217

5.1 5.2 5.3

219 219 222 222 223 223

Introduction Target devices Mobile-specific operating systems requirements 5.3.1 Wireless networking 5.3.2 Location independent computing 5.3.3 Physical constraints of devices 5.3.4 Increased levels of uncertainty in the environment 5.3.5 Differences in psychological affordance of small devices 5.4 Operating systems basics for wireless understanding 5.5 Operating system abstractions 5.5.1 Systems processes 5.5.2 Multi-processing environments 5.5.3 Memory management 5.5.4 Virtual memory 5.6 Information protection and security 5.7 Scheduling and resource management 5.8 Dividing to rule 5.9 Modern operating system concepts 5.9.1 The kernel 5.9.2 Multi-threading 5.9.3 Object-oriented programming 5.10 Operating systems requirements for mobile devices 5.10.1 Wireless networks and telephony 5.10.2 Processing power 5.10.3 Computing and computation 5.10.4 Mobile memory 5.10.5 Mobile network security 5.10.6 Multimedia

223 224 224 227 228 228 229 231 231 232 234 236 236 237 238 239 239 240 241 241 241 243

x

Contents

6

5.11 Mobile applications 5.11.1 vCard 5.11.2 vCalendar 5.11.3 Messaging 5.11.4 Subscriber Identity Module (SIM) 5.12 The Java Virtual Machine (JVM) 5.12.1 Java 2 Micro Edition 5.12.2 Configuration and profiles 5.12.3 Java Connected Device Configuration (CDC) 5.12.4 Java Connected, Limited Device Configuration (CCDC) implementation 5.12.5 JavaPhone 5.12.6 JavaCard – smart cards 5.13 Mobile device operating systems 5.13.1 Palm OS 5.13.2 Embedded Microsoft Windows 5.13.3 Symbian 5.14 Comparisons of mobile device platforms 5.15 Conclusions Short self-assessment questions and Group activities References and Bibliography

251 251 251 252 252 255 257 260 262 263 265

Personal area and mobile networking

267

6.1 6.2

269 270 271 273 275 276 277 278 278 278 279 279 279 279 280

6.3 6.4

6.5

6.6

Introduction The development of area networks 6.2.1 Personal Operating Space (POS) 6.2.2 Personal Area Networks (PANs) 6.2.3 Personal information appliances Wireless-enabled domestic appliances Environment characteristics 6.4.1 Mobile wireless environments 6.4.2 Static wireless environments 6.4.3 Smart spaces 6.4.4 Biddable spaces Local Area Networks (LANs) 6.5.1 The network backbone 6.5.2 Fibre Distributed Data Interface (FDDI) 6.5.3 Ethernet 802.3 6.5.4 Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Wireless networks 6.6.1 Power, range and data rate 6.6.2 IEEE 802.11b wireless Ethernet

244 244 245 246 246 247 249 250 250

280 281 281 282

Contents

6.7 6.8 6.9 6.10

6.11

6.12

6.13 6.14

6.15

7

6.6.3 CSMA/CA 6.6.4 802.11a 6.6.5 HiperLAN2 Personal area network intelligent gateways Bluetooth technology Bluetooth radio frequency channels Bluetooth piconets 6.10.1 Network master and slaves 6.10.2 Scatternets Establishing and maintaining wireless connections 6.11.1 Wireless operating modes 6.11.2 Creating network connections The physical connection 6.12.1 Time-slots 6.12.2 Frequency-hopping 6.12.3 Security 6.12.4 IEEE 802.15 Wireless surveillance Wireless service discovery and use 6.14.1 JINI 6.14.2 Universal Plug and Play (UPnP) 6.14.3 Salutation Conclusions Short self-assessment questions and Group activity References and Bibliography

Wireless applications: push and pull services and products 7.1 7.2 7.3 7.4 7.5 7.6 7.7

7.8 7.9 7.10 7.11 7.12 7.13

Introduction WAP push and pull messaging The Short Message Service (SMS) SMS pricing Push profiling Profiling cookies Base platform services 7.7.1 Digital content services 7.7.2 Digital content products M-commerce services for consumers Electronic cash (e-cash) Mobile electronic banking (e-banking) Mobile alerts Mobile gambling M-commerce services for business 7.13.1 Wireless business-to-business 7.13.2 Mobile collaboration 7.13.3 Wireless business-to-consumer

xi

282 284 284 285 287 289 290 290 291 292 293 294 296 296 297 298 299 300 301 302 304 304 305 306 307

311 313 314 316 318 318 319 320 322 323 324 326 327 330 330 331 331 333 334

xii

Contents

8

7.14 Wireless Internet business model 7.15 Mobility and location 7.15.1 Global Positioning Systems (GPSs) 7.15.2 Mobile network location 7.15.3 Location triangulation 7.16 Mobile systems thinking 7.17 Wireless business applications 7.17.1 Static mobile environments 7.17.2 Location-response mobile environments 7.17.3 Dedicated-embedded mobile environments 7.17.4 Wireless systems connectivity 7.17.5 Wireless systems flexibility 7.18 The economics of wireless Internet data 7.19 Mobile Multimedia Portals (MMPs) 7.20 Conclusions Short self-assessment questions and Group activity References and Bibliography Appendix 7.1 SMS texting

335 338 338 340 341 343 345 346 346 346 346 348 353 356 357 357 359 361

Pervasive and embedded mobile systems

363

8.1 8.2 8.3

365 368 370 371

8.4 8.5 8.6

8.7 8.8 8.9 8.10 8.11 8.12

8.13 8.14

Defining pervasive computing Technologies within the pervasive computing domain Networked pervasive computing 8.3.1 First generation pervasive computing 8.3.2 Second generation pervasive computing (and beyond) Embedded systems ergonomics Wearable computing Biometric systems 8.6.1 Fingerprints 8.6.2 Hand geometry 8.6.3 Facial features 8.6.4 Eye features 8.6.5 Voice features 8.6.6 Signature features Biometric issues and systems security Biometric systems applications Biometric systems integration Digital signatures Automobile telematics and vehicle telemetry In-vehicle user interfaces and applications 8.12.1 Voice-activated interfaces 8.12.2 Internet applications Universal Information Appliances (UIAs) Obstacles in pervasive computing

372 373 374 380 381 381 382 382 382 383 383 386 388 389 391 393 394 394 397 399

Contents

9

xiii

8.15 Conclusions Short self-assessment questions and Group activity References and Bibliography Appendix 8.1: MEMS – Big ideas for Small Devices

400 401 403 404

Security in a mobile world

409

9.1 9.2

411 412 413 413 414 415 415 415 416 418 418 420 421 422 424 425 426 428 429 430 430 430 430 431 431 432 432 433 434 435 436 437 438 439 440 443 444 447 448 449 450

9.3

9.4 9.5

9.6 9.7 9.8

9.9

9.10 9.11 9.12 9.13 9.14 9.15

Introduction Aspects of security 9.2.1 General security issues 9.2.2 General security threats 9.2.3 Mundane threats 9.2.4 Policy Wireless network security 9.3.1 Network environments 9.3.2 Communication channel threats 9.3.3 Misappropriation and misuse threats Access control Encryption 9.5.1 Codes 9.5.2 Code breaking The Diffie-Hellman key agreement method Security aspects of wireless networks Wide area wireless network security – 3G 9.8.1 User domain roles 9.8.2 Infrastructure domain roles 9.8.3 Network traffic 9.8.4 Network intruders 9.8.5 Off-line parties 9.8.6 Mobile terminals and UICC 9.8.7 Radio interface 9.8.8 Wired interfaces 9.8.9 Home environments and users 9.8.10 Requirements to reduce or avoid vulnerabilities Wireless Local Area Network (WLAN) security features 9.9.1 IEEE 802.11b 9.9.2 Service Set Identifier (SSID) 9.9.3 The authentication protocol 9.9.4 Wired Equivalent Privacy (WEP) Bluetooth and Personal Area Network (PAN) security 9.10.1 Ad hoc network vulnerabilities Bluetooth baseband security Bluetooth security profiles The headset security model Securing small devices Conclusions Short self-assessment questions and Group activity References and Bibliography

xiv

Contents

10

Enabling the mobile workforce: extending enterprise applications 10.1 10.2

10.3 10.4 10.5 10.6 10.7 10.8 10.9 10.10

10.11

10.12 10.13

10.14 10.15

The agile and mobile workforce Supporting the mobile workforce 10.2.1 Device and technology maintenance 10.2.2 Integrating killer apps 10.2.3 The cost of mobile worker access Mobile systems development Issues in M-commerce Privacy Social, ethical and legal issues Ethical business behaviour Ethical issues Ethical dilemmas in wireless business systems Rights and duties, and privileges and responsibilities 10.10.1 Duties 10.10.2 Rights 10.10.3 Privileges 10.10.4 Responsibilities Trust and control 10.11.1 Confidentiality 10.11.2 Freedom and capabilities 10.11.3 Freedom from constraint 10.11.4 Freedom to participate Surveillance Data protection 10.13.1 Data protection principles 10.13.2 Monitoring at work Impact analysis using a real-world case study Conclusions Short self-assessment questions References and Bibliography Appendix 10.1 Impact analysis using a real-world case study

453 455 457 457 458 459 460 462 463 463 465 466 467 468 468 469 469 469 470 471 472 472 473 474 475 475 477 481 483 483 484 485

M-commerce glossary

511

Index

523

More information can be found at: www.booksites.net/elliottphillips

Preface

No matter at what level one is involved in systems development, whether as a senior systems analyst or as a maintenance programmer, possession of two particular areas of knowledge provides an enormous advantage in making one’s contribution effective: an understanding of the capabilities of the technology and an understanding of what people want to do with it and want it to do for them. The quantity and quality of each knowledge domain necessary for any particular role might vary, but one without the other is a distinct handicap. It has been our intention in writing this book to try to provide both sets of knowledge with regard to mobile commerce and the supporting mobile computing and wireless technology. This has presented us with a bit of a dilemma as, being quite new, neither knowledge domain is particularly well defined. It is not at all clear exactly how much of the technology will evolve into everyday use nor which particular technologies will thrive and which will disappear without trace. It is inevitable that some of the ideas we present here will not emerge as common practice and that some of the technologies we describe will not be the ones to be widely adopted. We might have tried, and on occasion were certainly tempted to try, to mention every current device and idea; however, that path would have led either to a very long book or to one that was exceedingly broad but lacking any substance, and we felt that market was already well served. So we have tried to select technologies and models for their deployment and use that are indicative of the broad type of application and to present them with enough depth to give our readers a good feel for their richness and the issues that need to be considered. No doubt people will feel we have been too broad in some areas and too narrow in others, too deep and detailed or too superficial elsewhere. If you should think this we would simply ask you to bear in mind that we seek to give a flavour of a large and fast developing area. The book is intended to be neither a how-to book nor an academic review, but a sound introduction to the technologies and issues of an interesting and dynamic new area. This book covers the integration of mobile computing, wireless networks, mobile technology, and mobile business applications. The use of portable, mobile and wireless technology within the business information systems domain is described under the umbrella of ‘Mobile commerce’ (M-commerce). This term is used to describe the integration of these technologies, devices and systems.

xvi

Preface

The book is aimed at students studying within the following broad and specific subject areas: ◆

◆

Broad areas – Computing – Information Technology – Information Systems Specific areas – Mobile Computing – Wireless Computing – Mobile Commerce and Wireless Computing Systems

The aim is to provide a holistic framework for understanding the devices, technologies and systems used within the mobile commerce and wireless computing domain. These form the ‘what, how and why’ of M-commerce. We concentrate on understanding the integration of these devices and technologies within wireless networking domains. A clear and integrated understanding of M-commerce and wireless computing systems requires understanding the impact of mobile devices, technologies and systems on networked business systems activity. The book encourages the reader to develop a critical approach to the evaluation of competing mobile devices, technologies and systems, through emphasizing the competing risks from adoption of unfavourable approaches and non-adoption of favourable ones. Small and large case studies are referred to throughout the book to highlight areas of M-commerce and wireless computing. The reader is encouraged to supplement these reports with their own research and to evaluate the issues using a diffusion of knowledge framework. To enable this outcome, each chapter contains activities and exercises to encourage students to think about the concepts, knowledge sets, technologies and systems being described. The chapters focus on applying enabling technologies to enhance the efficiency and effectiveness of wireless computing systems in the M-commerce domain. The book aims to broaden the reader’s knowledge and understanding of the issues as they progress through the chapters, hopefully culminating in a holistic understanding of integrated mobile computing systems. The emphasis throughout is on providing a large amount of interactive tutorial material in each chapter, supported by numerous short and longer exercises and activities. We hope the product is both useful and, more importantly, interesting to students, lecturers and general readers in the mobile commerce and wireless computing systems domain.

Geoffrey Elliott & Nigel Phillips June 2003

Acknowledgements

First, we would like to thank Kate Brewin and Andrew Taylor at Pearson Education for their considerate and patient support. Secondly, our thanks go to Ethan R.R. McCarty, Web Editor for IBM Research Communications. Ethan provided kind and cooperative help in acquiring permissions to use a number of IBM resources. Thanks to Paul Carden for useful advice on the wireless Internet. Finally, we would also like to thank all those unnamed colleagues and students who provided suggestions and advice on a range of areas in the M-commerce domain over the last 18 months.

Geoffrey Elliott & Nigel Phillips June 2003

Publisher’s acknowledgements

We are grateful to the following for permission to reproduce copyright material: Figure 1.7 reprinted from Networked Applications: A Guide to the New Computing Infrastructure by David G. Messerschmitt, p.8, Copyright 1999, with permission from Elsevier; Figure 2.3 republished with permission of Lucent Technologies, adapted from ‘A mathematical theory of communication’ by Shannon in Bell Systems Technical Journal, Vol. 27, July-October 1948, Copyright 1948 by Lucent Technologies; permission conveyed through Copyright Clearance Center, Inc.; Table 3.3 from Pervasive Computing: Technology and Architecture of Mobile Internet Applications, Pearson Education, Inc. (Burkhardt, J., et al., 2001); Chapters 3, 4 and 7

xviii

Acknowledgements

screenshots, AOL browser window © 2003 America Online, Inc. Used with permission; Chapter 4 screenshot, Netscape browser window © 2003 Netscape Communications Corporation. Used with permission; Chapter 4 screenshot from http://www.w3schools.com, reproduced with permission from Refsnes Data; Chapter 7 screenshot from http://www.mobeyforum.org, reproduced with permission from Mobey Forum Mobile Financial Services Ltd.; Figure 8.3 after Figure in A practical guide to biometric security technology, IEEE Computer Society, January-February, reprinted with permission of IEEE (Lui, S. and Silverman, M., 2001); ‘Why Mobile is Different’ from The Economist, 13 October 2001, © The Economist 2001; Chander Dhawan for an extract adapted from ‘Mobile Computing: A System’s Integrator’s Approach’ published on www.mobileinfo.com; Steve Mann for an extract adapted from ‘Cyborg: Digital Destiny and Human Possibility in the Age of the Wearable Computer’ Random House/Doubleday 2001; and MTravel.com for the article ‘Air Canada begins trial of wireless IBM kiosks’ published on www.m-travel.com on 26th April 2002.; IBM and Stewart Wolpin for Appendix 8.1: MEMS big ideas for Small Devices; IBM and Dave Bevis and LindaMay Patterson for Appendix 10.1: Impact analysis using a real-world case study. We are grateful to the following for permission to reproduce photographs: Chapter 1, p.14 Kyocera Wireless Corp.; Chapter 3, p.107 The Vancouver Sun; Chapter 3, p.108 Dorling Kindersley; Chapter 4, p.168 Kyocera Wireless Corp.; Chapter 4, pp.168, 173 Kyocera Wireless Corp.; Chapter 5, p.xxx The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Chapter 7, pp.314, 321, 337, 347 Kyocera Wireless Corp.; Chapter 8, p.373 Fossil (UK) Ltd.; Chapter 8, p.376 IBM; Chapter 8, pp.378, 379 Webb Chappell. In some instances we have been unable to trace the owners of copyright material, and we would appreciate any information that would enable us to do so.

To Theresa, Holly and Ryan & Catherine

Elysium is as far as to Elysium is as far as to The very nearest Room If in that Room a Friend await Felicity or Doom -What fortitude the Soul contains, That it can so endure The accent of a coming Foot -The opening of a Door -Emily Dickinson1 (1830–1886)

1

Emily Elizabeth Dickinson was born in Massachusetts in the USA. She wrote over 1700 poems in her lifetime.

Mobile Commerce (M-commerce): definitions and context

1

‘I’ll put a girdle round about the Earth in 40 minutes.’ Puck in A Midsummer Nights Dream by William Shakespeare (1564–1616)

Chapter Aims: ■ ■ ■ ■ ■ ■ ■ ■

■

To define M-commerce in terms of location-independent connectivity within the pervasive computing domain. To briefly explain the development of wireless computing and outline the characteristics of each generation of development. To provide a context for understanding the integrated multimedia nature of current third generation (3G) wireless environments. To develop an understanding of the diffusion of innovation and technology adaptation within the M-commerce domain. To review the role of the Mobile Internet within M-commerce and understand the importance of mobile information assets. To explain the importance of location-specific products and services and differentiate wired E-commerce from wireless M-commerce. To provide an understanding of theory and practice and an analysis of trends in pervasive computing systems. To introduce the application of M-commerce and provide an understanding of the roles and responsibilities of various entities within the wireless Internet industry. To review the software and hardware aspects of networked, wireless business systems and provide a subject context for how these computing areas relate to M-commerce.

2

Mobile commerce (M-commerce): definitions and context

M-commerce

Definitions

Evolution of wireless telecommunications Pervasive Computing First generation BluetoothTM

Wireless LANs Second generation

Embedded Technology 3G

Third generation

Broadband (2Mbp/s) Data-centric Services (e.g. Mobile Internet)

UMTS

Personal Communication Systems (PCS)

Diffusion of Innovation

Smart Phones (wireless PDAs)

Technology adoption

Location based Services

Mobile working

Wireless Telemetry Mobile Commerce Business Systems

The Knowledge Context Map

Defining M-commerce

1.1

3

■ Defining M-commerce Mobile commerce (commonly referred to as ‘M-commerce’) is concerned with the use, application and integration of wireless telecommunication technologies and wireless devices within the business systems domain. The area of M-commerce includes reference to the infrastructures and electronic technologies necessary for wireless data and information transfer, in all its multimedia forms (i.e. text, graphics, video and voice). It also incorporates the study of the various wireless technologies, and the portable mobile devices, used to send and receive data and information (e.g. mobile phones, Personal Digital Assistants (PDAs), and wireless modems). The use of wireless technologies extends the nature and scope of traditional electronic commerce (E-commerce) by providing the additional aspects of mobility (of participation) and portability (of technology). Therefore, M-commerce is sometimes referred to as mobile E-commerce. M-commerce can be considered to be a flexible solution to many of the negative aspects of fixed-wired E-commerce. Wireless-based network infrastructures, and the portable mobile technologies that support such infrastructures, provide flexibility and mobility within the business systems domain. Despite this general understanding, defining M-commerce can still be a semantic exercise in its own right. Within the context of this book, M-commerce is referenced to mobile computing and pervasive computing systems, theory and practice. Therefore, M-commerce is succinctly defined as the interconnection of portable computing technologies, and the wireless telecommunications networking environments necessary to provide location independent connectivity within the business information systems domain.

Definition of M-commerce ‘The mobile devices and wireless networking environments necessary to provide location independent connectivity.’

By far the most commercial application of wireless telecommunications has been the ability to access the Mobile Internet from portable devices, such as PDAs and particularly mobile phones. The Mobile Internet relies on a number of different networking infrastructures and technologies to support wireless Internet access. However, the Mobile Internet is but one application amongst many others within the M-commerce world. In a similar way, the mobile phone has come to be seen as the primary device in the wireless world. Figure 1.1 shows the basic components of the M-commerce environment. However, the mobile phone is only one device amongst many other portable mobile devices (e.g. wireless PDAs, wireless vending machines, wireless local area networks, etc.) that need to be studied to appreciate the full breadth and richness of the technologies, devices and applications available in the M-commerce world.

4

Mobile commerce (M-commerce): definitions and context

The M-commerce Systems Environment

Wireless Vending Devices (M-wallet capable)

Wireless connectivity

Location independent connectivity

WLAN

Corporate Gateway

Wireless modems

(e.g. 802.11b)

Voice, pictures, SMS, and data

Wireless office environments

Virtual office environments (M-commerce activity)

Figure 1.1 Basic M-commerce environment

1.2

■ A short history of wireless computing In 1897, Guglielmo Marconi first demonstrated the ability to provide continuous, wireless (voice) contact with ships sailing off the coast of the United Kingdom through radio-wave signal communication. Since then mobile wireless communications have evolved along a logical path from relatively simple first generation (1G) analog technologies to current third generation (3G) digital and broad bandwidth technologies that incorporate a vision of mobile devices, and supporting infrastructures providing what is termed a complete ‘personal communication system’ (PCS)1. Third generation technologies allow users to transfer any form of multimedia data and information between remote wireless locations to provide full location independent connectivity. Therefore, 3G technology enables mobile phones, and other mobile communications devices, to be used as data and information lifestyle portals, rather than merely as voice communication devices.

1.2.1


First generation wireless communication First generation, cellular, wireless communications devices evolved slowly and came into general use in the business information systems domain only

1

Definitions of analog and digital telecommunications can be found in the glossary to this book.

A short history of wireless computing

5

in the 1980s. Up to that time wireless communication was possible but it was practised only in certain environments, particularly government agencies and the military. For example, in 1946 AT&T Bell introduced the first commercial mobile phone to the USA (following military applications) allowing telephone calls between fixed-wire stations and mobile users. However, the initial technology was of poor quality and, therefore, of little use for the majority of business systems applications. By the 1960s research and development into mobile communications (by various telecommunications utilities around the world) greatly improved the technological environment of commercial mobile telecommunications. For instance, AT&T Bell in the USA developed the Improved Mobile Telephone Service (IMTS) that became the backbone of commercial-sector mobile telecommunications. However, it was not until the late 1970s and early 1980s that various developments in microprocessor technology, and improvements in cellular network infrastructures, led to the birth of reliable, first generation (1G), wireless telecommunications systems. These were based primarily on voice, rather than data, transmission. The 1980s also saw the birth of wireless mobile phone and telecommunications companies that are now amongst the most influential in the Mcommerce world, such as Nokia in Finland, Ericsson in Sweden and Motorola in the USA. Furthermore, the 1980s saw the simultaneous development of different mobile network analog standards for wireless telecommunications. Several countries (i.e. Sweden, Japan and the USA) started developing their own standards for mobile networks that were based on different bandwidths and network protocols; this made country-to-country communication (known as roaming) extremely difficult. Although roaming is now a standard feature of most mobile telecommunications networks in the 21st century, some of the early-legacy limitations of wireless communication still exist, particularly in terms of the protocols used to implement wireless data communication and Mobile Internet access across networks. The various early analog systems included the Nordic Mobile Telephone (NMT) system in Finland, Norway and Sweden; the Advanced Mobile Phone Service (AMPS) in various parts of Asia, the USA and Canada; the Extended Total Access Communication System (ETACS) in the United Kingdom; and the Japan Digital Cellular (JDC) network system in Japan.

1.2.2


Second generation wireless communication The popularity of wireless telecommunications increased in the late 1980s and early 1990s, and there was an increasing recognition that 1G systems were becoming unworkable because of expanded demand for network capacity, a lack of security features and the proliferation of different wireless network standards. These problems led to the development of second generation (2G) wireless systems that were based on digital (rather than analog) technology. The main 2G development occurred in the early 1990s with the introduction of

6

Mobile commerce (M-commerce): definitions and context

a higher capacity (and more globally compatible) telecommunications network known as the Global System for Mobile Communication (GSM). The GSM network was primarily a European-centric development, but the standard spread widely to other parts of the world and made efficient (and less costly) international call roaming a commercial possibility. The GSM network was an important development in the evolution of modern mobile commerce as it not only unified a range of different standards, but was also the first standard to fully specify the complete network architecture. Second generation mobile phones use digital encoding whereby communication between the phone and the base station takes the form of an encrypted stream of data, making interception more difficult than was the case with 1G technology. As well as voice communication, 2G mobile phones can also send and receive limited amounts of data in the form of services, such as text messaging, via the Short Messaging Service (SMS), and Mobile Internet browsing, via the Wireless Applications Protocol (WAP). There are also other proprietary protocols, such as iMode. Figure 1.2 provides a diagrammatic representation of accessing the Mobile Internet using a 2G, WAP-enabled mobile phone. These various technologies, network infrastructures and applications will be studied in greater detail in Chapters 3 and 4 of this textbook.

Connecting to the Mobile Internet with Second Generation (2G) phones (An example of WAP connection)

To access the Mobile Internet you need the following: 1. WAP enabled phone (or similar proprietary protocol) 2. A connection to a national or international network 3. Wireless Internet Service Provider (i.e. Mobile Internet Portal) 4. A data enabled Subscriber Identity Module (SIM) card in the mobile phone.

Mobile Internet Content (via WAP portal). News, email, sports headlines etc. 3 Connection to a Wireless Internet Service Provider WAP

Connection to a Digital Network (e.g. GSM)

2

1+4

Figure 1.2 Second generation phone connection to the Mobile Internet

However, one significant drawback to 2G GSM networks is the fact that they are primarily voice-centric telecommunication networks with only limited

A short history of wireless computing

7

data transmission characteristics. Therefore, a range of enhanced 2G mobile phones was developed in the late 1990s and early 2000s to offer extended data capabilities, such as higher transmission rates and always-on connectivity via the General Packet Radio Service (GPRS). These enhanced 2G services were normally referred to as ‘2.5G’ technologies (i.e. enhanced transitional technologies between the second and third generation of development). For example, GPRS enables the WAP protocol and other applications to be accessed more easily and more quickly than through GSM. Also, GPRS-enabled mobile phones give the impression of always being connected to the network so that information flows to and from the mobile phone (and anything it is connected to, such as a laptop computer or PDA) almost instantaneously. Therefore, E-mails can be received on a mobile phone handset without the need to dial-up, and WAP content can be accessed at a quicker rate.

1.2.3


Third generation wireless communication Third generation (3G) technology is aimed at providing a wide variety of services and capabilities in addition to voice communication, such as multimedia data transfer, video streaming, video telephony, and full, unabridged Internet access. 3G mobile phones normally have colour display screens and provide high-speed data transfer and always-on connectivity. 3G mobile phones are designed to support large numbers of users more efficiently than 2G networks and allow for future expansion in user capacity. Therefore, the emphasis with 3G technology is on providing data centric services (such as the Mobile Internet) with enhanced voice and multimedia capabilities. In order to support 3G technology a new network service replacement for the GSM network was developed called the Universal Mobile Telephony System (UMTS). The details of second and third generation telecommunications are covered in Chapter 2 of this book. The motivation for 3G is to provide an economically viable and technology-enhanced PCS portal that permits the transfer of economic costing models in the electronic commerce (E-commerce) domain to the M-commerce domain. 3G technologies were first introduced to Japan in 2001 and spread to Europe and the USA in 2002. Interestingly, 3G mobile phones and networks were tested in controlled environments prior to 2002. For example, in Europe 3G technology was tested in 2001 on the Isle of Man, a small semi-independent island off the coast of the United Kingdom2. 3G technology is aimed at integrating both the business and social domains of a user’s life; this is why 3G mobile phones and other devices are often referred to as ‘lifestyle portals’. Figure 1.3 illustrates the integrated nature of the 3G environment.

2

The controlled evaluation of 3G technology on the Isle of Man was covered by the BBC in a television news report in April 2001.

8

Mobile commerce (M-commerce): definitions and context

Activity 1.1

Discuss the evolution of wireless mobile telecommunications from 1G to 3G systems. What were the major technological changes that defined each generation of technological development? Explain why 3G mobile phones (and other wireless mobile devices) are often referred to as ‘life style portals’. What activities do you think may be supported by mobile devices and technologies?

Business Sphere Mobile Videophone

Public Sphere Traffic Information System Personal Security

Videoconferencing Car Navigation Database E-Mail

Mobile Communications Networks for Multimedia

Information Services

Video-Based Karaoke on Demand Portable Television Interactive Television Music on Demand Interactive Games Video on Demand

Disaster Information System Remote Supervision System

Information Services for Pagers News Weather Forecasts Financial Information

Electronic Newspapers Electronic Books Televised Shopping Home Schooling System

Private Sphere

Figure 1.3 Integrated multimedia nature of the 3G domain – the Personal Communications System (PCS)3

3

The PCS diagram is based on ideas and diagrams by DoCoMo in Japan.

A short history of wireless computing

9

Enhancements and improvements in 3G technology compared with 2G technology include: broad bandwidth data transmission (at rates of 2 Mbp/s compared with GSM narrow bandwidth transmission speeds of 9.6 kbp/s); enhanced security and encryption features; improvements in integrated circuitry and general battery life for mobile devices; improvements in screen displays and the ability to handle multimedia data (i.e. video streaming and graphics); and continued miniaturization of mobile phones and other mobile devices with concurrent improvements in storage capacity. One of the more interesting applications of 3G is the capability to connect to location-specific information. This application of location dependent information is covered in greater detail in Chapters 6, 7 and 8. It has been predicted by many commentators in the wireless industry press that the number of mobile phones connected to the Mobile Internet will exceed the number of Internet-connected Personal Computers (PCs) before 2007 (based on both 2G and 3G technology). If this is the case then the mobile phone will become the most prevalent device for accessing the Internet. As with the wired Internet situation in the mid-1990s where there were a number of E-commerce opportunities for those who were the first into the commercial domain of the web with a ‘dot.com’ idea, so similar opportunities exist today with the Mobile Internet in the mid-2000s. These opportunities are no longer just E-commerce opportunities; they have become M-commerce opportunities. A similar analogy can be made with the progress from the electric telegraph (known as the ‘Victorian Internet’ by some commentators4) to the voice-based telephone in the last quarter of the 19th century. The telegraph in the 1890s, like the Internet in the 1990s, was a revolutionary communications technology that transformed both the social and business aspects of human life. It is a little known fact that Harrods department store in London transacted comparatively more business over the telegraph in the last decade of the 1890s than it did over the computerized Internet in the last decade of the 20th century. The development of the telephone (known originally as the ‘speaking telegraph’) transformed telegraphic communication by making it increasingly available to non-specialists. In a similar manner the Mobile Internet, accessible by an Internet-enabled mobile phone, may do for the Internet what the telephone did for the telegraph (The Economist, 2001). The use of the telegraph to transmit and receive messages in Morse code in the 19th century and the extended use of the wired telephone in conjunction with the Internet in the late 20th century are examples of technologies that have become an integral part of the business systems environment. M-commerce is concerned with the holistic integration of portable mobile technologies, devices and wireless infrastructures into the business information systems domain in more detail. 4

An interesting account of the development of the telegraph, and wired telephone, can be read in a book entitled ‘The Victorian Internet’ by Tom Standage, 1998.

10

Mobile commerce (M-commerce): definitions and context

Activity 1.2

1.3

Outline the main enhancements and improvements in 3G technology over 2G technology and discuss why broadband is so important for accessing the Internet via mobile phones and PDAs. Discuss the importance of video streaming on mobile phones and suggest a couple of applications for it within the M-commerce domain.

■ Diffusion of M-commerce innovation The growth in the number of people accessing the Internet via mobile phones is currently limited by the capacity of the underlying wireless technologies, devices and applications. In addition, the spread and adoption of new business ideas is often a slow process for any individual or commercial organization. Every new innovation possesses a steep initial learning curve where incline is not always related to complexity, as much as to the difficulty of conceptualizing a new idea into an understandable reality. Many innovations require a lengthy period from the time they become available to the time they are widely adopted. This problem of diffusion of innovation is an understood concept within the information technology domain. Therefore, the problem for many individuals and business organizations is focused on how to speed up the rate of diffusion of an innovation. Also incorporated into the equation is the problem of the technological expectations of mobile device users. For example, although 3G technologies offer extensive multimedia capabilities, the expectation is that, rather than downloading and watching video clips on a 3G mobile phone, a user is initially more likely to use only a sub-set of the technology’s capabilities. Their personal expectations may be more realistic ones, such as using the mobile phone for wireless telephony (voice communication as a phone), or to access E-mail, or to download news and weather information. However, the diffusion of innovation is encouraged in the M-commerce world by the cost-effective availability of portable mobile devices (e.g. mobile phones, PDAs and other handheld electronic organizers). These devices, through their common availability and use by consumers, encourage business organizations to seek wireless mobile commerce opportunities to engage with the customer or consumer. This in turn provides a motivation to incorporate wireless mobile technologies and devices into the business systems domain. An example of such opportunities is the capability to directly market (or mail) products to a customer via the Mobile Internet to a mobile phone, or to provide location dependent information on demand to mobile phone users. This form of activity, traditionally known in the E-commerce world as the business-to-consumer (b2c) relationship, is the main vehicle for M-commerce opportunities in the mid-2000s. Currently, the type of relationship, known in the E-commerce domain as the business-to-business (b2b) relationship, involves the trading and data transmission between two commercial organizations (primarily via electronic means). Many business organizations

Obstacles to M-commerce

11

in the M-commerce world develop exclusive relationships with certain wireless Internet portal providers and, because many Mobile Internet portal providers have exclusive relationships with specific organizations (i.e. banks or retail outlets), these organizations are able to ‘garden wall’ their customers (and therefore insulate them from competitors). However, these initial opportunities for exclusivity in dealing with corralled groups of consumers are slowly diminishing as many wireless Internet portal providers allow individuals and organizations to place Mobile Internet pages within their domain. (The proprietary iMode wireless Internet service in Japan is an example of a Mobile Internet service provider which offers individuals and organizations the opportunity to publish their own Mobile Internet content, in a similar manner to the wired Internet.)

1.4

■ Obstacles to M-commerce The obstacles to M-commerce, such as the cost of mobile devices and Mobile Internet services and difficulty in accessing efficient and fast cellular telecommunications networks, are diminishing each year. Thus mobile commerce is becoming more attractive to both business organizations and individuals (and many educators). The main obstacles that are continuously being addressed in research and development within the M-commerce world are as follows. (a) Efficient and fast wireless telecommunications services are often focused within specific areas (e.g. Western Europe, the USA and Japan), and are not always available in geographical areas with very low population densities (e.g. desert areas where transmitter coverage is poor). Conversely, the lack of a wired telecommunication infrastructure in many developing countries has led these countries to adopt wireless telecommunications in preference to wired telecommunications, including the use of satellite communication phones. (b) Wireless Mobile Internet access via a mobile phone remains more costly than wired Internet access via a laptop computer (or PC), and data transmission speeds are limited over wireless network infrastructures using 2G technology. (However, some 3G technologies and devices often deliver data content and data transmission speeds that are indistinguishable from those available on the wired Internet.) It is still the case that Mobile Internet users are accustomed to paying for Internet content and correspondingly expect to pay for certain levels of service and reliability (or they will not use the service again). PC-based Internet users in contrast normally expect things to be free and are correspondingly willing to accept a certain level of technological imperfection.

12

Mobile commerce (M-commerce): definitions and context

(c) Concerns over privacy and security still pervade the wireless data transmission world despite the fact that 3G technology is inherently more secure than 2G technology. For example, the lack of privacy and inferior security with 2G technology still dissuades people from carrying out commercial transactions over the Mobile Internet. (This concern was reinforced by knowledge that many government and business organizations banned the use of 2G mobile phones for private or secure conversations (or data transmission).) Aspects of wireless security are covered in Chapters 7 and 8 of this book. (d) Many individuals and organizations still harbour concerns over the health issues of wireless technology (particularly with regard to microwave radiation emission levels). A large amount of research has been undertaken by various governments in Europe, the USA and Japan into the effects of using wireless mobile devices and technologies. (Private research has also been conducted by commercial organizations that manufacture mobile phones and other wireless devices.) Up to the year 2002 the studies remain inconclusive. However, many governments are requiring mobile phone device manufacturers to publish health evidence. For example, European Parliament legislation in 2002 made it a requirement for all mobile phone manufacturers to publish radiation levels for all manufactured mobile phone devices, thus providing additional information to consumers in their purchase. As 3G technology, and inevitable technological developments in wireless infrastructures and devices, becomes pervasively embedded in the wireless domain the obstacles in the way of the diffusion of wireless technologies into the business information systems domain will continuously diminish. Activity 1.3

1.5

Outline the main obstacles to the smooth development of M-commerce and discuss how these obstacles are being overcome or ameliorated within the wireless world. List the various wireless communication mobile devices available in the open market and discuss the strengths and weaknesses of each device. Are there any common features across these devices (e.g. voice telephony)? If so, what purpose do these features serve in the wireless world?

■ The Mobile Internet and mobile information assets Combining the Internet with mobile phones produced the first tangible business opportunities in the M-commerce world. Accessing the Internet anywhere, anytime, and untethered by fixed-location wired technology (e.g. PCs and laptops), provides various business opportunities. For example, organizations are able to provide both Internet information and other services based on awareness of a user’s location. Therefore, the wireless industry tries to deploy Mobile Internet services based on the various benefits of mobility.

The Mobile Internet and mobile information assets

13

Internet users who are moving have expectations and requirements that are different from those who are stationary. Two types of mobility service predominate. (a) Information that is provided on a geographical location (e.g. calling up a directory of restaurants in a specific location, such as the area of Queens in New York, or requesting the location of bank cash machines in the local vicinity). (b) Information that tracks an individual user (via their mobile phone) to determine their specific geographical location anywhere in the world. These technologies are often referred to as Geographical Positioning Systems (GPS). Such location technology can be used to support location-based services. The continuing aim of the mobile phone manufacturers and the Internet industry is to use geographical location information to enhance the value of the Mobile Internet. Location-tracking services are encouraged by both businesses and national governments. For example, the Federal Communications Commission in the USA, in the late 1990s, encouraged mobile phone network bearers to implement location technology in order to determine the geographical location of a mobile phone user calling up an emergency service number (i.e. the emergency 911 number in the USA or 999 in the United Kingdom). The caller’s location can then be determined in order to co-ordinate and direct emergency services. The technology is based on inherent characteristics of wireless mobile phone networks. Normally, mobile phone networks are segmented into cells, hence the term ‘cellular’. An activated mobile phone can be located by determining the cell from which the mobile phone is transmitting voice or other data. Location information is a prerequisite element in wireless communication. In order for voice or Internet data to be transferred from one location to another in the cellular telecommunications network, the network must know where the activated mobile phone is located (to ensure that the voice message or datagram arrives at the correct location). Chapter 4 provides a thorough analysis of the protocols and network architectures necessary for Mobile Internet access and wireless telecommunications. In the business world location-dependent services are used to track the logistical distribution of goods and services in the context of b2b transactions. But the biggest area of M-commerce is the business exploitation of mobility location information in the context of b2c systems. Mobility is an attribute that businesses implement to differentiate the wired Internet from the Mobile Internet. Chapter 8 provides a detailed analysis of the business benefits of such tracking systems.

14

Mobile commerce (M-commerce): definitions and context

Location Assets

Location-based Service Information

Location-based Product Retailing

Location-based Products

Location-based Access

Location-based Maps (directions)

Wireless vending & access

Figure 1.4 Location assets

The Mobile Internet can use location to act as a trigger for a wireless telecommunications network to perform or affect an action supporting a specific location-based service (see Figure 1.4). The following are just some of the location-based services available via enabled mobile phone devices: (a) Location-based product retailing. A wireless mobile phone user can enter a shopping centre (or shopping mall) and register their presence (via their mobile phone) with the mall’s embedded location awareness systems. The user can then request the location of a specific product, and the embedded systems communicate the desired data, in terms of the location of the shop in the mall, or the location of the product in a shop. (b) Location-based services information. A mobile phone user can request – based on their present location – an information list of various service providers; for example, a list of Chinese restaurants within a one mile radius, or the location of the nearest plumber or electrician in the immediate area. Therefore, direct advertising and sales can be enhanced by providing information to an individual based on a specific request, at a specific location and at a specific time. These three parameters differentiate the wired Internet from the Mobile Internet. (c) Location-based maps. A user can request a map of the area in which they are located. This provides their position and a map of the local area. In addition, information requests can be made for the direction to a specific location within the vicinity. A value-added service for

The untethered Mobile Internet

15

motorists is the ability to request Internet-based information to determine the best route to take to avoid traffic congestion. (d) Location-based purchasing. A growing area of significance in both the wired and wireless Internet worlds is use of virtual money to buy products and services. For example, a mobile phone can be issued with virtual money (or Internet coupons) to buy products and services in specific stores. The mobile phone device user is able to pay for goods and services by transmitting the virtual money (or coupons) to the embedded cash receipt systems within the store (e.g. electronic wallet). (e) Location-based access. As well as capability to locate a mobile phone user, a number of mobile phone manufacturers are embedding technology within handsets to enable users to access specific locations. For example, Nokia in Finland have embedded technology into some of their mobile phones that allows them to be used as door keys to access homes and offices. The embedded key-lock technology in the office or house door can be programmed to permit access only to specifically programmed mobile phones. Activity 1.4

1.6

What is the location asset? Explain why location is such a unique asset within the wireless world. What sorts of location products and services can be offered in the commercial world? Discuss who would potentially use location-based products and services. What are the advantages and disadvantages of the Mobile (or ‘wireless’) Internet?

■ The untethered Mobile Internet Within the Mobile Internet domain the characteristics of space and time are paramount in distinguishing the Mobile Internet from the wired Internet. Thus business organizations are able to concentrate on thinking about the best ways of exploiting the most significant advantages of wireless technology and its devices, those of portability (i.e. it can be carried anywhere) and mobility (i.e. it can be used anywhere). However, the wired Internet and the wireless Mobile Internet should not be considered to be mutually exclusive, or even different. In the provision of many products and services the wired Internet and the Mobile Internet are often used in conjunction with one another in a supportive capacity. For example, wireless Mobile Internet portal providers often provide regular wired Internet sites to provide additional Internet services that cannot be fully provided over the wireless Mobile Internet. For instance, in the United Kingdom, British Telecom provides a wireless Internet portal called Genie, and also supports its wireless Mobile Internet services with a regular wired Internet site. The characteristics of Mobile Internet portal providers are looked at in more detail in Chapter 4.

16

Mobile commerce (M-commerce): definitions and context

Case study 1.1

Why mobile is different For a start, people are used to paying for it

How do you make money on the Internet? In the late 1990s, this was the question on everybody’s lips. The answers bandied about included ‘building communities’, ‘ensuring stickiness’, ‘B2C’, ‘B2B’ and many others. Buzzwords came and went, and eventually nearly everyone went bust. The problem was that advertising revenue was insufficient to keep most sites running, and there was no standard way to charge for things on the Internet. There still isn’t. Getting people to type their credit-card details into a web page raises security concerns, and makes purchases of less than a few dollars impractical. A handful of sites selling books, CDs, flights and holidays look as though they will survive. But most news and content sites are losing money, and many are now trying to introduce subscription fees. Many more have folded. Why should things be any different on the mobile Internet? Mobile is different from the fixed Internet in three important respects. First, a mobile phone is a far more personal device than PC. lt is likely to be used by only one person, who will probably have the phone with him for most of his waking hours. Whereas e-mail messages go to a machine sitting on a desk, text messages go directly to the mobile phone’s user. Often the network operator knows exactly who that user is, including his name and address. In order to route calls to and from the mobile, the network operator also needs to know where it (and therefore probably its user) is at all times. Second, network operators can determine what menus and services appear on their users’ phones. Whereas on PCs users have lots of scope to play around with the settings, on mobile phones all they can easily change is the ringing tone and the screen logo. The ability to set the default portal – the starting page that users see when they connect to the mobile internet – is a big advantage, because it allows operators to act as gatekeepers. This will cost you Last, and most important, people know that using mobile phones costs money, and there is a mechanism for the network operator to charge them for that use. What is more, users seem prepared to pay a ‘mobility premium’ to do things while on the move. Sending an e-mail or instant message over the Internet from a PC is essentially free; sending a text message from a phone costs an average of 10 cents, but users are prepared to pay because they regard it as good value, or because it makes their lives easier. And even when text messaging is more expensive, people still use it. In some places, sending a text message home while ‘roaming’ in a foreign country can cost as much as €l (92 cents). Such charges are currently under investigation by the EU’s competition commission. But compared with the cost and hassle of buying a postcard and a stamp, this still seems reasonable enough to many people.

The untethered Mobile Internet

17

In short, if you have a mobile phone, the network operator knows who you are, where you are, can direct you to the portal of its choice, and can charge you money. This is a very different world from that of the fixed Internet. Mobile has some drawbacks, of course. Mobile devices have more limited screens and keyboards than PCs, and slower connections. Also, says Niklas Savander of Nokia, mobility makes people much more impatient. Researchers have found that a five-second delay to access something on an Internet-capable phone seems far longer to users than a five-second wait to call up a web page. ‘With the same response time, people rate mobile as slower,’ he says. ‘So we have a slower connection, but users want a faster response.’ For me, here, now But the combination of personalisation, location and a willingness to pay makes all kinds of new business models possible. Tomi Ahonen, head of 3G Business Consulting at Nokia, gives the example of someone waiting at a bus stop who pulls out his Internet-capable phone to find out when the next bus will arrive. The information sent to the phone can be personalised, reflecting the fact that the user’s location is known, and perhaps his home address too; so bus routes that run from one to the other can appear at the top of the list, saving the user from having to scroll and click through lots of pages and menus. A very similar service, which allows users to find out when the next bus is due by sending a text message from a bus stop, is already available in Italy. Would-be providers of mobile Internet services cannot simply set up their servers and wait for the money to roll in, however, because the network operators – who know who and where the users are, and control the billing system – hold all the cards. This has changed the balance of power between users, network operators and content providers. On the fixed Internet, the network access provider acts as a ‘dumb pipe’ between the user’s PC and, say, an online bookstore or travel agent. The access provider will not know how the connection has been used, and there is no question of claiming a commission. Mobile network operators, on the other hand, are in a far more powerful position. ‘Wireless is a smarter pipe,’ says Chris Matthiasson of BT Cellnet. This means that operators are much less likely to be disintermediated. Having avoided one mistake made on the fixed Internet, however, wireless operators may be tempted to make another, by setting up ‘walled gardens’ of services and content. In theory, restricting users to a handful of approved services will enable operators to capture a much larger chunk of the expected bonanza in data revenues. In the 1990s, online services such as AOL, Compuserve and Prodigy operated on the walled-garden principle; but as soon as one of them offered unfettered Internet access, the others had no choice but to follow suit. The walled-garden model will turn out to be just as unsustainable on the mobile Internet, because users get annoyed by it.

18

Mobile commerce (M-commerce): definitions and context

Case study Continued

Furthermore, unlike Internet access providers, wireless operators charge by usage, either for every minute spent online, or for every byte downloaded. This means they make money on transporting data come what may, so it makes sense to offer users the widest choice of content possible to encourage them to run up transport charges. That is how imode works; the vast majority of DoCoMo’s data revenues come from transport, not the sale of content (though the firm does take 9% on the sale of other providers’ content). A typical i-mode user spends ¥2,000 (about $17) per month on data-transport fees, and only ¥400 on content subscriptions. Operators therefore generally offer a selection of approved services through their own chosen portal, and also give subscribers the option of going elsewhere. This is what AOL does with its dial-up Internet service; it offers services such as instant messaging, chat-rooms and e-mail, as well as access to the web. But surveys show that most users still spend most of their time within what used to be AOL’s walled garden. The best way for operators to keep users within their walled gardens, says Katrina Bond of Analysys, is to offer attractive services. The fact that operators know who and where their users are – and may be able to keep this information to themselves – can give their home-grown or approved services a valuable advantage. The upshot is that the operators need decent content and services to drive traffic; and the content providers need the co-operation of the operators if they are to charge for their wares. A number of business models have emerged to govern the relationships between the two. Show me the money The simplest one of these involves sharing revenues from text messages. Lycos, a web portal, provides a service that allows PC users to send text messages from a web page and receive the replies on their PCs. The effect is to stimulate text-message traffic between mobile phones and PCs. The PC users do not pay to send messages, but the mobile users do; and through agreements with mobile operators, Lycos gets a cut. There are other services, such as mobile games, that encourage mobile users to send text messages; the content provider gets a share of the extra revenue generated. Sometimes the operator also charges for the messages at a higher rate. Another model involves the use of premium-rate text messages as a means of charging for one-off lumps of content, such as ringing tones, logos or horoscopes. Users send a text message to a special number, are charged accordingly, and have the content delivered in the form of a text-message reply. More elaborate is a model sometimes called ‘reverse billing’, in which services are charged directly to the user’s phone bill. In effect, the operator bills the user on behalf of the content provider, and then hands over the money.

The untethered Mobile Internet

19

In theory, reverse billing could be used as a means of payment for online commerce; a book, CD or cinema ticket could be charged directly to the user, as though it were an expensive phone call. And since mobile operators are used to handling a large number of small transactions, their systems can handle such transactions at around a tenth of the cost of a bank or credit-card transaction. This means that micropayments, which have never taken off on the fixed-line Internet, are feasible on the mobile one. But users may prefer to pay lumpy subscription fees rather than a small charge for every morsel of information they access. Following the example of i-mode, whose sites work on monthly subscription fees, T-Motion, a mobile portal owned by Deutsche Telekom, has decided to try that model for WAP content, starting from November 1st. Subscribers to its T-Motion Plus service will pay €10 ($9) a month for a bundle of free ringing tones and text messages, plus news, weather, financial updates, sport reports and games; this revenue will be split 50/50 with the content providers. T-Motion will track the popularity of the content, and will replace the least popular services every three months. With this model, the paid-for services cannot be given away free on other portals, or users will not be prepared to pay for them; the effect is to produce a walled garden of sorts, with premium services that only subscribers can access. The most radical model is the ‘mobile virtual network operator’, or MVNO, in which a network operator acts as a wholesaler of airtime to another firm, which then markets itself to users just like an independent operator with its own network infrastructure. Virgin Mobile, a British mobile operator, is in fact an MVNO that resells voice and data airtime on the network belonging to another operator, One2One. The MVNO allows content providers to get their hands on transport fees, but operators feel ambivalent about the concept. On one hand, MVNOS can brand themselves to appeal to a wider range of customers, and thus boost overall use of the network; but on the other, MVNOS turn network operators into dumb pipes, giving them a smaller piece of the action. For the time being, most operators have chosen to deal with customers direct, rather than become wholesalers to MVNOS. In various combinations, all of these models are in use now, but operators are still struggling to implement new billing systems. Most operators, says Nokia’s Mr Savander, have between 20 and 40 separate billing systems to handle different kinds of services; one has 54. Software firms are competing to offer consolidated billing systems that will support any or all of these business models. Which model will prove most successful remains to be seen, but there is certainly money sloshing around on the mobile Internet. Unlike on the fixed-line Internet, people are prepared to pay for content and services they really want. But what exactly might those be? As on the fixed Internet, there are two distinct markets: consumer and business. Although it is still early days, there are already signs of a ‘killer application’ in each. ‘Why Mobile is different’, The Economist, 13 October 2001.

20

Mobile commerce (M-commerce): definitions and context

Activity 1.5

1.7

Discuss the main characteristics of the Mobile Internet (sometimes referred to as the wireless Internet). Is the Mobile Internet the same as the normal Internet? What factors differentiate Internet access on a PC from Internet access on a mobile phone or a wireless PDA? What are the main advantages of the Mobile Internet outlined in the previous case study and what are the advantages of accessing the Mobile Internet on the move?

■ M-commerce versus E-commerce In many respects E-commerce and M-commerce are not very different. Both concepts aim to exploit commercial opportunities via electronic technologies. E-commerce is concerned with data and information transfer, and with Internet access, via wired technology; whereas, M-commerce is concerned with data and information transmission, and Internet access, via wireless technologies and various portable devices. E-commerce serves customers and clients that are stationary, while M-commerce customers are moving and dependent upon a portable PC, such as a mobile phone or PDA. The similarities between E-commerce and M-commerce have led many people to refer to M-commerce as ‘mobile E-commerce’. However, this limits the definition of M-commerce too much. There are a number of fundamental differences between E-commerce and M-commerce. For example, M-commerce enables location-based services and products (as we saw in the previous section). Furthermore, mobility is treated as an asset, rather than a by-product of the technological domain (e.g. no more need to wait in line at airport check-in desks, etc.). In addition, the Mobile Internet does not pretend to duplicate the wired Internet. The Mobile Internet is constrained by a number of factors, such as display screen size and memory capacity. Therefore, the type of data and information presented within the wireless domain is often transient (and ephemeral), and relevant only to one place at one specific time. The definition of M-commerce extends many of the concepts of the wired Internet. Table 1.1 provides a comparison of some of the factors that differentiate the concept of E-commerce from that of M-commerce.

Table 1.1 Comparison of E-commerce and M-commerce Factor Product Product Product Product

or or or or

service service service service

focus provision assets attraction

E-commerce

M-commerce

Product focus Wired global access Static information and data Fixed non-time-constrained access

Service focus Wireless global access Dynamic location-based data Mobility and portability of access

The ability to access the Internet and conduct commercial activity is one of the most important aspects of both E-commerce and M-commerce.

The wireless world

21

However, each provides a different mode and means of accessing the Internet and each concentrates on tailoring the data and information of the Internet to the needs of the users of either static data products (for E-commerce) or dynamic and mobile data services (for M-commerce). It is a curious fact that the use of Internet-based M-commerce varies between global regions (and national economies). For example, in Japan the wireless industry concentrates primarily on providing Internet-based services to mobile phone customers, and generates a significant amount of income from the provision of Mobile Internet products and services. In contrast, the provision of Mobile Internet services in Europe and the USA is of less economic significance to these areas. Activity 1.6

1.8

Discuss and compare the factors that differentiate the concept of E-commerce from that of M-commerce. Discuss the four features: Focus, Provision, Assets and Attraction. Why is the type of data and information presented within the wireless domain often referred to as transient (or ephemeral) and only relevant to one place at one specific time? What sort of information is time and place dependent?

■ The wireless world It appears from various studies and research reports that smaller countries, and many developing countries without the legacy of a wired telecommunication infrastructure, are investing in M-commerce ideas and technologies to provide a base to compete with larger, industrialized economies. For example, more people own mobile phones than wired phones in Egypt. The reason for this is the absence of a fixed-wire telecommunication infrastructure. New phone users often have little choice but to adopt connection to a wireless telecommunications provider because a regular wired telecommunications infrastructure does not exist. Business organizations also opt for wireless telecommunications as the technology platform of choice in most developing countries. A wireless infrastructure is cheaper to establish and easier to promulgate via mobile phone technology. Another example is Scandinavia (i.e. Finland, Norway and Sweden) which has limited scope to fully establish a fixed-wire telecommunication infrastructure due to its difficult geographical terrain. However, Scandinavia is well known for its innovation and leadership in wireless technology, spearheaded by Ericsson of Sweden (who concentrate primarily on the provision of wireless infrastructure and secondarily on manufacturing mobile phones), and Nokia of Finland (who concentrate primarily on manufacturing mobile phones and other portable wireless devices). The global nature of mobile commerce is represented in Figure 1.5. According to the Stockholmbased Research Group for Societal and Information Studies, over 47% of the population of Sweden, between the ages of 16 and 65, uses the Internet

22

Mobile commerce (M-commerce): definitions and context

several times per week, while over 71% uses the Internet several times per month. Therefore, the provision of effective and efficient Mobile Internet access, and research into mobile-to-mobile commercial activity, is a significant aspect of Internet-based commerce in Scandinavia5.

Figure 1.5 The wireless world

5

Special issue on Scandinavian Solutions. Tornado-Insider.com, November 2000.

Pervasive computing systems, theory and practice

1.9

23

■ Pervasive computing systems, theory and practice The term ‘pervasive computing’ is a label used to explain the idea that computing in the 21st century is available anytime, anywhere, and in any device. It refers to the strongly emerging trend towards numerous, casually accessible, often invisible computing devices, frequently mobile or embedded in the environment, connected to an increasingly ubiquitous network infrastructure composed of a wired core and wireless edges (National Institute of Standards and Technology, Pervasive Computing, May 2001). Computing technology is embedded in most appliances we use every day, such as automobiles, televisions, fridges, elevators and many other devices we take for granted in our everyday lives. Devices that contain embedded computing technology are sometimes referred to as information appliances. Pervasive computing is a natural evolution of wired network computing, which in turn evolved from client–server computing. Pervasive computing affects the devices and appliances people use in their everyday lives (often in ways that are unnoticeable). One of the benefits of pervasive computing is the fact that it can exist around us without anyone realizing it is there (either in active or inactive form).

Pervasive computing ‘…is computing power freed from the desktop – embedded in wireless handheld devices, automobile telematics systems, home appliances, and commercial tools-of-the-trade. In the enterprise, it extends timely business data to workers in the field… In our personal lives, it expands our freedom to exchange information anytime, anywhere.’ IBM Pervasive Computing web site

There are three important aspects to pervasive computing. (a) Computing is spread and distributed throughout the working and social domains of life in an unmanaged and dynamic wireless-networked environment, where users are predominately mobile. (b) Devices and appliances contain embedded computing technology that can monitor and control devices and possess the capability for wireless network transmission of data (e.g. elevators that can remotely inform the maintenance computers at the head office that there is a fault). (c) Communication is made easier between individuals, between individuals and various information appliances, and between devices (device-todevice – d2d) within a wireless-networked environment.

24

Mobile commerce (M-commerce): definitions and context

Within the domain of pervasive computing, data and information are available, and accessible, from any mobile position and can be accessed anytime, anywhere and from any device. Activity 1.7

Define what is meant by ‘pervasive computing’. What is the significance of mobile devices and embedded technologies within the pervasive computing domain? Provide a list of examples of pervasive and embedded mobile technologies. What are the main applications of pervasive computing?

Search the Internet for articles on ‘pervasive computing’ and provide a summary of your current findings.

1.10

■ Trends in mobile and pervasive computing Pervasive computing is a trend that has not been ignored by business organizations, particularly with regard to incorporating wireless networking and pervasive computing technologies into the regular business information systems domain. In thinking about the significance of pervasive computing and wireless computer networking, David Messerschmitt in his book Networked Applications – A Guide to the New Computing Infrastructure analyzed three main trends in computing in the 21st century. These are mobility (where computing is anywhere), ubiquity (where computing is everywhere), and embedding (where computing is disguised and subsumed within devices) (Messerschmitt, 1999). These three factors exist as three important aspects of M-commerce. Table 1.2 illustrates these three important trends in wireless networking and pervasive computing. Pervasive computing is, therefore, a significant part of the M-commerce domain. Wireless-networking technology and increasing trends towards mobility and portability of devices encourage business organizations to look at innovative ways of using pervasive computing ideas and techniques in the business systems environment. Such technologies cannot be disentangled from general business systems thinking and practice. Pervasive computing technologies are increasingly an integrated part of the business information systems domain.

Trends in mobile and pervasive computing

25

Table 1.2 Trends in Pervasive Computing Trend Mobility (computing anywhere)

Description Networked computers can be taken anywhere and still benefit from full network services.

Comments Laptop computers and personal digital assistants are the precursors. Mobility requires ubiquitous networking access analogous to the cellular telephone.

Ubiquity (computing everywhere)

Networked computers are unobtrusively sprinkled throughout the physical environment.

Information kiosks, mobile phones with web browsers, and personal environment. digital assistants are steps in this direction. In the future, as computers gain a similar size and resolution to paper, magazines and books, they should become as ubiquitous as the printed word is today.

Embedding (computing within)

Networked computers are embedded in most everyday products.

This is already common. Automobiles, consumer electronics, toys and appliances have computing within. In the future, many more products – even as mundane as light switches and light bulbs – will not only have computing within but also network connections.

(Source: Messerschmitt, 1999, p. 8

Pervasive computing and mobility, within the business systems domain, provide for a different way of working. In many ways the importance of M-commerce is not merely in cutting out wired cables, but rather in the

26

Mobile commerce (M-commerce): definitions and context

systems and process changes that are enabled by the technology. The next section looks at a number of applications of M-commerce technology within the business information systems domain. Activity 1.8

1.11

Discuss the main trends in pervasive and mobile computing. To what extent do you think that pervasive computing is an important feature of the M-commerce domain? To what extent do wireless-networking technology and increasing trends towards mobility and portability of devices encourage business organizations to look at innovative ways of using pervasive computing?

■ Applications of M-commerce The lifestyle and business applications of mobile telecommunications and pervasive computing are limitless. Such technology holds particular appeal for organizations with mobile workforces. For example, business professionals, such as architects, insurance assessors, journalists and sales executives, can be enabled to carry out their responsibilities more effectively and efficiently using wireless technologies and mobile devices. This gives rise to the mobile professional who uses mobile computing technology in different ways to meet the specific objectives of their work. For example, journalists write copy on laptops while on location. This text is then sent to the newspaper editor (working at the office or remotely at home) via a wireless modem, such as the Nokia Cardphone 2.0 (that allows high-speed, wireless communication between laptops and other remote, geographically distributed computer systems). At the same time the newspaper’s photographer independently sends digitized pictures related to the story for the late edition. The page designers, who do not need to be geographically located within the editorial team’s head office, receive the edited copy for display production. This type of systems integration and location independent connectivity is only possible through the integration of wireless technology with mobile devices. There are many case studies available in the business world which explore the lifestyle and business of M-commerce in terms of the wireless workforce. The main early adopters within the wireless workforce were, in many cases, the same users who were first to adopt laptops in the early 1990s, for example sales executives, health care and pharmaceutical workers, and field workers and location engineers for utilities (i.e. gas, electricity and telephone). The tools of the mobile workforce are normally a mobile phone, portable laptop computer or handheld PDA. In many business applications the mobile phone, used in conjunction with a PDA (or palmtop computer), has replaced the laptop computer. For example, when Goldman Sachs employees in the USA were given a PDA and e-mail pager, known as the BlackBerry, the use of their laptops fell by 45%6 (The Economist, 2001). 6

The BlackBerry PDA and E-mail pager was originally developed by a Canadian wireless company called Research in Motion.

The trend towards mobile working

27

The BlackBerry pager was one of the first devices to have the small keyboard and always-on wireless data connectivity that allows users to send and receive e-mail on the move. In 2002 the device was upgraded to incorporate voice telephony and act more as a mobile phone. The BlackBerry had the advantage over laptops of being portable. Therefore, employees are able to catch up with their e-mails on the move (rather than via a PC or laptop) and can deal with e-mail correspondence anywhere and at any time, for example in a taxi or at a client’s remote home location. In addition, such technology requires lower support costs, and its user-friendly inputting and outputting facilities encourage productivity. There is a lot of evidence that the amount of pertinent data sent back from remote wireless workers ‘in the field’ increases after transferring them from laptops to handheld wireless devices.

Activity 1.9

Outline the main business applications of mobile communications technology (e.g. e-mail, pagers, voice, etc.). Discuss which industries or professions particularly lend themselves to mobile working. How do mobile devices and technologies affect the way the mobile workforce operates? Discuss whether distributed working is better than centralized working. Search the Internet for references to mobile working and provide a list of the main benefits that mobile technology can bring to the mobile workforce.

1.12

■ The trend towards mobile working In many respects all occupations in the 21st century are affected by the trend of mobility, to the extent that nearly everyone in an organization may be a mobile worker to some degree. Reasons for this include the growth of flexible and off-site field working, telecommuting, and the inherent geographical spread of many large corporations. For example, the way that British Telecommunications (BT) utility field engineers in the United Kingdom carry out their daily tasks and responsibilities provides a good insight into the practical use of wireless networks and mobile technologies. BT telephone engineers no longer need to travel to a remote geographically located headquarters in order to receive their schedule of jobs for the day (or week). BT telephone engineers are all issued with laptops with mobile phone, wireless communication connectivity. Each evening the engineers are required to log-on to the BT scheduling server to receive a detailed schedule of their activities and jobs for the following day. Jobs that require more than one telephone engineer (i.e. larger telephone network installation teams) or more specialized support are co-ordinated so that engineers collectively arrive at a job at the same time, with the requisite dedicated support. The allocation of jobs is automated and is prescribed by a decision support system. By logging the progress of a job, in terms of the start and finish of the task, the engineers can be remotely co-ordinated and monitored via the information they communicate back to headquarters.

28

Mobile commerce (M-commerce): definitions and context

The job of the telephone engineer has, therefore, become more independent and less likely to require human or social interaction with other engineers, apart from the times of co-scheduling for a job. Tasks and individual engineers are remotely assigned and co-ordinated by remote computer systems based on decision support scheduling algorithms and technologies. The progress of jobs throughout the scheduled period can be continuously communicated back to the head office by the field engineers, via wireless mobile devices.

1.12.1


Wireless telemetry and wireless telematics Another important application of wireless technology and mobile devices is wireless telemetry that allows the monitoring and analysis of data produced by a remote device via wireless technology. A more detailed analysis of wireless telemetry is undertaken in Chapter 8. Wireless telemetry is sometimes referred to as ‘wireless telematics’. The term telematics was originally used to identify the convergence of telecommunications data and information processing. However, within the mobile and pervasive computing domain, wireless telematics has been largely associated with wireless communications systems in automobiles and racing cars. For example, Mclaren cars and BMW cars have independently introduced In-Vehicle Information Systems (IVIS) into some of their automobiles to detect remotely when and where an individual vehicle has broken down. The IVIS can trigger emergency recovery services once the automobile’s wireless telemetry systems have communicated both the automobile’s position and the nature of the fault back to the company’s recovery centre. The wireless telematics system can also carry out an engine analysis remotely to determine the cause of the breakdown via remotely gathered telemetry data from the automobile’s embedded systems. The technology is essentially based on location tracking of the vehicle with the additional ability to diagnose the automobile’s problems from a remote geographical position. In the future ‘next generation telematics systems’ will concentrate on providing the Internet within automobiles.

Wireless telemetry ‘Allows the monitoring and analysis of data produced by a remote device via wireless technology.’

The trend towards mobile working

Case study 1.2

29

Automobile telematics What is telematics?

Telematics is a new industry centred on the provision of information services within motor vehicles. Effectively, the driver of a vehicle can engage with an information system, such as the Internet, while on the move and from any location at any time. Telematics represents the convergence of telecommunications with mobile computing dedicated to motor vehicles. These systems are often referred to as ‘In-Vehicle Information Systems’ (IVIS). For vehicles, a telematics system consists of computing power and a wireless connectivity to a data service such as the Internet, or a Global Positioning System (GPS). Telematics can also be used for monitoring vehicles and determining their location at any time. There are a number of applications for telematics, ranging from notifying an operator when the engine fault warning lights come on to remote repair via wireless telemetry. Telematics systems can also be used to inform breakdown and recovery services that a vehicle is broken down by the side of a road, and where that vehicle should be located. In addition, GPS can inform an operator as to where to send the police and other emergency services. Other applications include security – for example, if a driver is locked out of their vehicle then a telematics system can remotely unlock the vehicle. A number of luxury cars offer this service. Most new cars have some form of telematics built into them for a range of purposes, mainly to monitor vehicle performance. The vehicle telematics domain is financially lucrative, particularly the safety and location awareness aspects.

These Internet-on-wheels systems will provide the advantages of the Internet and location-based services within automobiles. There are also other applications of wireless telemetry for d2d (device-to-device) monitoring. For example, Toshiba, a large Japanese company, uses wireless technology to remotely monitor photocopiers, so that technicians and engineers can be despatched to repair faults as soon as there are signs of a problem.

1.12.2


Tracking and monitoring the mobile workforce The ability to track, monitor and locate users by wireless means is a very important application within M-commerce. Wireless technology, used in conjunction with mobile devices, enables sales teams, logistical tracking systems, and mobile workforce employees to be geographically tracked and located in their working activities at any given time. This area is often known as professional telematics. Sales teams can be located and centrally co-ordinated, and the distribution of products can be tracked on behalf of both the business and customer to determine the stage of delivery.

30

Mobile commerce (M-commerce): definitions and context

Data-enabled mobile phones (and other devices) are also a good solution for fleet management because a cellular solution provides ubiquitous network signal coverage in areas that are not covered by the private radio spectrum. In addition to the facility to track sales teams, the Mobile Internet can also be used by the sales team to engage with central company data and information held on the Mobile Internet. For example, a sales person can, in the presence of a customer, check product databases and delivery schedules held on the Internet via a data-enabled mobile phone. With more advanced, handheld, wireless devices the sales person, or mobile professional, can also process the order electronically and generate a report or invoice. In some handheld wireless logistical devices a delivery person can not only log the time and date of delivery to a customer, but also get the customer to sign on the handheld device screen. The signature is then digitized, stored and appended to the acceptance note to verify delivery for both the customer and the delivery person. This data is immediately transmitted back to the company’s central database confirming delivery and acceptance of the order. Such delivery systems are in operation with many parcel delivery organizations. For example, Parcel Force (a subsidiary of the Post Office) in the United Kingdom operates with the assistance of wireless, handheld devices to acknowledge a customer’s acceptance of an order. These examples demonstrate that M-commerce permits and enables business activity to be conducted with the customer, or client, with the support of complete access to data and information resources which are available at any location. Mobile devices and wireless technologies can offer relatively high levels of connectivity within the working and social domains of the mobile professional’s life. These examples also reveal that wireless technologies and mobile devices can offer solutions to everyday tactical problems. Different examples can also be found on the Global Mobile Commerce Forum web site. Activity 1.10 Define what is meant by ‘wireless telemetry’. What advantages and disadvantages are present in tracking and monitoring the mobile workforce? Discuss how the remote and automated tracking of the mobile workforces assists management decision making. Do you know of any cases where people have been tracked by their mobile phone signal?

1.12.3


Customer-focused products and services There are a number of other customer-focused services offered by the interconnection of wireless devices (specifically mobile phones), the Mobile Internet and wireless network technologies, as follows. (a) Bill payment and electronic banking. A number of banks in Europe, the USA and Japan offer banking services via data-enabled mobile phones.

The trend towards mobile working

31

Customers can check bank balances, transfer funds between accounts, and even seek loans. The mobile phone enables banking activity to be conducted from any location, at any time. There is an economic cost benefit to banks because mobile phones are part of life, purchased by the user, and already in everyday use by many banking customers. Mobile phones can also be used to make on-line bill payments either by providing bank account details or by transferring virtual electronic cash (sometimes known as e-cash). Many banking organizations have set up subsidiary companies specifically to deal with Mobile Internet customers. For example, the HBOS bank in the United Kingdom set up a subsidiary company called the IF bank primarily to provide banking services via WAP-enabled mobile phones. Customers can check bank balances and transfer money between accounts by using an on-line form (via a mobile phone screen) written and produced in a programming language such as WML (the Wireless Mark-up Language). Chapters 3 and 4 of this book go into detail on the relationship between WAP and WML. In Japan all banks offer on-line banking services via the iMode wireless Internet service. (b) Purchasing goods and on-line trading. Wireless Internet-enabled mobile phones allow users to purchase and, in some cases, trade goods on-line. For example, theatre and cinema tickets can be bought on-line, and airline tickets can be reserved. In some airports, particularly in Europe and the USA, airline seat booking can be done on-line using a mobile phone to communicate with an airline check-in kiosk in the airport terminal (using Bluetooth technology). Mobile phones can also be used to purchase drinks, sweets and candy from vending machines. Vending machines not only accept payments from wireless devices but also use wireless technology to transmit data on stock levels and maintenance requirements. This is known as device-to-device (d2d), or machine-to-machine (m2m) communication. Methods of payment include debiting pre-paid accounts, or customer bank accounts, or charging the transaction to the customer’s mobile phone bill, which is the case with many Mobile Internet transactions in Japan. One of the most popular uses of the Mobile Internet is on-line trading of stocks and shares. Customers can not only trade on-line but can also receive text message alerts to buy or sell stocks in their portfolio, and general information on stock market performance. There are many other on-line services such as gambling, on-line auctions, entertainment and games, and various concierge services, such as booking taxis. (c) Entertainment and lifestyle services. In a similar manner to business organizations offering access to products and services via corporate Internet web sites, so these same organizations can offer further services to customers via the Mobile Internet. These products or services are accessible by mobile phone, or mobile phone connected to a compatible PDA (usually via infrared data transfer). Accessing entertainment and

32

Mobile commerce (M-commerce): definitions and context

downloading games is one of the most popular applications of wireless M-commerce, particularly in Japan, where the iMode wireless Internet service is mainly accessed by purpose-built mobile phones that can handle multimedia data on colour display screens. Some games are free whilst others can be downloaded for a fee. Fee-based entertainment services include gambling, buying lottery tickets, horoscopes and fortune telling. A popular iMode service is Photonet, where users can take a digital photograph, upload it to a server, and download it back to a mobile phone. The growth of 3G mobile phone technology has enabled games and entertainment to become more dynamic and multimedia-based. Games that incorporate colourful dynamic graphics and movies are more attractive in the entertainment context. 3G technology makes possible full multimedia video streaming and broadcasting, for instance the potential to watch live news broadcasts, and the ability to download favourite clips from films and television. Multimedia-based wireless devices also enable video-mail and electronic postcards to be sent to mobile phones, and in-built cameras can take digitized photographs that can be sent instantly to another mobile phone user. In the future, 3G technology may also provide additional services, such as videoconferencing and web-camera capabilities. (d) General information kiosk. The Internet is a vast network of databases. The capability to access the Internet from a mobile phone converts the mobile phone into a general information kiosk. The mobile phone can then provide general information on news and events, or locationspecific information, such as traffic reports and weather forecasts for a particular area. The mobile phone can also access location-based information services to provide up-to-the-minute data and information on local services (e.g. restaurants, taxi companies, laundrettes, hotels, etc.). Activity 1.11 Discuss the significance of each of the customer-focused services outlined earlier. From your experience, or through a search of the Internet, provide various examples of customer-focused services. Search the Internet and provide examples of entertainment and lifestyle services available in various countries.

1.13

■ Effectiveness and efficiency in mobile domains The use of Internet and data-enabled mobile phones within the business systems domain has advantages in improving productivity and reducing support costs. For example, Nissan, a Japanese car manufacturer, found that giving its sales people wireless access to up-to-the-minute inventory and pricing data reduced the average number of visits required to close a sale from five to three and allowed a 40% cut in back-office staff. A similar

The M-commerce value chain

33

productivity gain was achieved at McKesson HBOC, the USA’s largest drug wholesaler. It introduced wireless devices to track inventory, distribution and shipment of products. The company spent $53 million on 1300 handheld computers and on equipping its distribution centres with wirelessnetwork coverage. Warehouse workers use the technology to monitor stock levels and to record and check the content of each shipment, thus eliminating the requirement to count stock by hand and reducing errors. The company has achieved an 8% productivity gain and an 80% fall in the number of incorrect shipments (The Economist, 2001). The successful adoption of wireless technology encourages other companies to incorporate wireless technologies into their own business systems. However, technology is adopted into the business systems environment in an evolutionary manner. There is usually a staged approach that is sometimes referred to as the wireless technology adoption lifecycle (see Figure 1.6). The first stage involves extending existing business information systems and processes to mobile devices in order to achieve productivity gains. The second stage involves the transformation of current business models using wireless technology and mobile devices. In the third and final stage (sometimes referred to as the future phase) entirely new business models may develop based purely on the new opportunities and capabilities of mobile devices and wireless technologies. The adoption of wireless technology is influenced by various ‘drivers’ (referred to as TUB drivers): (a) Technology drivers (b) Usage drivers (c) Business drivers. These adoption lifecycle drivers are outlined in more detail in Figure 1.6.

1.14

■ The M-commerce value chain The circle within Figure 1.6 describes the M-commerce value chain. A value chain is a standard business tool used to show the relationship, or sequence of events in terms of technology or applications development, and their value contribution to a business organization. Stage 1 can be viewed as the stage of early adoption, whereas stage 3 can be seen as the point at which new business activities and additional profit-creating systems can be implemented to gain benefit from location-independent connectivity (e.g. location-based services and mobile customer support services). Within the wireless industry there are a number of entities with different roles and responsibilities in the M-commerce systems domain. For example, there are the mobile device users, the device manufacturers, the network bearers, the wireless Internet service (and portal) providers, and the content creators

34

Mobile commerce (M-commerce): definitions and context

and providers. The relationship between these players in the wireless Mcommerce domain is further illustrated in Figure 1.7.

Usage Drivers: – use by mobile professionals – accessible Mobile Internet – mobile device portability – relevant and useful data – business and life style usage

Technology Drivers: – common wireless standards – universal network coverage – full multimedia capabilities – powerful mobile devices – broad bandwidth coverage

M commerce Systems Domain

Stage 1. Extending existing business information systems, and processes, to mobile devices

Stage 2. Transformation of current business models using wireless technology and mobile devices

Stage 3. Entirely new business models may develop based on the new opportunities and capabilities of mobile devices and wireless technologies

Business Drivers: – growth in use of mobile devices – mobile user marketing focus – customer and supplier support – business systems integration

Figure 1.6 Lifecycle of wireless technology adoption

The M-commerce value chain

35

The wireless Internet and wireless data value chain indicates that, as wireless technology and mobile devices become increasingly more available and the technology itself becomes more powerful and usable within business systems, so businesses seek opportunities to create new business models. Business organizations can only judge for themselves where they currently reside in the wireless, M-commerce value chain (i.e. at stage 1, stage 2, or stage 3). Nevertheless, there are a number of reasons why business organizations should offer wireless Internet and other wireless data services, especially if they already offer regular web services via corporate web sites, as follows. (a) Technological innovation in the wireless M-commerce domain has been expanding exponentially. Advances in wireless technology and mobile devices have provided an opportunity for business organizations to utilize wireless technologies more effectively (through faster 3G data communication at speeds of 2.0 Mbp/s)7, and to become more efficient (through the lower purchasing and servicing costs associated with of mobile devices compared to wired computing devices. (b) User-friendly mobile devices, incorporating useful and attractive multimedia applications and mini-browsers, have extended the benefits of accessing data from the Mobile Internet. Mobile Internet and other wireless data can be provided in text, graphics or other multimedia forms (e.g. video streaming). High-speed data transfer makes the technology useful for business information systems usage. (c) Wireless programming applications have reached a level of sophistication (and availability) that enables component-based construction and object-oriented theory to be applied to wireless-systems applications. Networked computing systems thinking has broadened out to include wireless technologies, unfettered by wire-based, network architecture thinking. This has enabled business organizations to explore various tools, techniques and systems infrastructures to create new market opportunities, or extend the level and nature of their products and services. (d) Organizations that already have a web site presence on the Internet rely on publicity to encourage people to browse their regular sites. There is often a high entry cost in terms of publicity and marketing of an organization’s web site. However, wireless mobile commerce allows business organizations to target the owners of mobile phones directly. For example, someone with a known interest in a specific subject area can be targeted directly (via their mobile phone) with information and data on products and services, that can also have the added value of being location-based and focused for a user at a given time and place. The business organization goes to the customer rather than relying on the customer to randomly (or accidentally) browse the organization’s web site. (e) It is apparent from market capitalization data that wireless telecommunications companies are amongst the largest and most influential in the 7

Broad bandwidth data transmission speeds of 2.0 Mb/s, via UMTS (and other 3G technologies) compare very well with GSM transmission speeds of only 9.6 kb/s.

36

Mobile commerce (M-commerce): definitions and context

business world. The computing software and hardware companies of the 1980s and 1990s were the dominant industry. But the wireless telecommunications companies of the 21st century have now overtaken computer hardware and software manufacturers in size (i.e. market capitalization) and often in income (i.e. profit and earnings). The growth of the wireless telecommunications industry, particularly in Europe, the USA and Japan, now makes wireless telecommunications a more significant global industry than computing software and hardware. Activity 1.12 Explain the significant aspects of each of the stages of the wireless technology adoption lifecycle. Outline the main technology drivers present in the wireless world and discuss how these drivers may influence wireless systems adoption within the business environment.

Mobile Internet Access Provider

The Mobile Internet User

(The Network Bearer)

(Mobile Internet and other wireless data services

Wireless Internet Service Provider (Wireless Internet Portals)

Mobile Internet Content Provider

Mobile phone and other mobile device manufacturers

(Creation and Provision of Mobile Internet Content)

(e.g. Sony, Motorola, Nokia, Ericsson, Psion Palm, Compaq, Hewlett Packard)

Figure 1.7 Wireless Internet industry roles and responsibilities

It should be noted that in some cases these services and provisions are often aggregated by some wireless Internet services (e.g. iMode). However, Figure 1.7 can be viewed as the logical systems domains of the wireless Internet industry. At one end of the industry there are the users and the mobile device manufacturers (who are keen to satisfy user needs by offering attractive mobile devices). At the other end you have the Mobile Internet content creators and providers. In the middle of the industry (at the backbone) are the network bearers and wireless infrastructure providers.

Bluetooth technology

1.15

37

■ Networked wireless business systems The ultimate deliverable of M-commerce within the business systems context is the distributed wireless office where communications technologies, in co-operation with mobile devices (e.g. mobile phones, PDAs, handheld computers, and wireless modem laptops), are integrated into a wireless-based networked information environment. This situation offers connectivity, with the additional asset of location independence and mobility, within both the working and social domains of life. The emphasis is on wireless applications within distributed business environments. A major area of research into the applications of wireless technologies and mobile devices is in the arena of computer networking, particularly in the context of Wireless Local Area Networking (WLAN). The main advantage of WLAN is the flexibility it provides to business systems, allowing for true location independent connectivity. Information on WLANs can be found on the WLAN Alliance web site.

Activity 1.13 Explain the significance of wireless networking and compare the advantages and disadvantages of wireless networking with those of wired networking. Investigate what wireless network technologies are available within the business environment and prepare a report on your findings.

1.16

■ Bluetooth technology Short-range wireless networking was enhanced in the early years of the 2000s by the development of Bluetooth technology. The technology was a brainchild of the Swedish mobile phone manufacturer and wireless infrastructure provider, Ericsson. But the specifications of the technology were further developed by the Bluetooth Special Interest Group (SIG), comprising a consortium of individuals and companies in the wireless-telecommunications and computing industries. The Bluetooth SIG is responsible for developing the radio communications protocols and publicizing the benefits of the technology. Bluetooth permits d2d wireless communication between two (or more) devices with the requisite embedded technology. It allows short-range, but high-speed, wireless Radio Frequency (RF) communication for both voice (i.e. telephony) and data. Bluetooth enables d2d communication at rates of 1.0 Mb/s within a range of separation of 100 m (or just over 300 ft). It operates in the globally unlicensed 2.45 Gigahertz frequency spectrum. Bluetooth technology effectively enables the wireless office, whereby mobile phones, PDAs, wireless laptop computers, and other computing hardware (e.g. printers, keyboards and mice, etc.) can be connected via a WLAN. This type of technology allows systems flexibility and enables mobile devices to upload and download data without wired connectivity.

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Mobile commerce (M-commerce): definitions and context

Did you know? The name Bluetooth derives from the 10th century Danish king called Harald Blatand (or ‘Bluetooth’ in English). He is famous for uniting Denmark and Norway and bringing Christianity to Scandinavia.

Bluetooth technologies can be used in many innovative ways. Take for example a taxi company that embeds Bluetooth technology in its taxis. A customer locates available taxi firms in her immediate location by accessing taxi data on her Mobile Internet-enabled phone while waiting by her broken-down automobile in a dark lane late at night. (This is an example of a location-based service.) The customer is able to telephone her preferred taxi company. The company locates her mobile phone signal, determining her geographical location, and states what time a taxi will arrive. (This is an example of mobile phone location awareness and tracking.) The caller is furthermore provided with progress reports, sent to her mobile phone, on the expected time of the taxi’s arrival. Because of Bluetooth technology embedded in the taxi, which provides short-range communication between mobile devices, when the taxi approaches the customer can ‘upload’ data from the taxi’s embedded systems to confirm that it is the correct taxi (from previously provided data on registration and name of driver). On arrival the taxi’s embedded Bluetooth technology can confirm that she is the correct customer from the data being received from the customer’s mobile phone. Once collected, the customer can pay her bill on-line via her mobile phone and advise the driver (via, for example, auto-route software) of the best route home. At the same time the relieved customer can log into her e-mail, or SMS, commonly known as texting, to inform friends and family of her delay. This is an example of wireless information systems integration showing the inter-relationship of embedded technology with wireless data communications. Activity 1.14 Discuss the importance of Bluetooth technology in the wireless world. Explain the technical specifications of Bluetooth and discuss the advantages and limitations of Bluetooth technology in the wireless-networking systems domain. Search the official Bluetooth Web site to get all the current information on Bluetooth technology and its application within the M-commerce domain.

1.17

■ Factors determining M-commerce innovation and adoption in the 21st century The big challenge facing anybody wishing to exploit the opportunities offered to M-commerce by new technological developments lies in realizing

Factors determining M-commerce innovation and adoption in the 21st century

39

the potential for innovative practice inherent in the rapidly growing cluster of technological innovations emerging from the convergence of information and communications technology and its extension to wireless communications channels. The mere existence of new technological capabilities is not enough in itself to ensure that that those capabilities will be appreciated, and even if they are appreciated they may not be adopted. Conversely it is often the case that new technology is adopted because it increases efficiency within existing practice while the greater competence to be achieved through its use in new practice goes unnoticed. The process whereby innovations are adopted by a community or larger social grouping is known as the diffusion of innovation and the people who study this process are known as diffusion scholars. Diffusion scholars have identified four main elements that need to be considered for a proper understanding of the diffusion process. These are the innovation, the communication channels, the time and the social system (Rogers, 1995). Figure 1.8 outlines the factors determining M-commerce innovation and adoption.

Communication Channels

The Innovation

Diffusion of Innovation

Time

The Social System

Figure 1.8 Factors determining M-commerce innovation and adoption

An innovation is anything – an idea or technology – that is new to a potential adopter. It may not be new to the world and, in fact, it may be a very old idea, but if it seems new to the agent considering it, it is an innovation – it calls for a change in the thinking and behaviour of the adopter. Of particular interest to change managers is which characteristics of an innovation affect an individual’s decision to adopt and which factors affect the speed with which innovations spread through a social system. Also of concern are the possibilities for re-invention – where an innovation is adopted but not used in the same way as by previous adopters – and pseudo-adoption. Pseudo-adoption is particularly common in organizations where adoption is imposed by

40

Mobile commerce (M-commerce): definitions and context

authority; members of the organization will ‘talk-the-talk’, paying lip service to the new approach, but not actually ‘walk-the-walk’ and change their attitudes or behaviour. These problems are particularly acute for organizations wishing to take advantage of the new pervasive computing paradigm and develop mobile commerce because the technology is very new to the world and introduces fundamental new capabilities with the potential for profound social impact. Innovation is to a very large extent synonymous with technology. Technology is defined as ‘a design for instrumental action that reduces the uncertainty in the cause–effect relationships involved in achieving a desired outcome’ (Rogers, 1995). Typically an innovation (or a technology) will consist of both a hardware and a software aspect. The hardware aspect is some physical object or device and the software aspect is the information that explains its use. This should not be confused, as it is by Rogers, with the hardware and software divide in a computer software application, where it is the application software that represents the physical aspect of the innovation which it invokes in the hardware when it is run – the software aspect is provided by the user manuals and help files. Some innovations only have software components, e.g. techniques and methods. In addition to the software aspect of an innovation that provides information about its use and how it reduces uncertainty in a problem area, there is a second aspect of software information about the innovation that provides evaluative data about its effectiveness and the consequences associated with its adoption. Innovations are not typically isolated but tend to come in clusters, particularly as new discoveries and inventions introduce new possibilities, and technologies are developed to provide the capability to exploit these. Very often the question is not one of adopting just a single innovation but the entire cluster. Once one innovation in the cluster has been adopted then others are much more likely to be adopted, e.g. once people start using mobile phones then they are much more likely to start using SMS. This is an interesting example because, while SMS is not a compelling reason to adopt a mobile phone in the first place, it often becomes the primary use of the phone once adopted. Activity 1.15 Research the current technological innovations in the wireless computing world and review their respective importance within the M-commerce domain. Discuss why some innovations are successful and provide a list of critical success factors for all new innovations.

1.17.1


Five characteristics of innovation Diffusion scholars have identified five characteristics of an innovation that affect the likelihood of its adoption. These are relative advantage, compatibility, complexity, trialability and observability. Each of these will be

Factors determining M-commerce innovation and adoption in the 21st century

41

explained with reference to the example of the mobile phone, an innovation that has shown remarkably rapid adoption. (a) Relative advantage is how much better the innovation is perceived to be compared with the existing alternatives. Better might be in terms of cost, social prestige, convenience or satisfaction. For instance, mobile phones had a considerable convenience advantage over fixed line phones because they were always with the person; they did not need to find a phone to make a call or run to answer it when they were called. (b) Compatibility is the degree to which the innovation is perceived to fit in with the existing values, needs and experience of the potential adopter. This applies at both the individual level – the compatibility with the selfimage of the potential adopter, is it the sort of thing they would do? – and at the social level, is it the sort of thing that is done around here? (c) Again mobile phones are used in a very similar manner to fixed line phones although different costs and billing present some barriers. Complexity refers to the degree to which the innovation is or is not easy to understand and to use. If a potential adopter requires special training or education before they can understand and use the innovation, adoption is likely to be slower. Mobile phones operate in a similar way to traditional phones so there was little new for a potential adopter to learn. (d) Trialability is the degree to which the innovation can be experimented with on a limited basis without making an absolute commitment to adopt. If adoption is an all or nothing affair then it obviously carries a high risk; being able to test the water greatly enhances the chances of an innovation being adopted. (e) Finally observability is the degree to which it is possible to see those who have adopted it making use of the innovation. Mobile phones are extremely observable and both the obvious convenience and the personal satisfaction of being able to call any time anywhere are obvious to all.

Activity 1.16 Within the idea of ‘diffusion of innovation’ five characteristics of an innovation have been identified that affect the likelihood of a technology being adopted. Explain each of these five characteristics and relate them to technologies within the wireless world.

1.17.2


The socio-technical perspective of technology innovation and adoption For diffusion scholars a communications channel is any means by which a message gets from one individual to another. The relationship between the communicating individuals has considerable impact on the type of messages

42

Mobile commerce (M-commerce): definitions and context

that can be effectively communicated and the effect that that communication can have on the receivers’ decision to adopt or reject the innovation. Mass media, radio, television, newspapers, etc., are extremely effective at spreading awareness and knowledge, quickly informing the majority of a social system of the existence of the innovation. However, it is interpersonal face-to-face channels that tend to have most effect in persuading an individual to adopt, particularly when the communication is between people of similar social, economic and educational background. The more similar people are the more homophilous they are, and the more differences they have the more heterophilous. People are more likely to be persuaded by others who are similar to themselves in terms of education, social status, religious and political beliefs, location, occupation, interests, mutual subculture, language and personal character. For people who are highly homophilous very little knowledge transfer can take place. For knowledge of an innovation to be transferred the two parties must differ at least in as much as one of them has adopted or rejected the innovation and the other has not. Similarly individuals might be highly heterophilous with the exception of being adopters of a particular technology cluster, so that innovations within that cluster will spread rapidly between them while innovation of other sorts will not. Time is relevant to diffusion studies in a number of ways. It takes time for a potential adopter to decide whether or not to adopt, and it takes time for adoption of an innovation to spread through a population. Some people will adopt early when there is little social support for the idea while others will adopt only after the majority of the social system have done so. Typically an innovation decision goes through a number of stages: awareness, persuasion, decision, implementation, and confirmation. Of course if the decision is to reject then there is no implementation, but even after rejection there might still be a confirmation phase that, if it raises new awareness, might lead to persuasion and adoption. Similarly the confirmation phase might lead to an adopted innovation being discontinued if its benefits prove less than was promised or some unexpected negative effect is revealed or a better alternative is realized. The number of people in a social system adopting a new innovation over time always follows an ‘S’ shaped curve with initially just a very few adopters – the innovators – which rises slowly to include the early adopters and then quite sharply as first the early majority and then the late majority adopt and then levels off as the laggards slowly join. There is, however a potential gap between the early adopters and the early majority which in many cases is not jumped and then the innovation never spreads to the majority. From a diffusion perspective a social system is a set of interrelated units that are engaged in joint problem solving to accomplish a common goal (Rogers, 1994). A unit might be an individual, a group, an organization or a sub-system but whatever the unit of analysis each is distinct and individually identifiable and each co-operates with the others at least to the degree that they all seek a common goal. Social systems tend to contain two distinct forms

Factors determining M-commerce innovation and adoption in the 21st century

43

of communication structure: a formal structure of power, influence, authority and responsibility termed the social structure and an informal structure of interpersonal relationships termed the communications structure. Communication relationships tend to be strongest between homophilous units, often leading to the development of cliques. Units at different levels in a hierarchy of authority and responsibility tend to be of different social and educational backgrounds and therefore more heterophilous, making it relatively easy for innovations to diffuse amongst members of the same level and relatively difficult for them to diffuse between levels. This is why organizational change is often accompanied by restructuring of the authority and responsibility relationships, which is a particular problem when an organization seeks to use technology to move authority and responsibility to interface workers, often called worker empowerment. The sort of loosely connected team and group structures that mobile commerce makes possible can radically change social structures and remove many of the traditional face-toface communications structures. Structure, both of the formal social and informal communication variety, is a form of information because it reduces the uncertainty in a situation. Changes that reduce traditional structures without replacing them with alternatives are likely to give rise to increased uncertainty leading people to reject the innovations or, where that is not possible, to increased anxiety and stress. Social norms can also have significant influence on the acceptance of an innovation. If the change is only one of degree then it is much more likely to be adopted than if it is one that goes against established norms of behaviour. Such norms can differ widely even within the same social and cultural setting, so for instance within a retail chain different branches can have distinctly different norms of behaviour so that an innovative behaviour that is acceptable and readily adopted in one will be rejected by another. Activity 1.17 Outline the various ‘levels’ of socio-technical communication and discuss how wireless mobile devices and wireless business systems have impacted on general business activity. Does wireless technology provide a different socio-technical communications experience compared with wired technology?

Within a social system some members have more influence on the behaviour and opinions of their fellows than others. The degree to which a unit has such influence is a measure of their opinion leadership. Innovators and early adopter are very often perceived as being more or less odd or ‘nerdy’ and typically have very little opinion leadership apart from in their own subcultural group. Opinion leaders can either hinder or promote innovations. Opinion leadership does not typically connect with formal leadership roles but with informal ones determined by competence, social accessibility and conformance to a system’s norms. If the norms are pro-innovation, opinion leaders are likely to be pro-innovation, and vice versa, although a typical system will have a mixture of both pro- and anti-innovation opinion leaders.

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Mobile commerce (M-commerce): definitions and context

More than anything else it is their role in the communication channels that gives opinion leaders their influence; they typically form important, highconnectivity nodes in the network and so operate as representatives for the composite opinions to which they are privileged. A change agent is anyone who is tasked with or assumes the role of promoting an innovation. A change agent should aim to influence the opinion leaders. However, if there is a high degree of heterophily between the change agent and the opinion leaders this can be difficult; without the support of at least some opinion leaders the change agent is almost certainly doomed to fail.

1.18

■ Conclusions Mobile commerce is a new way of running a business using many innovative technologies and organizational structures. Although it is a natural extension of many existing technology clusters, it also represents a departure into never-before-encountered possibilities; it is by no means clear what will be required to realize this potential – to know what particular technologies will provide the capabilities to exploit them. It is, however, clear that to develop competence in exploiting these capabilities is going to require innovative practice and social and communication structures. Organizations that can develop effective new practices and the structures to support them will do very well; those that cannot adapt will disappear. This is, therefore, worth keeping in mind as the many new innovative ideas that make up mobile commerce are going to be adopted within the social system in which you work. In Europe and Japan the M-commerce focus is on delivering to the customer (or consumer) technologies, such as Internet-enabled mobile phones, and the provision of Mobile Internet services. In the USA the main M-commerce focus is on the use of palm computers, other mobile devices (e.g. the BlackBerry mobile E-mail device), and other wireless technologies to improve the effectiveness of business systems processes. In many cases the European view is from the perspective of diffusing wireless telecommunications and Mobile Internet access opportunities as a lifestyle consideration. The US view is from the perspective of the wireless-networked hardware and software environments that support mobile working. However, as wireless technologies and affordable mobile devices become globally available, the focus will diminish. Currently, the European and Japanese focus is driven by the large mobile phone manufacturers, like Nokia and Ericsson, whereas the American market is driven by the wireless infrastructure and mobile computing device companies, like Motorola (for wireless infrastructure), and Compaq and Hewlett Packard (who manufacture mobile-computing devices, such as palmtop computers, with Mobile Internet access capabilities). Chapter 7 of this book goes into detail on mobile devices, their use, and the growth of wireless, mobile information systems.

Short self-assessment questions

45

In essence, competitive advantage in M-commerce resides in the ability of business organizations to exploit and explore the business possibilities available to an industry. The growth and spread of M-commerce, like many other technological developments in the past, is being driven by three factors: (a) developments in mobile wireless applications and technologies (innovation); (b) proliferation and use of wireless technologies by (potential) customers (adoption); (c) desire by organizations to expand markets and add value to products and services (increased competition). In many industries there is short-term gain in the ability to exploit wireless technologies to advantage, and be amongst the first to do so. In the longer term, and many industries are at this stage, sustainable gain for businesses resides in exploring innovative ways of incorporating wireless telecommunications and mobile devices into the networked business information systems domain. The aim is to achieve location independent connectivity for business advantage, both internally for employees and suppliers, and externally for customers and clients.

Short self-assessment questions 1.1

Outline and explain the main differences distinguishing M-commerce from E-commerce.

1.2

What are the main differences distinguishing analog and digital technology?

1.3

What are the main advantages of GPRS over GSM communications technology?

1.4

Define the term ‘roaming’ within the wireless telecommunications world.

1.5

What is the current data transmission rate for broadband technology?

1.6

Define the term ‘location dependent products and services’ within the wireless world.

1.7

Define the main features and characteristics of the Mobile Internet (or wireless Internet).

1.8

What is meant by ‘garden walling’ within the Mobile Internet domain?

1.9

What are the main features and capabilities of a ‘smart phone’?

1.10

Outline the main location-based products and services generally available in the M-commerce world.

1.11

Define pervasive computing and outline its three main aspects.

1.12

Explain the significance of embedded technologies and systems within the wireless mobile domain.

1.13

Define and explain the term ‘mobile professional’ within the context of wireless business systems.

1.14

Explain the characteristics and features of wireless mobile working.

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Mobile commerce (M-commerce): definitions and context

1.15

List the applications of wireless telemetry and explain how it allows remote monitoring.

1.16

Outline the main technical characteristics of Bluetooth technology.

1.17

Explain the main advantages and disadvantages of WLAN.

1.18

Outline and explain the main stages of the wireless-technology adoption life cycle.

1.19

What are the four factors determining M-commerce innovation and adoption?

1.20

Outline the main M-commerce technology adoption differences in Europe, the USA and Asia.

Group activity

Three challenges in mobile commerce!? The first challenge How to attract customers? The second challenge Ergonomic constraints (the problem posed by small screens and input interfaces)? The third challenge Slow connection speed (i.e. links working slowly and limited data transfer capability)?

Required ■

Discuss how each of these three challenges is being overcome in the wireless world.

■

Discuss in particular how 3G technology ameliorates the third challenge.

■

Discuss which products and technologies adequately deal with the second challenge. Clue: what is the trade-off between using mobile phones and wireless PDAs (smart phones)? Present a group report outlining the main factors in creating a successful Mobile Internet presence. Groups may present to each other. Some factors to get you started…

1.

Using links and associations with PC-based web sites and exploiting the customer base of a normal PC web site. Therefore a site can be offered in PC mode or mobile device accessible mode.

2.

Finding interesting and innovative products and services. Make sure these have a location dependent aspect. Limit access to services rather than expensive products with complicated delivery logistics.

3.

Advertising mobile sites via SMS and other media outlets. Rate the effectiveness of each advertising channel or medium.

4.

Enhancing customer trust through secure (and security-conscious) communications channels. Is wireless security less robust than wired security?

References and bibliography

■

47

References and Bibliography

■ Books Akiaiwa, Y. (1999) Introduction to Digital Mobile Communications. John Wiley and Sons. ISBN: 0471175455 Bussey, G. (2000) Marconi’s Atlantic Leap. Published by Marconi Communications. ISBN: 0953896706 Deital, H. et al. (2001) E-business and E-commerce for Managers. Prentice-Hall. ISBN: 0130323640 Elliott, G. & Starkings, S. (1998) Business Information Technology: Systems, Theory and Practice. Addison-Wesley-Longman. ISBN: 0582298024 Louis, P. J. (2001) M-commerce Crash Course: The Technology and Business of Next Generation Internet Services. McGraw-Hill. ISBN: 0071369945 Messerschmitt, D.G. (1999) Networked Applications – A Guide to the New Computing Infrastructure. Morgan-Kaufmann Publishers. ISBN: 1558605363 Milojicic, D. et al. (1999) Mobility: Processes, Computers and Agents. Addison-Wesley. ISBN: 0201379287 Norris, M. & West, S. (2001) eBusiness Essentials: Technology and Network Requirements for Online Markets. John Wiley and Sons. ISBN: 0471521833 Prasad, R. et al. (2000) Third Generation Mobile Communication Systems. Artech House Publishing. ISBN: 1580530826 Rogers, E. (1995) Diffusion of Innovations. The Free Press (Fourth Edition) ISBN: 0029266718 Schiller, J. (1999) Mobile Communications. Longman Higher Education. ISBN: 0201398362 Singhal, S. et al. (2000) The Wireless Application Protocol: Writing Applications for the Mobile Internet. Addison-Wesley. ISBN: 0201703114 Standage, T. (1998) The Victorian Internet. Phoenix Publishing. ISBN: 0753807033

■ Papers Ark, W.S. & Selker, T. (1999) A look at human interaction with pervasive computers. IBM Systems Journal, 38, 4, 504–7. Elliott, G. (2001) Defining wireless mobile commerce (M-commerce) within the business information technology domain: A case study approach. Proceedings of the 11th Annual BIT Conference, Manchester, UK, October 2001. ISBN: 0905304381 Elliott, G. & Patel, S. (2001) The development of mobile commerce and its integration into the university syllabus for business information technology. Proceedings of the BIT World Conference, Cairo, Egypt, June 2001. ISBN: 0905304365

■ Surveys The Economist (2001) A Survey of the Mobile Internet. The Internet Untethered. 13th October 2001.

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Mobile commerce (M-commerce): definitions and context

■ Web sites Mobile phone manufacturers www.ericsson.com www.nokia.com www.motorola.com www.sony.com Wireless telecommunications network providers www.orange.co.uk www.vodafone.co.uk www.btcellnet.co.uk www.one2one.co.uk www.at&t.com

General mobile commerce sites www.MobileCommerce.org www.forum.nokia.com IBM Pervasive Computing www.ibm.com/software/pervasive Global Mobile Commerce Forum www.gmcforum.com WLAN Alliance www.wlana.org

Commercial communications and networks

2

‘The distance is nothing; it is only the first step that is difficult.’ Translated from Letter to Alembert, 1763 by Madame Du Deffand (1697–1780)

Chapter Aims: ■ ■ ■ ■ ■ ■ ■ ■ ■ ■

To describe the fundamental aspects of communication. To explain the challenges presented by distance. To distinguish between the different types of thing – data, information and meaning – that can be communicated at a distance. To introduce Shannon’s communications reference model. To describe the fundamental aspects of communications networks and explain their benefits and the additional challenges that networking presents. To introduce the International Standards Organization Open Systems Interconnectivity (ISO-OSI) model. To describe the main types of media used for carrying communications channels. To describe the different devices used to deliver network communications and explain their basic functions. To describe the different network topologies. To describe the different types of bounded and unbounded media networks and explain the essential elements of their operation.

50

Commercial communications and networks

Variety Commercial Communications

Definitions of Information Channel Capacity

Communications

Shannon's Communication Theory

Information and Meaning

Meaning Context and Perspective

Communications and networks

Reduced Uncertainty

Error in Estimation

Data and Knowledge Modulation and Digitization

Bound and Unbound media ISO-OSI Network Protocols Telecommunications and Networks

TCP/IP Network Devices

Circuit Switching

Telecommunications Infrastructure

Packet Switching

The Knowledge Context Map

Network Topologies

Network Addresses

Introduction

2.1

51

■ Introduction Networks of communication are a fundamental aspect of all forms of organization. A breakdown of communication is very often the primary cause of organizational failure. This is most clearly true in commercial enterprises where there is a direct relationship between the effectiveness of an enterprise’s communications network and its survival. The ability for all types of employees, in all types of positions, to access their company’s intranet any time and anywhere via their laptop, PDA or mobile phone promises order of magnitude improvements in the effectiveness of those communications networks. However, just because technology offers the potential for increased effectiveness it does not follow that people confronted with that technology will automatically adopt practices that realize its full potential. In fact, early adopters of new technology typically use that technology to support established processes and practices. For instance, when computerized accounting packages reduced the preparation of the monthly sales accounts from days of sweated labour to the press of a button, organizations were quick to lose the sweated labour. But they continued to produce monthly reports even though the technology enabled weekly and daily reports with equal ease. Developments in wireless communications technology are introducing fundamental new communications capabilities. While these capabilities offer clear advantages by overcoming some well understood limitations of current technology that are sufficient to see the new technology adopted, these advantages are within current practice. True exploitation of these new capabilities will only be realized when new practices that leverage the full potential of location independent network computing are discovered. Hopefully this book will help you discover these new practices and unleash this full potential. This chapter starts by reviewing the basic concepts of communication in order to provide a common foundation of ideas on which later sections will build. This may seem a little too theoretical if you are desperate to hear about the specific, new, mobile networking technologies, but it is theory which will provide the necessary grounding you need if you are to properly appreciate and exploit the technologies introduced in later sections. The challenges of effective communication at a distance are the same whether wired or wireless technologies predominate. Indeed, all large network infrastructures today incorporate a mixture of wired and wireless technology. It is the mode of connection at the point of use that characterizes a network as fixed or mobile; the intermediate technology will nearly always be a hybrid. So, if you make a phone call using a phone wired-in to your local exchange you are using wired technology; even if for most of the distance they travel the signals are sent wirelessly via satellite. Similarly, if you use a mobile phone that connects, via radio, to a basestation just 50 m away you are using wireless technology; even if for most of the distance the signals travel the fixed wires carry them.

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Commercial communications and networks

Galileo Galilei made many contributions to modern science, but is perhaps most famous for pointing his telescope at the heavens and confirming that the Earth orbits the Sun and not the other way around, and getting himself into a lot of trouble with those who felt the Sun goes round the Earth. Although this is rightly seen today as one of his most important scientific achievements, much more significant in his day was the use he made of the telescope for improving commercial communications. It was the donation of his first telescope to the Doge of Venice and its subsequent sale to many worthy merchants that made Galileo’s fortune (and gained him the influence that kept the geocentrics at bay). A merchant equipped with a telescope can see what ships are coming in, and therefore predict how the market will change, pre-empting the competition. Ships equipped with telescopes were better able to navigate – they could spot land earlier, avoid pirates more easily (if they were a merchant vessel) or find them more easily if they were a military vessel) and send messages over greater distances. Before the invention of wireless telegraphy and radio, sailing ships communicated using flags of different colours, shapes and patterns to send signals between ships and between ship and shore. Some of these signals were broadcast constantly, such as the flag that announces the ship’s allegiance (and therefore whose navy is protecting it) and whether it is a merchant or a warship, and flags to show that there was plague or fever on board. Commanders of fleets and flotillas used other, usually slightly more complicated, signals in order to transmit their orders – this is why the ship that carried the commander of the fleet was called the flagship. In theory there is an unlimited number of combinations of shape and colour and pattern that could be employed so the possible messages might seem limitless. In practice this apparent variety was very much constrained by the need to make each signal clearly distinguishable from all other possible signals at a distance and in poor visibility. Did you know? Before radio communication the navies of the world used flag signals to communicate orders and commands to other ships.

Over time navies developed a standard set of signals to cover the most common situations. To handle the specific requirements of a particular mission prior to sailing a commander would discuss possible courses of action with the captains of the other vessels in the fleet and agree the signals that they would use to communicate the decisions. They would meet up from time to time as needs dictated and circumstances allowed so that the meaning of a particular signal might change several times throughout a voyage. In reasonably good conditions more complex systems could be sent from one vessel to another using a coding system such as semaphore. The telescope increased the distance over which a user could discriminate between different signals. It allowed more complicated messages to be

Introduction

53

broadcast to the fleet, increased the distance at which semaphore was effective and reduced the likelihood of errors. The merchants of Venice were masters of mobile commerce in Galileo’s day and they were quick to appreciate the advantages to be gained from using the telescope, although it is doubtful that anyone appreciated all those advantages at once. This brief discussion highlights the main elements involved in effective commercial communication at a distance and the benefits that technology can bring. In order to send a message some means is needed to encode that message (the coloured flags) so that it can be transmitted over a distance (run up the mast). In order for the message to be understood the receiver must be able to translate the code back into the original message. In the course of transmission the signal can become distorted and so difficult to read. Technology can improve matters by reducing noise (the distortions) and increasing the effective length of the channel (the medium through which the message was sent). Note that from an organizational perspective there are two levels of meaning associated with the message. The symbols that make up the signal need to be understood by the receiving agents so that they can be converted to a written or verbal message, but the same phrase might have very different meanings depending on circumstances. Challenges associated with the former are engineering challenges while those associated with the later are organizational or management challenges. Nelson and Winter (1990) give us the following picture of an organization in routine operation: A flow of messages comes into the organization from the external environment and from clocks and calendars. The organization members receiving these messages interpret them as calling for the performance of routines from their repertoires. These performances include ones that would be thought of as directly productive – such as unloading the truck that has arrived at the loading dock – and others of a clerical or information-processing nature – such as routing a customer’s inquiry or order to the appropriate point in the organization. Either as an incidental consequence of other sorts of action or as deliberate acts of communication, the performance of routines by each organization member generates a stream of messages to others. These messages in turn are interpreted as calling for particular performances by their recipients, which generate other performances, messages, interpretations, and so on. At any given time, organization members are responding to messages originating from other members as well as from the environment; the above description of the process as starting with information input from external sources or timekeeping devices is merely an expositional convenience. There is, indeed, an internal equilibrium ‘circular flow’ of information in an organization in routine operation, but it is a flow that is continuously primed by external message sources and timekeeping devices. (p. 103)

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Commercial communications and networks

Nelson and Winter had in mind a ‘typical’ business organization; not all business organizations easily fit their description, or could be said to behave routinely, but very many do. Consider for a moment a Venetian sailing ship when the lookout spots storm clouds on the horizon and the captain orders the sails to be shortened. Clearly their description could equally well be applied to very many forms of non-commercial social organization, such as government departments and market economies, that for the most part operate in a routine manner. Indeed, it is just such routine behaviour that we tend to term ‘normal’. Something that is not addressed in the above quote but has become increasingly evident with the growth in communications since 1982 when it was written, is that organizations routinely receive, produce and process vast numbers of ‘unnecessary’ messages – a condition we know today as information overload. Hence one of the effects of introducing improved communications into organizations in routine operation is to routinely overload organization members with information. Implicit in the above quote is that the organizational members in whom performances are called forth by the various messages are people. To simplify the language and avoid convoluted sentence constructions the term ‘agent’ will be used to describe any entity that is capable of producing performances on receipt of messages and generating messages that call for performances of others. Agent can apply to people, individuals or groups – including organizations and collections of organizations. Agent can also apply to computational electromechanical devices individually or collectively. But whether human or cybernetic, single or collective, ‘agent’ will always apply to a distinct and identifiable entity. Activity 2.1

2.2

Consider some common organizational routines that you are familiar with. Try to identify all the messages that come from the environment and from clocks and calendars and the different agents that receive them and the performances they invoke. See if you can identify all the messages the performances generate. How many different media (e.g. E-mail, post, telephone, gesture, schedule, etc.) were involved? To what extent are these performances tied to particular locations? What tethers the performances to the locations?

■ The nature of commercial communication This chapter is primarily concerned with the various mechanisms and associated infrastructure that organizations can employ to enable this flow of messages to take place efficiently and effectively. In addition to general networking concepts, we also focus on those aspects of communication networks most relevant for understanding mobile commerce systems. Typically, regardless of the mobility of its workforce and its physical assets, an organization consists of a mixture of mobile and static resources. The organization’s business models must develop and maintain the information

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55

infrastructure, appliances, applications and content to ensure effective integrated operation of those resources. Commerce has always been ‘mobile’; its mobility is the natural consequence of the laws of supply and demand. To make a profit a merchant needs to know what people are prepared to pay. The merchant also needs to know where products and services can be obtained at a good price and how to get them from the supplier to the consumer before (or for less than) the competition. This requires that they have accurate and up-to-date information. This information – the right information in the right place at the right time – is itself a valuable commodity. The effective delivery of information ensures the effective delivery of goods and services. However, constraints on the delivery of information have meant that it is usually not possible to get complete coincidence between when and where the information is needed and when and where it is available. In many ways we are still communicating by running flags up a pole; many of our messages can only be seen if we are in sight of our desktop. Wireless communications technologies remove this constraint on the ability of the communications infrastructures to supply upto-date information to the agent that needs it as and when they need it. The new capabilities that removal of this constraint enable should perhaps be referred to as mobile information commerce as their chief characteristic is to have real-time, full, information availability anywhere and at any time. The basic concepts of communication are the same whether that communication takes place face-to-face or over short or long distances and whether the parties involved in the communication are static or mobile. However, as the size, number and frequency of messages, the number of participants, their distance apart and their mobility increase, so too do the difficulties of ensuring reliable error-free transmission of messages and their associated meaning. A broad range of options are currently being developed to ensure that engineering solutions will meet all anticipated needs for any volume of messages between any number of static and mobile agents over any distance.

2.3

■ Communication and language complexity (a) What exactly is a message? (b) What does it take to transmit a message between two or more agents? (c) How is meaning associated with a message? Communication is a complex many-layered phenomenon. Communication as the transmission of messages from one party to another is the basic engineering problem that Claude Shannon1 addressed in his landmark paper on

1

Claude Shannon founded the subject of ‘Information theory’ and proposed a linear schematic model of a communications system. He was born in 1916 and died in 2001.

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communication theory (Shannon, 1948). Claude Shannon, who died aged 84, perhaps more than anyone else laid the groundwork for today’s digital revolution. His single-handed exposition of information theory, stating that all information could be represented mathematically as a succession of noughts and ones, facilitated the digital manipulation of data without which today’s information society would be unthinkable. More correctly, his theory applied not only to data but also to communication of all kinds and, combined with the pulse code modulation system of digital telecommunications transmission devised in 1937 by Englishman Alec Reeves, effectively laid the foundations for today’s modern digital communications and broadcasting networks, the Internet and much more (Obituary for Claude Shannon by Andrew Emerson in The Guardian newspaper on Thursday March 8th 2001). Communication as the transmission of meaning between different parties is what information systems designers hope to achieve. Beyond shared meaning is shared understanding – think about all those times when you thought you understood someone only to discover they meant something entirely different from what you thought they meant. At this level meaning and understanding get bound up with intention – common purpose and coordinated action that is effective in meeting that purpose are the hallmarks of an organization with good communication. Communication is one of those things that people are naturally good at. The ability to communicate complex abstract ideas is one of the defining characteristics of humanity. This general everyday familiarity makes it a difficult subject to discuss objectively – it can be hard ‘to see the wood for the trees’. Explaining the mysteries of language is well beyond this current text; it is, however, necessary, in exploring a subject so intimately bound up with methods and means of communication, to be as clear as possible about some basic concepts. Communication between any two agents requires that they share some common language. They must each be familiar with a set of expressions and ascribe somewhat similar meanings to them or communication is impossible. This set of expressions and their common meaning forms the universe of discourse between the two agents. It is a minimum requirement for communication to take place, but does not ensure that the two agents will actually understand each other. However, it is the nature of language that, should two agents wish to, they can, through successive communication in it, develop a better understanding of each other’s meaning and extend the language to create new common meanings. So, however vague and thin the initial universe of discourse, meaning can always be made clearer and more precise with use. The natural languages with which we are all familiar such as Arabic and English are particular forms of a much larger family of languages that also includes the specialist formal languages created for use in mathematics such as computer programming languages.

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Did you know? The study of natural languages is called ‘linguistics’ while the study of the set of all possible languages is called ‘semiotics’.

Two sorts of conventions define a language in its most general sense. The format is some set of symbols or letters that make up the alphabet such that they can be produced in unlimited quantity like the letters on this page or the sounds (‘phonemes’) in speech. A second convention or set of rules specifies how these symbols should form expressions or words. Typically an expression is an arbitrary linear series of letters in which repetitions may occur. Expressions, including symbols, are not concrete physical objects but refer to types of object in the same way that the words apples or documents do. A particular instance of an expression is called an inscription (Curry, 1977). If we are interested in the meaning a language conveys then we need to consider those expressions that also obey the rules for forming sentences. The rules for determining what constitutes a sentence in a language are its grammatics and expressions that obey these rules are called the phrases of the language (Ibid.). Information theory as defined by Shannon (1948) is concerned with the transmission of expressions. When we design and build information systems we are much more concerned with the transmission of meanings and so we analyze the semantics of the phrases in the language of a particular domain. The three main classes of phrases are noun, sentence and functor. A noun is a name of some object, either real or imaginary; a sentence expresses a statement; and a functor is a method of combining phrases to form other phrases. The concept of a functor is a very general one but we only need to consider a few examples to understand its basic meaning. An operator is a functor that combines nouns to form other nouns; verbs (or predicators) combine nouns to form sentences and subnectors form nouns out of sentences (Curry, 1977). In the object-oriented systems approach to analyzing a situation objects are identified through analyzing the sentences about them. The nouns identify the objects and object attributes and the verbs identify the behaviour or methods that are applied to them. Once the main objects of interest have been identified further analysis concentrates on the relationships between them, in particular whether they are specializations or compositions or aggregations of other objects, use other objects, are used by other objects or are otherwise associated with each other – that is related by a functor. Functors are particularly important for overcoming functional views of objects by mapping concepts in one domain into associated concepts in another. For example, manufacturing and sales have very different functional views of a product. These need to be integrated into a common corporate view in order to develop an organizational ontology to support corporate information portals so that a search from a sales manager and a production manager, each using their own language, will be equally successful.

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Domains of discourse develop around practices and associated activities creating sub-languages where common expressions develop specialist meanings. In particular any group of people regularly engaged in a common set of activities will develop specialized language that compresses long descriptions into short expressions, e.g. a complicated accounting procedure might be summed up as ‘I’m doing the 712s’ and this will carry much more ‘information’ to people ‘in the know’ than a lengthy description of the actual activities will to an outsider. Being able to encode complex ideas in this way is an essential part of effective communication in business domains. This clearly goes beyond the simple meaning of the words to indicate repertoires of performances that those words invoke. Activity 2.2

2.4

Make a list of all the different communities you belong to in your world (e.g. family, course group, sports groups, work group, etc). For each group make a list of the phrases that are peculiar to that group (i.e. where the meaning is instantly known to the group). Take a selection of phrases and see how many your colleagues can guess the meaning of and which ones were hardest to guess? Does this surprise you or is it what you expected?

■ Information and meaning Communication can be described as the exchange of comprehensible information. There must exist a degree of shared meaning between each party involved in the exchange of signals or nothing ‘meaningful’ can be communicated.

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59

It is quite common in books on information systems to see data described as simple ‘meaningless’ values and information to be data plus meaning. Knowledge is then described as the ability to use information to take effective action and the three terms data, information and knowledge are considered to form a hierarchy of increasing meaning. Some have even extended this view to include understanding and wisdom! (Davenport and Prusak, 1998). Figure 2.1 shows the flow of meaning from data to wisdom. There is a slight problem with this approach in that in an attempt to provide a pure and simple definition of knowledge the concept of data has been corrupted!

Data

Information

Knowledge

Wisdom

Figure 2.1 The flow of meaning from data to wisdom

The term information is used in a number of different ways in both technical literature and everyday speech. These various meanings of information (see Figure 2.2) are not actually contradictory but are different aspects of a phenomenon. It is useful to have a clear understanding of a number of these different aspects in order to understand the related aspects of communications.

Uncertainty

Reduces

Channel Capacity

Measures

Information

Measures

Error

Figure 2.2 Different meanings of information

Measures

Variety of a set

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2.4.1


Information as channel capacity Information is a measure of the maximum capacity of a communication channel – the variety of symbols that can be transmitted through a channel in some unit time. This is the perspective adopted by Claude Shannon (1948) in his communication theory. It is primarily concerned with the maximum capacity that limits the information flow in a particular channel given a particular set of symbols. Shannon popularized the use of logarithms as a means of measuring information; this has the conceptual advantage that given two channels A and B with information-carrying capacities a and b respectively then their combined capacity will be a + b. It is also useful because of the simple conversion in logs from one base to another using: logxb loga b = –––––– so that whatever base might be convenient for a particular logxa channel it can be easily compared. In particular, converting to base 2 so that all channels can be compared in terms of bits (binary digits) is typical in electronic communications.2 Shannon also introduced the idea (based on a suggestion of John von Neumann) of calling information ‘entropy’, which in physics is the term used for the measure of disorder in a system. Information as a measure of disorder seems at first glance counter-intuitive. Intuition tells us that given more information we should in general be more certain, the world should appear more ordered not less. This is to overlook the fact that Shannon information is concerned with a medium’s potential for holding or transmitting information. A system is disordered if all possible states are equally likely to occur. A medium’s information holding potential is maximized when it is equally likely to hold all possible messages. A channel’s capacity must be measured in terms of the time it takes all possible messages up to some specified length to pass.

2.4.2


Information as a measure of variety Information is a measure of the variety of a set, typically the variety of a set of symbols – i.e. the number of distinctions that can be made with the symbols. Using this viewpoint we can talk about how many distinctions can be made using some number of the symbols. This is the perspective adopted by Ashby (1956) in his Introduction to Cybernetics and is a generalization of Shannon’s ideas. The emphasis is on the importance of identifying the underlying set, a concept that helps us appreciate levels of information and associated meaning in a message. Compare the set as letters of the Latin alphabet plus the space symbol with that of the most common 600 words in the English language. The latter is clearly a sub-set of the former, but its individual members have more meaning. Consider a set of 52 playing cards. If we consider the cards individually then there are 52 distinctions that they

2

Bits are used to describe the information capacities of both analog and discrete channels.

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can make. If we consider the number of distinct groups of three cards then there are 52^3 = 140,608 distinctions allowing for repetitions or 52*51*50 = 132,600 if a card can appear only once in each triplet. This second number is smaller that the first because the condition that any particular playing card can appear only once in a triplet is a constraint on the variety. The British traffic light system consists of three lights arranged vertically with red at the top, green at the bottom and amber in the middle. This system has a possible variety of eight including all off and all on, but only four combinations are actually used. The same information could be conveyed by just two lights, but having the larger set and imposing constraint makes the four states more easily distinguishable and so reduces the possibility of misreading.

Language also uses constraint in this way. A good English speaker has a vocabulary of about 15,000–20,000 words. Using the 26 letters of the English alphabet such a vocabulary wouldn’t need words of more than three characters 26*26*26 = 17,576, and nearly half a million words could be expressed using words of four letters or less. They would, however, be quite impossible to remember or distinguish between. So the establishment of meaning in a signal is closely related to establishing constraint on a large set of possibilities in order to determine a small set of probabilities.

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2.4.3


Information as a means of reducing uncertainty Information is that which reduces uncertainty about a situation such that a decision can be made. ‘Information is a difference in matter-energy that affects uncertainty in a situation where a choice exists among a set of alternatives’ (Rogers, 1995). This is the perspective we adopt in everyday language when we say we are ‘informed’. Whereas the previous two definitions have been concerned with the possible expressions that might be transmitted, this definition is concerned with what happens when a particular instance is transmitted. It focuses on the actualities rather than the range of possibilities but assumes knowledge of the range with different possibilities associated with different actions. The set of alternatives and the conditions that favour one over the rest are the set of possibilities about which we might be informed. This sort of information is what the military calls intelligence. It tends to be highly time, place and context dependent. Knowing that the traffic light is green is only useful information when approaching the junction that it controls. What decisions it makes possible will further depend on whether the approach is made in a vehicle or on foot.

2.4.4


Information as a measure of an agent’s ability to estimate a parameter Information is a measure of the correctness of an estimate of some parameter (i.e. the degree to which an estimation process is free from error). The more information we have the more certain we are that our estimate will be correct. This is the view of information developed by Ronald Fisher who laid the foundations of much of modern statistics. Given a set of measures of some phenomena, say weekly sales revenue, then we wish to estimate what revenue to expect in the future. It is assumed that there is some underlying trend which defines the value of the parameter θ and that each measurement involves some intrinsic noise x giving a data vector y = {y1, y2,…, yn} where y = θ+x. Some procedure is then applied to estimate the value of θ; this procedure is considered ‘smart’ if it is on average a better estimate of θ than any of the data values y. In general there will be many possible estimates all of which are correct ‘on average’; such estimates obey a relation e2I ≥ 1 called the Cramer–Rao inequality, where I is called the Fisher information (Frieden, 1998). As the error e is determined by the intrinsic noise of the phenomena (i.e. not the result of measurement error), I is a measure of the intrinsic uncertainty of the phenomena being measured. I increases as the quality of the estimation increases (and e decreases) so I measures the quality of the estimation process. This rather physical description might seem at odds with the previous discussions, but simply put it means that the better we are at estimating the outcome of some process the more information we have about it, literally

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63

the better informed we are and so the better able we are to choose an appropriate course of action. All of the above definitions of information concern an agent interacting with the world or part of it, and what that agent can know about the state of the world. The first two are concerned with measuring the capacity of a channel or a set of symbols to convey information in some way, while the second two are more concerned with the meaning associated with the information. This brief tour of information started from a general measure of possible states to specific choices in actual states. Activity 2.3

2.5

Define data, information, knowledge and wisdom. Discuss whether each word becomes more difficult to define along the meaning continuum. Describe what is meant by the term ‘channel capacity’ in information theory. Discuss what is meant by ‘information as a measure of variety’? Can information be encapsulated?

■ Data and knowledge We know that information exists whenever we detect the possibility of variation, but that information becomes data only when an underlying set is determined and actual instances of members of that set are recorded. Given a source of variation in matter-energy we have a source of information that can be assigned to an unlimited number of underlying sets. Consider a stream of binary values: each actual bit in the stream is a member of the set {0,1}, while each consecutive pair of bits is a member of the set {00,01,10,11} etc. There is an unlimited number of ways in which we could treat the stream to produce data values. When it comes to using that information to make choices between alternatives then some ways of turning it into data and some information streams are more useful than others. To know the more useful streams and sets for a particular system of interest is to know that system. To be able to identify and name them is to know about the system. To determine that some thing represents a datum presumes that it has first been established what underlying set it is an example of. For a system to be observed and data collected some knowledge of that system must be presumed. That is, to collect data from a system some sort of theory of that system must exist which specifies what is to be observed and how it is to be categorized. The philosopher Karl Popper has argued this point very well in his words ‘All observations are theory-impregnated. There is no pure, disinterested, theory-free observation.’ (Popper, 1995) New meaning and new understanding come about through the critical evaluation of theories and by measuring how well theory accords with experience.

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When we send a signal we transmit information. Regardless of whether or not the signal has any meaning for the recipient they will be able to recognize it as information. However, unless it has some meaning for them, they will not be particularly informed by it, although the very presence of information from a particular source, or at a particular time, might reduce their uncertainty about the world. An observer can notice variation and hence variety without any clear understanding of the underlying set or sets. For information to represent data then the underlying set, the data domain, must be determined. This point is particularly important with respect to mobile communications systems. Simply being able to receive a signal from different sources is not sufficient to support communication. It is important that both sender and receiver also agree upon some shared meaning. The symbols that make up a signal are often referred to as data, but this is only correct if the underlying set or sets is known. This is why Popper insists there can be no data without knowledge. To treat observations as data some assumption must have been made about the set to which that data belongs. Very often advances in our knowledge about some phenomenon come about when we view the information we have from observation as representing data based on a different set or sets.

2.6

■ Shared meaning When people contemplate the world, whether through private internal dialogue or through conversations with others, the mind’s eye continually shifts between different viewpoints or perspectives. These viewpoints can be labelled ‘inside looking out’, ‘outside looking on’, ‘outside looking in’ and ‘outside looking at’. They develop naturally as we grow from an infant, unable to distinguish between self and other, to a totally differentiated state from which as mature adults we appreciate the distinctions between parts and wholes and the many networks of interconnected relationships that make up, and by which we define, our ‘reality’. Innovation often requires that we re-assess and re-order those relationships in order to adapt that shared meaning to accommodate the implications of the new technology. Typically this accommodation involves a redefinition of object and relations as generally perceived from these different perspectives. Table 2.1 identifies the main characteristics of the most common perspectives and highlights some of the ways we might need to re-think our world to accommodate emerging wireless innovations.

Shared meaning

65

Table 2.1 Common observer perspectives Perspective

Description

Inside looking out

This is a highly personal, ‘first person’ perspective, in which information is anything that helps the agent to make choices. It is also all the sources of perturbation and variety in their environment. While all of this can be detected in an information source, we pay attention only to the strange and unexpected. This is the perspective from which we need to consider Personal Area Networks (PANs) and environmentally aware devices that can interact with intelligent spaces and access location-based services. In particular it is important to appreciate that ‘location independence’ does not mean ‘context-free’ but quite the opposite.

Outside looking at

This is the ‘second person’ perspective, the standard face-to-face perspective when two people talk, each seeing the other as a whole – it is the communications perspective. It is also the perspective from which we perceive things as wholes – as complete identities. This is the perspective from which to consider two personal mobile devices interacting peer-to-peer. Just as two people meeting for the first time need to perform greeting rituals where they introduce each other before they can have meaningful conversations, so to do their mobile devices. Similarly, just as individuals remember each other so that on subsequent meeting the introductions are quicker, the same should be true for their mobile devices.

Outside looking in

This is an impersonal, ‘reductionist’ perspective where the third person – ‘objective observer’ – analyzes the subject into component parts. Information is seen as flowing between these components, communicating and controlling the behaviour of the whole. It is from this perspective that we see a mobile phone as made up of a transceiver unit, a memory unit, a keyboard, a display and a microphone and speaker set. These have traditionally been bundled together into a single device but PANs make this unnecessary so that a PDA can be used as a screen and keyboard and the headset works with the phone and the CD music player.

Outside looking on

This is an impersonal reductionist perspective where a subject is considered as a component part in a larger whole. They receive information from other parts, process it and pass it on. This is the perspective from which we assemble our new devices to provide a variety of capabilities old and new. It is the networking perspective from which we form new objects by linking disparate nodes together to provide capabilities and services. In this perspective mobile devices are components that form PANs, which in turn form components in local and wide area networks.

Activity 2.4

Consider a town centre in which the adoption of wireless mobile technology is being considered and look at it from the point of view of the following users: (1) a pedestrian; (2) a motorist; (3) a town planner; and (4) an organization planning to open a new superstore. For each user try to adapt each of the perspectives described in Table 2.1 and, within these, list what they would consider to be the most important aspects of the proposal. How might mobile device and wireless networks change things?

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2.7

■ Communication and information theory All communications systems can be considered to contain the same basic set of elements (see Figure 2.3). An information source is translated into a signal and transmitted through a channel, in which it is subject to noise and distortion, to a receiver; the receiver attempts to recover the original message from the signal received from the channel and translates it into a form appropriate for its intended recipient. This is the schema discussed by Shannon (1948) in his landmark paper on communication systems.

Information Source

Transmitter

Receiver

Signal

Destination

Received Signal

Noise Source

Figure 2.3 A schematic of a general communication system from Shannon (1948)

2.7.1


Source The originator of a communication – the agent with something to say – is called the source. The source might be a person or a computer program or a machine. In spoken communication the source is the speaker. The information source produces a message or sequence of messages to be communicated. Clocks and calendars are message sources, as are sensors and any observable phenomena that we can arrange to encode.

2.7.2


Transmitter A transmitter is a device that converts the signal from the source into a signal that can be carried by the channel. When we speak the transmitter is our voice box – throat and mouth. Very often a transmitter performs a number of transformations of the source signal in sequence. In a (wire-based) telephone a microphone converts speech into electrical signals that are then transmitted along a telephone wire. A radio transmitter converts the source into electrical signals via a microphone and then into modulations of radio amplitudes or frequencies.

Communication and information theory

2.7.3

67


Channel A channel is a means of carrying a signal through some medium. When we speak the medium is air and the channel is sound waves. A particular medium might have many different channels; radio frequencies represent a particular medium with each frequency representing a different channel. Different channels in the same medium can carry different signals at the same time without interference, while passing different signals through the same channel at the same time typically leads to the destruction of the information in both. Television channels are an example of the former while Ethernet is an example of the latter. Suitable media for communications systems include: copper wire, glass fibres, laser light, infrared wave, radio waves, and microwaves.

2.7.4


Noise It is not possible to transmit a signal through any channel with complete fidelity each and every time. In the early days of telephone and wireless communication development much attention was given to eliminating noise in the channel. This research eventually showed that the complete elimination of noise was not possible and that, beyond a certain level of fidelity, the cost of noise reduction becomes prohibitive. This increasing cost means that there comes a point when it is more cost-effective to detect and correct errors than it is to avoid them in the first place. Noise is anything that makes it hard for the receiver to be certain exactly what was sent. A bad photocopy or fax contains noise if it is hard to read; bad handwriting is ‘noisy’.

2.7.5


Receiver A receiver is a device that converts the signal from the channel into a form that can be understood at the destination. When we are spoken to the receivers are our ears, which convert the sound waves into electrical impulses in the brain that we associate with words. The receiver performs the inverse operation to the transmitter. If the transmitter needed to perform a number of different transformations to create the transmitted signal then the receiver will typically need to go through a similar set of inverse transformations to recover the original message. So a radio receiver will receive a modulated radio wave and convert this into electrical pulses that are then passed through an electrical speaker to produce sound waves.

2.7.6


Destination The agent or agents that the source intends to communicate with is called the destination. In spoken communication the destination is the listener. It is typical in conversation for the source and destination to alternate

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between the two parties – two-way, one-to-one communication. You should not fall into the trap of assuming that this is the only form of communication that this model applies to – it works equally well for one-to-many ‘broadcast’ situations. When communication is two-way, the transmitter and receiver are frequently combined into a single unit called a transceiver (Figure 2.4).

Source

Transmitter

Receiver

Destination

Destination

Receiver

Transmitter

Source

Agent Alice

Transceiver

Transceiver

Agent Bob

Figure 2.4 Two agent communication via transceivers

2.7.7


Channels and transportation To transport a signal from one point to another there must be some physical link or chain of links between the two points that forms a channel for the message to pass between the source and the destination. The transmitter must code the message from the source into a form that can be carried by the channel. If the channel between source and destination consists of more than one type of medium then devices are needed to receive the message from one medium and translate it into a suitable form for transmission in another. If there is more than one possible destination that a message could go to, then the particular destination needs to be specified with the message and the network needs some means of routing the message to the appropriate target. These basic aspects of a communication network are not new.

Case study 2.1

Political messaging A senator in ancient Rome who wishes to communicate with a general somewhere in Gaul entrusts a secret (coded) message to a messenger and orders him to deliver it to the general. From the point of view of the general and the senator the channel is simply the messenger, but that messenger might need to use a variety of different means of transport to get to his destination. Although he walks away from the senator and delivers it personally to the general on foot, he might have used a cart, a boat, a horse, and a barge (for him and his horse) in the course of delivering the message. While in some ways the situation today has changed dramatically from that of ancient Rome, in other ways it is exactly the same. When Milbank (The British Labour Party HQ in London) sends a pager text message to MPs electioneering around the country

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(something Milbank is famous for doing a lot of) it appears to the source that they type a text message on a screen and to the destinations that they receive a text message on a screen, but the actual transportation of the message will have taken many forms. The single message will be converted to separate messages addressed to each MP on the address list then sent first via Ethernet to a router, via glass fibre to a radio transmitter, via digital radio to a satellite, and then again as radio frequency to various ground stations, via a variety of different cabling to more radio transmitters and then to each final destination. Of course the routing of the message is a lot more complicated than this makes it sound because the messages are not sent as a single item on their separate journeys but are broken up into small packets, each sent separately to the destination and often taking vastly different routes. Messages swarm across networks rather than slither down a fixed channel. This provides opportunities to balance the load on the network and optimize available capacity provided that the transmission rate is sufficient to ensure an acceptable quality of service. While there is considerable convergence between the capabilities of different types of communication network there is no convergence on any particular medium or channel type; in fact the variety of both medium types and the transmission methods on them continues to grow as engineers seek to optimize services in different environments and cope with increasing demands for speed, bandwidth and security. The technological developments that most affect mobile communications are those leading to the implementation, across a wide variety of bearer network types, of a basic set of voice and data ‘transceiving’ capabilities – as well as common global standards for wireless communications.

Activity 2.5

2.8

Within information theory who, or what are the ‘source’ and the ‘transmitter’? Who or what are the ‘receiver’ and the ‘destination’? Explain how the basic components of communication inter-connect and relate to one another within a networked environment. Could the ideas conceptualized in the case study be transferred to other environments apart from the political one?

■ Telecommunications and networks For most of the 20th century, telecommunication was concerned with real-time voice transmission, which networks utilized the latest technology to optimize. Towards the end of the 20th century, particularly in the 1990s, data networks started to dominate network traffic with computer-to-computer communication exceeding person-to-person in a context of considerable growth in both voice and data traffic. The growth in the public use of the

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Internet, largely through public telephone networks, has seen the emphasis placed on voice by these networks slowly decline. Telecommunications systems of all types have been undergoing considerable changes, with traditional voice-oriented networks becoming much more data centric, and data networks becoming capable of handling voice. Although mobile commerce naturally concentrates on new developments in wireless networking, it is also important to appreciate its dependence on developments in traditional fixed access point networks, particularly with respect to the development of Universal Personal Communications and associated Intelligent Network services. Any wireless network contains a mixture of wired and wireless channels. Ericsson, the telecommunications infrastructure giant, sees a fundamental shift taking place in the way in which telecommunications networks will be operated and used in the future with users divided into three main service groups: private persons, companies and communities (see Figure 2.5).

Operations Private persons

Companies

Communities

Telecommunications services

Teleservices Terminals and local networks Bearer services PSTN

PLMN

X.25

Frame relay

Figure 2.5 Overview of telecommunications and networks

All the bearer services will be ‘packet switching’3 and equally capable of handling voices, data and multimedia. In the traditional view (see Figure 2.6) networks offered their subscribers a choice between different bundles of services. Competition between networks was limited often to a single

3

Packet switching is a mode of operation in a data communications network whereby messages to be transmitted are first transformed into a number of smaller, self-contained messages known as packets. Packets are stored at packet-switched exchanges and are reassembled into a complete message at the destination.

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71

provider who owned the infrastructure in the subscriber’s location and access to that network was via a single specialist device.

Network

Services

has

have

subscribers

Figure 2.6 Traditional view of telecommunications and networks

In the future it is anticipated that users will have a variety of different devices and rent appropriate services via a network service provider who will undertake to provide those services over a range of networks. This is illustrated in Figure 2.7.

Services

users

have

Network have

Figure 2.7 New approach to telecommunications and networks

There is a wide variety of different media suitable for carrying communication channels, but they can all be classified broadly as either bound, such as copper wire and glass fibre, or unbound, such as radio frequency or infrared frequency. While the location independent nature of mobile commerce might on the face of things point to the overriding importance of wireless communication for its realization, wireless transmission is only one of a number of transportation media that are needed for effective delivery of messages. Without a fast, high quality, bound media infrastructure for data communications, wireless systems would not be effective, and the alwaysavailable information portals services needed for effective mobile commerce would not be deliverable.

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Activity 2.6

2.9

Describe the ‘new’ approach to networking and discuss its components. Why is it anticipated that in the future ‘network users’ will use a variety of different devices and rent appropriate services via a service provider who will undertake to provide those services over a range of networks? What are the consequences of this multinetwork provision of services?

■ Media types in telecommunications There are a variety of types of construction for bound media that are effective in carrying communication signals, and for each there are a number of methods for encoding signals and transmitting them through the media.

2.9.1


Bound media By far the most common form of bound medium is copper wire with some form of electrical signal forming the channel. To use electrical signals a circuit must be completed between the transmitter and receiver, so two wires are actually needed. Electrical signals generate electromagnetic fields when propagated along wires and this can lead to noise in the signal. Wires can be constructed in ways which minimize this problem; typical solutions are coaxial cable, twisted-pair and shielded twisted-pair. Electrical signals are quite effective over short distances, but they deteriorate the further they need to travel as the resistance of the wire weakens the signal and noise inevitably creeps in. Long-distance, copper wire media need to be filtered to remove noise and amplified to boost the signal at regular intervals.

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73

Fibre optic is a popular alternative medium that uses light to provide a channel. Various methods of light modulation can be used to create a signal. Light is not subject to interference the way that electricity is, and it can travel much further without the need for filtering or amplification. However, connecting fibre optic cables is much more expensive; they are delicate, need to be carefully housed, and great care is needed with introducing bends. On the other hand fibre optics can carry many more signals simultaneously than copper wire. Typically any extensive communications network will incorporate a variety of media types including copper wire and fibre optic as well as microwaves and radio satellites which are forms of unbound media.

2.9.2


Unbound media Unbound media all use a particular section of the electromagnetic spectrum such as light, radio waves, infrared and microwaves. While radio waves are by far the most prevalent, and becoming ever more so with developments in mobile telephony, other wavelengths also have an important role. Infrared waves are used in a variety of devices to provide low power, short-range control and data transfers. Infrared is widely used in household remote control devices where actual data transfer is minimal and one-way. Its more data-intensive uses include transferring files between PDAs, or between PDAs or laptop computers and mobile phones, or as a means for transferring data between PDAs and desktop PCs. Infrared is also used for creating static PANs, e.g. providing wireless mouse and keyboard connections to PC or interactive TV digital decoders. Infrared is only effective over short distances (less than 5 m) in direct line of sight; usually the receiver needs to be within a 30° line of sight cone of the transmitter. Laser light can be used to communicate effectively over very long distances in direct line of sight or using mirrors. The laser light is coherent, there is very little signal degradation over very long distances, and it can be directed to a specific point; however, the signal cannot penetrate mist or dust or smoke particles and so is of limited use where such atmospheric conditions prevail. However, it can be very effective where they do not, such as between satellites in outer space, in tunnels and in voids in large buildings. Microwaves operate in a similar fashion to light; although they cannot penetrate solid structures and transceivers must be arranged in line of sight they are not affected by clouds or dust and can be used effectively in the atmosphere. Telecommunications infrastructures make extensive use of microwaves relays; like light, microwaves are directed and can be aimed at their specific target. Unlike light and microwaves, radio waves radiate in all directions from their transmitter and they can penetrate many solid objects such as walls and floors. Although radio frequency (RF) offers many advantages it does pose some conceptual problems when thinking about networks. There are no connections as such, nor any clearly definable boundary. Devices can join and leave a network at any time, and the shape of the network can change dynamically as devices move about. This poses additional security concerns as any suitably enabled device could join a network. It is also harder

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to protect a wireless network from interference. Not all stations on a mobile network are necessarily capable of communicating directly with all others; each is restricted to those whose radius of effective communication intersects with their own. Both the size of this effective radius and the rate at which data can be propagated between different devices can change as the positions of devices and the state of the environment change. In general reliable connection between mobile devices using RF connections is best mediated by a fixed network with RF access points supplied by base stations that provide coverage of a geographical area. However, highly mobile ad hoc networks offer exciting new possibilities, particularly with respect to PANs linking together devices as and when they enter a user’s Personal Operating Space (POS). Fixed-access RF base stations offering global coverage is the strategy being pursued by 3G mobile telecommunications initiatives that will supply wide area wireless network capabilities. Wireless local area networks such as IEEE 802.11 and HiperLAN2 offer both fixed access point and ad hoc connection simultaneously, while PAN technologies such as Bluetooth and the other IEEE 802.15 varieties are ad hoc although potentially any member of a Bluetooth piconet4 can communicate with any other member even if they are not directly connected. Bluetooth and PANs are discussed in more detail in Chapter 6.

Activity 2.7

Different media have different advantages and disadvantages. Consider how many different ways you might arrange for the following types of communication to take place. (1) Sending E-mail from an airport or train station. (2) Using Instant Messaging (IM) with a group while in a shopping centre. (3) Connecting retail outlets throughout a country for interactive training. Try to think of several alternative ways of achieving each outcome. What problems might each approach encounter? Search the Internet to discover more information on PANs. How do these differ from other types of network infrastructure? 4

A piconet consists of between two and eight Bluetooth devices where one device takes the master role and the other devices fill a slave role. A pico means 1 trillionth or 10–12 but is used here just to mean small.

Modulation and digitization

2.10

■ Modulation and digitization

2.10.1


Modulation

75

Modulation is a term used to describe a means of encoding a signal on an electromagnetic wave. The two most common and familiar forms are from the radio dial – Amplitude Modulation (AM) and Frequency Modulation (FM).

Carrier wave

Message

Amplitude Modulation

Frequency Modulation

Figure 2.8 Modulation

Each works by modification of a carrier wave, see Figure 2.8. In AM the transmitter converts the variations in the message code into variations in the amplitude of the carrier wave and the receiver converts these variations in amplitude back to the original message. In FM modulation the transmitter encodes the message by varying the carrier wave frequency and the receiver recovers the message by reversing the process. FM is less likely to be distorted but can only effectively encode the message if the carrier frequency is very high. It requires more power than AM, has a shorter effective range, and is more susceptible to interference from other FM signals.

2.10.2


Digitization Both AM and FM can be used to encode digital signals, but they each require at least one complete cycle to encode a single bit. Phase modulation enables more than one bit to be encoded in a single cycle.

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The phase of a wave is the point in time at which its peaks and troughs occur. Figure 2.9 shows two versions of the same wave whose phase differs by about 90°.

Figure 2.9 Waves with different phases

By changing the phase of a carrier wave by a fixed amount, digital signals can be encoded (see Figure 2.10). It is quite straightforward for the receiver to detect by how much a wave’s phase has been shifted.

180 Phase shift

90 Phase shift

180 Phase shift

Figure 2.10 Phase modulation

The transmitter takes a group of bits at a time, calculates their value, and then shifts the phase to correspond to that value.

2.11

■ Communications network infrastructures A network is a collection of transceiver ‘nodes’ connected by one or more communications channels.5 Two nodes are part of the same network if they can (in principle) each send signals to and receive signals from each other. That is, a common medium that supports at least one channel of communication or an unbroken chain of such channels with appropriate translation points connects them both. An effective mobile commerce strategy is one capable of using to advantage a combination of network types depending on prevailing circumstances. The greater the level of channel redundancy the more robust the communications system will be. An ideal situation is one where the engineer has available

5

The term network is used here to generally describe the interconnection of computers and both fixed and mobile devices by communications channels.

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77

redundancy in both the available media and the available channels within them. Messages can then be delivered using the most effective means appropriate to their importance. Various dimensions can measure the importance of a message: time, cost, fidelity and necessity. The importance of a message can be measured in terms of the following: (a) Necessity. How important is it that the message is received? (b) Time. How important is it to deliver the message quickly? (c) Cost. How important is it to minimize the cost? (d) Fidelity. How important is it that the message is undistorted? A communications network is a technology that enables many agents to talk to each other simultaneously on a one-to-one and a one-to-many basis; communication can be either one-way or two-way; and, if two-way, then either synchronous or asynchronous. There are a growing number of technologies that support communications networking. Until recently these technologies were highly specialized, dealing in some particular mode of communication for a particular type of agent, e.g. one-to-one, two-way, synchronous, person-to-person as in the fixed-line telephone and one-to-many, one-way as in television. Particular technologies have been developed to meet specific needs; however, they all need to overcome the same basic set of problems. As lessons have been learnt and new more effective technologies have been developed, the different approaches have started to converge both in terms of the functionality they offer and the underlying mechanisms they use to deliver that functionality. So interactive TV requires two-way, synchronous communication, telephony now supports conference calls, and mobile phones have asynchronous SMS – i.e. ‘text message’ – capabilities, and they are all looking to packetswitching, digital technologies as the basic delivery mechanism. This convergence is not likely to lead to a single ‘grand unified network,’ but rather to a mesh of complementary networks, each using the same logical communications but with different physical realizations and each offering the same suite of services. Some will be preferred over others for particular types of communication, but all will be adequate at a pinch. The consistency of this mesh will be by no means uniform. Different combinations of types of network will overlap in different geographical areas with many more alternatives existing in metropolitan areas, particularly in business parks and office complexes, and some specialist networks only existing where the particular physical or business environment warrants them. The networks making up this mesh will be a mixture of wired and wireless carriers, but all will be digital, thus greatly simplifying information sharing. Wired networks are conveniently categorized by the distances they are designed to cover into global networks, including Wide Area Networks (WANs) and Local Area Networks (LANs). Other types of specific wired-network in existence include the Public Switched Telephone Network (PSTN), and the Packet Switched Data Network (PSDN). Wireless networks can be

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characterized by the effective range of their transceiver technology into Wireless Wide Area Networks, including Wireless Local Area Networks (WLANs) and Wireless Personal Area Networks (WPANs). Traditional ‘wired’ networks such as the national and international telephone networks often include many wireless channels such as microwave and satellite relays. Similarly, wireless networks employ traditional wired networks to transfer data between network cells. It is the channel at point of delivery and the consequent freedoms and constraints imposed on the user that determine the characterization of these services as wired or wireless. It is nevertheless a very important distinction that says a lot about the capabilities and constraints of network client devices. In particular, on wired network there is generally little difference in transmission speed capabilities between client and server devices. In contrast, there is typically considerable asymmetry between the transmission capabilities of wireless base stations and mobile user transceivers, with the latter being highly dependent on limited battery power. This asymmetry is familiar from traditional broadcast networks such as radio and television where a small number of high-power transmitter agents communicate with a large number of low-powered receiver agents. It is typical in such power asymmetries to distinguish between downstream – message flows from high power transmitters to low power receivers – and upstream – message flows from low power transmitters to high power receivers. Standards, such as the IMT 20006 3G mobile phone standard, often distinguish between upstream and downstream when specifying minimum capability levels; it is important to keep this in mind when planning and designing mobile network applications because it is often only the higher downstream rates that are quoted. For instance, a typical broadband cable connection will supply 512 mbps downstream and 128 mbps upstream. Chapter 3 goes into greater detail on the history and evolution of wireless cellular telecommunication networks. Activity 2.8

Define what is meant by a ‘network’ (i.e. describe the term ‘node’). Discuss the role of time, necessity, cost and fidelity in measuring the importance of a message. Discuss the issue of ‘power asymmetries’ and distinguish between downstream message flows and upstream message flows. Search the Internet for information on IMT 2000. To what extent is this an international standard? Do all countries in the world use the same radio frequency spectrum?

6

Third Generation Telecommunications Networks (3G) are synonymous with the International Mobile Telecommunications 2000 standard (IMT 2000). IMT 2000 was an attempt to harmonize 3G networks and provide a base for standardization. The 2 GHz band was chosen for IMT 2000 networks in 1992 (although the USA uses other spectra as well).

Types of channel

2.12

79

■ Types of channel The terms baseband and broadband distinguish between types of channel. In baseband networks there is a single channel that must be shared by each agent on the network. The main engineering challenge with baseband is to ensure equality of use between the agents (no one agent must be allowed to hog the band) and to handle conflicts that can occur when two agents attempt to access the band at the same time. In broadband networks the cable carries multiple channels simultaneously. Broadcast and cable TV are familiar examples of broadband systems, but these are increasingly being used to carry multiple, non-continuous content as well.

2.12.1


Circuit switching This is a method of communications whereby a continuous path is first established by switching (i.e. making connections) and is then used for the duration of the transmissions. Circuit switching is used in telephone networks and a number of digital data networks. In a circuit switching network, every time a user device attempts to connect another device on the network the network must establish a circuit between the two devices. Traditionally this role is performed by an exchange; if the receiving device is connected to the same exchange then the line from the transmitting device is plugged in to the line to the receiving device. In early exchanges this task was performed by the operator who literally plugged a wire into two sockets corresponding to caller and called and created a circuit; if the destination was not at the local exchange then the operator had to make a trunk call to first establish a circuit with another exchange. In modern systems this is all accomplished using electronic switches, and very often the cables are broadband carrying many signals simultaneously, but there is still effectively a dedicated circuit established between the two devices for the duration of the call. For voice transmissions this is an extremely inefficient system because the greater part of any person-to-person conversation is composed of pauses so that resources spend a lot of time carrying no data. Even when data files are exchanged more time is actually taken up with low-level control traffic than with actual high-density data traffic.

2.12.2


Packet switching Packet-switching networks break a message up into short segments called ‘packets’. Each packet is individually addressed and may take an independent path from transmitter to receiver. This method makes more effective use of the available channels, thus enabling better balance of network load, but it makes the transmission process more complicated because packets can arrive out of order and have to be reassembled, and it needs to be determined whether a given packet is simply late or if it has been lost and needs to be retransmitted. Lost packets can severely affect the message transmission

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rate, but the occasional lost packet can be ignored for voice, audio and video transmissions without significant loss. An example is Code Division Multiple Access (CDMA). This is a type of digital cellular network where calls are split into packets and the packets are tagged with identifying codes. There are two main implementations of CDMA technology. These are cdma2000 in the USA and Wideband CDMA in Europe, Japan and other parts of South East Asia. CDMA technology makes very good use of spectrum, creating three times the capacity of TDMA7 networks.

2.12.3


Protocols and protocol stacks Protocols and standards are closely linked but distinct concepts. A standard is a minimal set of requirements necessary to ensure some minimum level of service. It will typically define normal operation of a service and require that the timeliness, transparency, reliability and other properties of the service or system be measured according to particular methods and fall within stated ranges. For instance the International Telecommunication Union (ITU) specifies in their IMT 2000 standard for 3G mobile telecommunications three data transmission rates depending on whether the transceiver is stationary (moving at less than 10 km/h), moving in an urban environment (less than 120 km/h), or fully mobile (greater than 120 km/h). A standard does not say how these requirements should be realized in practice.

Did you know? The specified data rates for IMT 2000 networks are 384 kbps for pedestrians and mobile users in vehicles travelling up to 120 km/hour in urban environments, 144 kbps for mobile users in vehicles travelling over 120 km/hour in rural environments, and 2 Mbps for services to stationary devices.

A protocol is an agreement between two or more parties about how they should conduct themselves to ensure that some agreed standard is met. The protocol is not concerned with meeting the performance requirements of a standard as such, but with removing ambiguity so that both parties understand and use the same structure and order of operations. Protocols define grammar so that all parties communicating using a particular protocol share the same meaning for the parts of the communication. Essentially a communication protocol is an agreement about the symbol set and the rules of grammar that define ‘well-formed’ expressions. Both standards and protocols tend to come in sets with different varieties being designed to suit different communication requirements, e.g. where communication is one-way or two-way, synchronous or asynchronous, voice or data, etc. 7

Time Division Multiple Access (TDMA) networks are digital cellular networks in which calls are sliced into time periods and interleaved with others on the same channel.

The International Standards Organization reference model

81

While some devices are more specialized than others, nearly all offer a variety of modes of communication and therefore need to select the appropriate protocol to deliver each requested service. Often different services will use a mixture of protocols some of which are the same and some different, e.g. a mobile phone uses telephone numbers to specify the destination address for both voice and short text message calls but uses different, lower level protocols to encode them and the same protocol to physically transmit them over the channel. In general, communication over a network is more complicated than between two devices connected via a common channel. Two devices connected to a network might have quite different characteristics, such as ways of representing data. Depending on the type of communication, they might simply send out messages or require confirmation that they have been received; messages might be broadcast to all other nodes on the network, multicast to a select few or sent to a specific address, which might be on the same local network segment as the sender or at the end of a long chain of different types of network. A network therefore requires a large number of different types of protocols for dealing efficiently and effectively with these different requirements. This makes networks very complex and confusing things for an application programmer to deal with. Some relief can be gained by collecting the different protocols together into logical clusters depending on which protocols rely on which others. Activity 2.9

2.13

Define the terms ‘baseband’ and ‘broadband’. Describe the differences and similarities between circuit switching and packet switching. Describe the use and role of CDMA within a packet-switching, digital, cellular network. What role do protocols and protocol stacks play within the networking environment?

■ The International Standards Organization reference model The International Standards Organization (ISO) has developed a sevenlayer reference model for Open Systems Interconnection variously referred to as the OSI reference model or just the OSI model (see Figure 2.11). It was the original assumption that all new network implementations would aspire to reflect the model with clear distinction for each level. This has not proved to be the case in practice, partly because the distinctions between some of the layers are more theoretical than real. This is particularly true at the higher level layers which are implemented in software either as operating system level services or even stand-alone applications. At the lower levels where implementation is increasingly more hardware-specific, the layers have increasing definition and the data link layer is often divided into distinct sub-layers. Despite these limitations the model has persisted because it is an extremely useful pedagogic device that facilitates discussion of the important issues even amongst experienced network engineers.

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Most of the distinctions that are discussed in this chapter are prominently located at the data link and physical layers enabling a variety of network types to operate over a diversity of media. However many 2G and 2.5G mobile networks have peculiarities that require special handling at higher level layers and the Wireless Application Protocol (WAP) set has been specifically designed to cope with these peculiarities. There is a detailed discussion of the WAP and the mobile wireless Internet in the next chapter. Each layer of the OSI model can be considered to be a combined transmitter and receiver unit in our standard communications model, with the layer above fulfilling the roles of source and destination and the layer below taking the role of channel. Two agents communicating using an OSI-compliant protocol stack can be logically considered as communicating on a virtual channel at any level of the stack. However, it is only the bottom two layers, data link and physical, that actually count as transceivers in the Shannon Model; the other layers are essentially grammatical and concerned with giving various meanings to parts of the message that enable the network system to handle its effective delivery, making sure that all of a message is delivered to the right address without any errors. Search the Internet for information on ‘The International Standards Organization’. What are the main aims and objectives of the ISO?

Application Presentation Session Transport Network Data link Physical The seven layers of the OSI reference model

Figure 2.11 OSI reference model

Distinctions between the layers in the OSI model are theoretical and may not always be justified in practical implementations, particularly at the higher Session, Presentation and Application levels. However, most differences between actual networks and the model arise because the protocol is

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83

older than the OSI model. Associated with each layer are a number of protocols that provide services associated with that layer that can be called upon by the layer above. Each layer-one device is logically linked to the same layer of the device with which it is in communication (see Figure 2.12).

Application

Application

Presentation

Presentation

Session

Session

Transport

Transport

Network

Network

Data link

Data link

Physical

Physical

Figure 2.12 Logical links between layers of the reference model

Each layer represents a set of important tasks that the layer above might require to be carried out. Often a particular implementation of a protocol stack will offer alternative protocols at the different layers, allowing layers above to choose according to the requirements of a particular task. For instance the Internet protocol stack known as TCP/IP (see Section 2.14 for details) offers both reliable, connection-oriented TCP and unreliable, connectionless User Datagram Protocol (UDP) transfer methods at the network layer. Data file transfers require the reliability of TCP and so the overhead of additional co-ordination in message passing which it entails is worthwhile; audio broadcast can cope with the occasional lost packet and can handle a data stream more efficiently in a connectionless mode.

2.13.1


Application layer The application layer provides services to applications running on a computer or other device that requires access to the network. It provides a highlevel interface between the applications and the services provided by the various protocols further down the stack. There are also a number of specialist network applications that can be used as stand-alone programs or to supply operating system services at this level. Some of the more well known are the Dynamic Host Configuration Protocol (DHCP), Trivial File Transfer Protocol (TFTP), Domain Name System (DNS), Network File System (NFS)

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and Routing Information Protocol (RIP). Although logically positioned at the application layer, typically they also encapsulate proprietary presentation layer and session layer functionality. In general the separation in functionality between the top three layers is largely theoretical and not found in practice. However, they are useful for appreciating the different tasks that need to be accomplished.

2.13.2


Presentation layer The presentation layer deals with any syntactical differences between applications on the two communicating devices, providing translation services where necessary. Very often this is not an issue and requests pass straight through this layer to the session layer below. But if for instance a text file is to be transferred between a PC using ASCII8 and a mainframe system using EBCDIC9, then the presentation level handles the translation so that the text that appears to the user of one system is the same as that on the other despite the different local encoding schemes. The presentation layer might also be used for encryption/decryption and compression/decompression of files. The translation is a two-phase process. The network system defines a transfer syntax and each application maintains an abstract syntax – which is its native syntax on that machine. The sending machine translates from its abstract to the transfer syntax and the receiving system transfers from the transfer syntax to its abstract syntax. If translation services are requested then a negotiation between the two systems first takes place to determine which presentation context is to be used. The transmitting system sends information about the transfer contexts it can use for its abstract context and the receiving system chooses one that it can best use to perform the translation into its own abstract context.

2.13.3


Session layer Session layer functionality is most commonly bundled into specific applications along with presentation layer functionality. As the name implies, functionality at this layer is concerned with establishing, maintaining and terminating connections between networked devices. The session layer is a little confusing, partly because the original OSI model was constructed from two competing models, and this is the layer where most compromise was

8

American Standard Code for Information Interchange (ASCII) is a standard computer code in which eight binary ‘bits’ are used to describe alphanumeric characters within a computer.

9

Extended Binary Coded Decimal Interchange Code (EBCDIC) is an eight-bit transmission code for the exchange of data between items of equipment.

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85

needed. It contains 22 different services with a certain amount of overlap in some areas. These services provide application programmers with a toolkit for managing dialogue between devices. The two most important services in the session layer are dialogue control and dialogue separation. Dialogue control is concerned with all aspects of message transmission from establishing a connection to sending messages and terminating the connection after ensuring that each system has received all of its messages. Dialogue separation was introduced to enable systems to recover a dialog after a systems failure without having to start again from the beginning. As networks have become more reliable, it is now less important on wired networks than it was when the OSI was developed; however, it still has an important role for wireless networks, particularly when operating in difficult conditions. Essentially it involves creating checkpoints in the transfer process so that everything up to that point can be saved to permanent store and an interrupted process can be restarted from the last checkpoint. This is something that must be explicitly implemented by an application developer, but it might be an effort well worth making for applications that need to operate in highly dynamic mobile environments such as a user travelling on a train in a built-up, industrialized area.

2.13.4


Transport layer The transport layer offers a variety of services that provide varying levels of assurance and associated operational overhead. Its services include such things as packet acknowledgement, guaranteed delivery, flow control, and end-to-end error checking. Transport layer protocols are closely linked to particular network layers protocols. Application, presentation and session layers provide application programmers with a toolkit of services. The data link and physical layer provide a uniform set of services over a variety of physical media. The transport and network layers work together to provide a complementary set of services suitable for a particular network application. The transport layer provides two basic types of protocol, connection-oriented and connectionless; network layer protocols are also connection-oriented or connectionless; and any particular type at the transport layer can be mapped to either type at the network layer, depending on the type of service required. The various combinations allow for error recovery, multiplexing, connectionless and full connection-oriented service. For full connectionoriented services the transport layer provides services to ensure segmentation and reassembly with appropriate retransmission of lost or corrupt packets. Flow control enables a receiving system to tell the transmitter to reduce the speed of transmission so that it is not overwhelmed which might result in a loss of data. The transport layer also provides error detection and recovery on the whole message and can request packets to be sent again.

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2.13.5


Network layer The network layer is primarily concerned with getting messages received from the transport layer to their final destination. It takes the messages passed down by the transport layer, packages them into datagrams, and adds a header to each one. This address will be particular to the network protocol and will need to be read by all the routers it passes through on its way. In fact routing is one of the main services provided by the network layer. Routers that it meets on the way might connect to different types of network segment, which requires the original datagram to be fragmented – for example, if a packet on a Token Ring network with a frame size of 4500 bytes passes to an Ethernet segment with a 1500 bytes frame size. Like the transport layer the network layer also provides connection-oriented and connectionless protocols. In a connection-oriented protocol the network layer establishes a connection with the destination machine before any part of the message is sent. Then during sending it waits for confirmation of the safe receipt of each packet or retransmits as appropriate. This type of connection guarantees full and proper delivery of the message at the cost of some overhead in additional messages and waiting time for confirmations. Connectionless transmission makes no checks and simply sends the data. Typically, network layer, connectionless transmissions are associated with a transport layer, connection-oriented protocol that uses guaranteed delivery and flow control making the network overhead unnecessary. LAN connections are usually connectionless.

2.13.6


Data link layer The data link layer contains a set of protocols for packaging the message up for transmission over the physical network providing local addressing, arbitrates access to the network and performs basic transmission packet error checks. While the network layer provides an envelope with the final destination address, the data link layer provides a second envelope which provides the address of the packet’s next stop on the local segment, so data link addresses are frequently rewritten as the packet is routed about the network. The layer uses a checksum to perform basic error checking on these local hops. The data link layer header also specifies the network layer protocol needed to process the data on the destination machine and to read the network address for routing. Apart from supplying header information and performing error checking, the data link layer is also responsible for controlling access to the physical medium known as Media Access Control (MAC). The mechanism for media access is closely linked to the most efficient use of the physical media, which determines such things as the size of the frames to be transmitted and the maximum length of a cable segment. Most wired networks utilize a baseband cable segment, use of which needs to be negotiated between all the devices on the segment. Efficient use

Transport Control Protocol/Internet Protocol (TCP/IP)

87

of the network requires that each device has the opportunity to transmit on a regular basis – messages are split into packets to prevent any one machine from monopolizing the network. The data link layer sends each packet as a separate message using any one of a number of control mechanisms. On wire-based local area networks two mechanisms predominate. Token Ring circulates a token between all devices on the network whenever a device is ready to transmit, it waits until the token arrives, captures it and sends a packet of data; it must then release the token before sending another packet. This is also the mechanism used by the fibre optic backbone standard. There is only ever one token (provided the network is operating properly) so there can be no possibility of a collision on a Token Ring network; however, the longer the segment and the more devices attached to it the slower the network becomes. The other main wired access mechanism is commonly known as Ethernet and uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD). The wireless form of Ethernet uses a similar mechanism called Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). Both these mechanisms are discussed more fully below.

2.13.7


Physical layer The physical layer, as its name implies, is concerned with the generation of codes on the physical medium that actually connects the systems in the network. Most of the differences between bound and unbound media networks are to be found at the physical and data link layers of the OSI model where the separation makes most sense. Beyond these layers the nature of the physical medium is encapsulated in a set of services that are common to all media types so that applications will operate seamlessly regardless of the underlying medium.

Activity 2.10 Outline the role and purpose of each layer of the OSI model. To what extent are these layers sequential? Discuss why logical layering in protocol design is a good thing to achieve. What are the advantages of logical protocol layering?

2.14

■ Transport Control Protocol/Internet Protocol (TCP/IP) The Transport Control Protocol (TCP) and Internet Protocol (IP) are just two out of a large family of protocols used on the Internet but they give their names to the whole integrated suite. TCP/IP makes two important contributions, as follows: (a) it is independent of the physical network; and (b) it assigns a unique universal network address to every device connected to it.

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TCP/IP defines both connection-oriented, reliable and connectionless, unreliable packet-switching data distribution mechanisms between these addresses. Although many of these protocols deal with data transfer and are concentrated at the network and transport layers of the OSI model, there are also several at the application and at the data link layer. TCP/IP is the family of protocols used on the Internet and has become a de facto industry standard widely used in many network settings. This dominance has been helped by the fact that the protocols are lightweight, eminently scalable (they allowed the Internet to grow) and are public domain. Figure 2.13 shows an overview of the relationship between OSI and TCP/IP. The TCP/IP family is not managed and developed by any of the traditional standards bodies such as IEEE or ISO but is publicly and democratically developed over the Internet by all and anybody that can and cares to contribute courtesy of the Internet Engineering Task Force (IETF).

OSI

TCP/IP

Application Application Presentation Session Transport Transport Network

Internet

Data link

Link

Physical

Figure 2.13 Correspondence between OSI and TCP/IP protocol stacks

The comparison between the two stacks is only approximate. TCP/IP does not define link layer functionality on LANs where the interface adaptor handles these functions, but it does supply a protocol Address Resolution Protocol (ARP) for resolving IP addresses into MAC addresses. It also supplies the two most common protocols for modem and other direct connections – Point-toPoint Protocol (PPP) and Serial Line Internet Protocol (SLIP). The IP is situated at the Internet layer and provides basic, connectionless, unreliable data packet transfer. The Internet layer also holds a system diagnostic and reporting protocol, the Internet Control Message Protocol (ICMP).

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89

The TCP and the UDP both operate at the transport layer. TCP is connection-oriented and reliable while UDP is connectionless and unreliable. An application chooses one or the other depending on its requirements and the services provided by other protocols higher up the stack. The TCP/IP transport layer also incorporates some but not all of the functionality to be found at the session layer of the OSI model. At the application layer many of the protocols such as File Transfer Protocol (FTP) are stand-alone applications, while others are simple mechanisms used by other applications to perform a specific service such as the DNS (Domain Name Service) and the Simple Mail Transfer Protocol (SMTP). A key feature of IP is that it assigns a unique address to every properly configured machine connected to the network. This address is independent of the hardware and guaranteed unique because it is assigned by a single authority. While PCs with network interface cards have unique Ethernet Token Ring addresses, many other computers are assigned names in an ad hoc fashion, and there is no way of guaranteeing that addresses are unique simply based on hardware or local configuration mechanisms. There are some limitations imposed by the current 48-bit size of the address – as more and more nodes are added to the network the number of available addresses (248) – is running out, but a new 128-bit alternative is in the pipeline which should be enough for every toaster and wireless surveillance camera, and indeed all other conceivable electronic devices in the world, to join the Internet without any chance of running out of addresses.

2.15

■ Communications network devices

2.15.1


Transceivers Any device that can transmit signals to and receive signals from the channel in the physical medium is a transceiver. Transceivers connect user devices such as telephones and computers to the network, but they are also an important component in most devices used to make networking and internetworking effective. The physical and data link layers or the OSI model cover transceiver operation. Network Interface Controller (NIC) is a common name for transceivers that connect computer and peripheral devices to a LAN. They typically embody the data link and physical layers of the OSI model.

2.15.2


Repeaters Repeaters as the name implies simply repeat the signal on a network cable, amplifying it so that the network can be extended to cover greater distances. Bridges, hubs, routers, switches and gateways typically have signal amplification built in and so are also repeaters.

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2.15.3


Bridges A bridge always connects two parts of the same type of network channel – just as a physical transport bridge always connects a road to a road and railway to a railway. Bridges amplify the signal like a repeater, but they also have packet-filtering capabilities – only packets that have business on the other side of the bridge (i.e. are addressed to a system that exists there) are passed over and amplified.

2.15.4


Hubs A hub is a multi-port repeater that forms the centre of a star topology. Each agent is connected to the hub by a single cable. When it receives a signal from an agent it propagates it to all the other machines. Typically it will also amplify the signal enabling it to travel longer distances without decay.

2.15.5


Routers Routers connect different LANs together to form an intranet or connect a LAN to a WAN, such as the Internet. A router has network layer functionality that enables it to read the network address of the packets it receives. Only packets for nodes on its network segment are passed on. Routers do not forward broadcast messages. Unlike a bridge, a router can link different types of network such as Ethernet and Token Ring.

2.15.6


Switches A switch is a combination of a sophisticated router and a multi-port bridge or hub; it is a relatively new device that paradoxically is logically similar to an old-fashioned circuit switch. The switch reads the network address of the destination machine and only transmits the message on the line with that address. So a switch system effectively eliminates the shared medium.

2.15.7


Gateways Gateways provide application layer interface between different types of network or between a network and a mainframe computer where high-level protocol translation is needed. However, the term ‘gateway’ is also frequently used as a synonym for router, particularly in MS Windows systems.

2.15.8


Wireless access points The most common form of wireless Access Point (AP) is a transceiver connected to a wired LAN component such as a PC or a router. The AP provides a gateway between a wired network such as a broadband cable Internet service and wireless enabled devices. Any device with a compatible transceiver can communicate with the access point if it is in range – typically 30 m in a normal building, further if in direct line of sight. Wireless APs act like servers (of fixed network services) to Mobile Terminals (MTs).

Network topologies

2.15.9

91


Mobile terminal An MT is any portable or mobile device fitted with a wireless transceiver. Portable devices are those that may be readily moved from one place to another but are generally used while stationary, such as a laptop computer. Mobile devices are used while on the move, for example PDAs. Depending on the standard the transceiver is based on, mobile terminals can connect to access points or other terminals or both, as and when they come into range.

Activity 2.11 Outline the role and purpose of each network device described previously. Explain how these network devices relate to one another in an integrated networking domain. Discuss the growth of MT devices and provide examples of current wireless mobile devices used in the leisure or work environment.

2.16

■ Network topologies Topology refers to the different ways in which the nodes are connected together to form a network. It applies particularly to bound media networks where the arrangement of the cabling variously constrains the possibilities for message flow, but it also applies to wireless networks.

2.16.1


Mesh Topology In a full mesh topology every node is directly connected to every other. With such an arrangement each node can always connect directly to any other node. For large numbers of nodes it is very expensive and hard to manage. Imagine if you had a separate telephone line coming into your home for each subscriber to your network! The mesh topology is largely theoretical, but network backbones and RF base stations seek to have a very high level of connectivity with areas frequently experiencing high traffic having a full or nearly full mesh topology.

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2.16.2


Bus topology A bus topology has each computer connected together by a single ‘daisychain’ cable – called the bus because signals are carried from one node to the next. When a device sends a message it travels from the transmitter in each direction for the entire length of the bus. The original Ethernet was designed to use a bus topology.

2.16.3


Star topology In a star topology each node is connected to a central node. Messages are propagated down to the central node and then back up to each machine. Most modern Ethernet installations use a star topology, although the signal is still propagated from one station to the next as if they were simply daisychained together. However, increasingly intelligent switches that know the address of the machines they connect are being used instead of simple hubs, making networks much more efficient.

2.16.4


Star bus This is a combination in which two or more star networks are daisy-chained together. Often the bus provides a high-speed, backbone connection such as fibre optical cable to create an internetworking solution between the different LANs in an organization. Specialist equipment is then needed to translate between the two media technologies.

Network topologies

2.16.5

93


Hierarchical star This is a combination of stars where some nodes on the star are other stars. This can result in quite large networks which, if intelligent switches are used for the hubs, can be extremely fast.

2.16.6


Ring A ring, as the name implies, is similar to a bus topology but the two ends are joined. The ring topology is entirely theoretical and not used by any network implementations. Token Ring networks use a star topology to implement a logical ring.

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2.16.7


Ad hoc wireless Wireless topologies do not follow the same easily distinguished geometrical relationships that are found with cabled media. Radio frequency transceivers transmit signals in all directions about their antenna. The signal can be received by any compatible transceiver whose antenna is in range. Effective range is 30 m for a wireless LAN such as IEEE 802.11 or HiperLAN2, both of which support the ad hoc topology. In the ad hoc topology there is no forwarding of messages from one transceiver to another. Only those devices that are in range of each other can communicate. So two devices might be part of the same network but not able to exchange messages. Ad hoc topologies are designed to be very dynamic with devices joining and leaving the network all the time, so they have no particular shape or boundary. Ad hoc topologies are very much peer-to-peer networks.

2.16.8


Infrastructure wireless Infrastructure wireless topologies have much in common with wired networks and typically have a wired network component with additional wireless access points to allow mobile devices to connect without the need for a docking station. The infrastructure topology is essentially a client–server network with a wired network providing services through its access points.

2.16.9


Piconet Bluetooth is designed to make use of a particular type of ad hoc topology called a piconet. While general ad hoc networks are peer-to-peer and the infrastructure topology is basically client–server, piconets use the master–slave paradigm. Any Bluetooth-enabled device can become the master of up to seven others in its range. The master–slave relationship is more democratic than the title implies; no device can be a master to another unless

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95

it agrees; and the arrangement is essentially an election to achieve a single control node to avoid a ‘too many cooks’ situation developing. A device that is a slave in one net can be a master in another, creating an extended network called a ‘scatternet’. A device cannot be master to its master’s slave or its master so avoiding deadly-embrace control loops. A typical use of a piconet is in a PAN when a user device such as a PDA can control (be master to) other devices in the user’s personal operating space. If one of those devices is a hi-fi system control unit that also controls its modules via Bluetooth links it would be a slave to the PDA and a master to the record deck. The flexibility inherent in the piconet idea presents many challenges for control and co-ordination and these are covered in greater detail in Chapter 6.

2.16.10


Network addresses An essential part of any network is the assigning of unique addresses to each node on the network. Network interface cards are manufactured with unique addresses for Ethernet and Token Ring networks. The IP assigns a unique name to every computer on the Internet using a 48-bit address divided into four levels of domain. Because of the huge growth in Internet access this very large number of possible addresses is starting to look inadequate. Plans to embed radio network chips in domestic appliances so that they can access the Internet to contact their manufacturers in order to download the latest software and report faults mean that demand for addresses is expected to soar and so plans are well advanced to extend the IP address to 128 bits, giving some 3.4 × 1038 possibilities. Given a world population of 10 billion or 109, 128 bits gives 3.4 × 1029 device addresses per person which should be enough for a little while. Of course another problem with addresses is that we have so many different ones: home and work IP address, home and work telephone, mobile telephone, fax, E-mail, etc. Plans are also under way to develop a single address or universal personal identity. In a mobile environment it is the user that a message needs to find not a particular network node.

Activity 2.12 Discuss and describe the main types of topology found within the networking domain. Which of these topologies predominates in the wireless environment? Describe the types of network that you use in your everyday life while connected to a computer. Search the Internet to discover more information on Bluetooth technology. This will prepare you for future chapters. How does Bluetooth integrate into wireless networks?

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2.17

■ Conclusions Commerce relies upon effective, that is to say efficient, affordable, accurate and timely communication. Business continually seeks out new technologies that increase capacity, reduce cost, increase reliability or improve the ability to deliver at the right time and in the right place. In the 16th century the telescope represented a major technological advance in business communication as did the development of the telegraph in the 19th century. The 19th century also saw the seeds of development in computing and wireless communications that led in the 20th century to a whole raft of technologies that started out very different and have slowly converged. The telephone, wireless and television all started out as analog technologies that operated in very different ways and required very different infrastructures, equipment and technologies. With the development of the computer and digital communications through wired networks, these very different technologies have slowly converged in a common concept of the digital packet of information. This allows traditional wireless media such as radio and television to be broadcast over wired media like the Internet, and traditional wire-based data transmission to be carried out point-to-point wirelessly. Much of the credit for this remarkable achievement must go to the vision of Claude Shannon and the clarity with which he has explained the essence of communication from an engineering perspective. The challenge for the 21st century is to achieve a similar level of clarity that ensures that meaning can be as effectively transmitted as information. The development of standards for a variety of suites of protocols has also greatly enhanced the effectiveness of communications and has been the chief enabler of the Internet and World Wide Web. Without agreement in the form of clear unambiguous public standards the opportunities for interoperability and the incentives to entrepreneurs to exploit them are very much reduced. Proprietary schemes restrict opportunities, slow growth and stifle innovation. If the new wireless networks are to experience the same levels of growth, development and associated prosperity that the Internet has witnessed they must be built on open systems standards. It is important to realize that neither the convergence of technologies to packet-switched, digital communications technologies nor the use of common protocols has in any way restricted the variety of network configurations, media types or device designs. In fact quite the opposite is true; given this common core of technologies and standards, invention is able to take off in many possible directions safe in the knowledge that as long as the new devices are compatible they will find a market. The particulars of the development of the telephone service to 3G are explored in Chapter 3. Chapter 5 looks in detail at some of the operating systems used by mobile devices. More detail on local and personal area networks is given in Chapter 6.

Conclusions

97

Short self-assessment questions 2.1

What are the main challenges to be met for effective communication at a distance?

2.2

How are communication and commerce related?

2.3

In the broadest terms what defines a language? What do we call the study of all languages that fit this definition?

2.4

What is a domain of discourse?

2.5

Explain the four different technical uses of the term ‘information’. How do these relate to the different perspectives we have of the world and our relationship to it?

2.6

What are the differences and what are the similarities between bound and unbound media?

2.7

Explain the different types of wave modulation.

2.8

Distinguish between the different types of communications network.

2.9

What is a protocol?

2.10

Explain the purpose of the ISO-OSI reference model.

2.11

Compare the TCP/IP suite of protocols with the ISO-OSI reference model.

2.12

Describe the main devices needed to implement a local area network.

2.13

Explain how the data link and physical layer of the ISO model separate hardware from software.

2.14

Describe the main wireless topologies.

2.15

Explain how a circuit-switched network works.

2.16

Explain the differences between bridges and gateways.

2.17

What is the IEEE 802 standard?

2.18

What is a piconet?

2.19

What is the difference between baseband and broadband?

2.20

Compare a star bus topology with a hierarchical star topology.

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Group activity

Wireless computing infrastructure: designs and considerations An extensive new retail and entertainment complex is being planned to rejuvenate the city centre in preparation for its planned hosting of a major world sporting event. It will consist of a number of themed complexes housing a variety of small, medium and large retail, catering and entertainment units linked by walkways through atriums and with an extensive waterfront section and outdoor arena. The centre will also offer extensive parking and provide bus, tram and light railway links. It is expected that the centre will receive many visitors from all over the world and will feature in many broadcasts during the sporting event. The mayor and the town council wish to make the best possible impression as a modern, technologically advanced city in order to attract tourists and business conferences in the future. Your group has been retained as consultants to advise the developers on the most appropriate communications infrastructure. You have been asked to address four main areas:

Required ■

personal communications

■

commercial communications

■

site navigation

■

security Present a group report detailing the different technological options and their usefulness and suitability for use in addressing each area.

■

References and Bibliography




Books

Ashby, W. R. (1956) An Introduction To Cybernetics. John Wiley and Son. ISBN: 0412056704 Burkhardt, J. et al. (2002) Pervasive Computing: Technology and Architecture of Mobile Internet Applications. Addison-Wesley. ISBN: 0201722151 Curry, H.B. (1977) Foundations of Mathematical Logic. Dover Publications. ISBN: 0486634620 Davenport, T.H. & Prusak, L. (2000) Working Knowledge: How Organizations Manage What they Know. Harvard Business School Press. ISBN: 1578513014 Frieden, B. Roy. (1998) Physics from Fisher Information: A Unification. Cambridge University Press. ISBN: 052163167X

References and biblography

99

May, P. (2001) Mobile Commerce: Opportunities, Applications and Technologies of Wireless Business. Cambridge University Press. ISBN: 052179756X Nelson, R. & Winter, S. (1990) An Evolutionary Theory of Economic Change. The Belknap Press of Harvard University Press. ISBN 0674272285 Popper, K. (1995) The Myth of the Framework: In Defence of Science and Rationality. Routledge, an imprint of Taylor & Francis Books Ltd. ISBN: 0415135559 Rogers, S. (1995) The Diffusion of Innovation. The Free Press. ISBN: 0029266718




Paper

Shannon, C. (1948) A mathematical theory of communication. The Bell Systems Technical Journal, 27, pp 379–423, 623–56. July, October 1948.




Technical references and other sources

Ericsson ‘Understanding Telecommunications’ http://www.ericsson.com/about/telecom/ International Organisation for Standards http://www.iso.org

Internet Engineering Task Force http://www.ietf.org.

Wireless protocols: context and usage

3

‘Only connect! That was the whole of her sermon. Only connect the prose and the passion, and both will be exalted, and human love will be seen at its highest.’ Howards End, by E.M. Forster (1879–1970)

Chapter Aims: ■ ■ ■

■ ■ ■

■ ■

To describe and explain the history, evolution and development of wireless, cellular phone systems and technologies. To outline and explain the development of the Wireless Applications Protocol (WAP) in Europe, and similar technologies in the USA and Asia. To provide an insight into the layered network architecture and systems infrastructure necessary to support WAP within the wireless telecommunications domain. To provide a comparison of WAP with traditional, wired network architecture models such as TCP/IP and the overarching OSI framework. To analyze the importance of WAP in supporting access to the Mobile Internet and provide a comparison with other wireless Internet services such as iMode. To provide a comparative analysis of WAP and iMode and develop an understanding of the various costing and billing models applied within the Mcommerce domain. To review and compare the characteristics and benefits of accessing the Mobile Internet from mobile phones and other portable, wireless mobile devices. To review future developments of WAP, iMode and similar Mobile Internet services and to provide an insight into the use of third generation (3G) broadband wireless technologies.

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History and Evolution of Wireless Cellular Phone Networks

Cellular Telecommunications Cellular Communications

FDMA

Evolutionary Paths

CDMA GSM Cellular Network Management

TDMA GPRS

UMTS

IMT-2000

Wireless Application Protocol (WAP)

The Mobile Internet

Wireless Operational Features

Mobile Internet Network Operators

Mobile Internet Products and Services WAP Architecture & Protocol Layering

Comparison of Wired and Wireless Network Protocols

WAP Functionality and Adaptation

A Case study of iModeTM

Service Bearer Adaptation WAP and iModeTM billing models

The Knowledge Context Map

cHTML & xHTML

Introduction

3.1

103

■ Introduction The previous chapter looked at the use of networks and communication protocols within the pervasive computing domain. Computer networking protocols define the steps necessary for computers to communicate with each other over networks, such as the Internet. This chapter extends the work of Chapter 2 by first providing an explanation of the historical development of wireless cellular networks, and second explaining the use and role of the WAP in specific detail. The WAP was first developed in 1997 and published in version 1 in May 1998. It is a broadly used and accepted protocol standard designed to enable different kinds of wireless devices to communicate and access the Internet. There are a number of wireless protocol standards, but WAP appears to be the approach adopted by the majority of wireless device producers and users within the mobile commerce domain at the end of the 20th century and the beginning of the 21st. The reasons for the wide usage of WAP are threefold, as follows. (a) WAP is an open specification standard that can be used by any individual or organization as no patents are established for the protocol. (b) WAP is supported by large mobile telecommunications organizations that manufacture mobile phones and provide wireless networks in Europe, the USA, Asia and many other parts of the world. (c) Commercial computing developers and manufacturers, such as IBM and Sun Systems in the USA, Nokia and Ericsson in Europe, and Mitsubishi in Japan have built a number of applications that utilize WAP. The WAP was managed and overseen by the WAP Forum (see Figure 3.1). This organization became the Open Mobile Alliance (OMA) in July 2002. The Open Mobile Alliance was established by the consolidation of the WAP Forum and the Open Mobile Architecture Initiative. The OMA comprises a group of companies and organizations, with a commitment to a shared set of principles, who have come together to drive the growth of the mobile industry. The mission of the OMA is to grow the market for the entire mobile industry by removing the barriers to global user adoption and by ensuring seamless application interoperability while allowing businesses to compete through innovation and differentiation (the OMA web site, 2002). The OMA is in effect a standards organization that includes all elements of the wireless value chain, and tries to contribute to timely and efficient introduction of wireless services and applications to the market. The OMA home page is shown in Figure 3.2. The central aim of OMA is to standardize the way mobile telephones, and other mobile devices, such as Personal Digital Assistants (PDAs) and smart phones, access information and data services, particularly linking the Internet to the mobile device community. The OMA supports the WAP standard and encourages its development. Hence, through the OMA, WAP continues to be a de facto standard in the mobile (wireless computing) world at the start of the 21st century. Whether WAP continues into the future as the de facto standard remains to be seen and will only be evident

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at the end of the first decade of the 21st century. Nevertheless, an appreciation of the wireless world requires an understanding of both WAP and the other comparative protocols within it. The main advantages of WAP are convenience, in terms of standardization, and availability, in terms of acceptance and usage. Any information held on the Internet, such as personal or business web pages, can also be provided in WAP accessible format. Many Internet Service Providers (ISPs) offering browser access to conventional web pages via a fixed-wire personal computer also provide access to abridged versions of web page information in WAP format. This is possible because many ISPs configure their web servers to respond to WAP information requests by storing WAP pages alongside conventional web pages on the same servers. In the same way that conventional web pages can be created using specific programming languages like HyperText Mark-up Language (HTML), WAP pages can be created by specific programming languages for wireless devices and technologies, such as the Wireless Mark-up Language (WML). The use of WML to present WAP-enabled data and information will be looked at in greater detail in Chapter 4. The use of WAP and WML in conjunction permits access to information on the Internet from suitable mobile devices where convenient and at any time and from any location. Later in this chapter, the importance of the Mobile Internet within the mobile commerce domain will be shown.

Figure 3.1 WAP Forum home page Source: http://www.mobeyforum.org/ Reproduced with permission. AOL browser window © 2003 America Online, Inc. Used with permission.

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105

Search the Internet to discover more information on the OMA. What are the main objectives of the Alliance? Who are the main members of the Alliance? How does the OMA support the WAP? (Provide example of how WAP is supported by the OMA.) Activity 3.1

Discuss and describe the use and purpose of WAP within the wireless world. What role does WAP play within the M-commerce world? What are the main benefits of possessing a WAP-enabled mobile phone? What services are available through WAP?

Figure 3.2 OMA home page Source: http://www.openmobilealliance.org. Open Mobile Alliance Ltd. AOL browser window © 2003 America Online, Inc. Used with permission.

3.2

■ Wireless cellular phone networks Wireless, cellular, mobile phone communication is the fastest growing field in the telecommunications industry. Wireless, cellular phone networks achieve mobile communication by transmitting data (e.g. voice telephony, pictures, video streaming and general digital data) via radio waves. Mobile phone voice telephony is not the only traffic within a cellular, wireless communications network. Wireless, cellular networks can host ‘paging’ (i.e. the antenna or satellite broadcasts short messages to subscribers alerted to a message via a bleeper, although messages are only one-way!) and access to the ‘Mobile Internet’ (i.e. on-the-move access to the Internet from a mobile device).

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Wireless radio-wave messages can be sent and received via static or mobile antennas or satellites. Antennas are normally Earth-bound devices, whilst satellites orbit the Earth in either stationary or non-stationary orbits. Communication satellites consist of large transponders that listen to a particular radio frequency, amplify the signal, and then rebroadcast it at another frequency. Antennas and satellites are the broadcasting devices of a telecommunications network. Wireless radio-wave networks are normally divided up into ‘cells’ – hence, the word ‘cellular’ when applied to wireless mobile phone networks. Each cell is serviced by one or more radio ‘transceivers’1 (i.e. receiver/transmitters). The cells are arranged so that each one uses a different radio frequency from its immediate neighbour. As a mobile device user moves around from one cell to another the ‘call’ is passed on to the frequency of the new cell. Radio-wave communication in a cellular network is ‘fullduplex’. This occurs when communication can be achieved by sending and receiving messages on two different frequencies, known as Frequency Division Duplexing (FDD). A cellular network topology allows frequency reuse by letting related cells reuse the same frequencies, which enables the efficient usage of limited radio resources. For example, cell size and transmission power are designed with reference to each other so that cell phone transmissions cannot travel far beyond the current cell. This allows the network to re-use the same small number of frequencies throughout the network (May, 2001). Full-duplex systems are more sophisticated than ‘half-duplex’ systems that rely on single frequencies for sending and receiving signals (e.g. mobile radio systems in ambulances and other emergency vehicles). A cellular network can itself be connected to other networks, such as a fixed-wired telephone network (e.g. the Public Switched Telephone Network – PSTN). Activity 3.2

3.2.1

Explain and define what is meant by a ‘cellular’ radio network? What is the main difference between a full-duplex and a half-duplex system?


History and development of cellular radio networks The development of wireless communication systems began in earnest in the 1930s. For instance, wireless ‘walkie-talkies’ were used during the Second World War (1939–1945) to enable troops in the field to communicate with one another by wireless means. A Canadian named Donald L. Hings is credited with developing the first military walkie-talkie for the Canadian Army in 1942.2 Donald L. Hings came up with many portable two-way radio designs, both before and during the Second World War. Pre-1939 designs included compact aircraft-mounted radios and portable voice sets. The earliest portable voice sets date back to 1937. 1 2

Radio transceivers are devices in the wireless telecommunications world that are both transmitters and receivers of radio waves. Donald L. Hings was awarded the Order of Canada medal from the Canadian Government for his research into wireless ‘walkie-talkies’.

Wireless cellular phone networks

107

Donald L. Hings. Inventor of one of the first portable and mobile wireless devices through his development of the military ‘walkie-talkie’ in the 1940s. Source: Courtesy of The Vancouver Sun/photograph by Glenn Baglo.

The war effort developed portable radios, units no longer restricted to a car, truck, or tank. Unlike in previous wars, the foot soldier could now carry a radio with him, communicating with headquarters, squad leaders, or other soldiers while moving about. The personal radio had arrived and it has never left. Before the Second World War most radio transmitters and receivers were big, bulky, and extremely heavy. Each piece could weigh 15 kilograms or more. They were so heavy that equipment collectors call these old radios ‘boat anchors.’ The first step to make a radio truly portable was to reduce size and weight. The Galvin Manufacturing Company, now Motorola, combined a receiver and transmitter into a single hand-held unit. They called it the Handie-Talkie. Weighing 2.3-kg, the Handie-Talkie had a range of 1.6 to 4.8 kilometers. This miniature marvel used five small vacuum tubes and put out one third of a watt. Motorola made 130,000 hand held units between 1941 and 1945. The SCR-536 was typical. Pulling out the antenna turned the radio on, pushing the antenna back in turned it off. While the 1943 Handie-Talkie somewhat resembles a large radio-telephone of today, it was Motorola’s backpack model, the Walkie-Talkie, that heralded a new era in personal, portable communications. (Tom Farley – TelecomWriting.com – American Personal Communications, from Walkie Talkie to Cell Phone)

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Wireless protocols: context and usage

Source: Confederate Memorial Hall. Copyright Dorling Kindersley.

The development of wireless radio communication was facilitated by the use of Frequency Modulation (FM), previously described in Chapter 2. Edwin Armstrong, who died in 1954, was a pioneer of FM radio communications. FM communication techniques, along with downsizing in electronics, made handheld wireless devices more convenient and effective. Early mobile devices were limited by size, weight and communication distance. For example, Motorola’s first commercial device designed by Daniel E. Noble and known as the SCR-300 weighed almost 16 kg and had an average range of 16–32 km. These early mobile communication devices used Amplitude Modulation (AM) rather than Frequency Modulation.3 In 1948 the ‘transistor’ was developed by AT&T in the USA. The transistor would dependably amplify and switch signals at lower power consumption rates within a wireless radio network. The transistor was a milestone in the development of radio communication.

Wireless cellular phone networks

109

Did you know? An American military officer named Colonel Edwin Armstrong pioneered vacuum tube technology and invented radio circuits that transformed the wireless communications industry in the second half of the 20th century.

The spread of wireless mobile devices from the military arena into the civilian and commercial world in the 1950s took place only on a small scale. One reason for this was the limited amount of available radio wave frequency spectrum. Governments around the world license the availability and use of radio spectrum. In the 1960s Motorola introduced a transistorized two-way radio (known to its users as ‘the brick’). Throughout the 1970s and 1980s mobile, handheld wireless phones became smaller and more convenient. In the 1970s digital technology began to replace analog technology within the wireless communications domain (i.e. digital telephone switches appeared in the 1970s). Much of this work on digital telephone communications was undertaken by Motorola’s research laboratories in the USA. Other parallel developments in digital communications were taking place elsewhere in Europe and Asia, particularly by Sony in Japan. Commercial cellular phone networks and devices really only took off in the 1980s although phone devices were still rather large and cumbersome. The mid-1990s saw mobile phones downsize to the extent that they became unobtrusive. The late 1990s saw the development of additional wireless mobile devices, such as PDAs and smart phones, that has led to the ‘digital mobile age’ and M-commerce. Activity 3.3

3.2.2

Outline the significant events in the history and development of portable, and mobile, wireless devices. What technological developments arose to enable wireless communication to be used in the civilian and commercial worlds? How does downsizing affect device portability?


Current and future cellular communication networks The first commercial cellular wireless networks, referred to in Chapter 1 as ‘first generation’ (1G) systems, used analog rather than digital technology. Common analog cellular networks include the Advanced Mobile Phone Service (AMPS) in the USA, and the Total Access Communication System (TACS) in the United Kingdom. Frequency Division Multiple Access (FDMA) was the original mobile phone, multiple access method employed by the 1G AMPS. This was an analog service and has since become known as the Narrowband Analog Mobile Phone Service (NAMPS). To provide the service, the region to be served is divided into a set of cells each served by a base station capable of serving a band of 1000 frequencies. Each time a phone in 3

FM communication is more efficient and less subject to interference than AM in its utilization of power sources from mobile devices.

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Wireless protocols: context and usage

a cell initiates a call it is assigned a frequency for the duration of that call. Similarly, if a phone in the cell receives a call it is assigned a frequency. This is logically equivalent to circuit switching but using frequencies rather than physical switches to make the connections. Although in theory a band of frequencies can be subdivided into countless slightly different frequencies, in practice devices vary about a frequency and there needs to be sufficient distance between separate channels to prevent interference. Different cells on the network can use the same frequency at the same time provided they do not overlap. FDMA was technically simple to implement but made poor use of available bandwidth. A frequency is allocated for the duration of the call and carries signals only from a single unit regardless of how little traffic is actually present. FDMA carried an analog signal only and could handle voice but not alternative forms of data. Did you know? The first car-based telephone system was set up in St Louis, Missouri, USA, in 1946. The system used a single channel radio transmitter on top of a tall building. It required a button to be pushed to talk, and released to listen. It operated in the manner of Citizens Band (CB) radio. Tanenbaum, 2002

First generation systems were essentially analog and employed FDMA. However, 2G systems were, and are, based on digital transmission. 2G systems use a variety of different technologies including Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA) and Personal Digital Cellular (PDC). In the USA, two standards are used for 2G systems: IS-95 (CDMA) and IS136 (D-AMPS). In Europe there is just one digital cellular network system called the Global System for Mobile communications (GSM).4 Japan uses a 2G system called PDC. The use of GSM as a single network approach has led to avoidance of the problem, witnessed in the USA, of network incompatibility in the early days of 2G networks. GSM is also the most widely used 2G digital network in the world. GSM is used by over 100 countries around the world at the start of the 21st century. Digital networks offer improvements in data and voice transmission (i.e. through the reduction of traffic ‘noise’ and interference) over analog systems. Voice and data traffic is clearer and also more secure over digital networks. Digital cellular networks operate mainly in the 800 Megahertz (MHz) radio spectrum band. The leading types of transmission techniques are CDMA and TDMA. The Japanese PDC network uses the TDMA transmission technique and operates in the 1500 MHz radio spectrum band. GSM also normally uses the TDMA transmission technique. GSM operates on the 1800 MHz and 900 MHz radio spectrum bands outside the United States of America and on 1900 MHz inside the United States of America (May, 2001). However, this is not a problem in the 21st century as many mobile phones and other mobile devices offer dual-band phone capabilities that allow phones to be used throughout the world (i.e. a comprehensive world-wide ‘roaming’ 4

The development of GSM was heavily backed by European governments through the European Union throughout the 1990s.

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capability). GSM technology supports WAP that provides access to the Mobile Internet. But access to the Mobile Internet is slow with GSM-supported WAP and screen dynamics is lacking. Therefore, a more advanced network technology arose, referred to as 2.5G and preceding 3G. 2.5G technology represents a state of development between 2G and 3G. Figure 3.3 indicates the evolutionary paths of wireless networks from 2G through to 3G. Generation two-and-a-half (2.5G) is in effect 2G devices with finely tuned increases in performance. For example, the basic data transmission rate for a GSM network is 9.6 kbps. (Some GSM networks have been modified to use an enhanced coding scheme that allows a data transmission rate of 14.4 kbps.) This narrow bandwidth limits the ability of GSM network phones (and other mobile devices) to quickly and efficiently transfer data, such as web links. However, 2.5G networks sometimes use High Speed Circuit Switched Data (HSCSD)5 to allow two 14.4 kbps channels to be used to provide a 28.8 kbps service. This 28.8 kbps service allows network operators to provide value-added services, such as wireless modems for laptops and Mobile Internet access from PDAs.

TDMA EDGE GSM

GPRS WCDMA

PDC CDMA2000 1XEV cdmaOne

CDMA2000 1X

2G

2.5G

3G

GSM = Global System for Mobile communication TDMA = Time Division Multiple Access CDMA = Code Division Multiple Access WCDMA = Wideband Code Division Multiple Access GPRS = General Packet Radio Service

Figure 3.3 The evolutionary path from 2G to 3G wireless technology

5

HSCSD was championed by Nokia in the late 1990s (although Ericsson and Siemens also supported HSCSD systems).

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Notes on CDMA and TDMA: Code Division Multiple Access (CDMA) works by dividing calls into fragments that are labelled and identified before being transmitted over several frequencies at the same time. The use of multiple frequencies reduces transmission interference. In CDMA systems all users use the same frequency at the same time, their signals being separated by a unique code. CDMA uses the same frequency in all cells, a situation referred to as frequency ‘reuse one’. A base narrow-band signal is multiplied by a spreading signal that has a higher rate than the message data rate. This spreading signal is a pseudo-random noise sequence – the resulting signal appears completely random, but a receiver with the right code can nullify the effects of the spreading signal and recover the original message. The most widely used version of CDMA is ‘CDMAone’ based on the IS-95 standard with nearly 100 million subscribers. Time Division Multiple Access (TDMA) works by allocating a time slot in a channel to each device on the network. Calls are divided (or ‘sliced’) into time periods on the same channel and transmitted. TDMA systems use the digital nature of the signal that divides the signal into packets each a few milliseconds long. A signal is allocated to a particular frequency for a short period of time and then is moved to another frequency. TDMA is the technology underlying the majority of 2G systems including those of North America, GSM in Europe and PDC in Japan. Both CDMA and TDMA allow multiple digital calls to be aggregated for transmission and disaggregated at the receiving end of the digital cellular network.

The main, interim 2.5G systems are based on either Cellular Digital Packet Data (CDPD) networks (mainly in the USA) or the General Packet Radio Service (GPRS) in Europe and many other parts of the world. Effectively CDPD is an enhancement to AMPS (analog) networks, and GPRS is an enhancement to GSM (digital) networks, primarily through its introduction of packet-switching behaviour to GSM networks. GPRS was marketed in the M-commerce world as a technology that was ‘always-on’ (i.e. always connected to the Internet or local business network and with no need to keep dialling for a connection). GPRS allows users to connect and stay connected to packet-switched data networks (e.g. IP and X.25). Interestingly, the introduction of GPRS extended the useful life of WAP well into the first decade of the 21st century. Another technology seen in the interim between 2G and 3G, known as Enhanced Data rate for GSM Evolution (EDGE), enhanced modulation over normal GSM networks (in expectation of 3G). EDGE was used to enhance basic TDMA systems in the 800 MHz, 900 MHz, 1800 MHz and 1900 MHz bandwidth range for the purpose of increasing kbps capacity. EDGE also provided enhanced connectivity to the Internet. 3G cellular systems will predominate over 2G systems by the end of the first decade of the 21st century (2001–2010). The International Telecommunication Union (ITU) has been undertaking research on 3G systems since the mid1980s. Their version has materialized with a 3G system called International

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Mobile Telecommunications – 2000 (IMT–2000). The European focus is on a 3G network infrastructure called the Universal Mobile Telephone System (UMTS). The specified characteristics of IMT–2000 are data transmission rates of 384 kbps for pedestrians and vehicles travelling at a speed of up to 120 km/hour in built-up city environments and 144 kbps for the same categories of mobile phone users travelling over 120 km/hour in rural environments. However, and significantly, the data transmission rate for traffic to stationary devices is 2 Mbps. This is a significant increase in capacity over normal GSM systems. 3G networks utilize Wideband Code Division Multiple Access (WCDMA). This separates into cdma2000 in the USA and WCDMA in Europe, Japan6 and other parts of the world. The aim of all 3G networks is to offer the following: (a) world-wide connectivity and ‘roaming’ (i.e. the ability to use a mobile phone in a country without network restrictions); (b) high data transmission capacity and rates for both circuit and packetswitched data; (c) efficient spectrum utilization. Activity 3.4

What are the main technologies underpinning 2G and 3G networks? Explain the significance of CDMA and TDMA and discuss the importance of ‘packet-switching’ within digital cellular networks. Search the Internet for references to the IMT–2000 standard and the UMTS standard. What is the aim and purpose of each of these 3G network standards?

3.2.3


Cellular radio networks A cellular network consists of both land base stations and orbiting satellites. The cellular network is normally composed of the following components (Walters and Kritzinger, 2000): (a) Mobile Station (MS) – a device used to communicate over the cellular network; (b) Base Station Transceiver (BST) – a transceiver used to transmit/receive signals; (c) Mobile Switching Centre (MSC) – sets up and maintains calls made over the network; (d) Base Station Controller (BSC) – controls communication between a group of BSTs and a single MSC; 6

The first 3G systems (utilizing WCDMA) were launched in Japan in 2001.

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(e) Public Switched Telephone Network (PSTN) – the land-based section of the network. Figure 3.4 illustrates the use of wireless ‘cells’ to form clusters of cells, each with a BST. The cells cover geographic regions. The more cells there are in a region, the greater the coverage by a mobile phone or other wireless device. Cells will deal with wireless data traffic (e.g. voice or digital data) from MSs in each cell (e.g. pedestrian mobile users or those using mobile devices in vehicles). Base Station Controllers (BSCs) are connected to MSCs. The MSCs in turn can be connected to the PSTN – or similar fixedwire telephone networks – and also to other mobile networks.

Cells are grouped together (in a ‘beehive’ lattice) to form a cluster Base Stations serve a ‘cell’

Base Station Transceiver (BST)

Mobile Station (MS) is a mobile device used to communicate over a cellular network Base Station Controller (BSC) Base Station Controller (BSC)

Public Switched Telephone Network (PSTN) – a land line service

Mobile Switching Centre (MSC)

Figure 3.4 A cellular wireless network

Cell clusters can vary in size from 4, 7, 12, to 21 cell clusters. Digital wireless communication within cells is through electromagnetic waves. Every base station transmitter covers a cell. Cells vary in size from a few hundred metres in a city (or urban environment) to over 10 km in rural areas that do not have large buildings interfering with the wave signals. Every cell can handle multiple channels. However, it should be noted that the hexagonal shape of the cells is for illustrative purposes only. Hexagonal shaped coverage is artificial and used only to illustrate and simplify the design of a cellular system. In reality the signal coverage overlaps in a looser shaped cell. The size of a cell is dependent upon the amount of usage. For example, more channels are needed in cities

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and urban areas than in rural areas. The ‘size’ of a cell can be altered by varying the power and sensitivity of the BST. In order to achieve mobility, a cellular wireless network must be able to track a subscriber (or mobile device user) to a specific location and allow calls and transmission to be made while on the move (e.g. in an automobile).

3.2.4


Cellular mobility management Locating mobile device users is an essential part of a cellular network’s tasks. It is necessary for the network to monitor the location of every registered mobile device user in order for the mobile station to connect to the subscribed network upon request. When a mobile station (or mobile device user) arrives in a cell, the device, when switched on, sends a message identifying itself to the BSC. The BSC sends this message to the MSC, which enters the identity of the mobile station in its Visiting Location Register (VLR). The MSC then notifies the server on the wireless service provider’s premise that it must update the Home Location Register (HLR) with the new information about the mobile station’s location. Mobility management consists of a distributed database (the VLR and HLR), and an associated protocol (known as the ‘mobility management layer’) to maintain location information for all the mobile stations on a network (Walters and Kritzinger, 2000). This is illustrated in Figure 3.5.

Cellular Network

Mobile Station (MS) (Mobile Device User) Base Station Transceiver (BST) Base Station Controller (BSC)

Mobile Switching Centre (MSC)

Public Switched Telephone Network (PSTN) – a land line service

VLR

Visiting Location Register HLR

Home Location Register

Figure 3.5 Cellular mobility management

Service Provider Server

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A query to the centralized HLR is all that is necessary to find the current location of a mobile device user. In order to keep the HLR current, a considerable amount of information is transmitted across the network. The HLR is updated every time a mobile station moves from one BSC’s area into another. Mobility management is also responsible for the authentication of mobile stations to the network. Mobile device users entering an MSC’s domain must be authenticated before they can use the wireless network’s resources. This ensures that only valid subscribers make use of the network (Walters and Kritzinger, 2000). Cellular networks must handle both voice traffic and other forms of digital data traffic, such as accessing the Internet on the move. A common 2.5G application for this purpose is WAP. It uses protocol layers, described in detail later on in this chapter, that provide security and enable the development of M-commerce applications related to the Internet. Activity 3.5

3.2.5

Describe the main components of a cellular wireless network. What relationship exists between a base station and an MSC? Why are cell ‘sizes’ smaller in urban areas than in rural areas? Explain the purpose of mobility management within a cellular network. What are the main functions of mobility management within a cellular network?


Wireless operational features There are various asymmetries in wireless networks between the power available to client and service systems. In Wide Area Networks (WANs), such as mobile phone systems, clients have extremely limited power compared with network-access base stations. In recognition of these differences, standards distinguish between ‘upstream’ – client-to-service communications – and ‘downstream’ – service-to-client communication. Table 3.1 outlines the main bandwidth features of wireless telecommunications.

Table 3.1 Telecommunications Frequencies – Power, Range and Data Rate Frequency

Designation

Abbreviation

Wavelength

3–30 kHz 30–300 kHz 300–3,000 kHz 3–30 MHz 30–300 MHz 300–3,000 MHz 3–30 GHz 30–300 GHz

Very Low Frequency Low Frequency Medium Frequency High Frequency (short wave) Very High Frequency Ultrahigh Frequency Superhigh Frequency Extremely High Frequency

VLF LF MF HF VHF UHF SHF EHF

100,000–10,000 m 10,000–1,000 m 1,000–100 m 100–10 m 10–1 m 1 m–10 cm 10–1 cm 1 cm–1 mm

kHz = kilohertz, or 1,000 Hz MHz = megahertz, or 1,000 kHz GHz = gigahertz, or 1,000 MHz

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The information transmission capacity of a wireless channel depends on the power of the transmitter and the range of the transmission. For a given power output the channel capacity decreases as the range is increased, due to the increased difficulty of distinguishing between codes as the signal becomes weaker. In mobile phone networks where there is a high level of ‘asymmetry’ between server and client systems, increasing the range by increasing the power of the client is difficult, due to the limitations of battery technology, and undesirable, due to health and safety considerations. Therefore, in order to increase data rates, new generation systems need to reduce the range that a signal must travel. This requires the building of many more base stations to support 3G services. Mobile telecommunications networks are only wireless between the user of the mobile device (client) and the nearest available base station (network). Base stations are connected to the core network using fast, highcapacity media (these media types were described in Chapter 2). Typically, the core network will connect the base stations in a mesh topology minimizing the path length between any two base stations and hence between any two users. Mobile telecommunication systems world-wide are in a state of continuous transition. Different progression routes from 2G to 3G need to be followed depending on the particular underlying technology used to implement the 2G system.

3.3

■ The Wireless Applications Protocol (WAP) WAP was a commonly accepted first standard for accessing data from the Internet. Therefore, it is an important knowledge prerequisite to understanding the architecture and telecommunications infrastructure necessary to support WAP applications within the mobile computing domain. In order for mobile commerce to be practical and useful it must be supported by robust and reliable wireless connectivity within computer-based systems infrastructures. Reliable access to mobile systems is critical to the implementation and support of mobile commerce. The characteristics of connectivity within the wireless domain are different from those that impact on fixed-wire computer systems. For example, display screens are necessarily small, in order to maintain portability, keyboards are rare in relation to mobile technology devices, memory is limited and, significantly, telecommunications bandwidths are limited and vary within the mobile domain. Therefore, applications and data have to adapt to each device and not the other way around. Standardized and commonly integrated mobile systems architectures are difficult to achieve within the information systems environment. One approach to building standardized and integrated mobile systems architectures is to employ open standards, rather than proprietary standards. Proprietary standards are those created, developed and patented by individuals or single organizations. The drawback of proprietary standards for

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effective mobile commerce is the fact that permission is needed from the owners or developers of such standards (or applications) and widespread usage of these is limited. The best approach to an integrated, accessible and easily maintainable mobile systems architecture is to build information systems using open standards in the computer software and telecommunications domains – for instance, the use of open standards like Java and XML in software development, in conjunction with the open WAP standard for wireless telecommunications. The use and application of such open standards in the software development domain is looked at in greater detail with regard to the development of WAP-readable WML pages in Chapter 4 of this book. The design and development of information systems architectures that incorporate wireless applications and devices are best achieved by integrating available open standards. Deploying open standards-based systems development provides flexibility and lower dependence on specialized expertise. This is particularly relevant within wireless networked systems because of the range of mobile devices available and the range of operating platforms utilized by mobile devices. Table 3.2 provides some evidence of the diversity of mobile devices and networks available. Table 3.2 Mobile Computing Devices and Networks Portable devices

Network protocols

Personal Digital Assistants (PDAs) PocketPC Smart phone Two-way pagers Web-enabled phone

802.11 Advanced Mobile Phone System (AMPS) Code Division Multiple Access (CDMA) Cellular Digital Packet Data (CDPD) Global System for Mobile Communications (GSM) Short Message Service (SMS) Time Division Multiple Access (TDMA)

PC web browser WAP phone

Common standards within the computing world have the advantage of allowing content and application developers to operate a single format delivered over multiple networks; and the market for mobile devices becomes greater with the removal of user fear that purchased devices will become redundant too quickly. Table 3.3 provides an overview of the different mobile device communication protocols and their properties within each generation of cellular technology.

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Table 3.3 Cellular Devices and Technologies by Generation of Development 1G

2G

Protocol Technology

2.5G

AMPS, C-Net GSM, TDMA, CDMA GPRS, HSCSD, EDGE Analog, circuit-switched Digital, circuit-switched Digital, circuit-switched or packet-switched Speech quality Poor High High Bandwidth Low Low Medium Security None Depending on protocol, High low to high

3G UMTS, WCDMA Digital, packet-switched High High High

Source: Pervasive Computing: Technology and Architecture of Mobile Internet Applications by Burkhardt/Honn/Hepper et al., © 2001. Reprinted by permission of Pearson Education, Inc., Upper Saddle River, NJ.

In developing networked computer systems that integrate both wireless telecommunications and various mobile devices and technologies, the following issues should be considered within the M-commerce domain: (a) standardization and compatibility (b) connectivity and bandwidth (c) mobile device independence (d) security. There are two main data communication relationships to consider within the wireless information systems environment. The first relationship is that between a fixed (or immobile) computer server and a mobile device, such as a mobile phone, PDA or laptop computer with an integrated, wireless modem. The second relationship is that between two mobile devices, such as mobile phone to mobile phone, or PDA to mobile phone. These relationships can be seen as modular connectivity. The connected modules are both physical, in terms of technologies and devices, and logical, in terms of protocols and applications. Such an object-oriented approach to the development of networked, wireless information systems architectures dovetails appropriately with the modularity of the WAP standard; the WAP standard consists of a suite of components including network protocols, an application browser mark-up language, scripting, telephony and security components. The modularity of the WAP standard aligns itself effectively to modular systems network architectures. It also fits nicely with object-based computer systems development theory and practice within business organizations. The latest WAP specification developments can be found continuously updated on the WAP Forum web site. The aim of mobile commerce is to allow traditional electronic commerce (E-commerce), based on fixed-wire connectivity, to align with mobile commerce (M-commerce) systems architectures. The WAP suite of architecture standards defines the nature and parameters of how computer-based systems communicate and deliver content and services to mobile devices over wireless networks. The underlying architecture is based

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on a client–server relationship. Applications and data are converted to travel between the server (sometimes referred to as the host computer) and the client (or mobile device) within the WAP environment. In order to test and write applications to be readable by WAP-enabled devices, WAP emulator software can be used on computers to simulate and test the actions of both WAP gateways and WAP-enabled mobile devices, such as mobile phones which are currently the main technology device utilizing WAP. A number of freely available WAP emulation software applications packages exist to simulate WAP effects. For example, the Nokia WAP emulator is available to download from the Nokia Forum web site. One of the most widely used free emulators is available from OpenWave.com. This web site also provides up-to-date information on product improvements and the latest mobile device applications. Figure 3.6 shows the underlying client–server relationship within the WAP systems architecture domain.

HTTP Web Server

WAP Gateway

WAP

HTTP

Formats: WML WML Script WML Bitmap

Mobile WAPenabled Device (e.g. mobile phone or PDA)

Computer WAP Emulator

Figure 3.6 Elementary client–server WAP architecture

The WAP protocol is primarily intended to allow Internet access for mobile devices, such as mobile phones, PDAs, smart phones and other portable, handheld devices. It accesses web sites (located on computers and computer servers) specifically designed and created for mobile wireless devices. These normally had inherent limitations in handling and presenting data because of miniature screen displays and narrow bandwidth limitations in 2G, although the user engagement experience improved with 2.5G and 3G technology. Within the WAP domain, files are normally located on a computer web server written in programming code that is WAP-readable, for example WML. This is a coding language similar to HTML – which is used to code traditional, PC-based web pages. WML Script refers to script files written in WML, and WML Bitmap refers to graphics files written in the WML format. WML is a long-standing and commonly accepted programming language used to create web content to be viewed on mobile devices, although there are other software applications that will be looked at in detail in Chapter 4. The WAP Forum is mainly responsible for the development and evolution of

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the WML specifications. Due to narrow bandwidth, low storage memory and small-screen constraints on mobile devices, normal web pages, with graphics and icons, cannot be viewed as effectively as normal web pages browsed on a personal computer. However, WML deals with these constraints by removing unnecessary graphics and pictures from web page content. But to survive in the longer term, WAP standards will change to accommodate more dynamic web content. In essence, WML is used in conjunction with WAP to deliver the content of the Internet in abridged format. Content can be viewed by portable mobile devices with in-built mini-browsers capable of reading WML pages. Figure 3.6 shows a simple WAP applications and networked environment. The web server and the WAP gateway are part of the ‘host’ (or server) side of the server–client relationship. The wireless mobile devices (e.g. mobile phones, PDAs, etc.) are part of the client domain in the client–server relationship. The web servers store the WAP-readable files. These servers may also host other files in different formats for other communications protocols, such as HTML files readable via the HyperText Transfer Protocol (HTTP). The WAP gateway is normally a computer that acts as a proxy server, residing between the web servers and the wireless mobile devices. A WAP gateway would normally receive a request from a wireless mobile device, commonly a WAP-enabled mobile phone, then translate the transmission request and forward it to the appropriate web server that was hosting the Internet content. The web server would then respond by sending the requested WML document (or page) back to the WAP gateway. The WAP gateway then analyzes and checks the WML page, sometimes known as parsing, to ensure correctness and compliance with WAP standards and sends the document (or page) back to the wireless mobile device. In order to understand the stages of how the WAP protocol works in practice, take the example of a WAP-enabled, wireless mobile phone user requesting an Internet page. The mobile phone user would scroll (on screen) the information categories available to be requested and select the category by pressing a key on the phone pad. The information categories usually have Uniform Resource Locator (URL) assignments (as do all web pages). The mobile phone then sends the URL request to a WAP gateway, using the WAP protocol. The WAP gateway then creates a traditional request for the specific URL, using the HTTP – see Figure 3.3 – and sends it to the web server hosting the Internet content. The HTTP request is then processed by the web server which will fetch the requested file and add an HTTP header to it, before returning the WML content to the WAP gateway. It should be noted that URLs may refer to a static WAP file or may use a Common Gateway Interface (CGI) script to create or translate pages into WAP/WML-readable content. The WAP gateway then verifies and checks the HTTP header and WML content and binary encodes the content for optimal use on the telecommunications network being used for transmission. It then sends a WAP response incorporating the WML content back to the mobile phone. In the final stage the mobile phone receives the WAP

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response and processes the WML page to display the requested information and content on screen via a screen-based mini-browser. Figure 3.7 outlines the high-level, client–server architecture operating within the WAP domain. The diagram also shows the sequence of steps necessary (from step 1 to step 4) to request information available on the Mobile Internet via a WAP-enabled mobile phone.

Client

Origin Server

Gateway

Encoded Request WAE User Agent

Request Encoders and Decoders

Encoded Response

Response (Content)

CGI Scripts etc.

Content

Figure 3.7 High-level client–server WAP architecture.

Activity 3.6

3.4

Describe the main purpose and role of the WAP. What function does a protocol play within a network? Describe the main components of the WAP suite of architecture standards. Why is a WAP network architecture described as a ‘client–server’? Explain the role of ‘gateways’ and ‘emulators’ within the WAP domain. Explain the relationship between WAP and the WML.

■ WAP architecture layers Having understood the mechanisms and processes for requesting Internet pages (and other content) using the WAP protocol within a client–server architecture, it is important to understand how WAP specifications are layered, in both the client and server side of the WAP communications protocol. The WAP protocol is embedded into WAP-enabled mobile devices on the client side and embedded into the computer infrastructure on the server side. The basic WAP architecture is logically layered. The WAP architecture standards encompass network protocols, security, and software applications environments. The logical layers rest on top of one another within the logical architecture model. The layers are dependent upon one another to provide services within the mobile wireless domain. The layers are embedded in both the server side technology and the client side technology so that the

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123

two parts can effectively communicate with one another in a wireless environment. The logical information systems layers, rather than the physical systems layers, of the WAP architecture model are shown in Figure 3.8. These layers reside as a ‘stack’ of protocols within the WAP domain.

WAP Layers:

Servers and

Wireless network channels

applications

(Communication and Transmission)

Devices (e.g. mobile phone)

Server Side

Client Side

Architecture

Architecture

Application Layer

WAE

WAE

Session Layer

WSP

WSP

Transaction Layer

WTP

WTP

Security Layer

WTLS

WTLS

Datagram Transport Layer

WDP

WDP

Network Bearers & Underlying Radio Technologies: Global System for Mobile Communications (GSM) General Packet Radio Service (GPRS) Code Division Multiple Access (CDMA) Cellular Digital Packet Data (CDPD) Universal Mobile Telecommunications System (UMTS) or G3 Key: WAE

Wireless Applications Environment

WSP

Wireless Session Protocol

WTP

Wireless Transaction Protocol

WTLS

Wireless Transport Layer Security

WDP

Wireless Datagram Protocol

Figure 3.8 WAP layers – The logical model

The use of layering is common in network protocol architectures. It provides for simplification in the network environment by separating the functions and actions into layers and assigning protocols to perform each layer’s tasks and activities. Protocol layering allows tasks to be more logically grouped. All of the WAP protocol layers acting together provide the methods and processes for communicating (and delivering) services and applications within networked, wireless environments. The following sections are a topdown analysis of the WAP protocol layers.

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Did you know? WAP is based on the International Organization for Standardization (OSI) model of layered network architectures.

3.4.1


The Wireless Application Environment (WAE) layer This is, in logical terms, the top layer of the WAP protocol. This is where the software applications for presenting information and running scripts reside (e.g. WML and WML Script). This layer interacts directly with the end-user (i.e. the mobile phone user or PDA user). At this top layer the end-user can access Internet URLs and use mini-screen web browsers on portable devices. The main function of the WAE layer is to provide an environment that allows various service providers and multiple operators to develop applications and services that can be rendered on a multiplicity of WAPenabled mobile devices and portable technologies. This layer defines the format of content (e.g. data formats, images, phone book records, etc.). The WAE layer also encompasses various software applications, such as the WML, which is similar to HTML but optimized for use on portable, handheld mobile devices, and WMLScript that is a software scripting language similar to Java. Other programming interfaces and telephony services, such as the Wireless Telephony Application (WTA), are also included at this level, with the main purpose of accessing the in-built voice and telecommunications functions of many mobile devices (e.g. those built into mobile phones and some PDAs).

3.4.2


The Wireless Session Protocol (WSP) layer This layer controls the server-to-client and client-to-server connections. The WSP layer supports the interface between the WAE layer above and the WTP layer below in the WAP protocol stack. This protocol layer further provides for the basic networking protocols used to support Internet browsing. This layer is concerned with the suspension and resumption of sessions (e.g. client pull or server push) for information sending and receipt over a network. A session is defined as the connection of two nodes on a network for the exchange of data or any live link between any two data devices. The following browsing functions are supported at the WSP layer: (a) HTTP/1.1 functionality (and wireless encoding); (b) protocol feature negotiation; (c) facility for data push (or server push) from the WAP server to the client device (e.g. mobile phone); (d) facility for long-lived sessions; (e) functionality for suspension and resumption of sessions.

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125

The suite of protocols within the WSP layer is optimized for low-bandwidth bearer networks. WSP is designed to allow a WAP proxy server to connect a WSP client (e.g. mobile phone or PDA) to a standard HTTP7 host server or computer (see Figure 3.3 for a visual explanation of the client–server architecture underpinning the WAP environment), thereby allowing an ordinary web server to publish content to WAP-enabled mobile devices. In addition to browsing, the WSP layer supports the WAE layer above by undertaking the following functions: (a) establishing the session between the WAP server and the WAP client (or user device); (b) terminating the session between the WAP server and the WAP client (or user device); (c) feature negotiation between the WAP client (i.e. user device) and the WAP server; (d) supporting compact encoding of information; (e) supporting simultaneous asynchronous transactions.

3.4.3


The Wireless Transaction Protocol (WTP) layer This layer deals with the request and response aspects of the WAP protocol. It is designed to be particularly efficient and well suited for dealing with devices with very little processing power and low bandwidths (like mobile phones and PDAs). Such limited-capability devices are sometimes referred to as ‘thin clients’. The WTP layer runs on top of a datagram service providing a transaction-based protocol. The term transaction set within computer networking refers to the formatted data that contains the information required by a receiving device to perform a transaction or operation. For example, in an Electronic Data Interchange (EDI) standard a transaction set is defined as having three sections – header, detail and summary – and comprises a predefined group of segments in each section. The WSP supports the wireless exchange of information between devices and applications. The WTP supports three classes of transaction service: (a) unreliable one-way requests (class 0); (b) reliable one-way requests (class 1); (c) reliable two-way request–reply transactions (class 2). The WTP also improves reliability of data transfer by ensuring that the number of network system ‘handshakes’ is kept to a minimum, and it supports 7

The HyperText Transfer Protocol (HTTP) is the basic protocol underlying the World Wide Web (WWW). It is a simple stateless request–response protocol.

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selective re-transmission of lost data packets and supports the flow control of packets. The WTP also supports asynchronous transactions and messagebased services.

3.4.4


The Wireless Transport Layer Security (WTLS) This layer provides the WAP security protocols. It ensures levels of privacy and user authentication. The WTLS is essentially based upon the computer industry standard known as the Transport Layer Security (TLS) protocol and complies with the Internet Protocol Standard Transport Layer Security. The WTLS protocol supports WAP over low (or narrow) bandwidth channels and has been optimized for low bandwidth and high latency transmission. The WTLS protocol provides the following: (a) data integrity (by ensuring that the transmitted data is unchanged and uncorrupted); (b) privacy (by ensuring that transmitted data is encrypted and cannot be understood by intermediate parties that may have intercepted the data stream); (c) authentication (by establishing the authenticity of the terminal or user device and the application server); (d) denial-of-service protection (by detecting and rejecting data that is not successfully verified). The WTLS protects the upper layers of the WAP protocol. It also protects against denial-of-service attacks that are not uncommon in Internet domains. The WTLS protocol is also of significant importance in securing confidence in M-commerce by users of WAP-enabled mobile devices. The aim of WTLS is to provide secure communication between devices and computer systems. High levels of security are essential to support various Mcommerce applications, such as the transferring of financial data (i.e. via credit card transactions) and the exchange of electronic business cards.

3.4.5


The Wireless Datagram Protocol (WDP) layer This is a transport layer protocol that offers a consistent service to the rest of the WAP layers (or stack), irrespective of the network bearer used. This layer deals with Internet Protocol (IP) network traffic and supports communication between the bearer services below the WDP layer and those above it. The WDP deals mainly with source and destination addresses. It is capable of interfacing with the upper layers in a variety of ways in order to execute an application. If the network bearer is an IP network, then the standard User Datagram Protocol (UDP) is used; if not then some additional form of adaptation is undertaken within the WDP layer of the WAP protocol. Like the

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other protocols in the WAP stack the WDP is designed to support narrowbandwidth applications and devices (i.e. thin clients). Did you know? A ‘datagram’ is a form and method of transmitting information across a communications network.

The datagram is normally broken up into sections and is transmitted in packets across the network. The WDP can support data-capable bearer services that are themselves supported by a variety of radio interfaces. It is an intelligent protocol as it maps itself on to and optimizes the specific parameters and characteristics of the bearer services. Thus the WDP layer is responsible for effective communication between physical devices or terminals. One of the aims and characteristics of the WDP is ‘bearer adaptation’, which means that the protocol hides the inherent differences between the various signalling and communications channel protocols used globally over wireless networks. Activity 3.7

3.5

Outline the logical layers of the WAP. Describe the main purpose and role of each layer in the WAP stack. What function does each layer play in ensuring standards of communication between a client and a server? Briefly explain the characteristic of ‘bearer adaptation’ within the WDP layer of the WAP stack.

■ WAP functionality and adaptation Bearer adaptation is that aspect of the WDP that maps it on to the bearer service. Therefore, WAP can be used to support a variety of radio technologies, including the following that we have discussed previously. (a) Global System for Mobile Communications (GSM). A very common standard in Europe, Australia and Asia. In the USA GSM operates at a different frequency. (b) General Packet Radio Service (GPRS). A more advanced (and enhanced) network that is offered in addition to GSM or as a replacement for GSM in the 2G domain. It provides for ‘continuous’ Internet accessibility. (c) Time Division Multiple Access (TDMA). This service is primarily used in the USA and is based on time division multiplexing that divides radio frequencies into time slots. (d) Code Division Multiple Access (CDMA). This is an old service, as previously discussed in this chapter, first developed by the military in the USA in the early 1940s and used mainly in the USA and Canada.

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(e) Advanced Mobile Phone System (AMPS). This is a fairly global service based on analog, rather than digital, communications infrastructures. (f) Integrated Digital Enhanced Network (IDEN). This service was developed by Motorola in the USA and is sometimes known as ‘iDEN’. (g) Personal Digital Cellular (PDC). This telecommunication service is widely used in Japan and provides both voice and data services. (h) Cellular Digital Packet Data (CDPD). This is a digital service used mainly in the USA and Canada. It uses frequency division multiplexing and utilizes free space in a voice network to transmit data. (i) Universal Mobile Telephony System (UMTS). This enhanced service provides broad bandwidth data capabilities that transformed the way the Internet can be viewed on mobile devices by allowing colour video streaming. Many commentators argue that WAP has little future in the 3G wireless world. But this may not be so! Given the variety of current (and expected future) bearer services, the WAP protocol stack has, by necessity, been designed with flexibility and adaptability in mind to allow WAP to map on to the variety of current (and future) wireless network bearers and their inherent bearer protocols. Given the variety of network bearers, outlined above, and the differences in coverage of network types across the globe, it is essential that the WDP layer within the WAP protocol does provide for current and future bearer adaptation. The WDP layer merely provides a datagram service that enables one end-point to send a data message to another end-point in a wireless network. However, the WDP in itself guarantees neither the reliability and security of the data nor the ordering and timeliness of its arrival at its destination. These higher level services are dealt with by the WAP protocols above the WDP layer. Within WAP the security, session and application layers above the WDP layer are, therefore, designed to function independently of the underlying wireless network, because the WDP layer permits these higher layer protocols to find a consistent interface with the variety of network types and bearer services. This is accomplished by adapting the WAP transport layer, or WDP layer, to the specific features of the network bearer. By keeping the transport layer interface and features consistent the WAP protocol enables interoperability between devices over different wireless network bearers. There are currently a large number of different 2.5G and 3G mobile phone technologies and networks. They all take a digital cellular approach to providing geographical coverage and use digital signals to encode voice,8 but they differ markedly in the way their services are implemented. The

8

It is the use of digital rather than analog encoding that primarily distinguishes 2G from 1G approaches.

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International Mobile Telecommunications 2000 (IMT–2000) defined a set of 3G standards for world-wide, mobile voice and data systems on which all the network providers are committed to converge. However, implementing this standard is expensive, as it requires many more base stations in order to achieve the high transmission rates. Therefore, most networks are looking at a staged migration path involving a 2.5G intermediate technology. In part, this is because of a need at the start of the 21st century to start to develop the data services and paths to revenue generation that 3G will eventually enable by the end of the first decade of the 21st century. Because of its adaptability and flexibility, WAP has been referred to as ‘an all-terrain vehicle’; it is flexible enough to deal with different network environments. WAP has been very effective in supporting transitionary 2.5G technologies and networks. The original differences in the 2G and 2.5G networking implementations required WAP to contain many specialist protocols at the higher levels of the OSI model in order to provide a uniform platform for IP services. Many of the original provisions of the WAP standard will become redundant as true 3G systems come on line at the end of the first decade of the 21st century. Nevertheless, WAP continues to be considered as a sort of all-terrain vehicle for mobile phone networks. Like allterrain vehicles in general, it can cope with a wide variety of different environments but is not ideally suited to, and tends to appear slow and cumbersome in, any one particular environment.

3.6

■ Service bearer adaptation As we have clearly mentioned, the WAP protocol is designed to support all of the different (a) bearer types, (b) bearer services and (c) bearer protocols within the wireless domain. If WAP were not as flexible as this, then the WAP protocol would not be as popular within the M-commerce world. The various bearer types (or networks) have been outlined previously. However, the different bearer services include circuit-switched data services, Short Messaging Services (SMS) – or ‘text messaging’ as this service is often colloquially referred to by many mobile phone users – and various other packet data services. Additional variety is provided in the wireless world by the existence of many different types of network protocols (known as bearer protocols) which are specific to a particular type of network infrastructure. In addition, it should be noted that the network infrastructures themselves are also, in many cases, associated with particular areas of the globe or a particular set of mobile device manufacturers or network operators. Wireless protocol standards are, therefore, designed to be flexible and adaptable to satisfy this variety. The issues of this variety of technology are as follows: (a) different network bearers provide different levels of reliability, error rate and latency;

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(b) some network bearers transmit data packets, whilst other bearers utilize fixed circuit techniques; (c) one network bearer may not provide all of the same services as another. Figure 3.9 provides an illustration of the relationship between the transport layer, specifically the WDP layer of the WAP environment, and the underlying radio technologies (or bearer types).

The WAP Stack WAE

Wireless Applications Environment

WSP

Wireless Session Protocol

WTP

Wireless Transaction Protocol

WTLS

Wireless Transport Layer Security

WDP

Wireless Datagram Protocol

GPRS GSM

CDMA

PDC Underlying Radio Technologies TDMA

Figure 3.9 WDP architecture relationship with underlying radio technologies

Activity 3.8

3.7

Explain why it is important that the WAP standard incorporates ideas of ‘adaptability’ and ‘flexibility’. Explain why WAP is sometimes referred to as ‘an all-terrain vehicle’. To what extent has WAP been effective in supporting transitionary 2.5G technologies and networks?

■ Comparison of wireless and wired network Internet protocols It should be noted that most of the WAP layers are symmetrical; this means that they operate on both the client (or device) side and the server side of the network infrastructure. It should also be noted that these layers constitute a logical model. The physical manifestation of these logical layers will vary

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according to the technology hardware and proprietary systems employed. The manner in which these layers interface with one another is entirely up to the systems developer and determined, to some extent, by the technology used. There are a number of advantages of layering which explain why it is one of the most utilized logical structures within communications protocols. The following outlines a number of advantages to layering: (a) layering supports the principle of separation and grouping of tasks; (b) layering distributes functionality to different parts of the network architecture; (c) layers can be changed and maintained independently without affecting the other layers (as long as the service interfaces between layers remain unchanged); (d) layering fits quite well with layered protocol principles used for the Internet and WWW environments. However, there is one significant disadvantage. In upgrading one abstracted layer in isolation from other layers, an element of inefficiency can be introduced when that layer (however much improved) is used in conjunction with other layers which have not been so upgraded or optimized. So far in this chapter we have covered the characteristics and content of the WAP. But how does this wireless protocol compare with wired networked protocols, particularly those used to service the Internet? Within the wired networked computing world there are a number of underlying protocol suites, for example: (a) Multi-Frequency (MF) (b) Signalling System 7 (SS7) (c) Asynchronous Transfer Mode (ATM) (d) Integrated Services Digital Network (ISDN) (e) Transmission Control Protocol/Internet Protocol (TCP/IP). The main and underlying wired networked protocol used to service Local Area Networks (LANs), and particularly the Internet, is the TCP/IP. The TCP/IP suite was first developed by the Advanced Research Project Agency (ARPA) that was a part of the USA Department of Defense in 1957. This led to the development of the ARPANet, which was the predecessor of the modern Internet.9 TCP/IP is a layered suite of protocols, many aspects of which are replicated in the WAP protocol. The objective of the TCP/IP protocol is to 9

A very interesting account of the historical development, and evolution, of the Internet can be found in a book entitled Where Wizards Stay up Late, the origins of the Internet, by Katie Hafner & Matthew Lyon, Touchstone Publishing (Simon and Schuster), 1998.

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provide effective interconnectivity between multiple devices from multiple vendors. The TCP/IP suite has four layers, as described in Chapter 2 of this book: (a) the application layer (b) the transport layer (c) the network (Internet) layer (d) the physical link (sub-net) layer. The main advantage of TCP/IP is that it provides for the integration of private and stand-alone networks that perform a variety of different tasks and functions. The TCP/IP allows these very different networks to communicate with one another within both a Local Area Network (LAN) environment and a Wide Area Network (WAN) environment. The TCP/IP provides for local and remote network compatibility and is therefore predominant in supporting the millions of global and individual systems within the Internet. The physical manifestation of the TCP/IP is a plethora of hosts and computer signal routers used to bring the Internet to life.

3.8

■ The integration of WAP and TCP/IP within the OSI architecture model The TCP/IP and WAP layers, detailed earlier, closely correspond to the layers described in the Open Systems Interconnection (OSI) model for computer networking architectures. The OSI model was created by the Organisation Internationale de Standards (OIS) – International Organization for Standardization – as an overarching (and standardized) computer networking model that serves as a framework for all telecommunications signalling protocols.10 The OSI model (described in Chapter 2) established the idea of separating network functions into defined tasks and functions within a layered, computer networked environment. The OSI model defines the process of communication within seven hierarchical layers. The following sections are a brief topdown analysis of the OSI model layers, in order to put into context the TCP/IP and WAP protocols that have been covered so far in this chapter. (a) The application layer. This top layer provides services to the users, network management and File Transfer Protocol (FTP) and various other end-user access services.

10

‘Signalling’ is the term normally used to describe the language by which electronic networks exchange data and communicate with one another over a remote, computer networked environment.

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(b) The presentation layer. This layer provides the functions of data transformation and allows for a standardized applications interface and communications service. Functions include text compression, reformatting and encryption. (c) The session layer. This layer establishes, manages and terminates communication connections (or sessions) between computer systems and applications. (d) The transport layer. This layer ensures reliable and accurate end-point to end-point data transfer. It also provides for channel flow control and error detection and recovery. (e) The network layer. This layer is responsible for establishing, maintaining and terminating connections. It connects and disconnects a computer from the data transmission and switching technologies and devices used to connect remote computer systems. (f) The data link layer. This layer provides for accurate and reliable data flow across a physical link. It is responsible for electronic message flow control and message synchronization. (g) The physical layer. This is the basic engineering layer. It deals with the transmission of asynchronous and digital signals (or bits) over a physical link. There are two approaches to imagining and understanding the nature of architecture layers. One approach is to look at the layering from the topdown, observing the end-user view of the system as he or she sees it on a computer screen or mobile device, then drilling down one’s imagination (layer by layer) to the bottom of the system (where the physical engineering and digital messages reside over a telecommunications network). The other approach is to view the system from the bottom-up, observing the system from the point of view of the back-end (engineering, signalling and hardware) of the system, then drilling up through the layers to the end-user perspective at the top of the system. This chapter has adopted the top-down view in terms of presenting the WAP, TCP/IP and OSI layers. However, the reader should also analyze the processes and stages of how a data signal is created at the bottom physical layer and the stages and transformations of that message as it goes up through the layers, being coded, de-coded and transformed, as it travels up through a layered network architecture. Table 3.4 provides a comparative view of TCP/IP and WAP within the logical layered framework of the OSI model. The layered protocols have been mapped on to one another to reveal the similarities of WAP layering (or ‘stacking’) in comparison with the TCP/IP model and the OSI model. Activity 3.9

With reference to Table 3.4 describe the relationship between OSI, TCP/IP and WAP. Outline the role and purpose of each of the seven layers of the OSI model and describe how these layers map on to WAP.

Application (& Services) Layer

Application Layer (7)

Network (Internet) Layer

Physical Link Layer

Network Layer (3)

Data Link Layer (2)

Physical Layer (1)

Transport Layer

Transport Layer (4)

Session Layer (5)

Presentation Layer (6)

TCP/IP

OSI

SMS USSD CSD IS-136 CDMA CDPD PDC-P

Transaction Layer: Wireless Transaction Protocol Layer Security Layer: Wireless Transaction Layer Security Datagram Transport Layer: Wireless Datagram Protocol Layer (UDP/IP) Network Bearer Types:

Application Layer: Wireless Application Environment Session Layer: Wireless Session Protocol

WAP

Table 3.4 Logical comparison of OSI with WAP and TCP/IP architecture models

WDP &

WTLS

WTP

WSP

WAE

Underlying Radio Services: GSM GPRS UMTS

OTHER SERVICES & APPLICATIONS

134 Wireless protocols: context and usage

The Mobile Internet

3.9

135

■ The Mobile Internet So far in this chapter WAP has been explained in terms of a technical, wireless telecommunications standard that is specifically designed to enable Internet pages, designed in mark-up languages such as WML, to be viewed on the small screens of mobile devices, specifically mobile phones. The whole purpose and goal of WAP is to enable portable mobile phone users to access data and information on the Internet. It is a relatively cheap exercise to purchase a WAP-enabled mobile phone. Even if the mobile phone is not WAPenabled, Mobile Internet access is still possible by purchasing a mobile phone and compatible PDA. The Mobile Internet is sometimes referred to as the ‘wireless Internet’. When the mobile phone and PDA are connected together (often via infrared data transfer) the user can access the Internet on the PDA and also send and receive E-mails anywhere and at any time. The mobile phone is used to dial up the Internet service provider and delivers content to the PDA. However, without an Internet-compatible PDA direct access to the Internet via a mobile phone – the Mobile Internet – is only possible via a WAP portal provider over a telecommunications network operator (e.g. BT in the United Kingdom, AT&T in the USA and J-Phone in Japan). The WAP portal provider is a company or organization that provides access to the content of the Mobile Internet. WAP portal providers play the same role as ISPs. They effectively provide a window (or portal) on the Mobile Internet.

3.9.1


Mobile Internet network operators Within the WAP architecture there are a number of commercial and noncommercial organizations (or entities) that are responsible for the various aspects of the WAP services environment, in a similar manner to the bodies that are involved in providing Internet services to normal PC-accessible Internet environments. For example, ISPs and the WWW content providers are various bodies that are an accepted and appreciated part of the Internet domain for PCs and laptops. Within the WAP Mobile Internet domain similar entities exist to deal with wireless communication and access to the Internet. These are as follows: (a) Content providers

Server side operators

(b) Network operators (known as ‘network bearers’)

Server side operators

(c) Service providers

Server side operators

(d) Wireless device users

Client side operators

However, there are a number of interesting differences between accessing the Internet from a PC (or laptop) and accessing and viewing the Mobile Internet from a mobile phone. The first interesting difference between the Internet accessible from a PC (or laptop) and the Internet accessible from a mobile phone is the quality of the screen image. PCs and laptops can handle multimedia data and

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information and display it in all its glorious Internet colour, sound and imagery. This is not the case with most mobile devices, particularly mobile phones, where the displayed content is normally abridged and text-based. Furthermore, Internet access and participation is available in ‘open access’ as any organization or individual can publish a web page with relatively little technical, or organizational, restriction. Web pages can be designed in various mark-up languages, the commonest being HTML, and immediately published on the web for anyone to access and view. This is not so openly possible with the Mobile Internet, where there exist a number of parameters and restrictions on the extent to which organizations and individuals can participate and engage with the Mobile Internet. These restrictions on full open access to the Mobile Internet are usually at the discretion of the WAP portal providers. Many WAP portal providers only have commercial relationships with a selective set of companies. Therefore, anyone using a specific WAP portal provider is limited to the information and data specified by the companies and organizations that have a business relationship with the WAP portal provider. This reduces the amount and nature of information available through a WAP portal provider. This restrictive imposition of a virtual boundary around specific information sources (and organizations that own the data, like specific banking organizations or retailers) is known in the M-commerce world as ‘garden walling’. Activity 3.10 Define what is meant by the Mobile Internet or, as it is sometimes known, the ‘wireless Internet’. What information and services are available over the Mobile Internet? What role do wireless network providers play in the Mobile Internet domain? How do wireless portal providers put a ‘garden wall’ around Mobile Internet information? Search the Internet to discover more information on wireless network providers in your country or region. What types of ‘products’ and services do they provide?

3.9.2




Wireless Internet portal providers The traditional definition of a ‘wireless portal’ is a doorway, or entrance, to the Internet. Anyone can establish a wireless portal. The portal acts as a window onto other sites on the Internet. Some portals are garden walled, whilst others allow free access to any point of information on the Internet. Wireless portal providers are aggregators, providing access to wireless web services, such as browsing information content, E-mail, and ‘text-messaging’. Most wireless portals are commercial ventures, but many others are merely value-added services provided to existing PC-based customers and clients. Wireless portal providers try very hard to make mobile users list their portal as their mobile device’s ‘home page’. If the page is the first to be displayed each time a user logs-on, then the possibility of selective M-commerce is encouraged. Most providers of mobile devices and network services have their own dedicated Mobile Internet portals. It is through these carrier-branded

The Mobile Internet

137

portals that users have access to Internet services and can search the wireless Internet. This selective (garden-walled) access to information on the Internet is not favoured by all mobile device and mobile phone users, although with WAP anyone that wants to make content available through the Mobile Internet must create content compliant with the WAP. Nevertheless, the wireless Internet remains considerably more limited than the PC-based Internet in Europe and the USA (but not in Japan where iMode allows PC-like Internet content to be displayed on mobile phones). The applications of iMode will be discussed in more detail later on in this chapter. Not all wireless portals are commercial. Many are created by companies solely for their employees. These are known as ‘enterprise wireless portals’ and form an extension to existing intranet systems within a company’s computerized network. Did you know? Many wireless Internet portals are developed and set up by commercial companies for their employees. These are known as ‘enterprise wireless portals’.

Each year the number of wireless Internet portals increases. Many PC-based Internet portal providers also offer additional wireless Internet access as a value-added service to portal users. Nearly all mobile wireless devices are Mobile Internet compatible, for example smart phones, PDAs, 2.5G and 3G mobile phones. A number of devices are equipped with intelligent applications to discriminate between important and non-important Internet links and specifically identify information that the user would want to receive (defined by the user’s Internet-use profile).11 In the WAP domain the WAP service providers are normally commercial organizations. Many are owned, or part-owned, by the telecommunications network operators. For example, in the United Kingdom the four largest WAP portal providers are: O2, run and operated by British Telecom.12 Orange WAP Services, wholly owned by Orange Telecommunications plc, a pan-European wireless telecommunications operator; T-motion, owned by T-mobile; and Vizzavi, owned by Vodafone,13 a world-wide wireless telecommunications operator. There are other WAP portal providers, and these usually comprise companies in certain business areas such as retailing, finance or banking (e.g. Mviva and AvantGo in Europe). In Japan, and many other parts of Asia, the situation is similar. However, in the USA the situation is slightly different, with the existence of a wider variety of Wireless Internet Service Providers (WISPs) who are not necessarily connected to the large telecommunications utilities. Many are state-based wireless operators, providing state-based Mobile Internet portals. For 11

Wireless ‘cookies’ are used to store and define a user’s Internet usage and behaviour. Note that BT Cellnet de-merged its wireless operations in November 2001. The demerged wireless company is now called O2. 13 Vodafone is reputed to be the largest wireless telecommunications operator in the world at the start of the 21st century. 12

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example, the web site for the American Wireless Internet Service Providers Association (WISPA) provides a list of wireless ISP directories for 39 states. WISPA outlines its mission as follows: The Wireless Internet Service Providers Association is a non-profit organization and co-operative, formed to serve the interests of WISP's and ISP's worldwide. WISPA is being founded on the common idea that as owners of our respective businesses, we know what is best for those businesses and can work together to meet our own needs. Our purpose is to unite wireless ISP's in a borderless association; determine member needs and interests; develop programs and services to meet those needs and interests. We will strive to help create the standard skills, knowledge, and ethics required to continue to have a hand in the evolution of our industry. WISPA’s members will work toward the promotion and marketing of wireless Internet access as a viable medium while leveraging our combined member resources. Finally, we will steer this organization in the direction of becoming the leading professional association of the wireless Internet delivery industry. WISPA web site

As we have seen, many WAP portal providers usually garden wall their products and services. They also support their Mobile Internet activities with normal PC-based web site support. Wireless portal sites provide a means of advertising and encourage mobile phone (and other mobile device) users to engage with the Mobile Internet. Each WISP tries to offer unique customer services and products to its mobile phone clients, such as the capability to send ‘text messages’ (SMS) to other mobile phones free of charge from a personal computer and the creation of customer E-mail accounts. Most WISPs also have various business links and partnerships with retailers, banks and other business services, for example buying and selling stocks and shares, or placing a bet on a sporting event. For instance, the Abbey National Bank in the United Kingdom has a partnership with Mviva to provide on-line, mobile phone banking information and services (e.g. transferring money between bank accounts and checking bank balance statements). Many telecommunications operators also provide normal PC-based web site support for mobile phone applications and services. Figure 3.10 shows an example of a PC-based web site for O2 that provides information, applications and support to its Mobile Internet customers. In effect, the site provides support to O2’s mobile phone (and PDA) subscribers. Activity 3.11 What is meant by a wireless Internet portal provider? What information and services are available from a wireless Internet portal provider? What role do wireless portal providers play within the M-commerce world? How do wireless portal providers create a ‘garden wall’ around Mobile Internet information and applications? Search the Internet to discover more information on wireless Internet portal providers in your country or region. What types of services do they provide?

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139

Figure 3.10 An example of a PC-based web site supporting mobile phone subscribers Source: http://www.openmobilealliance.org. Open Mobile Alliance Ltd. AOL browser window © 2003 America Online, Inc. Used with permission.

3.10

■ The Mobile Internet–services and products The usage and interest generated by the Internet in the mid-1990s led to high growth in personal computer sales. Likewise, the ability to access the Internet from mobile and portable devices, particularly mobile phones, has created an increased interest in, and demand for, Mobile Internet phones that provide more than mere voice telephony. The development of the Mobile Internet has encouraged business organizations to explore innovative ways and means of reaching customers in new and unique ways. This form of business is known in E-commerce as business-to-customer (b2c) trading. This relationship is enhanced with M-commerce because customers who subscribe to a WISP are restricted to the products and services of the business organizations that have a relationship with that WISP. Therefore, customers can be targeted in a more focused manner with specific products and services.

What are smart phones? The basic smart phone combines a mobile phone and a PDA. They normally integrate with either GSM, GPRS or UMTS and support ‘always-on connectivity’ to networks and information sources, such as the Internet. A number of smart phone devices also integrate ‘interface expansion slots’ to receive a Compact Flash card or a MultiMedia Card to extend the memory of the phone or to make other

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applications available, such as games, audio clips and office applications (e.g. word-processing and database applications). This is known as ‘feature expansion’. The extra memory can support an e-book or even movies. A number of smart phones incorporate voice recognition technology to enable the user to command the phone. Smart phones can normally connect to other devices, through either infrared data communication or wireless connectivity, via a wireless laptop modem. Note: the Infrared Data Association (IrDA) specifies several infrared communication standards.

Smart phone based on Microsoft Pocket PC 2000 operating system

This ability to target information to customers who are mobile phone users has led some business organizations to offer their own specific services outside the domain of the main WISPs. For example, the Halifax Bank in the United Kingdom offers both wired Internet banking and wireless Internet banking to its customers through its on-line banking division known as the ‘IF’ Bank (or ‘Intelligent Finance’ Bank). The IF Bank offers banking services directly to its customers via WAP-enabled mobile phones. Customers can check their bank balances and transfer money between accounts by inputting information to an on-line web form via a mobile phone screen. (The format of the screen form would normally have been written and produced using WML as a programming language.) The IF Bank encourages its customers to use their WAP-enabled mobile phones to conduct their banking transactions. The IF Bank can also send information on banking products and services directly to specific groups of customers via their mobile phones. Therefore, in a similar manner to a business organization offering access to its products and services on-line via wired, corporate web sites, so these same organizations can offer further, or ‘value-added’, products and services via the Mobile Internet, accessible from a mobile phone or PDA. This is a growing and significant market within the M-commerce world. There are a number of reasons why business organizations that currently offer web-based access to their products and services should also offer

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similar access via the Mobile Internet. First, the rapid technological advances made in mobile, wireless data telecommunications have enabled business organizations to become more effective (through faster data communication and transfer) and more efficient (via lower unit costs for data transfer). For example, GPRS and UMTS allow mobile phone users continuous and speedy connection to the Mobile Internet. (Chapter 2 outlined some of the data transfer speed comparisons between GSM, GPRS and UMTS.) Highspeed data transfer enables mobile (and portable) devices to become suitable and appropriate for business information systems usage. Therefore, mobile technology can be more readily subsumed within the information systems fabric of any business organization. Second, front-end computing applications that allow interaction and engagement with the Internet through the utilization of user-friendly, web browser technologies have extended to the Mobile Internet domain via the use of applications like WML. Wireless programming applications have reached (and will increasingly reach) a level of sophistication and availability that enables component-based (object-oriented) computing to be applied to the wireless information systems domain. For example, networked computing systems thinking and practice has broadened out to include wireless technologies and devices within the integrated information systems domain. Therefore, many organizations are exploring various ways and means of using wireless technologies to create new market opportunities. Third, business organizations that already have a web site presence on the Internet often rely on publicity to encourage people to browse their web sites and purchase their products and services. There is often a high cost in terms of publicity and marketing. However, wireless M-commerce allows business organizations to target the users of WAP-enabled mobile phones directly without the need for invitation marketing. For example, a customer group with a known interest in a particular area can be directly targeted via their mobile phone with information (or data) on that specific product or service. The business organization goes to the customer, rather than the customer accidentally (or randomly) browsing for competing products or services. In order to encourage increased use of and interest in the Mobile Internet the manner in which people engage with it is critical. Ergonomically inefficient screen design and slow data transfer speeds discourage use of the Mobile Internet. Therefore, WISPs are constantly looking for better technologies to encourage greater use of the Mobile Internet. For example, the use of colour, graphics and movies to advertise products and services would encourage more use of and access to the Mobile Internet. For many WISPs making the Mobile Internet attractive to customers is a primary business objective. One such example of this business objective can be explained with regard to a specific WISP in Japan called iMODE. It should be noted that iMode is a service brand rather than a technology or protocol stack (like WAP). Therefore, it could theoretically be applied to any operational mobile Internet data service.

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Activity 3.12 What is a ‘smart phone’? What products and services are available from the Mobile Internet? What restrictions are present in accessing the Internet via a PDA or smart phone? Do screen size and speed of data access have an effect on the user’s experience of the Mobile Internet? Search the Internet to find references to the use of smart phones and PDAs to access the Mobile Internet. What types of devices are available in your country or region? What Mobile Internet information is available to you in your region?

3.11

■ Other wireless Internet providers As we have seen in this chapter, WAP is effectively the de facto standard for wireless data telecommunications in Europe, much of the Americas, and many parts of Africa (and many other parts of Asia and the Pacific, such as Australia and New Zealand). However, in Japan there exists a proprietary wireless data and Mobile Internet access service called iMode. Because it is a proprietary standard, and not an open standard, the amount of available information, and its breadth of use, are limited in comparison with the WAP standard. Nevertheless, iMode is such an important aspect of the wireless world, and the history of mobile devices and networks, that no understanding is complete without a good knowledge of its role. The iMode service was first introduced in February 1999 by a Japanese company called NTT DoCoMo, a very large wireless (cellular) telecommunications company. iMode was the first commercial WISP to offer wireless web browsing and E-mail specifically from mobile phones. The iMode service was an unprecedented success in Japan where it has attracted just over 30 million subscribers in only three years (up to February 2003). The iMode wireless Mobile Internet service is worth studying because it is estimated that 81% of the world’s wireless Internet users were resident in Japan in the year 2000, and of these over 61% accessed the Mobile Internet using the iMode service.14 Therefore, the iMode case study (Section 3.12) provides interesting evidence of how to create commercial markets for Mobile Internet applications and services. The experience of iMode customers was used by many other wireless network operators and mobile device developers to create new and innovative products and services for 2.5G and 3G networks in Europe and the USA. The charge (or bill) for the iMode service is not based on the time a user is connected to a web site or service, but rather on the volume of data transmitted. Therefore, a user can stay connected to a single Mobile Internet web site for hours without paying for anything as long as no data has been transmitted. In Japan, the success of the iMode service is fundamentally based on low cost, simplicity, innovation and novelty. The majority of Internet information sites available through iMode are only available in the Japanese

14

Eurotechnology Japan. Report in the year 2000©. http://www.eurotechnology.com

A case study of iMode

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language and are aimed specifically at Japanese customers. However, outside Japan a branded ‘iMode type’ service was launched in Europe in the summer of 2002 via NTT DoCoMo’s Dutch business partner, KPN Mobile. (KPN Mobile was a subsidiary of KPN, a large telecommunications company based in Holland.) The European iMode service had an introductory start in Holland, Germany and Belgium in the year 2003. KPN Mobile was keen to launch its iMode service in conjunction with UMTS (or 3G) network bearer technology that would allow very fast data transmission of multimedia data and information (e.g. colour, graphics and video streaming). Search the Internet to find references to iMode. What products and services were, and are, available to the iMode service?

3.12

■ A case study of iMode The iMode service is not based on WAP. Therefore, it does not require WML to produce front-end applications for mobile phone screens. The iMode service is based on compact HTML (referred to as cHTML) as its mark-up language (which was developed by the Japanese browser software house known as Access Co. Ltd). As the name implies, cHTML is a cut-down version of HTML, which is a common language for building viewable web pages on either a PC or laptop. The iMode service supports high-resolution colour content, one of its successful attributes in attracting subscribers to the Mobile Internet compared with WAP access. The main advantage of iMode is the fact that the service is not garden-walled like many of the wireless service portals available in Europe and the USA. Companies and individuals alike are able to create their own compatible Internet sites that can be accessed through the iMode service. Therefore, iMode offers a level of involvement and free participation in the Mobile Internet that is similar to the wired Internet. This level of involvement is not offered by the large majority of other WISPs in the world today, who take a walled garden approach by restricting users to officially affiliated Internet sites. The iMode service is divided into Internet sites that are officially recognized by NTT DoCoMo (which is around 3000 sites) and compatible Internet sites that have been accepted unofficially into the iMode service domain (which was around 50,000 in the year 2002). A site that has been branded ‘official’ by NTT DoCoMo can be accessed from the pre-set menu of an iMode-compatible mobile phone and hence benefit from a charging (or billing) relationship with NTT DoCoMo. Some of the official sites are free while others charge a monthly fee ranging from 100 to 300 Yen in Japan. To use the iMode service to surf the Mobile Internet, or send and receive Email, the charge is normally 0.3 Yen per packet of data (128 bytes) transmitted (both sent as well as received). Unofficial sites are not listed on the iMode menu but can be reached by typing in the URL or sending a bookmark to a user’s mobile phone by E-mail.

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Wireless protocols: context and usage

Many companies and individuals create their own iMode-compatible Internet sites, and use these to publicize themselves or their products and services. The large majority of iMode sites are still in Japanese character text only. However, the latest European iMode-type services have extended the relative number of English language sites dramatically. The iMode official sites cover the main information categories outlined in Figure 3.11. The most popular sites are related to games and entertainment (e.g. downloading ringing tones or mobile phone games) and news information.

iModeTM (Wireless Mobile Internet Service)

Entertainment – – – – –

Karaoke & Games Ringing tones Phone screen savers On-line FM Radio/Music

Databases – – – – –

Restaurant listings Telephone directory Dictionaries Company directory Portal listings Electronic Mail (E-mail)

Information – – – –

News and Weather Transport times City maps General information

Transactions – Mobile on-line banking – Reserving tickets (airlines/theatres) – Mobile tracking

Cellular Phone Network (Underlying Network Bearer)

Figure 3.11 iMode information services and applications

The iMode-compatible mobile phones are (in the main) more sophisticated than the phones currently in use in Europe and the USA which are mainly built to accommodate WAP access to the Mobile Internet. Particularly in Japan, they often have larger screens than regular mobile phones. Some models are monochrome, whilst the majority have colour displays. (The

A case study of iMode

145

range of screen sizes currently varies from the smallest with 96 × 108 pixels to the largest with 120 × 130 pixels.) Most models can support, and show, small screen animations (known as animated Graphics Interchange Format (GIF) files) in a similar manner to regular PC-viewable web pages. (Currently, Joint Photographic Experts Group (JPEG) and Portable Network Graphics (PNG) format files are not supported within the iMode domain.) In Japan, iMode-compatible mobile phones currently transmit data at a relatively slow speed of 9.6 bits per second (kbps). This can be compared with regular PC and laptop modems that normally transmit data at 56 kbps. However, this apparently slow transmission speed is satisfactory for iMode because each E-mail is normally limited to 500 bytes, and most iMode Internet sites are small, made up of mainly text data and few graphics, often only around 1.5 kilobytes in size. Furthermore, iMode uses packet-switching to sustain continuous connection. One of the most popular features of iMode phones is the capability to read regular POP3 E-mail. A regular POP mail account can be set to forward E-mail to an iMode phone E-mail address. Did you know? In Japan iMode is most popular among users aged 24–35 years of age. The largest group is young women in their late 20s.

Activity 3.13 Describe the underlying network characteristics of iMode. What is cHTML and how does it relate to the iMode service? What are the characteristics of ‘official’ and ‘unofficial’ iMode Internet sites? How does the iMode service generate income from its products and services? What services are offered through iMode?

3.12.1


iMode service operation The information services and applications outlined in Figure 3.10 are handled by an ‘iMode centre’. The iMode centre performs the tasks of connecting to Internet sites, running programs and applications, handling data traffic, and transmitting E-mail. When a user of an iMode-enabled phone requests Internet information a wireless digital signal is sent to one of NTT DoCoMo’s gateways (a computer allied to a radio tower). The digital radio packets are then encoded via a proprietary NTT DoCoMo protocol. The gateway performs the tasks of authorization and access control, and channels the transmitted request over dedicated lines to Internet content providers. The content providers respond with content sent back down the dedicated lines to the gateway where the content is encoded and sent back to the iMode device user who originally requested the information. Figure 3.12 shows the relationship between the iMode device user and the iMode Wireless Internet

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Wireless protocols: context and usage

service.15 It should be noted that because iMode uses a stripped down version of HTML (known as ‘compact HTML’ or cHTML) it cuts out some of the translation function protocols that are found in the creation of WML pages within WAP. With iMode the Internet content providers create iMode sites in cHTML format and then merely upload the content to a regular web server, in the same manner as uploading content to normal web sites (viewable via HTTP). Therefore, cHTML content is also viewable via normal PC and laptop web browsers. (It should be noted that the iMode service sometimes refers to cHTML as iHTML.) As of the year 2002 iMode has also supported Java, a software development language that extends the richness of applications found within the iMode services environment.

Dedicated line

Packet Transmission Network

Bank Dedicated line between DoCoMo iMode Centre and banks

IP iMode Information Providers Internet

iMode-enabled Cellular Phone

Packet Transmission Network

DoCoMo iMode Centre Internet

Other IPs compatible with iMode

Figure 3.12 NTT DoCoMo iMode network architecture and infrastructure

In Japan, NTT DoCoMo, through its iMode service, dominates the wireless Mobile Internet market. In M-commerce terms NTT DoCoMo is a ‘market maker’ since they dominate the wireless Internet market and can dictate terms regarding the development of technologies, devices and applications within the Japanese wireless Internet and mobile phone market. NTT DoCoMo ensures that any technological developments are synchronized with other developments in applications and network infrastructures. This is achieved through close collaborative arrangements with equipment and

15

The diagram is partially based on a paper entitled Analysis of Existing Wireless Communication Protocols by Irene Aldridge. Columbia University, USA. Summer 2000.

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device manufacturers (e.g. mobile phones and PDA manufacturers), Internet content providers, and other platform providers. Hence, NTT DoCoMo can achieve effective M-commerce by making sure that wireless technologies, content quality, and user applications evolve at the same pace and ensuring synchronized integration.

3.12.2


Characteristics of iMode The success of iMode in Japan, and to a lesser extent in Europe, can be attributed to some of the inherent advantages and benefits of the service over other environments, such as the WAP Mobile Internet environment. Some of the benefits and advantages of iMode are as follows. (a) The iMode service does not garden wall content providers; therefore, it has a far richer collection of Internet sites than its competitors within the WISP provider domain. (b) The dominance of iMode in Japan ensures the collective adoption of singular cellular standards with regard to the devices, platforms and applications used. (c) The iMode service displays Mobile Internet content on mobile phone screens in a colourful and attractive manner, incorporating text, pictures and moving images. (d) The iMode service is a brand, rather than a specific technology; therefore it can incorporate various application protocols and is always open to future technologies. (e) The iMode service uses many features of the regular Internet, such as a version of HTML and Java, making it easier to design and upload Internet content to existing PC-based web sites (i.e. there is no need to translate content into WML16). (f) The pricing policy for accessing the Mobile Internet is relatively simple and based on data transmission costing, allowing many sites to be accessed for long periods at low cost. (g) The iMode service encourages the development of innovative devices and gadgetry and software applications to attract customers to the Mobile Internet. Although iMode has these positive characteristics, these same benefits can also be found by accessing the Mobile Internet through a PDA (linked to either a wireless modem or mobile phone). Accessing the Mobile Internet on 16

The dependence on translating Internet content to WML within the WAP domain may not always be the case. The WAP Forum is also considering a version of HTML called x-HTML (or extensible HTML) that may provide some of the benefits of cHTML.

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a PDA screen often produces a level of colour, graphics and movie content similar to the iMode service. It should also be borne in mind that experiences of accessing the Mobile Internet vary according to the technologies and devices used and the specific characteristics of the ISP (that in turn is differentiated by geographical location and experiences). For example, different companies implement wireless Internet services using WAP as a protocol stack in many different ways. The WAP-based EZweb service in Japan is in direct competition with iMode and consequently its implementation of WAP provides a very different user experience from that in Europe or the USA. Therefore, it is worth making a brief comparison of WAP and iMode as a means of understanding the M-commerce issues of the wireless Mobile Internet market for both service providers and users. Activity 3.14 What are the main characteristics of iMode? Why do you think that iMode was so successful in gaining large numbers of subscribers to its products and services when it was first introduced in the year 2000? Do you think that other network operators and mobile device developers of 2.5G and 3G technologies have benefited from the knowledge gained by observing iMode as a case study of Mobile Internet access?

3.13

■ A comparison of WAP and iMode A direct comparison between WAP and iMode cannot be made because it should be remembered that WAP is a protocol stack whilst iMode is a complete and holistic wireless Internet service. In reality it would be a purer and more direct pursuit to compare a particular WAP implementation (e.g. the EZweb service in Japan) with iMode. Nevertheless, many relevant comparisons can be made between the WAP infrastructure and the iMode service from an M-commerce perspective. This section reviews WAP in comparison with iMode and looks at some of the differences in implementing WAP in Europe and the USA compared with Japan. The first difference is that iMode is a closed, proprietary service (and protocol), developed by a commercial organization, whereas WAP is an open, non-proprietary protocol. The second major difference from a user, and systems developer, perspective is the characteristic that iMode Internet sites are based on a mark-up language that is very similar to HTML (i.e. cHTML) and can (in many ways) interface with regular WWW sites. Therefore, it is a relatively simply programming activity to translate existing web content into Mobile Internet content. This characteristic, allied with a desire to make the service more open and less garden-walled, has encouraged thousands of individuals and companies to develop unofficial (or private) sites on the iMode service. Thirdly, the advertising, marketing and charging mechanisms are different. The WAP protocol in Europe is focused mainly at the business market,

WAP and iMode billing models

149

whereas the iMode service is specifically aimed at attracting as many individual subscribers as possible. The iMode service is based on billing only for the transmission of data packets. In the United Kingdom and Europe, in particular, WAP implementations are based on circuit-switched (dial-up) technology whereby the Mobile Internet subscriber has to dial up in order to connect to a site. In contrast, the iMode service is based on packet-switching that allows continuous connection to the Mobile Internet as long as the mobile phone is within the iMode radio signal range. (But it should be stated that WAP implementations in Japan also use packet-switching, and a number of European and American services also offer continuous connection to the Mobile Internet via GPRS.) Differences in the display of Internet content on mobile phones are not a result of an inherent difference between WAP and iMode but, rather, of a difference in attitude. The subscribers to the iMode service expect colourful graphics and moving images, whereas in Europe and America the screen displays for WAP-generated content are usually limited to four or five textbased lines and very limited multimedia displays. However, the attitude of mobile phone designers in the USA and Europe is changing to incorporate more attractive multimedia screen display characteristics for mobile phone users. To this end many telecommunications companies in Europe have massively leveraged themselves (i.e. gone into debt) to acquire radio spectrum, broad bandwidth to implement the super-fast UMTS (or 3G) technology17 on mobile phones and other wireless devices. Activity 3.15 What were the main differences between the iMode service and other 2G networks and mobile devices when iMode was first brought onto the market at the start of the 21st century? Do 2.5G and 3G devices around the world now provide many of the same products and services once only carried by iMode? Why is this now possible when it was not possible at the start of the first decade of the 21st century?

3.14

■ WAP and iMode billing models WAP service providers and iMode service providers are similar in the nature and categorization of Internet content provided, but not in the manner in which the information is presented. Both concentrate on providing news information, banking services and finance (e.g. trading stocks or equities), retail on-line shopping, directories, games and entertainment. However, in the USA and Europe emphasis is placed on business applications, such as checking banking details or stock portfolios, whereas both iMode and WAP

17

The government in the United Kingdom raised over $22 billion (in the year 2000) through the sale of broadband radio spectra licences to telecommunications companies to allow them to operate 3G Mobile Internet services.

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Wireless protocols: context and usage

services in Japan are market focused on games and entertainment and other social activities. However, an interesting comparison can be made on the basis of the business billing models used by WAP implementers in Europe and the USA compared with WAP and iMode billing in Japan. Figure 3.13 provides a comparative study of WAP and iMode billing models.

WAP Service Providers

iMode Bill Monthly fee $3 Data transmission ($0.004 per packet) Premium sites ($1 to $3) $15.00

Packet Transmission

WAP Providers

Internet Content Providers iMode

Internet Content Providers WAP

iPage

iPage

iPage

iPage

WAP users are charged (or billed) for connection time. Different charges apply for different service offerings.

Circuit-switched (dial-up) Transmission

Pay Bill iMode-enabled Cellular Phone

NTT DoCoMo collects 9% of subscription fees from content providers. NTT DoCoMo

WAP Cellular Phone

Figure 3.13 WAP and iMode billing models

The normal WAP implementations in Europe and the USA are based on billing subscribers for Internet connection time only. For example, if a user looks up a sports headline from a news service for five minutes, they are billed for the five minutes of connection time. The cost of connection time will vary according to the ‘cost-per-minute contract’ with the different mobile phone providers. The situation is the same for WAP implementations in Japan where different charges apply to different service offerings. However, iMode users have a more complex billing environment. First, iMode users are only billed for each packet of information downloaded (or

Conclusions

151

transmitted) to their iMode-enabled mobile phone. (The cost is approximately 0.5 Yen or US$0.004 per data packed downloaded.) Therefore, if the iMode user looks up a sports headline from a news provider for five seconds or five hours the bill is the same as long as they do not download additional information. Secondly, there is normally a basic monthly fee for subscribing to the iMode service (of approximately 300 Yen or US$3.0). Thirdly, an iMode user can subscribe to additional premium Internet sites for an extra charge, which will vary according to the number of premium sites subscribed to on the iMode service. Activity 3.16 What are the billing differences between iMode in Japan and various other WAP implementations in the rest of the world? Do you think that iMode benefits from being a relatively cost-effective Mobile Internet service?

3.15

■ Conclusions The most important development affecting access to the Mobile Internet has been the development and use of broadband wireless services, such as UMTS and WCDMA. These services, in conjunction with more sophisticated mobile phone devices that can support multimedia Internet pages, will allow the display of active Internet content (e.g. video streaming, music and movies). Broadband arrived in Japan in the year 2001 and in Europe in the year 2003. Such technology impacts on the attractiveness and convenience of using mobile devices to access the Internet, thereby increasing consumer demand. For example, the Nokia 7650, third generation technology (3G) mobile phone has a colour display screen and in-built camera for multimedia and movie capture. Camera phones are now commonplace in the mobile phone market. Both WAP and other Mobile Internet implementations offer colour and they have similar functionality. It was believed that WAP would disappear with the development of 3G technology and networks. However, WAP reinvented itself at the end of 2.5G to become useful within the 3G mobile environment. The OMA, which developed out of the WAP Forum, has prolonged the life of WAP. Therefore, the distinction between iMode implementations and WAP implementations of the Mobile Internet is less pronounced, mainly due to the fact that WAP implementers are adapting their services to support iMode compatibility and vice versa. Also iMode service operators have adapted their services to allow WAP-enabled phones to access iMode content. Therefore, there is a growing trend towards technology convergence. ‘Convergence’ is the watchword of the wireless industry. The further coming together of WAP, iMode and the wired WWW may lead to a convergence of mark-up languages used. The second significant trend in the Mobile Internet world is the spread of the Extensible Mark-up

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Language (XML) which can provide programming richness in both the wired and wireless Internet domains. The ultimate driving aim of wireless providers is to offer Mobile Internet services that are as good as, or better than, wired Internet services. However, this will only arise if the costing models for the Mobile Internet are the same as the cost models that exist for accessing the Internet through fixed-wire channels.

Short self-assessment questions 3.1

Outline and explain the three main reasons for the use of WAP.

3.2

What is the mission and purpose of the Open Mobile Alliance?

3.3

Explain the difference between half-duplex and full-duplex wireless transmission.

3.4

Who was Donald L. Hings and what was his contribution to the development of mobile cellular radio?

3.5

What was the role and purpose of 2.5G cellular technologies and networks?

3.6

Define what is meant by the phrase the ‘evolutionary path from 2G to 3G networks’.

3.7

Explain the main underlying difference between CDMA and TDMA.

3.8

What are the three main benefits of 3G networks over 2G networks?

3.9

What is ‘cellular mobility management’ within a wireless network?

3.10

Explain the difference between upstream and downstream communication.

3.11

Outline the main components of the elementary client–server WAP architecture.

3.12

Describe the purpose of each of the five main protocol layers of the WAP standard.

3.13

Explain what is meant by service bearer adaptation within the WAP domain.

3.14

What is the Mobile Internet and what kinds of mobile devices can receive the Internet?

3.15

What are wireless Internet portals and what function do they have in the wireless world?

3.16

Outline the main services and products available over the Mobile Internet.

3.17

What are the main differences between the iMode service and the WAP Mobile Internet service?

3.18

Outline the main network components of the iMode service and discuss what function they serve.

3.19

What are the main billing differences between WAP and the iMode service?

3.20

What is the role and function of ‘smart phone’ technology within the wireless world?

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Group activity

Cellular wireless networks Work in three groups as follows. The first group Discuss the main triggers (or critical factors) in the development of cellular mobile networks and technologies since the 1930s. The second group Explain how cellular wireless networks operate and outline the role and purpose of each of the following aspects of a wireless network: (a)

Mobile Station (MS)

(b) Base Station Transceiver (BST) (c)

Mobile Switching Centre (MSC)

(d) Base Station Controller (BSC) (e)

Public Switched Telephone Network (PSTN) The third group Discuss the main operational features of wireless networks (e.g. transmission frequency, wavelength, etc.) and explain the difference between ‘upstream’ and ‘downstream’ network communication.

Required ■

Each group should record their discussions and report to the other groups.

■

Then each group should discuss the evolution of wireless cellular networks from 1G through to 3G indicating the protocols and technologies pertinent to each generation of wireless technology.

■

Then a general discussion and report should be made on how the WAP standard is used and applied in the current wireless network domain.

■

Finally, you should investigate the types of products and services found on the Mobile Internet with reference to the types of technology (i.e. PDAs and mobile phones) used by those involved in the group discussions (with possible demonstrations).

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■

References and Bibliography




Books

Burkhardt, J. et al. (2002) Pervasive Computing: Technology and Architecture of Mobile Internet Applications (2001) Addison-Wesley. ISBN: 0201722151 Dodd, A. Z. (2001) The Essential Guide to Telecommunications. Prentice-Hall. ISBN: 0130649074 Feit, S. (1998) TCP/IP. McGraw-Hill Education. ISBN: 0070220697 Louis, P. J. (2001) M-commerce Crash Course: The Technology and Business of Next Generation Internet Services. McGraw-Hill. ISBN: 0071369945 May, P. (2001) Mobile Commerce: Opportunities, Applications and Technologies of Wireless Business. Cambridge University Press. ISBN: 052179756X McGrath, M. (2001) WAP in Easy Steps. Computer Step. ISBN: 1840781122 Morris, S. & Dickinson, P. (2001) Perfect M-Commerce. Random House Business Books. ISBN: 0090416522. Norris, M. (2001) Communications Technology Explained. John Wiley and Sons. ISBN: 0471986259 Norris, M. & West, S. (2001) eBusiness Essentials: Technology and Network Requirements for Online Markets. John Wiley and Sons. ISBN: 0471521833 Singhal, S. et al. (2000) The Wireless Application Protocol: Writing Applications for the Mobile Internet. Addison-Wesley. ISBN: 0201703114 Tanenbaum, A. S. (2002) Computer Networks. Prentice-Hall. ISBN: 0130384887 van der Heidjen, M. & Taylor, M. (2000) Understanding WAP: Wireless Applications, Devices and Services. Artech House. ISBN: 1580530931




Papers

The Economist (2001) A Survey of the Mobile Internet. The Internet Untethered. 13th October 2001. Walters, L. O. & Kritzinger, P. S. (2000) Cellular Networks: Past, Present and Future. ACM Crossroads (Student Magazine – Electronic Publication). ACM 2000–2002.




Web sites

European Telecommunications Standards Institute http://www.wapforum.com Information on the Open Mobile Alliance (OMA) http://www.openmobilealliance.org

Information on iMode http://www.nttdocomo.net Information on the Japanese wireless Internet market: http://www.eurotechnology.com http://www.mobilecontentforum.org http://www.mobilemediajapan.com

References and bibliography




155

WAP applications and emulators

Nokia WAP Emulator is available to download from the Nokia Forum web site http://www.forum.nokia One of the most widely used free emulators is available from Openwave.com http://www.openwave.com

American Wireless Internet Service Providers Association (WISPA) http://www.wispa.org

4

Wireless programming for mobile devices: context and usage ‘They have been at a great feast of languages, and stolen the scraps.’ Moth in Love’s Labour’s Lost by William Shakespeare 1564–1616

Chapter Aims: ■

■

■ ■ ■

To outline and explain the development of programming languages for mobile devices, particularly the Wireless Mark-up Language (WML) and associated mobile device languages such as xHTML. To explain the context and usage of mobile device programming languages and provide examples and initial guidance for those wishing to study wireless programming in further detail. To outline the tools and techniques used to develop and host a Wireless Applications Protocol (WAP) site accessible by enabled mobile wireless devices. To provide an understanding of the steps necessary to develop personal WAP sites and outline the development of WAP hosting services. To introduce students to the basic command structures of WML and the eXtensible HyperText Mark-up Language (xHTML) in the development of basic software programs in order to highlight examples of wireless Internet services and content.

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Wireless programming for mobile devices: context and usage

Software Development for the Mobile Internet: The Wireless Mark-up Language (WML) and xHTML

Open Mobile Alliance (OMA) Software Development for Mobile devices (i.e. mobile phones)

WAP/WML standards

WML development environments (i.e. SDKs)

The World Wide Web Consortium (W3C)

Developing an Internet web site for mobile devices – the Mobile Internet WML/WMLScript Program development

eXtensible HyperText Mark-up Language (xHTML)

WML and xHTML convergence

Products and Services for the Mobile Internet

Hosting WML and xHTML sites Internet commerce via wireless mobile devices – Mobile Commerce

The Knowledge Context Map

Characteristics and Features of WML and xHTML

Introduction

4.1

159

■ Introduction The previous chapter looked at the development and use of the WAP with regard to the necessary hardware communication protocols required to operate wireless mobile devices, particularly mobile phones. This chapter looks at the use of Internet software languages specifically designed to develop applications to enable mobile devices to access and interact with the wireless Internet.The Open Mobile Alliance (OMA) takes responsibility for the evolution and development of a language known as the WML that was specifically designed to support WAP-enabled devices. WML is a similar language to the HyperText Mark-up Language (HTML) that is commonly used to develop web-readable pages on personal computers for the wired Internet. WML is a language that allows WAP-enabled, wireless devices (particularly mobile phones and some wireless PDAs) to view Internet pages. The web sites have to be read by WAP-enabled mobile phones. The iMode service in Japan and other parts of Asia uses cHTML and other sevices use xHTML. However, WML is in many respects similar to the HTML language in that both languages use tags as the fundamental building blocks in the creation of web pages. WML is the HTML equivalent for small-screen, wireless mobile devices that offers the user a limited form of access to the Internet. It should be noted that WML is mainly targeted at small-screen, low memory, mobile devices. The WML pages have to be small to accommodate both the small screen size and relatively slow data transfer speed of mobile phones (although the advent of 3G broadband transmission has alleviated the latter constraint to a large extent). It should also be noted that WAP and WML are predominantly concerned with mobile phone technology. Many modern PDAs do not utilize WAP, but instead allow minibrowser access to the web in a similar form and manner to a personal computer with a large viewable screen. The WML uses a limited variety of mark-up tags to define its language environment. (Appendix 4.1 contains a list of WML tags and basic commands.) WML is defined using the rules and principles of the eXtensible Mark-up Language (XML) and is, therefore, a close relative to it. The main purpose of WML is to allow the user of a WAP-enabled mobile phone to navigate around the WAP applications environment, and specifically to view Internet content. For example, WML supports the use of embedded links as commonly found in normal web pages. WML pages are viewable via mini web browsers built into WAP-enabled mobile phones. In a similar manner to HTML being used to format text in web browsers, such as Internet Explorer or Netscape Navigator, so WML has been designed and developed for use with constrained mobile devices, such as mobile phones, that have the following characteristics and limitations: (a) narrow bandwidth; (b) small viewable screens and low-resolution displays;

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(c) limited power supplies and small memory capacity; (d) limited input capabilities in the absence of a keyboard or mouse. Normally, the WML source files are located on a web server and are encoded, decoded and transported using the HyperText Transfer Protocol (HTTP) to the WAP gateway (see Figure 4.1). Remember from the previous chapter that the WAP gateway is normally a computer that acts as a proxy server, residing between the web servers and the wireless mobile devices. The WAP gateway compiles the WML code and transmits the compiled byte code to a mobile device (e.g. mobile phone) via the WAP. In essence, a WAP application will normally consist of various code files located on a Web server. These files will normally have been written in WML (on a WAP emulator) and will often also consist of files in WML Script1 and graphics files in WML Bitmap format (again, see Figure 4.1). The use of WML in conjunction with WAP permits a user access to information on the Internet from a mobile phone (or other small wireless device) at any time and from any location – a huge advantage. Often WML pages are abridged versions of HTML pages, offering only the pertinent, text-based information from the web site. But higher versions of WML allow the use of colour graphics and limited dynamic animations. However, even lower versions of WML still provide the pertinent textual information with anchored links, as well as the significant benefit of not being dependent on a traditional, PC-based Internet connection. The WML language, and its WAP environment, is not intended to be a sophisticated web language; rather it is intended to be a robust application for enabling access to Internet information from mobile phones (and other limited-capacity mobile devices). The use of WML depends upon the availability of a browser in the mobile phone (or other device) that can interpret and read WML code, in a similar manner to PC browsers reading HTML code. WAP-enabled mobile phones would normally contain an embedded browser. The WML language is similar to HTML, but not a sub-set of that language. There have been a number of evolutionary versions of WAP and WML. For the latest versions see the OMA web site for the most up-to-date WML information. Activity 4.1

Outline the main role and purpose of the WML. Explain its significance in the early development of the Mobile Internet. What devices mainly use WML? Do PDAs use WML to display Internet information? If not, what alternative techniques are used to access the Mobile Internet? Search the Internet for the OMA. What version of WML is currently being used?

1

The WML Script language is similar to JavaScript and is designed to add dynamic functionality to the static content of WML pages.

The development and use of the xHTML

Web Server

HTTP

WAP Gateway

HTTP

Formats: WML WML Script WML Bitmap

WAP

161

Mobile WAPenabled Device (e.g. mobile phone or PDA)

WAP Emulator (Computer)

Figure 4.1 The WAP and WML environment

Each new version of WAP strives to provide convergence between different protocols and their respective coding languages. For example, the early WAP 2.0 version introduced in 2001 attempted to build upon the latest Internet standards, one of these being the xHTML. The WAP 2.0 version allowed code developers to write applications for both the fixed-wire PC and WAP-enabled wireless devices. Later versions after 2002 added more functionality, particularly with regard to the incorporation of dynamic Internet page content. The use of xHTML to write wireless Internet content is particularly popular because of its similarity with normal HTML – a popular Internet page developer’s language. The use of xHTML is also a common feature of a number of wireless Internet providers, such as the iMode service in Japan. WML is effectively a sub-set of the XML. In a similar manner, xHTML is very similar to normal HTML (from version 4.0 onwards). In many ways xHTML is a cleaner version of HTML for use with mobile devices.

4.2

■ The development and use of the xHTML The xHTML is a code sub-set of the XML. It is also compatible with ordinary HTML and is similar to it with very few exceptions. The development of xHTML was recommended and stimulated by the World Wide Web Consortium (W3C). The W3C was created to develop the true potential of the WWW. It promotes the development of common protocols, and also promotes the web’s evolution. One of its main objectives is to ensure the web’s interoperability. The W3C has over 500 member organizations from around the world, and is a very powerful group in shaping the nature and evolution of the web. It was the W3C that recommended that developments of WAP incorporate the development of xHTML. The W3C web site provides a range of material on web-related matters, concerning both the wired web and the wireless web. The web site also offers a range of ‘tutorials’ on WAP, WML and

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xHTML. These are interesting and usually related to the current versions of web applications. Did you know? The World Wide Web Consortium (W3C) was chiefly instigated in October 1994 by Tim Berners-Lee – the inventor of the web – at the Massachusetts Institute of Technology in the USA.

The main advantage of xHTML is the fact that pages developed in xHTML can be viewed via normal web browsers on PCs and also by WAP-enabled devices like mobile phones. The xHTML environment goes a long way towards achieving convergence between wired-web languages and wirelessweb languages. Search the Internet for references to the W3C. What is the main purpose of the W3C? What is the mission of the W3C?

4.3

■ WML and xHTML convergence As technology develops in the wireless world, so levels of convergence appear in both the hardware and software areas of wireless mobile computing. In particular, the standards developed by the OMA and previously the WAP Forum, such as WAP protocols, WML and WML Script, are converging with standard Internet formats from the W3C. This is beneficial to both users and systems developers in the wireless computing world because the number of different protocols and software languages which need to be understood diminishes with the trend towards convergence. One of the great areas of convergence is in the wireless software field with the coming together of WML and xHTML. The latter language has the advantage of being similar to the HTML language used to develop content for the wired web. The WAP standard accommodates both WML and xHTML. The trend towards convergence will continue for a number of years until the end of the first decade of the 21st century. The main overarching convergence is between systems in the wired Internet world and systems in the wireless Internet world. The HTML (and thus xHTML) language is based on SGML (Standard Generalized Mark-up Language) that was intended for web browsers. However, HTML for the wired web is really a static display language. Therefore, the eXtensible Mark-up Language (XML) was developed to deal with dynamic data handling. The use of XML enables the sophisticated development of commercial applications in E-commerce and, now, in M-commerce, where commercial applications are dependent upon data capture, storage and handling, and where there is a need for more sophisticated server-side procedures and programming. The xHTML environment is an evolution of HTML as it incorporates many of the rules common to XML.

WML and xHTML convergence

163

The use of xHTML does have inherent advantages over WML in that commercial software developers familiar with HTML do not have to learn a new language. This is an advantage to software developers and computer consultants where ‘time-is-money’ in the software development domain. Furthermore, the WML environment is limited in its ability to control screen content and layout. For instance, the display of content will vary depending upon the mobile device used and the particular manufacturer (e.g. the display on a Nokia phone will be different from that on a SonyEricsson phone for the same WML program). xHTML improves upon WML in the manner in which it can handle interoperability control issues such as consistency of screen layout. The syntax of xHTML is largely similar to HTML (from versions 4.1 onwards). The aim of W3C is to encourage the use of xHTML in order to develop converged standards between wired web platforms and technologies and wireless web platforms and technologies. Therefore, web content developers need not make a distinction between publishing on the wired web or the wireless web. Also, many Software Development Kits (SDKs), often provided free by mobile phone manufacturers, are capable of handling wireless content in both WML and xHTML. Search the Internet for examples of SDKs. In particular, search for the OpenWave SDK and the Nokia SDK. What versions are currently being used? What is the role and purpose of these SDKs? It is important for the reader to understand both the nature of the hardware environment (i.e. communication protocols) and the software environment (i.e. WML and xHTML) in order to appreciate the connectivity between the two areas in the wireless computing world. However, given the emergence of xHTML (and its similarity to normal HTML), the reader may ask why this chapter concentrates on WML. There are two reasons. First, WML is an interesting example of a wireless programming language that will still be largely in use at the end of the first decade of the 21st century. Secondly, it is likely that the readers of this book will have at least a rudimentary understanding of HTML, and will not be so interested in learning what is already known and familiar. However, in order to enable the reader to develop programs in xHTML, this book contains a list of xHTML command tags and syntax rules in Appendixes 4.1 and 4.2 which will enable someone with HTML knowledge to translate (and even customize existing) content into mobile device displayable content. The W3Schools.com site (see Figure 4.2) contains a range of useful tutorials for anyone who wants to specialize in software development for the Internet. It provides tutorials on WML, WMLScript, xHTML, ASP, JavaScript, etc.

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Figure 4.2 Web tutorial portal Source: http://www.w3schools.com, Copyright Refsnes Data. Reproduced with permission. Netscape browser window © 2003 Netscape Communications Corporation.

Activity 4.2

4.4

What is the role and purpose of WML and xHTML in the wireless Internet world? What is meant by WML and xHTML ‘convergence’? Explain how and why convergence occurs and outline its main aspects. What role do SDKs play in the development of Mobile Internet content? How easy, or difficult, is it to develop a Mobile Internet page using WML or xHTML?

■ A comparison of WML and xHTML transmission protocols The manner in which WML and xHTML are transmitted between the client (or user) and the server (or host) differs in some respects. The previous chapter outlined the WAP stack. It was seen that WML required a WAP gateway to encode (compile) WML and WML Script content before transmission to the client device. The content is normally encoded into binary format called Wireless Binary eXtensible Mark-up Language (WBXML). However, xHTML content is not encoded (or compiled) by the gateway but instead is forwarded on to the mobile device unchanged as xHTML content, in a similar manner to regular wired-web content being passed through a computer web server. Figure 4.3 shows a comparison of the effect on the transmission of WML/WML Script files and xHTML files. However, it should be noted that micro-browsers supporting the WAP standard (version 2 onwards) can display both xHTML and WML content. This is shown in Figure 4.3.

Creating an Internet WAP site

WAP Server

Hosting WML (text) WMLS (text) xHTML (text)

165

WAP Gateway (Proxy) WML (text) or xHTML (text)

Encodes (compiles) WML into binary form Does not compile xHTML

WML file compiled in binary format (i.e. filename. wmlc) xHTML file in text format (un-compiled)

WAP 2.0 Standard Compliant Mobile Device Supporting: WML WBMP xHTML GIF

Figure 4.3 Comparison of WML and xHTML transmission

4.5

■ Creating an Internet WAP site In a similar manner to creating and publishing HTML pages within the normal PC-based web site domain, so anyone can also produce and publish Internet content that is viewable on WAP-enabled mobile phones. There are a number of steps in the process of creating a WAP site, as follows: (a) Download to your PC a WML and/or xHTML software developer’s toolkit (referred to earlier in Figure 4.1 as the WAP emulator). (b) Create a WML or xHTML suite of pages on the WAP emulator. (c) Register and publish your WML or xHTML site on the computer server of a WAP hosting service.

4.5.1


Step 1 – Downloading an emulator In order to build and test a WAP site it is essential to have access to a WML or xHTML software developer’s toolkit with a WAP phone emulator to ‘emulate’ (or simulate) the effect of the code on the viewable small screen. The WAP emulator allows the developer to view their efforts via the Web. This is the simplest way of creating WAP-viewable web sites. However, there are a number of other ways to develop WAP pages. For example, it is possible to write WML code with Microsoft Windows NotePad editor. However, it is a slightly more cumbersome process and requires the pages being uploaded to the

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web, and having a dial-up connection to a WAP phone to display changes each time the page is edited. Therefore, it is far simpler to download a WAP emulator that enables the WML or xHTML code developer to view WAP pages instantly without the need for a dial-up connection. There are a number of free WML and xHTML developers toolkits available on the web. These are, as we discussed earlier, often generically referred to as SDKs. Most of them provide both a developer’s toolkit and an emulator within the application domain. The main sources for these free WAP developers toolkits are the web sites of the large mobile phone companies. For example, the following is a list of mobile phone companies that offer free WAP developers toolkits after registering on their sites: The The The The

Nokia WAP developer toolkit – Nokia WAP Toolkit Motorola WAP developers toolkit – Motorola ADK Ericsson development toolkit – Ericsson WapIDE Openwave toolkit – Openwave

Figure 4.4 Openwave SDK portal Source: http://www.openwave.com. Openwave Systems, Inc. AOL browser window © 2003 America Online, Inc. Used with permission.

The Openwave toolkit (see Figure 4.4) is probably the most useful in that it is free and not based on any particular mobile phone characteristics. For demonstration purposes this chapter uses the Openwave toolkit because it

Creating an Internet WAP site

167

provides a code development and emulation environment for both the WML and xHTML languages. The xHTML language is an increasingly popular alternative to WML. The normal selection of a particular toolkit would be likely to be based on a user’s model and make of mobile phone. Most of these sites also provide other useful material, such as user guides and peripheral software for each toolkit. Using the Openwave toolkit the WAP emulator display will look something like Figure 4.5. On the left-hand window is an area available to build the code, in this case a program to convert currencies, and in the right-hand window is a mobile phone emulator to simulate, and view, the screen content after transmission.

Figure 4.5 The Openwave Toolkit emulator Source: http://www.openwave.com. Openwave Systems, Inc.

The functions of the WAP environment are normally accessed through the buttons on a mobile phone. Normally, scrolling through WAP page options, or viewing the content of anchored links, is achieved with the arrow keys. Figure 4.6 looks at the common semantics used for the buttons and functions of a mobile phone, although a specific and detailed analysis of the keypad functions of most mobile phones can be found in the user guide for each

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Wireless programming for mobile devices: context and usage

make of phone. These keypad functions allow the user to navigate WAP pages and content, and they vary between phones. Soft keys are normally used to select a menu item from a list of on-screen options. The arrow or scroll key is normally used to locate the menu and arrow to the various options before selection. However, many phones combine both the scroll and selection functions in one scroll key. For example, many of the Sony mobile phones have a Jog Dial that allows a user to scroll options from a menu and then click the dial to select an option.

Figure 4.6 Normal keypad functions on a mobile phone Source: Kyocera 7135 smartphone. Courtesy of Kyocera Wireless Corp.

4.5.2


Step 2 – Creating and building the WAP or xHTML site The editing window of the WAP emulator allows code to be developed and manipulated. The browsers found in WAP emulators vary in visual design to reflect the different interfaces of actual makes of mobile phone. The emulator works by compiling the WML code into byte code (this is known as parsing) that can be viewed on the simulated phone display. However, it should be noted that the final version of the WAP page should be tested in real mobile phone working conditions. Each WML document is composed of a ‘deck’ containing data that is grouped into code blocks called ‘cards’. A deck can contain many cards, but each card will normally display as a single page on the mobile phone emulator. A user on a mobile phone can navigate the cards

Creating an Internet WAP site

169

by scrolling and selecting. In most editors, in order to start creating a deck, select file then new from the menu bar at the top of the editor window. Each new deck selected is normally presented with outline headers and other tags already displayed. Often the tags are coloured to differentiate a command tag from ordinary text. Normal WML files have the extension ‘filename.wml’, whilst WML Script files normally have the extension ‘filename.wmls’. Once a WAP page has been created (and maybe debugged) then the show button on the window menu bar should normally activate and simulate the deck on the emulator. Having built a WAP site the final step is to publish it to the WAP world.

4.5.3


Step 3 – Registering and publishing a WAP site Some normal Internet Service Providers (ISPs) also offer the additional service of hosting WAP pages as well as normal Internet pages. However, there are a number of specific WAP hosting services, some of which are free whilst others charge a fee for hosting WAP content on their servers, for example Wapdrive (see Figure 4.7).

Activity 4.3

What are the main steps involved in creating an Internet web page for a mobile phone? What is the purpose and role of an ‘emulator’ in the creation of web pages for mobile phones? Describe how an emulator operates.

Figure 4.7 Wapdrive Source: Courtesy of WAPdrive.com

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Wireless programming for mobile devices: context and usage

4.6

■ Developing a basic WAP site using WML The WML and xHTML code domains use instructional tags to determine the content and appearance of WAP pages. Both are mark-up coding languages. Modern mark-up languages originate from the world of newspaper printing where computerized systems and software were developed to interpret (or mark up) certain commands, such as font size and layout. This was based on the SGML. HTML is a simplified derivative of SGML that is specifically aimed at web browser technology. As the web developed and became more data-based, so there was a need for a more sophisticated and flexible language to deal with data types. This led to the development of the XML that allows programmers to create their own mark-up elements. WML is an abridged coding sub-set of XML aimed directly at wireless devices that use the WAP protocols to access the Internet. WML consists of commands and instructions for the micro-browsers on low-powered, small-screen, wireless devices, particularly mobile phones. WML code is organized into ‘decks’ and ‘cards’. A deck contains a number of related cards in a stack. A WML document is, therefore, referred to as a deck. The cards within a deck represent a separate viewable entity. Cards contain both content (viewable by the mobile phone user) and instructions (not viewable by the mobile phone user) for the WML micro-browser. The micro-browser is responsible for interpreting the cards to the viewer; this is a process technically known as ‘rendering the cards’. The browser renders the cards one at a time to the user on the user’s selection and activation of options from the screen. Figure 4.8 shows an example of a WML deck containing three cards.

WML Deck of three cards (threecards.wml)

Card One

Program

Card Two

Program

Card Three

Program

Figure 4.8 Example of a WML deck with three cards

Most WML pages displayed on a mobile phone consist of very basic user interface elements – for example, pictures (basic graphics and screen

Developing a basic WAP site using WML

171

dynamics), text (information), lists of choices (options), and places for the user to enter information (input fields). The given sequence of activity on the display, following the action of a user by for example pressing a specific keypad, is determined by the event bindings. Events (such as pressing a keypad) are bound together with an activity or task (such as displaying the next card) in the event sequence. In simple terms, when a user selects an option from the menu display on the screen the micro-browser detects the event and carries out a corresponding activity or task. The activity of browsing from one card to another is often referred to as navigation. Links can be made to cards in the same deck, or in different decks, and also external sources and servers. WML is similar to HTML in its use of anchored links (hyper-links) within cards providing a link pointer to another card. As a user navigates from one card to another, the micro-browser records the sequence of events in its navigation history in order to allow the user to move backwards and forwards through the pages previously used. This is sometimes known as the history stack. One of the limitations of small-screen displays is that links and text need to be articulated in very few words; there is not the scope to be verbose, or wordy, in WML given the limited screen displays of mobile phones. This fact often determines how much content is put into a card or page of display. Also the appearance of a WML ‘deck of cards’ on a display screen is often determined by the model of mobile phone and the specific micro-browser used, and is somewhat beyond the WML author’s control. The reason for this is the fact that WML is supported on a variety of different mobile phones and other wireless devices. Therefore, most WML authors are concerned more with how a WML application works than with how it inherently looks. This is not, however, a major problem with the technology, as WAP users are mainly concerned with targeting information rather than browsing the web (which is more appropriately done on a PDA with a larger colour screen and built-in browsers that act in a similar manner to PC-based browsers). Therefore, most WML pages consist of request and response actions to retrieve a specific piece of information or data (e.g. an address, telephone number or equity price). This provides precise, point-to-point retrieval, but is restrictive in terms of the dynamic scope available to the user to randomly browse the web at leisure. In a similar way to the functioning of PC-based browsers, the microbrowsers on mobile phones expect to identify the nature and type of file content they are reading. This identification is primarily made through the file extensions. That is why many computer servers that are configured to read normal HTML web content need to be additionally configured to read WAP content (and its specific file types). In essence, web servers need to be re-configured to recognize WAP media types. The nature of this reconfiguration is dependent upon the server documentation specific to the computer system used.

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Activity 4.4

4.7

What is the role of instructional ‘tags’ in WML and xHTML? Explain how WML code is organised into ‘decks’ and ‘cards’. What is meant by ‘rendering the cards’? What is the activity of ‘card navigation’ and what is a ‘history stack’?

■ WML and WML Script In essence WML was originally developed for specifying content and aspects of the user interface for narrow-bandwidth mobile phones and pagers. The WML program offers support for managing the navigation between cards and decks, and specifically includes commands for event handling. These can be used for navigating or executing scripts. WML Script, based on ECMA Script (a standardized form of scripting language developed by Netscape), is similar to JavaScript but is designed specifically to add dynamic functionality to the static content of WML. WML Script is part of the WAP application layer and can be used to provide client-side procedural commands to WML cards and decks. In effect WML Script is used to complement WML. WML Script is optimized for the WAP environment (e.g. narrow-bandwidth devices) and, therefore, does not include some of the more advanced features of ECMA Script in order to keep it as lean as possible. An important feature of WML Script is the use of client-side program libraries that reside in many mobile phones (and other wireless devices). This use of WML Script libraries reduces the size of the WML script code that is needed in WML. WML Script files are compiled in a similar manner to WML files. Therefore, in order to handle WML Script byte code, most WAP-enabled devices, particularly mobile phones, contain an interpreter to execute the WML Script functions. The use of WML Script will be expanded upon later in this chapter. A user can usually navigate through cards in a deck by using the soft keys on the mobile phone to follow links contained in each card. The deck is the WML file and this is the file that is loaded into the mobile phone when a Uniform Resource Locator (URL) is called over the web. The contents of the first card in the deck will be displayed on the user’s screen, normally after the WML file content and the user input have been validated by a WML Script. The script is stored in a text format file with the extension WMLS (filename.wmls) on the computer web server. The file, on calling, is compiled by the WAP gateway and then forwarded on to the mobile device (e.g. mobile phone), in the same manner that WML content is transmitted from the web server through the WAP gateway and on to the mobile device at the client-side. The content is encoded (or compiled) by the WAP gateway into binary form (called WBXML). The binary format code is then interpreted by the mobile device (i.e. mobile phone) via a WML/WML Script interpreter. For example, the interpreter executes the commands and functions of a WML Script file and returns the results to the display screen. The interpreter normally uses an Instruction Pointer (IP) to maintain a current audit and record of instructions and the variables within a script. WML Script is

The WML language basics – elements and attributes

173

used to call various functions that provide dynamic functionality to static WML content. Figure 4.9 shows the sequence of activity from a client device calling a file from a web server to its binary compilation and interpretation back on the client-side device. It should be noted that the client-side device usually contains WML Script libraries of standard functions that make WML programs more efficient.

WAP Gateway Web Server

HTTP

WAP

WML WML Script

WML Script

Text/Code Files

Compiles (Binary)

Embedded in device: WML/WML Script ‘Interpreter’

WML Script Libraries Byte Code Instruction Pointer (IP) Call & Operand Stack Variables

Figure 4.9 WML/WML Script interpreter

Activity 4.5

Explain the relationship between WML and WML Script. What is the function of WML Script and what role do Script libraries play in the development of web pages for mobile devices, such as mobile phones?

Activities 4.6 to 4.15 The remaining activities in this chapter are optional and relate to the program examples that follow. The introduction of each code command in WML is followed by a short example. These examples can be tested using SDK. Most mobile phone manufacturers offer SDKs free on their web sites. The SDK used in this chapter is available free from Openwave.

4.8

■ The WML language basics – elements and attributes Those who are familiar with HTML will recognize similarities with WML.2 Both are, as stated earlier, based on the mark-up of elements. The elements are identified by the tags (or command syntax). The tags are enclosed in chevron brackets, in a similar manner to HTML. All elements must have a start (open) tag and an end (close) tag. The elements can be extended and

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enriched with attributes that appear with the start tags and enrich the element in some way (e.g. naming a card or styling some text). It should be noted that WML is a case-sensitive language and all tags and attributes should be written in lower case. In terms of program layout and formatting (i.e. the use of tabs and spaces), the WML document layout of the program has no effect on how the deck and cards will appear on the micro-browser. However, good programming practice means that most WML (and xHTML) developers indent and space programs in such a way that they distinguish the opening and closing of elements and attributes and are readable to other programmers. See Figure 4.10 for an example of the layout of a basic program. . The use of comment lines is good programming practice. Figure 4.15 shows a more detailed example of the use of WML document navigation elements in practice.

Information Economics 2: grade average = 57%%

Mobile Commerce: grade average = 89%

Figure 4.15 Example of WML document navigation elements Source: http://www.openwave.com. Openwave Systems, Inc.

4.10

■ Push and pull browsing Events, tasks and anchors are all part of understanding the process of navigating between cards and decks. All micro-browsers record a history of both local and external URLs visited. The URLs are stored in a ‘stack’ (just like the analogy of a deck of regular playing cards). Each time a user navigates to a particular card, that card is then pushed onto the top of the stack. However, when a user navigates backward (for example, through the prev element) the current URL is pulled off the top of the stack, thus revealing

WML option menus and variables

183

the URL of the last card pushed onto the stack. Micro-browser histories can be re-set by emptying the stack. This can normally be achieved by using the newcontext attribute within the card element. The newcontext attribute can only have two values: ‘true’ or ‘false’. If a newcontext attribute is set to the value ‘true’ then the card will be treated as if it is the first card in the stack and the user will, therefore, be unable to navigate backwards (from that card) through the stack. This is a useful attribute because many mobile phones have limited memory resources. Therefore, clearing stack histories helps to maintain the mobile phone’s memory efficiency. Note on special characters: The WML program environment supports the use of various character entities, such as the ampersand (&) and quotation marks (“ ”). These character entities have a particular meaning in WML and, therefore, cannot be used directly in a WAP deck or card to represent themselves on a display screen, for example, the use of the £ or $ signs in screen text. However, these grammatical characters are often useful for highlighting aspects of displayed text. Therefore, these special character entities are normally represented by the use of either the name reference or the numeric reference. Table 4.1 shows the name reference and numeric reference for a number of special characters. Table 4.1 Special Character Table for WML Character

Name reference

Numeric reference

Screen display

Ampersand Quotation mark Apostrophe Less than Greater than Soft hyphen

& " ' < > ­

& " ' < > ­

& " ’ < > –

Three examples of the use of special character entities in screen display test are as follows: (a)

Gin & Tonic

is represented on the screen display as Gin & Tonic (b)

10 < 20

is represented on the screen display as 10 < 20 (c)

" Gin & Tonic "

is represented on the screen display as "Gin & Tonic"

4.11

■ WML option menus and variables Within WML the element select is used to create a list and the element option is used to define the list items. For example, a WML programmer can

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create a list of options that a user can browse and make various selections. This area of WML programming of menus and lists is also concerned with the four main in-built intrinsic onevent values that were described earlier in this chapter in the context of the type attribute. These were as follows: (a) ‘onenterforward’ that occurs when a card is entered as a result of forward navigation; (b) ‘onenterbackward’ that occurs when a card is entered as a result of backward navigation; (c) ‘ontimer’ that occurs when a timer allows actions to occur without any user activity; (d) ‘onpick’ that occurs when a user selects an option from a menu list. In Figure 4.16 an example is given of the use of the select and option elements to define a list of three course units: engineering, science and technology. In the figure a multiple attribute has been used to enable a user to make multiple selections from the list, rather than be restricted to one option. This has been achieved by setting the multiple attribute value to ‘true’.

Please select option:

Engineering Science< /option> Technology

Monday 2pm to 4pm

Thursday 9am to 11am

Tuesday 4pm to 6pm

Figure 4.17 Selecting options and displaying content Source: http://www.openwave.com. Openwave Systems, Inc.

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The attribute ontimer can be used to re-locate to a specific URL (or page) after a timer has expired. For example, Figure 4.18 provides an example of timer navigation to another screen display. The timer attribute may be used to display a screen for a few seconds. These brief display screens are often known as ‘splash screens’.

This is the Timer Page

Timed out to this page

Figure 4.18 Use of the ontimer attribute

One of the most sophisticated features of WML is the use of variables to dynamically alter content in run time. Variables can be used directly within text-based content where the value of a variable can be substituted into the text in place of fixed data. Variables are normally used to capture user content or even control timers. It should be noted that variable names are always case sensitive. Variable names should begin with a letter or an underscore ( _ ) mark. They are often defined within parentheses (brackets) and preceded by the dollar symbol ($). For example a variable named ‘one_var’ would be referred to in WML code as ‘$one_var’ or enclosed in brackets to become ‘$(one_var)’. Within the syntax of WML, and given the variety of micro-browsers used, it is advisable to use parentheses in the establishment of a variable. On substitution of a variable, the format of the variable value may be converted by adding a conversion type to the variable name. For example, ‘escape’ or ‘no-escape’. The following are conversion types: (a) $(one_var:escape) – used to escape any non-alphanumeric characters; (b) $(one_var:unesc) – used to un-escape any alphanumeric characters; (c) $(one_var:noesc) – used to indicate no-escape at all. The element setvar is used to assign a value to a variable. The setvar element has two main attributes, name and value. The setvar element must be associated with a task element, for example, go, prev, or refresh. Variables can also be assigned values via the timer, input, and select elements. Other associated elements frequently used are onevent, where the attribute type can be set for ‘onenterforward’ or ‘onenterbackward’. These values can be used to allow a variable value to be set each time a user navigates to a particular card. Figure 4.19 shows the use of variables in action.

WML option menus and variables

187

$(variable)
Next card

Figure 4.19 Using variables in WML

Variables can also be set by user selection or user input. For example, the soft keys on a mobile phone can be used to change the value of a variable. Figure 4.20 provides an example of the setting of values by user selection. To set a variable value by inputting data the input element is used. The inputting of data is usually performed by pressing the alphanumeric key pads on a mobile phone.







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Unit is $(variable)

Figure 4.20 Setting variable values by user selection

Rather than select, variables can also be set by input text. The input element can appear in normal text. It is used to create an entry object to take alphanumeric text from a user, via the alphanumeric keys on a mobile phone. For example, a user may be asked for their name, or module title. Figure 4.21 shows the necessary syntax (or code commands) for utilizing the input element. The figure shows an example of a user being asked for their name. The format attribute is used to define the type of text acceptable as input data; in this example the format attribute indicates that only upper-case characters that are non-numeric are permitted. However, the asterisk (*) can be used to indicate that the user input can be of unlimited length. Table 4.2 outlines some of the available format restrictions for defining alphanumeric input formats. The permissible length of text input can be limited by a programmer. For example, the statement format = ‘5A’ indicates that the input must be limited to five characters, all of which must be upper-case characters that are non-numeric. Table 4.2 Defining Input Formats Format

Purpose of format

A a N X x M m

Only upper-case characters that are non-numeric Only lower-case characters that are non-numeric Only numeric characters Only upper-case characters Only lower-case characters All characters but they may be displayed in upper case All characters but they may be displayed in lower case

WML option menus and variables

189

Please enter your name (in uppercase):


Course Director’s message

Figure 4.21 Setting variable values by user input

The fieldset element can also be used to define data fields for variables. It is an effective way of grouping together associated text and fields. This enables the display of associated input fields and text on a single card (or page). Figure 4.22 provides an example of the use of the fieldset element to group together on one page data concerning a student’s name, age and gender details.

First name:


Last name:

Age:



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Your details: $(fname) $(lname) $(gender) Aged: $ (age)

Figure 4.22 Grouping variables using the fieldset element Source: http://www.openwave.com. Openwave Systems, Inc.

4.12

■ Passwords and security in WML One important aspect of requesting and displaying data is security. For example, it may be necessary to set a password hurdle for students requesting their module marks from a WAP page. If the type attribute in Figure 4.19 had been set to a value called ‘password’ instead of ‘test’ then the microbrowser would have obscured the characters as they were entered. The normal method of obscuring the data entry is through the display of asterisks instead of normal text characters on the screen. However, this merely

Passwords and security in WML

191

disguises the data being input by the user – it does not amount to any form of actual data encryption or security. Figure 4.23 shows the syntax for using ‘password’ for the attribute called type.

Figure 4.23 Password values in WML Source: http://www.openwave.com. Openwave Systems, Inc.

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4.13

■ Handling text formatting, tables and images in WML So far, this chapter has looked at the general screen navigation code for decks and cards. However, WML documents can also include other types of content, including various text formatting, screen tables and images. The text formatting elements in WML are similar to ordinary HTML formatting tags. These elements allow the WML programmer to highlight and emphasize text and font styles. Table 4.3 outlines some of the main formatting elements in WML. Throughout the WML program examples the element

has been used to define paragraph tags. The paragraph element is required to enclose all text content and can include attributes to set the text position to left, centre or right of the screen. For example, the command

Centre Text

would align the words ‘Centre Text’ into the centre of the screen. Paragraph attributes can also be used to set line-wrap or no line-wrap, although, it should be noted that the default mode is normally wrap. Table 4.3 Text Formatting Elements in WML Text format element

Purpose of text format element





Renders the text with emphasis Renders bold font Renders the text in italic font Renders text with strong emphasis Renders text with underlining (but be careful not to confuse these with anchors on screen) Renders text with a large font Renders text with a small font Actions a line break (an example of an empty element that is a single element with a closing forward /)




Multiple formatting elements can be used to define the look of text. For example, the bold font can be used with the italic font, so that a sentence is both bold and italicized. However, the elements need to be correctly nested in the program code lines. The element table provides a further formatting mechanism to enable a WML programmer to control the layout of text (and other content, such as graphics and images) in columns and rows. The table element is used along with the table row and table data elements to define the number of columns and rows in a table. Tables cannot be nested and the layout on screen will partly depend upon the mobile phone or other mobile device being used. These devices usually fix the layout, height and width of columns in device-specific table displays. Figure 4.24 provides an example of a two-row, two-column table. It should be noted that the cells in a table could contain either text, links (anchors) or image content.

Handling text formatting, tables and images in WML

193

Lecturer Grades

Aziz	Professor
Mike	Assistant Professor

Figure 4.24 Table formatting in WML Source: http://www.openwave.com. Openwave Systems, Inc.

WML can support basic graphic images; however, like HTML, WML decks cannot contain images directly, but instead include references to images that exist as separate graphics files. The Wireless Bitmap format (WBMP) is the special WAP graphic format used by WML to display images on small, wireless device screens. The img src element is used to display images in WML. Images can be aligned, and the attribute alt is compulsory to specify text to be displayed on the screen in the event that the image does not load properly. Figure 4.25 provides an example of the use of the img src element in WML. Images can also be used as links to other pages (in exactly the same manner as normal HTML web pages). Normally, the linking image will define itself as a link by a border around the graphic image. In Figure 4.20 the link

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is to ‘#card2’. Images can also be vertically and horizontally spaced by use of the respective attributes vspace and hspace.

SBU Crest

Figure 4.25 Using the img element in WML

Note: the use of xHTML provides additional facilities for dynamic graphics that are easier to handle than many versions of WML. For example, Figure 4.26 is a ‘GIF’ file available for xHTML applications.

Figure 4.26 The use of images in xHTML Source: http://www.openwave.com. Openwave Systems, Inc.

4.14

■ Capturing and sending information within the WAP environment Most WML applications are interactive; they require some response from a user in terms of inputting user data, for example asking for personal details

Capturing and sending information within the WAP environment

195

such as name and age, or even requesting credit card details. (Good security over wireless channels is important in ensuring that there are mechanisms to protect the data being transmitted.) This area of data transmission and collection has commercial applications and is particularly important for the existence and development of M-commerce. Within the WML language domain the postfield element is used to specify data fields to be passed to the computer server. The postfield element can be used to post data and also to get data from a computer server. The attributes used within the postfield element are name and value. The name and value attributes are used to specify the key and value to be passed to the server. The function of the name attribute is to identify the data that is being sent and is used (and processed) by the server side of the architecture. The value attribute is used to assign the actual data that is being sent. Once the data is obtained from the user it is sent to the computer server for processing. Most WAP-enabled computer servers would store various scripting programs to deal with the posted data. These scripting programs might be in WML Script or CGI script.3 For example, a scripting program hosted on the computer server could be used to check posted registration details or even passwords. The ‘get’ mechanism within HTTP normally encapsulates the data within the program header. The ‘post’ mechanism puts the data in the body of the program, thereby providing more security to protect it. Secure data transmission is a relatively advanced area of client–server computing and further study would be necessary in order to provide the reader with a deeper understanding of the issues involved. Figure 4.27 provides an example of posting data to a computer web server using the HTTP ‘post’ method that a CGI script is ready to process. The data is sent to the server using the go element. The method attribute is set to ‘post’.

Username

Figure 4.27 Posting data fields

3

The Common Gateway Interface (CGI) is a platform-independent standard that allows a client to execute and/or interact with a program or script running on a server. Currently, the most widely used language for CGI programming is Perl (Practical Extraction and Report Language).

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Please note that you will not be able to try this program out on your own computer because you do not have the CGI script on your system (i.e. the command: http://localhost/cgi-bin/verify.pl will not operate).

4.15

■ Application and web server access security As with E-commerce over the normal wired web, data security is a critical aspect of M-commerce over the wireless web. Within the WAP architecture the WTLS protocol (described in the previous chapter) provides for encrypted and authenticated transmission and communication. Most WAP micro-browsers support the standard ‘basic authentication’ mechanism used in regular wiredweb environments. This constitutes hardware level security. However, in addition, WML and WML Script provide for application level security. Within WML the access element can be used to maintain some level of privacy for a deck by controlling which other decks can have access to it. The access element is contained within the head element. The domain and path attributes are used to determine which other decks can access a particular deck. The access element protects against unwanted access to an application, but it does not protect the actual data within that application. The domain attribute enables a WML programmer to restrict access to a particular deck from URLs from a particular domain. (This is sometimes referred to as a ‘suffix-match restriction’.) The path attribute allows the WML programmer to restrict access to decks residing in a certain location and path on the web server. (This is sometimes known as a ‘prefix-match restriction’.) An example of the access element would be: .

4.16

■ WML Scripting within the WAP environment WML is inherently a static programming domain. Therefore, it does not provide direct facilities to act upon the content. However, the use of WML Script effectively extends WML by providing dynamic rather than static programs. WML Script is often used to utilize and configure the client-side mobile device (e.g. mobile phone). For example, a WML Script residing on a mobile phone (the client-side) may be used to navigate and collate input without continually referring to the computer web server (the server-side). WML Script is a subset of JavaScript; it is based on European Computer Manufacturers Association (ECMA) Script, but is customized to support mobile devices with limited capabilities (e.g. narrow bandwidth and memory). WML Script is defined as a procedural language similar to C. Therefore, an understanding of programming languages, such as, C, C++ and Java, is enormously beneficial in understanding the syntax of WML Script. One of the benefits of the WML Script environment is that it comes with a range of

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197

standard code library functions. Therefore, WML Script programs can be developed in blocks and various functions can be added and joined together. In the wireless world certain code libraries can be pre-installed on a mobile device (e.g. mobile phone) to reduce the amount of code that needs to be downloaded from a computer web server. WML Script files have the extension WMLS (filename.wmls). The study of WML Script is largely outside the scope of this book other than to put into context the software environments found within the wireless world. However, if you already have good programming knowledge of C, C++ or Java then you will have relatively little problem with WML Script. Nevertheless, enough will be explained to enable a reader to pursue further programming study of WML Script (and maybe a number of other procedural languages!) if they so wish. Therefore, the number of program code examples of WML Script that follows is limited, compared with the previous sections on simple WML. Again, the keen reader can pursue the details of WML Script programming from other programming-specific textbooks in the computing domain. The WML Script language is case sensitive and each complete command instruction is known as a statement. The statements in WML Script are (like the Java language) terminated with a semicolon (;). But variable names, function names and other identifiers must use consistent capitalization. WML Script is defined as having three elements: (a) variables

– that hold values;

(b) functions

– that combine values in different ways;

(c) pragmas

– that prepare the compilation.

The purpose of a WML Script is typically to allow manipulation of data by the script within the local device. WML Script possesses functions for controlling the micro-browser and manipulating data variables, together with basic, user interaction functions. Typically, WML Script provides such dynamic functionality as input navigation, input validation, dialogue messages, mathematical operations and string manipulation on data.

4.16.1


Variables Variables, and more particularly variable fields, are used to replace fixed alphanumeric data in run-time (i.e. during the running and operation of WML files and WML Script files). Normally, a variable name will be associated with a particular value. Before a variable can be used, it has to be declared so that the script interpreter can set a field space for it. A variable is declared by use of the var statement which is explained in more detail in the following section on WML Script statements. The text variable fields are known as strings. There are five basic data types (for variables) as follows.

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(a) Boolean representing dichotomous outcomes, such as, ‘yes’ or ‘no’, ‘true’ or ‘false’, ‘off’ or ‘on’, and even ‘1’ or ‘0’. (b) Integer data represented without decimal points (e.g. var example = 3;). (c) Floating-point data represented with decimal points (e.g. var example = 9.35;). (d) String data represented as text (e.g. var example =‘Welcome!’;). (e) Invalid data representing an invalid value resulting from an error of processing (e.g. 1 divided by zero), and mainly used for error detection and notification. Variables within WML Script make use of various operators. There are five main categories of operators: arithmetical (and bit) operators, assignment operators, logical operators, comparison operators and conditional operators. The WML Script environment supports all of the basic binary arithmetical operators. Assignment operators are used to assign values (or totals). The logical operators are used to test results. Table 4.4 lists the main operator types. Table 4.4 WML Script Operators Arithmetical operators:

Assignment operators:

+ – * / div % ++ –

= += -= *= /= div= %=

add numbers (or concatenate strings) subtract multiply divide integer division remainder increment decrement

Bit operators: > & ^ | ~ >>> = >>>= &= ^= |

assign (note: not an equal statement) add number and assign or concatenate string subtract number and assign multiply and assign divide and assign divide integers and assign remainder and assign

Comparison operators: bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise bitwise

left shift right shift AND XOR OR NOT right shift and zero fill left shift and assign right shift and assign right shift, zero fill and assign AND assign XOR assign OR assign


= == !=

less than less than or equal to greater than greater than or equal to is equal to is not equal to

Logical operators: && logical AND || logical OR ! logical NOT

WML Scripting within the WAP environment

4.16.2

199


Functions Functions are bounded sets of operations. A function can be invoked (or called) anywhere in a WML program to perform some type of dynamic, sequenced operation. Values known as arguments and parameters can be passed to a function when it is called. For example:

The above command calls the function ‘Welcome’ in the local file called welcome.wmls and passes the parameter in the variable ‘Hello’. Functions are declared with the keyword function and reside in files that are referred to as compilation units. These can often contain more than one function. However, each compilation unit will normally contain one function that is declared externally (i.e. it is externally visible within the client–server environment); and this is done by using the extern keyword. If this keyword is not declared then the function will not be externally accessible and will only be available to functions in the same local file. A declared function is associated with a unique name and a parameter list (or arguments) to be used by the function, and these follow the function keyword. For example, the command function test(x, y, z) has declared three arguments to be passed on call of this function. Once the function has been declared it is followed by a block statement that is contained within parentheses. The following is an example of a mathematical function to produce the square of a list of integers between 1 and 5 (inclusive): function Square(x) { Return x * x ; } extern function Test() { for (var i=1; i