6G: Sustainable Development for Rural and Remote Communities (Lecture Notes in Networks and Systems, 416) 9811903417, 9789811903410

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Lecture Notes in Networks and Systems 416

Sudhir Dixit Vimal Bhatia Sanjram Premjit Khanganba Anuj Agrawal

6G: Sustainable Development for Rural and Remote Communities

Lecture Notes in Networks and Systems Volume 416

Series Editor Janusz Kacprzyk, Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland Advisory Editors Fernando Gomide, Department of Computer Engineering and Automation—DCA, School of Electrical and Computer Engineering—FEEC, University of Campinas— UNICAMP, São Paulo, Brazil Okyay Kaynak, Department of Electrical and Electronic Engineering, Bogazici University, Istanbul, Turkey Derong Liu, Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, USA Institute of Automation, Chinese Academy of Sciences, Beijing, China Witold Pedrycz, Department of Electrical and Computer Engineering, University of Alberta, Alberta, Canada Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland Marios M. Polycarpou, Department of Electrical and Computer Engineering, KIOS Research Center for Intelligent Systems and Networks, University of Cyprus, Nicosia, Cyprus Imre J. Rudas, Óbuda University, Budapest, Hungary Jun Wang, Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong

The series “Lecture Notes in Networks and Systems” publishes the latest developments in Networks and Systems—quickly, informally and with high quality. Original research reported in proceedings and post-proceedings represents the core of LNNS. Volumes published in LNNS embrace all aspects and subfields of, as well as new challenges in, Networks and Systems. The series contains proceedings and edited volumes in systems and networks, spanning the areas of Cyber-Physical Systems, Autonomous Systems, Sensor Networks, Control Systems, Energy Systems, Automotive Systems, Biological Systems, Vehicular Networking and Connected Vehicles, Aerospace Systems, Automation, Manufacturing, Smart Grids, Nonlinear Systems, Power Systems, Robotics, Social Systems, Economic Systems and other. Of particular value to both the contributors and the readership are the short publication timeframe and the world-wide distribution and exposure which enable both a wide and rapid dissemination of research output. The series covers the theory, applications, and perspectives on the state of the art and future developments relevant to systems and networks, decision making, control, complex processes and related areas, as embedded in the fields of interdisciplinary and applied sciences, engineering, computer science, physics, economics, social, and life sciences, as well as the paradigms and methodologies behind them. Indexed by SCOPUS, INSPEC, WTI Frankfurt eG, zbMATH, SCImago. All books published in the series are submitted for consideration in Web of Science. For proposals from Asia please contact Aninda Bose ([email protected]).

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Sudhir Dixit · Vimal Bhatia · Sanjram Premjit Khanganba · Anuj Agrawal

6G: Sustainable Development for Rural and Remote Communities

Sudhir Dixit Centre for Wireless Communications University of Oulu Oulu, Finland Sanjram Premjit Khanganba Human Factors & Applied Cognition Lab Indian Institute of Technology Indore Indore, Madhya Pradesh, India

Vimal Bhatia Electrical Engineering and Centre for Advanced Electronics Indian Institute of Technology Indore Indore, Madhya Pradesh, India Anuj Agrawal Computer Science and Engineering Indian Institute of Technology Gandhinagar Gandhinagar, Gujarat, India

ISSN 2367-3370 ISSN 2367-3389 (electronic) Lecture Notes in Networks and Systems ISBN 978-981-19-0341-0 ISBN 978-981-19-0339-7 (eBook) https://doi.org/10.1007/978-981-19-0339-7 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Foreword I

The book covers a variety of feasible technology options, both wired and wireless, to enable 6G connectivity in rural and remote regions. Along with the enabling technology options, the book also covers important aspects such as human–computer interaction, business models for the local operator ecosystem, regulatory and rightof-way policies, security and privacy, and future challenges related to technology migration, urbanization, and scalability. A special feature of this book is that it covers both the optical and wireless technology aspects to realize 6G connectivity, which will be interesting to a broad range of researchers and practitioners. This book covers all such technical and non-technical aspects that will be of interest to researchers, decision-makers, academia, social workers, and the casual readers interested in technology/growth/empowerment. Further, the simple explanations, pictorial representations, minimal math, and conversational language will enable all the readers to grasp it, thereby helping them in decision-making and performing comprehensive analysis, which will ultimately benefit themselves and society. In summary, this book is a very interesting read for all, as it explains the technological advances in simple language for the non-expert in the field. It covers advances and challenges across the world in connecting the unconnected using 6G. The book also covers and compares the current connectivity issues in various Indian states including the outcomes of the authors’ visit to rural Madhya Pradesh and the North Eastern region of India. Many potential solutions for policymakers and engineers for improving connectivity and usability with business and entrepreneurship-driven models are covered for both India and Finland. This is very interesting collaborative research by the Indian and Finnish research groups with high impact for upliftment of rural and remote communities of both countries and the world. I congratulate the authors for writing this futuristic book and recommend it to all to read. 05 March 2022

Shri Shankar Lalwani Member of Parliament (Lok Sabha) Indore, Madhya Pradesh, India Member Standing Committee on Urban Development

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Foreword II

Mobile technologies have dramatically changed societies worldwide and have become essential parts of critical infrastructure. The first two generations brought voice connectivity to our pockets, and 3rd and 4th generation mobile internet connectivity. Now, with 5G and next with 6G, the pervasive digitalization of societies will dramatically change our daily routines. This development has taken place mainly due to the interests of developed economies. Most recently, 5G standard development has been driven by improving the economic efficiency of such countries. At the same time, increasing concerns about sustainable development worldwide are gaining more space in governments’ technology agendas. Sustainability involves all segments of society, and technological innovations have a crucial role in solving many burning problems. Wireless technologies are in a key position in most of the seventeen United Nations Sustainability Development Goals (UN SDGs). The global community has widely accepted UN SDGs to the center of 6G development. So far, only technical requirements via several Key Performance Indicators (KPIs) have been addressed when developing mobile cellular systems for the future. Key Value Indicators (KVIs) are also being defined for the global 6G standards development under several major 6G research programs, particularly those operating within Europe. It is fair to say that the change in attitudes is taking place now, and 6G can be expected to better answer the needs of SDGs. Remote areas connectivity solutions are in a vital position when developing 6G. The future of digital societies depends on always-on connectivity. The quality of life in developing regions can be drastically improved via reasonable and affordable solutions matching the local needs. More robust solutions for providing electricity to maintain networks and provisioning backhaul solutions are needed. New ways of thinking maybe necessary for service provisioning—what does the quality of service mean in remote sparsely populated areas compared to metropolitan areas? Besides novel technical solutions, innovative thinking is required in economics, politics, and regulation. The challenges mentioned above have been studied in collaboration with the 6G Flagship Program at the University of Oulu and a SPARC funded project within vii

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IIT Indore. The project team has captured some of the key challenges by going through connectivity coverage, user challenges, and developments across the world with detailed case studies in diverse topography of India. However, this is only the beginning of a longer journey deserving more research efforts in the future. I hope this book inspires both the R&D community and decision-makers to better understand and solve the urgent needs for sustainable development for a better future! 05 March 2022

Matti Latva-aho Director of 6G Flagship Centre for Wireless Communications University of Oulu FINLAND

Preface

5G brings enhanced quality of service (QoS) to the existing users via the technologies providing higher capacity, lower latency, higher reliability, massive connectivity, among others. However, the fact that about half of the global population has no access to the Internet at present has not been considered during the 5G research and development (R&D) and standardization, and hence it has missed on bridging the global digital divide. With the arrival of 5G, the digital divide will broaden further since the focus of 5G R&D has been on improving the existing users’ experience, to provide advanced services, and to increase the network operators’ revenues. As the research on beyond 5G (B5G)/6G communication networks is gaining momentum all over the world, it is necessary to focus on the aspects of connecting the unconnected, bridging the digital divide, and global digital inclusion from the very beginning. As part of the 2030 agenda for United Nations Sustainable Development Goals (UN SDGs), ‘access to Internet as a basic human right around the world’ has been projected as one of the most promising solutions to help achieve these goals. Moreover, it has also been mentioned (and widely accepted) that these goals cannot be achieved without affordable access to Internet by everyone, everywhere. Thus, the focus of B5G/6G research should also be on developing solutions to provide affordable access to Internet to the unconnected population, a majority of which resides in the rural and remote regions of the lower- and middle-income countries. This book provides an overview of the present state of Internet connectivity in different parts of the world, the main reasons behind the current digital divide, important factors to be considered to connect the unconnected and under-connected, various technological options and architectures that can be deployed in the rural and remote regions, techno-economic aspects and local micro-operator ecosystem, human–computer interaction (HCI), and the future challenges to ensure sustainable development of rural regions, and to prevent the digital divide from broadening further. As observed during and after the development of 5G technologies, there has been confusion and debate over ‘5G Vs Fiber’, and questions such as ‘will 5G replace fiber?’ what actually is 5G, and progression of softwarization for networking in general have been posed. However, in the telecommunications infrastructure, the ix

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fiber optics and wireless technologies complement each other. Fiber optics enable the Internet, act as a substrate for the telecom-cloud infrastructure, and form the backbone of long-distance communication, wherein the traffic from the wireless metro/access network aggregates. On the other hand, wireless technology enables last-mile mobile connectivity and is responsible for defining the end-user QoS and quality of experience (QoE). Thus, fiber optics and wireless (no matter whether it is 2G/3G/4G/5G/6G) have coexisted and complemented each other, and will continue to coexist in the future. This book covers both the fiber optics as well as wireless technology aspects to realize 5G and B5G connectivity. The regional demographics play a significant role in defining the telecommunication network coverage and the QoS. Moreover, it is necessary to consider the existing information and communication technology (ICT) infrastructure, and the ongoing projects to develop new technologies, methods, and business models for 5G/B5G connectivity in rural and remote areas. Chapter 1 of this book provides an overview of the broadband infrastructure in different parts of the world including India, Finland, Japan, Africa, Americas, among others. Interesting observations are drawn based on the existing wireless and wired network infrastructure in different countries, and the corresponding performance and QoS of the broadband services in such regions. Emphasis has been laid on the ongoing projects in different countries, region-specific needs, and the diverse challenges that need to be addressed to connect the unconnected rural and remote regions in different parts of the world. Chapter 2 focuses on key considerations to achieve affordable B5G/6G connectivity in rural regions from both the operators’ and users’ perspective. Various challenges to be addressed in the new B5G micro-operator ecosystem to be developed in rural regions are identified. Specifically, power issues, ease-of-use, security, resilience, risk, scalability, and other factors that are crucial for sustainable connectivity in rural regions are described. Special focus has been laid on the need of renewable sources of energy to support the power requirements of the ICT infrastructure to be deployed in the rural and remote regions, where power grids are either not deployed or have limited availability. Chapter 3 describes several promising wireless and fiber optics technology options to connect the unconnected from the view of rural and remote regions’ suitability. In different parts of the world, the presence of fiber optics is different. Moreover, it has been observed that in some regions, the existing and the ongoing fiber-optics deployment is either underutilized or cannot achieve the last-mile connectivity. The discussion on wireless technology options covers such possible scenarios in different parts of the world, where the advanced and affordable wireless options can achieve last-mile connectivity as well as act as wireless backhaul/fronthaul in the regions where fiber-optics networks are either non-existent or hard to be deployed, such as difficult terrains. Special emphasis has been laid on leveraging the existing telecommunications infrastructure in India, and alignment with the ongoing projects, such as BharatNet and others, to realize affordable wireless Internet in the rural regions of India. Moreover, technology options for innovative HCI are elucidated considering the illiterate and digitally disadvantaged rural population with a view to maximize

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the use of devices and service consumption. Security and privacy aspects considering the rural population are also emphasized. While there are different possible ways to connect the unconnected regions, and most of the technology is available currently, as discussed in Chap. 3, the main challenge is to customize and optimize at the systems level to realize affordable 5G/B5G connectivity. Chapter 4 describes various systems architectures to connect the unconnected regions, to improve the connectivity in the under-connected regions, and to provide affordable access to the Internet in the rural regions. Furthermore, the major global initiatives to improve rural and remote connectivity are discussed. In Chap. 5, the techno-economic challenges to reduce CAPEX and OPEX to achieve affordable 6G connectivity in rural and remote regions are discussed. Economic estimates for future communication technologies are also discussed, which will play a crucial role in cost-efficient network planning considering the possible modifications in the future networks. The concept of micro-operator ecosystem is described along with the aspects of sustainability and profitability for rural microoperator ecosystem involving village-level entrepreneurs. Issues related to licensing and permissions are also described for timely deployment of network solutions. The quality of service as well as the diverse service requirements have been evolving with every new generation of communications. Factors such as development of new network applications, gadgets, urbanization, technology migration, sociocultural aspects, and the expected conversion of users from freemium to premium in future necessitates the consideration of future technical challenges to address the aspects such as those related to scalability, sustainability, upgradation, and demand forecasting. Once the unconnected regions are connected, it will be another challenge to prevent the digital divide from broadening further and match the pace of progress in rural regions with that of the urban regions. Chapter 6 describes all the abovementioned aspects, future technologies, and the importance of technology migration. The authors gratefully acknowledge the funding agencies, namely, Ministry of Education (MoE), India; Scheme for Promotion of Academic and Research Collaboration (SPARC), MoE, India; and Ministry of Electronics and Information Technology (MeitY), India that supported the collaborative research of which this book is an outcome. The authors also thank Matti Latva-aho, Renata Kordasne Sebö of the Centre for Wireless Communications, University of Oulu, Finland and 6G Flagship project funded by the Academy of Finland. We also thank the Indian Institute of Technology (IIT) Indore, India, for providing the necessary infrastructure and hospitality during the visits of the faculty and student researchers who contributed to this collaborative research. The authors also acknowledge the members of the Signals and Software Group (SaSg) at the Indian Institute of Technology Indore, namely, Abhijeet Bishnu, Shaik Parvez, Krishnendu S, Pragya Swami, Puneet Singh Thakur, Justin Jose, Abhinav Singh, Deepak Kumar, and Vaishali Sharma for their valuable inputs and suggestions on different technological aspects covered in this book. We also thank IIT Gandhinagar, India, for providing the necessary support. The authors would also like to thank Swati Meherishi, Kamiya Khatter, Sushmitha Shanmuga

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Sundaram, Karthik Raj Selvaraj, and Lokeshwaran M from Springer for their editorial assistance to bring this book to production. Finally yet importantly, we hope that you will enjoy reading this book and bring to our notice any errors or omissions, for which we are solely responsible. Woodside, USA Indore, India Indore, India Gandhinagar, India March 2022

Sudhir Dixit Vimal Bhatia Sanjram Premjit Khanganba Anuj Agrawal

Contents

1 Digital Divide and Its Current State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.1 Current State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.2 Ongoing Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.3 Future Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 The World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.1 Current State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.2 Ongoing Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2.3 Future Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 5 8 8 9 10 10 12 13 14

2 Key Considerations to Achieve 5G and B5G Connectivity in Rural Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Users’ Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.1 Affordability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.2 Ease-of-Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.3 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1.4 Services and Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Operators’ Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Power Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Interference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4 Resilience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5 Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.6 Scalability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17 17 18 18 18 19 19 19 22 22 22 22 23 23

3 Technology Drivers for 6G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Wireless Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.1 Multiple-Input Multiple-Output (MIMO) . . . . . . . . . . . . . . . . 3.1.2 TV White Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.3 mmWave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3.1.4 Beamforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.5 Spectrum Refarming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Fiber Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Leveraging the Deployed Optical Fiber Network . . . . . . . . . . 3.2.2 Exploiting the Power Distribution Network . . . . . . . . . . . . . . 3.3 Technologies for Human–Computer Interaction . . . . . . . . . . . . . . . . . 3.3.1 Users in Rural Regions and the Associated Challenges . . . . 3.3.2 Touch and Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.3 Speech and Gesture-Based Inputs . . . . . . . . . . . . . . . . . . . . . . 3.3.4 HCI for People with Disability . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.5 HCI for Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3.6 Consideration for Elderly Population . . . . . . . . . . . . . . . . . . . 3.3.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.1 Biometric Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Data Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.1 Cloud Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.2 Edge Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30 31 33 35 38 40 41 43 43 44 44 45 46 47 48 49 49 51 53

4 Systems Architecture and Major Global Initiatives . . . . . . . . . . . . . . . . 4.1 Architecture for Connectivity in Rural Regions . . . . . . . . . . . . . . . . . 4.1.1 Remote Regions with no Infrastructure . . . . . . . . . . . . . . . . . . 4.1.2 Regions with Limited Infrastructure . . . . . . . . . . . . . . . . . . . . 4.2 Architectures for Enabling Affordable Service Provisioning in Rural Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Global Initiatives for Rural and Remote Connectivity . . . . . . . . . . . . 4.3.1 6G Flagship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.2 Basic Internet Foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.3 Broadband Commission for Sustainable Development . . . . . 4.3.4 IEEE International Network Generations Roadmap . . . . . . . 4.3.5 Wireless World Research Forum . . . . . . . . . . . . . . . . . . . . . . . 4.3.6 World Bank Digital Development Initiative . . . . . . . . . . . . . . 4.3.7 Internet Society—Wireless for Communities . . . . . . . . . . . . . 4.3.8 SMART Africa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.9 Organization for Economic Co-Operation and Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59 59 60 61

5 Techno-economic Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Economic Estimates for Future Communication Technologies . . . . 5.1.1 Quantum Communication Technology . . . . . . . . . . . . . . . . . . 5.2 CAPEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 OPEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75 75 76 77 78

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Contents

5.4 Micro-operator Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.1 Sustainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.2 Profitability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Licenses and Permissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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6 Future Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 6.1 Differentiated Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 6.2 Demand Forecasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 6.2.1 Urbanization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 6.2.2 First Responder Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 6.3 Technology Migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 6.3.1 Wireless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 6.3.2 Fiber Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 6.4 Haptic Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 6.5 Socio-cultural Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

About the Authors

Sudhir Dixit is a Co-Founder, Senior Fellow, and Evangelist at the Basic Internet Foundation in Oslo, Norway, and heads its US operations. He is also associated with the Academy of Finland Flagship Programme, 6G Flagship, led by the Centre for Wireless Communications, University of Oulu, Finland. From 2015 to 2017 he was the CEO and Co-Founder of a start-up, Skydoot, Inc. From 2009 to 2015, he was a Distinguished Chief Technologist and CTO of the Communications and Media Services for the Americas Region of Hewlett-Packard Enterprise Services in Palo Alto, CA, and the Director of Hewlett-Packard Labs India in Palo Alto and Bangalore. Before joining HP, he held various leadership and engineering positions at BlackBerry, Nokia, NSN, and Verizon Communications. He has been a technical editor of IEEE Communications Magazine and presently chairs the Working Groups 6G Visions and New Directions in Communication at the Wireless World Research Forum (WWRF). He is also the Vice-Chair for Americas at the WWRF. He was on the editorial board of IEEE Spectrum Magazine and sits on the editorial board of Springer’s Wireless Personal Communications Journal. He is a Co-Chair of the Industry Engagement Committee and Co-Chair of the CTU Working Group at the IEEE Future Networks Initiative. In 2018, he was appointed a Distinguished Lecturer by the IEEE Communications Society. From 2010 to 2012, he was an Adjunct Professor of Computer Science at the University of California, Davis, and, since 2010, he has been a Docent at the University of Oulu, Finland, and presently also a VAJRA Adjunct Professor at the Indian Institute of Science, Bangalore, India. A Life Fellow of the IEEE, IET, and IETE, Dixit holds a Ph.D. from the University Strathclyde, Glasgow, UK, and an M.B.A. from the Florida Institute of Technology, Melbourne, Florida. Vimal Bhatia is a Professor of Electrical Engineering and Centre for Advanced Electronics at the Indian Institute of Technology (IIT) Indore, India. He is also currently an Adjunct Faculty at IIT Delhi and IIIT Delhi. He has a mix of academic and industrial experience both in India and the UK. He completed his Ph.D. from the Institute for Digital Communications at The University of Edinburgh, the UK in 2005. His research interests are in the broader areas of wireless and optical communications, xvii

xviii

About the Authors

machine and deep learning, and signal processing with applications to telecommunications, and software product development. He is a PI/co-PI/coordinator for external projects with funding of over USD 17 million from MeitY, DST, UKIERI, MoE, AKA-Finland, TFK-Finland, IUSSTF, and KPMG. He has more than 300 peer-reviewed publications and has filed 13 patents (with 4 granted). He has supervised 15 defended/submitted Ph.D. theses. He is currently a Senior Member of IEEE, Fellow IETE, and certified SCRUM Master. He was also the General Co-Chair for IEEE ANTS 2018, and General Vice-Chair for IEEE ANTS 2017. He has served as founder head of Center for Innovation and Entrepreneurship, Associate Dean R&D and Dean, Academic Affairs. He has delivered many talks, tutorials and conducted faculty development programs for the World Bank’s NPIU TEQIP-III, and invited talks at WWRF46-Paris. He is currently Associate Editor for IETE Technical Review, Frontiers in Communications and Networks, Frontiers in Signal Processing, and IEEE Wireless Communications Letters. Sanjram Premjit Khanganba works as a human factors research practitioner. He has worked in the industry before full-time engagement in academic research. As an Associate Professor at IIT Indore, he is a faculty member of—Discipline of Psychology, Department of Biosciences and Biomedical Engineering, Center for Electric Vehicles and Intelligent Transport Systems, and Centre of Futuristic Defense and Space Technologies. He has been working in the field of Human-Computer Interaction (HCI) for the last 15 years. He earned his Ph.D. from IIT Bombay and an M.Sc. degree from Bangalore University. His scientific research revolves around investigating aspects of applied cognition in system development, design, and evaluation. He has a strong dedication towards addressing issues related to human-system interaction in the pursuit of technological innovation, improvement, and optimal utilization of human capabilities. He emphasizes community-level intervention in addressing real-world problems. He engages local community members in conducting user testing and conceptualizing services. His research contexts range from road safety and complex technological environments to social design. He leads a highly motivated interdisciplinary team of volunteers, U.G. students, and P.G. students with diverse academic backgrounds under the aegis of Focused Research Group in Human Factors. He employs experimental investigation in the laboratory as well as field-testing involving analysis of gaze and electrophysiological data. His research group is actively involved in constantly promoting research activities related to ICT and digital transformation within the framework of community systems primarily connected with remote areas of India’s Northeast Region (NER). His research at ‘Human Factors & Applied Cognition Lab’ concentrates on broad domains of—Automotive & Transport UX, Community Systems, Interactive Systems, Smart Environments & Automated Systems, Medical & Healthcare UI, Assistive Systems for Rehabilitation, and Human Performance. Currently, he is—an International Affiliate of American Psychological Association, a Member of IEEE Special Interest Group in Humanitarian Technology, a Member of Working Committee, Connecting the Unconnected, IEEE Future Networks, a Professional Member of Association for Computing Machinery, and a Life Member of Indian

About the Authors

xix

Society of Ergonomics. He is serving as a member of the Technical Committee of Visual Ergonomics, International Ergonomics Association. He is a founding member of the HCI Professionals Association of India. Anuj Agrawal is an Early Career Research Fellow at the Indian Institute of Technology (IIT) Gandhinagar, India. He received Ph.D. in Electrical Engineering from IIT Indore, India, in 2021. He works in the area of optical networks, multicore fibers, quantum key distribution, optical backhaul/backbone for beyond 5G wireless communications, and research for UN SDGs. He has been actively involved in collaborative research between IIT Indore and the University of Oulu, Finland, on 6G connectivity in rural and remote regions. He was a visiting researcher at the Center for Wireless Communications, University of Oulu, Finland in 2019. He has published several research papers in various leading journals and international conferences and received the best paper award at IEEE ANTS 2018 under the Ph.D. Student Forum track for his work on multicore fiber networks. He is a member of IEEE, OPTICA (formerly OSA), IEEE Communications Society, IEEE Photonics Society, IEEE Future Networks, IEEE Quantum, and the Optical Society of India. He has been actively involved in various volunteering activities such as contributing to IEEE and OPTICA chapters, IEEE ANTS, IEEE WRAP, and peer-reviewing for the journals of IEEE, OPTICA, Springer Nature, Elsevier, Frontiers, and Wiley.

Abbreviations

2D 3D ACSR ADC AfDB AI AP AWGN B5G BBNL BFSI BIF BON bps BS BSNL BTS CAPEX C-Band CCI CLS CoS CR CSCL CSR CTU D2D DAC DAM DC DESI

Two-Dimensional Three-Dimensional Aluminum Conductor Steel-Reinforced Analog to Digital Converter African Development Bank Artificial Intelligence Access Point Additive White Gaussian Noise Beyond 5G Bharat Broadband Network Limited Banking Financial Services and Insurance Basic Internet Foundation Backbone Optical Network Bits Per Second Base Station Bharat Sanchar Nigam Limited Base Transceiver Station Capital Expenditure Conventional Band Child-Computer Interaction Cable Landing Station Class of Service Cognitive Radio Computer-Support for Collaborative Learning Corporate Social Responsibility Connecting the Unconnected Device to Device Digital to Analog Converter Distance Adaptive Modulation Datacenter Digital Economy and Society Index xxi

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DigI DNA DoA DPG EAFRD EEG EM EON EoT EU FCC FD FD-CR FTTH GDP GoF GoI GP GPON GSMA HAP HAPS HCI HD HD-CR HF HP HSBNN IAB ICANN ICT ICT4D IEEE IIT INGR IoH IoT IPTV IRS ITU IVR KPI LEO LTE

Abbreviations

Digital Inclusion Deoxyribonucleic Acid Direction of Arrival Digital Public Goods European Agricultural Fund for Rural Development Electroencephalogram Electromagnetic Elastic Optical Network Everything on Tower European Union Federal Communications Commission Full-duplex Full-duplex Cognitive Radio Fiber to the Home Gross Domestic Product Government of Finland Government of India Gram Panchayat Gigabit Passive Optical Network Global System for Mobile Communications Association High-Altitude Platform High-Altitude Platform Station Human–Computer Interaction Half-duplex Half-duplex Cognitive Radio High Frequency Hewlett Packard High Speed Broadband Network in the North Integrated Access and Backhaul Internet Corporation for Assigned Names and Numbers Information and Communication Technology Information and Communication Technology for Development Institute of Electrical and Electronics Engineers Indian Institute of Technology International Network Generations Roadmap Internet of Health Internet of Things Internet Protocol Television Intelligent Reflecting Surface International Telecommunication Union Interactive Voice Response Key Performance Indicator Low Earth Orbit Long-Term Evolution

Abbreviations

M2M MAC MCF mDC MeitY MIMO ML MMF M-MIMO MNO MoE NBM NFAP NFV NGA NGO NG-PON NKN NLD NOFN NOMA OECD OFC OLT ONT ONU OPEX OPGW O-RAN OSNR OTP PDO PIN PM-WANI PoI PON PoP PU QKD QoE QoS R&D RAN RF

xxiii

Machine to Machine Medium Access Control Multicore Fiber Micro Datacenter Ministry of Electronics and Information Technology Multiple-Input Multiple-Output Machine Learning Multimode Fiber Massive-MIMO Mobile Network Operator Ministry of Education National Broadband Mission National Frequency Allocation Plan Network Function Virtualization Next Generation Access Non-Governmental Organization Next-Generation Passive Optical Network National Knowledge Network National Long-distance Provider National Optical Fiber Network Non-Orthogonal Multiple Access Organization for Economic Co-operation and Development Optical Fiber Cable Optical Line Terminal Optical Network Terminal Optical Network Unit Operational Expenditure Optical Ground Wire Open Radio Access Network Optical Signal to Noise Ratio One Time Password Public Data Office Personal Identification Number Prime Minister Wi-Fi Access Network Point of Interconnection Passive Optical Network Point of Presence Primary User Quantum Key Distribution Quality of Experience Quality of Service Research and Development Radio Access Network Radio Frequency

xxiv

RoI RoW RSS RU SAARC SBS SDG SDM SDN SINR SL SLA SNR SP SPARC SS-FON SSL SSMF STL SU TDM TRAI TRN TV TVWS UAV UE UHF UI UK UL UM-MIMO UN UNESCO URLLC USA VHetNet VHF VLE VNF VNI VR W4C WBAN

Abbreviations

Return on Investment Right of Way Reconfigurable Smart Surface Radio Unit South Asian Association for Regional Cooperation Small Base Station Sustainable Development Goals Space Division Multiplexing Software Defined Networking Signal to Interference and Noise Ratio Supervised Learning Service Level Agreement Signal to Noise Ratio Service Provider Scheme for Promotion of Academic and Research Collaboration Spectrally-Spatially Flexible Optical Network Semi-supervised Learning Standard Single-Mode Fiber Sterlite Technologies Limited Secondary User Time Division Multiplexing Telecom Regulatory Authority of India Trusted Repeater Node Television Television White Space Unmanned Aerial Vehicle User Equipment Ultra-High Frequency User Interface United Kingdom Unsupervised Learning Ultra-Massive-MIMO United Nations United Nations Educational Scientific and Cultural Organization Ultra-Reliable Low-Latency Communication United States of America Vertical Heterogeneous Network Very High Frequency Village Level Entrepreneur Virtual Network Function Visual Networking Index Virtual Reality Wireless for Communities Wireless Body Area Network

Abbreviations

WDM WMD WRAN WWRF XGS-PON

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Wavelength Division Multiplexing Weapons of Mass Destruction Wireless Radio Access Network Wireless World Research Forum 10 Gigabit Symmetrical Passive Optical Network

List of Figures

Fig. 1.1 Fig. 1.2 Fig. 1.3 Fig. 1.4 Fig. 2.1 Fig. 2.2 Fig. 2.3 Fig. 3.1 Fig. 3.2 Fig. 3.3 Fig. 3.4 Fig. 3.5 Fig. 3.6 Fig. 3.7 Fig. 3.8 Fig. 3.9 Fig. 3.10 Fig. 3.11 Fig. 3.12

Rural population and the population unconnected to the Internet in different countries [5, 6] . . . . . . . . . . . . . . . . . . . . Crucial aspects of rural connectivity . . . . . . . . . . . . . . . . . . . . . . . . Classification of global population to determine the technological challenges in connecting the unconnected . . . . . Growth of Internet subscribers in India in the last five years . . . . . Share of the population with access to electricity until 2019 [1, 2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solar resource map indicating the photovoltaic power potential in different parts of the world [4] . . . . . . . . . . . . . . . . . . . Wind resource map indicating the mean wind speed in different parts of the world [5] . . . . . . . . . . . . . . . . . . . . . . . . . . . mmWave connectivity fabric [28] . . . . . . . . . . . . . . . . . . . . . . . . . . mmWave coverage in shared spectrum [28] . . . . . . . . . . . . . . . . . . Outdoor mmWave applications [31] . . . . . . . . . . . . . . . . . . . . . . . . Hybrid-beamforming transmitter–receiver architecture for UM-MIMO system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spectrum availability for mobile broadband and sections of spectrum unsuitable for information transfer . . . . . . . . . . . . . . . ITU interactive transmission map [40] . . . . . . . . . . . . . . . . . . . . . . The predicted growth of global Internet traffic as per the Cisco Visual Networking Index (VNI) forecast 2017–2022 [42] . . . . . . . Role of optical networks in a Telecom-Cloud Infrastructure [43] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concept diagram of rural connectivity under BharatNet [44] . . . . Musapuri village in the Bhagwanpura block of Khargone, Madhya Pradesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFC deployed/proposed in the Bhagwanpura block under BharatNet [45] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Duct laying and GPON installation under the BharatNet [48] . . . .

2 3 4 6 20 20 21 28 29 29 32 33 33 34 35 36 37 37 38

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Fig. 3.13 Fig. 3.14 Fig. 3.15 Fig. 3.16 Fig. 3.17 Fig. 3.18 Fig. 3.19 Fig. 3.20 Fig. 3.21 Fig. 3.22 Fig. 4.1

Fig. 4.2 Fig. 4.3 Fig. 4.4 Fig. 4.5 Fig. 4.6 Fig. 4.7 Fig. 4.8 Fig. 4.9 Fig. 4.10 Fig. 4.11 Fig. 4.12 Fig. 5.1 Fig. 5.2 Fig. 5.3 Fig. 6.1 Fig. 6.2 Fig. 6.3 Fig. 6.4 Fig. 6.5

Fig. 6.6 Fig. 6.7

List of Figures

Transmission lines installed in the hilly regions of a Jammu and Kashmir [49] and b North—East region of India . . . . . . . . . . Overhead OPGW installation in POWERTEL [50] . . . . . . . . . . . . An illustration of the power of multi-mode HCI on user experience. (Courtesy HP Labs India) . . . . . . . . . . . . . . . . . . . . . . . People riding on bullock cart in Musapuri . . . . . . . . . . . . . . . . . . . A representative kutcha house at Musapuri . . . . . . . . . . . . . . . . . . . Cybercrime victims in different countries in 2019 [89] . . . . . . . . . Top 5 countries affected by ransomware attacks in the Q3 of 2020 [90] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Illustration of cloud storage in rural areas . . . . . . . . . . . . . . . . . . . . Illustration of an edge storage-enabled cellular network . . . . . . . . System model for device-to-device storage . . . . . . . . . . . . . . . . . . . Most common backhaul options to provide connectivity in rural/remote regions: a Fiber backhaul, b Microwave backhaul, and c Satellite backhaul . . . . . . . . . . . . . . . . . . . . . . . . . . Technology options to connect remote regions with no infrastructure [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solution to extend coverage in the holes using small cells [1] . . . . Connecting the rural clustered establishments using beamforming [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Basic concept of Frugal 5G [2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . Architecture of Frugal 5G [2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The concept of EoT [3, 4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bluetown’s microwave backhaul mesh network [3, 4] . . . . . . . . . . Architecture for rural connectivity by C-DOT [5] . . . . . . . . . . . . . Freemium model for access to heavy and lite bandwidth by rural consumers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A holistic view of rural connectivity infrastructure with freemium service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Popular regional content sharing during low congestion in a preemptive way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Funding for quantum initiatives around the world [1] . . . . . . . . . . Market growth forecast for QKD systems [2] . . . . . . . . . . . . . . . . . Micro-operator concept and ecosystem [3] . . . . . . . . . . . . . . . . . . . a Interweave CR scenario and b Underlay CR scenario . . . . . . . . IRS system model [16] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Various use-cases for the HAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . Factors necessitating the need of capacity enhancement of optical networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Increased capacity requirement in the B5G/6G era for submarine, terrestrial backbone, and middle/last-mile optical networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WDM fixed grid versus EON flexible grid . . . . . . . . . . . . . . . . . . . Multicore fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39 40 41 42 42 47 48 50 52 52

60 61 62 63 63 64 65 65 67 68 68 69 76 77 79 83 85 86 87

89 90 90

List of Figures

Fig. 6.8 Fig. 6.9 Fig. 6.10 Fig. 6.11 Fig. 6.12 Fig. 6.13

Difference between classical communication and QKD secured communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quantum–classical coexistence in optical networks . . . . . . . . . . . . Seismic-risk aware optical network densification . . . . . . . . . . . . . . Infrastructure cost of primary and backup paths in optical networks [52] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A representative mDC [40] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fog-computing enabled by high-capacity and low-latency optical networks interconnecting the mDCs . . . . . . . . . . . . . . . . . .

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92 94 95 96 97 97

Chapter 1

Digital Divide and Its Current State

Digital divide refers to the disparity among people living in various parts of the world, different organizations, as well as among geographic regions in terms of the accessibility to information and communication technology (ICT) resources [1, 2]. There are several other possible ways to define the digital divide depending on the reasons behind it including the non-availability of ICT services, ability to consume ICT services, among others. It is observed that the primary reason behind the current state of digital divide is the unavailability of ICT infrastructure in the rural and remote regions. However, to assess the digital divide in a region, it is necessary to capture the social, economic, cultural, and political aspects as well [2]. Bridging the digital divide requires efforts towards digital cooperation among all the stakeholders. For large sections of the global society, the disadvantages associated with being unable to access digital technologies are enormous. Regardless of how difficult the task is, wider efforts to reduce inequality need to have dedicated efforts to connect everyone. The disabled, the elderly, the poor, and the digitally illiterate sections of the society need special attention for digital empowerment. With a universal perspective, closing the gap is one of the greatest equalizers in promoting equality. The role digital technologies have played during COVID-19 pandemic [3] cannot be emphasized enough. Imagine the massive scale of this challenge if the world had to face it two decades ago, when we did not have the option to navigate life from our homes using fast internet, online services, and smart ICT devices. The pandemic has led to an inevitable surge in the use of digital technologies as the world had to adjust to new ways of work, lifestyle, and social behavior [4]. Unleashing the transformative power of digital technology requires joint efforts involving multiple stakeholders, such as governments, tech companies, civil society, policymakers, researchers, communities, among others. Industrial revolution 4.0 will not accelerate without harnessing the potential of digital technology.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_1

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1 Digital Divide and Its Current State

Fig. 1.1 Rural population and the population unconnected to the Internet in different countries [5, 6]

To establish or maintain telecommunications connectivity in a geographical region, the demographics of that region play a significant role to define the telecommunications network coverage and the quality of service (QoS). For example, the percentage of rural population in a country is one of the most important metrics to be considered while developing solutions to connect the unconnected population residing in the rural regions and to bridge the digital divide. It is observed that the share of the rural population in the total population of different countries of the world is different, as shown in Fig. 1.1. In India, over 65% of the population live in the rural areas [5, 7], whereas in the European Union, such as in Belgium, Finland, Germany, Switzerland, and Austria, the percentage rural population is about 2%, 14%, 24%, 26%, and 44%, respectively, of the total population [5, 6]. In the African and Asian countries, the share of rural population is usually higher than that in Europe and the Americas. However, this is not the case for all the countries. For instance, the rural population in Qatar is about 4%, which is lesser than most of the countries in the world. Similarly, South Africa has lower percentage of the rural population than Austria. Russia, a Eurasian country, has about 27% of the rural population. It is known that, currently, just over 50% of the global population has access to the Internet, where most of the unconnected population belongs to the rural and remote regions of the developing countries. As per the International Telecommunication Union (ITU)’s ‘Facts and Figures 2020’ report [8], in the least developed countries, about 17% of the rural population live in regions with no mobile network coverage, and only a 2G network is available to about 19% of the rural population. This can also be observed in Fig. 1.1, where the countries with the most unconnected population are among the least developed countries having a large percentage of the rural population.

1 Digital Divide and Its Current State

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Fig. 1.2 Crucial aspects of rural connectivity

In most of the developed countries, the population unconnected to the internet is lower than their rural population, which indicates a lower digital divide in the developed countries. One of the main reasons behind the unconnected population in the developed countries is the population living in the remote regions, having sparse and clustered settlements. However, this is not the case with some of the under-developed countries such as Nigeria, Afghanistan, Ethiopia, Niger, among others, where most of the population is rural. Thus, economical divide between the developing and the developed countries has a major implication on the current global digital divide along with the national rural–urban divides of different countries. The challenges in connecting the unconnected rural and remote regions of the world are different for different countries that depend on many factors, for instance, the availability of power grid, optical fiber cable (OFC) penetration, digital literacy, affordability, among others, which will need efforts and support- financial, political, as well as technical, at both the national and international level to bridge the global digital divide. Some of the most crucial aspects of the rural connectivity are shown in Fig. 1.2. Among these aspects, low population density is common in the rural regions of almost

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1 Digital Divide and Its Current State

Fig. 1.3 Classification of global population to determine the technological challenges in connecting the unconnected

all the countries as compared to its urban regions. However, this is not true beyond the national and continental boundaries. For instance, in the western European countries like Finland, the population density is about 18/km2 , whereas in Nigeria, it is about 226/km2 . Thus, the technological challenges in establishing the connectivity in the least developed countries are not the same as that for the rural/remote connectivity in the developed regions. Similarly, clustered settlement might not be the case for all the unconnected regions in the world, especially for the low-income countries like Ethiopia, Afghanistan, Nepal, and the countries with tribal population such as Papua New Guinea. Deployment of backhaul networks is one of the greatest challenges to be met to provide connectivity in the unconnected regions. The remote-rural regions of developed countries, where population density is very low, such as in Northern Finland it is about 0.17/km2 , development and installation of backhaul using technologies such as multi-hop wireless backhaul, satellite-based backhaul, or others will be required. However, for developing countries, where the percentage of the rural population is higher (say >50%) and the population density is also much higher than in some of the developed countries, the conventional OFC backhaul, viz., passive optical network (PON) should be preferred due to the number of people being connected, and the anticipated high bandwidth consumption in the future. Figure 1.3 shows a classification of population, which is important to understand the technological challenges and the preferred technologies to connect the unconnected global population. While most of the urban population is already connected, some of the remote-urban regions (i.e., regions having strong economy, developed infrastructure, digitally literate population, and access to other basic facilities) to be connected have different challenges than those for the rural regions. For instance, in remote-urban regions, affordability to pay for ICT services and adoption of technology are not among the critical concerns. Furthermore, the applications of communication networks are numerous and different in remote-urban regions than that in the rural regions. Human–computer interaction (HCI) is another key aspect to be

1 Digital Divide and Its Current State

5

addressed to make sure that every individual in the rural regions connects to the telecommunications networks and its applications, where digital literacy and local content creation and consumption will be crucial factors to address. Most of the unconnected sections of the society are concentrated in the rural regions, especially in the least developed countries having a higher share of the rural population than the urban population. The remote-rural regions having sparse and clustered settlements will require a mix of wired (fiber-optics) and wireless technologies to achieve telecommunications connectivity, whereas the rural establishments near the urban locations might be connected by extending the urban network. Thus, the technological challenges and the preferred technology for backhaul and access networks might differ for different regions in the same country. Further, the population density in each country is different, which requires different network architectures and different levels of network coverage. The rural regions have low mobility than their urban counterparts. This fact can aid in the development of lowcost mobile network solutions, whose cost and system complexity increases with mobility requirements. The rural population in the world is decreasing every year, thus, along with the consideration of current demographics, estimation of variations in rural population and their service requirements in the future is necessary for scalable and cost-efficient design of telecommunications networks. In summary, it is observed that to achieve beyond 5G (B5G) connectivity in the rural and remote regions, based on the several aforementioned regional factors, selection of appropriate technology and development of new region-specific solutions and use cases for improving the network coverage, QoS, and revenue stream need to be considered. In addition, the existing ICT infrastructure in a region should be leveraged to minimize the capital expenditure (CAPEX) for the services to be affordable and for the faster deployment of communication networks. To further reflect on the digital divide, its current state in different parts of the world and the efforts being made worldwide towards bridging the digital divide, the current state of telecommunication networks and technologies used in India and other different parts of the world are summarized below along with the major ongoing network deployment projects and possible future directions.

1.1 India In India, there are 795.18 million Internet subscribers as on December 31, 2020 [9], out of which, 308.17 million (38.76%) are rural subscribers and 487.01 million (61.24%) are urban subscribers. Thus, the ratio of rural to urban Internet subscribers in India is 1:1.58. However, the rural to urban population ratio is 1.82:1, which indicates that most of the people unconnected to the Internet are living in the rural India. The total population in India at the end of 2020 was about 1.347 billion, which indicates that out of ~875.55 million (65% of the total population) rural population, only about 35–36% of them are connected to the Internet. Thus, to bridge this digital divide and to connect the unconnected, efforts are being made by the Government of

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1 Digital Divide and Its Current State

Fig. 1.4 Growth of Internet subscribers in India in the last five years

India (GoI), researchers, policymakers, and industrial organizations to develop costefficient, scalable, and sustainable solutions for improving the telecommunications connectivity in the rural India. In Fig. 1.4, the trend of growth of Internet subscribers in India is shown, where it is observed that the number of Internet subscribers in India is rapidly increasing (mainly through mobile networks) and that the digital divide is also decreasing due to the ongoing projects being implemented in India, however, the pace of digital divide reduction is slow. This has, however, picked up pace due to COVID-19, motivating people to connect to Internet for their daily activities. At the end of 2015, out of the total Internet subscribers in India, about 70.6% were urban, and 29.4% were rural subscribers, whereas, at the end of 2020, 61.24% were the urban subscribers and 38.76% were the rural subscribers. Thus, the rural–urban Internet subscriber ratio in India has reduced from 1:1.96 to 1:1.58 in the last five years. This reduction in the digital divide in India has been achieved mainly due to the world’s largest rural broadband project named BharatNet (earlier known as National Optical Fiber Network (NOFN)) project through which all of the 2,50,000 Gram Panchayats (GPs)/village councils (office of village administration) are being connected by OFC to enable broadband connectivity in all the villages (about 6,40,000) of India. However, the current rural–urban Internet subscriber ratio of 1:1.58 is still too low since the rural– urban population ratio in India is 1.82:1. To bridge the national digital divide, the rural–urban Internet subscriber ratio should be about the same as the rural–urban population ratio. Thus, a great challenge lies ahead to connect every individual residing in the rural regions of India to the OFC drop point at the GP level, for which wireless networks will play a major role. Furthermore, providing backhaul connectivity at all the remaining GPs to be connected under the ongoing BharatNet project through feasible/cost-efficient alternative technologies is necessary for the

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GPs and villages where it is either difficult, infeasible, or expensive to dig up for OFC deployment. The BharatNet project extends the OFC network of the national long-distance (NLD) providers of India, namely, Bharat Sanchar Nigam Limited (BSNL) [10], RailTel [11], and POWERTEL [12] to the villages through the gigabit passive optical network (GPON) technology. NLDs connect different regions of India with the rest of the world through their optical fiber networks. RailTel owns a Pan-India optical fiber network with exclusive Right of Way (RoW) along the railway track. POWERTEL is the overhead optical fiber network of the Power Grid Corporation of India (POWERGRID) that uses optical ground wire on power transmission lines. The NLD providers’ networks act as the terrestrial backbone network through which the traffic aggregated from the metro and access networks of different regions of India is communicated to different parts of the world (using undersea OFCs). The current backbone optical network (BON) can handle the existing traffic demands; however, with the increasing traffic demands of existing users and with the increased user base created by the rural connectivity, it is necessary to proactively plan and analyze the solutions for capacity upgrade of BONs to ensure that the future optical networks can handle the traffic aggregated from the Internet users in B5G/6G era with satisfactory QoS. Several other projects are ongoing to improve the connectivity in India, to develop new use cases, and to improve the user experience. Using the NLD providers’ networks as backbone and deploying additional OFC for last-mile connectivity, the National Knowledge Network (NKN) [13] aims to connect all (1500+) universities, research institutions, libraries, laboratories, healthcare facilities, and agricultural institutions across the country. The Railwire Wi-Fi network [14], a collaborative project of RailTel and Google, aims to connect 1600+ railway stations across India, which will be one of the largest public Wi-Fi networks in the world. In this project, Google shall provide the radio access network (RAN) for mobile connectivity using RailTel’s optical fiber network as high-speed end-to-end network. Reliance Jio’s GigaFiber [15] high-speed broadband is being implemented in different cities across India. Several other projects are being implemented for improving the telecommunications connectivity in India by various organizations including Tejas Networks [16] and Sterlite Technologies Limited (STL) [17], both founded in India. However, none of these projects are targeting the 100’s of millions of users living in rural and remote communities as their core expansion strategy. With the expected arrival of 5G mobile communications in 2022 in India, the digital divide is broadening since most of the above-mentioned projects are focused on improving the urban connectivity in 5G/B5G era. In addition to BharatNet, efforts are also being made by RailTel towards contributing to bridging the digital divide in India through its ongoing Railwire Wi-Fi network project. Nevertheless, providing network coverage to villages and GPs with attractive services is likely to pose major challenges both to the policymakers and the service providers.

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1.1.1 Current State The Phase-I of BharatNet was focused mainly on optical fiber technology, under which 1,00,000 GPs were connected by OFC. The Phase-II [18] of BharatNet is being implemented, where other technologies, namely, wireless in unlicensed bands and satellite communication along with underground/overhead OFC have been considered to design backhaul network and connect the remaining GPs. As of 10 May 2021, 1,59,250 GPs out of the total 2,50,000 GPs are connected with OFC and installed with equipment, and a total of 5,21,322 km OFC has been laid [19]. Efforts are also being made to deploy Wi-Fi Hotspots at GP level. As of 10 May 2021, 64,968 Wi-Fi Hotspots have been made active.

1.1.2 Ongoing Projects Under the BharatNet Phase-II [18], average of 5 Wi-Fi access points (APs) are planned to be deployed at each of the 2,50,000 GPs. Initially, 1,05,000 GPs have been identified by agencies to install Wi-Fi [19]. Out of the 5 Wi-Fi APs per GP, 3 APs will be located at government institutions, such as police stations, post offices, schools, health center, etc., and 2 APs will be located at the choice of service providers. Each GP serves about 2.56 villages, which calculates to about 1.95 Wi-Fi APs per village. Thus, under the BharatNet project, a strong backhaul is being built for the rural broadband in India, and 1.95 Wi-Fi APs per village will provide basic Internet connectivity to the village population. However, it is imperative that local entrepreneurs should rise up to install additional APs for better coverage, but this requires novel business models and regulations to enable such an ecosystem to take off. Satellite communication has also been considered under BharatNet Phase-II depending on the terrain conditions for certain geographical regions of India, to connect locations that are difficult to reach using both OFC and wireless. For OFC backhaul, GPON technology has been used, and for wireless backhaul, unlicensed frequency bands of 2.4 and 5 GHz have been considered under BharatNet. More recently, the Prime Minister Wi-Fi Access Network Interface (PM-WANI) [20] scheme has been approved in December 2020 that aims to increase Wi-Fi access across India. As per the National Broadband Mission (NBM) of the GoI, Pan-India OFC deployment is also planned to be increased from the current route length of 2.2 million km to 5 million km, which is estimated to increase fiberization of telecom towers (i.e., to connect the towers with OFC) from current 30% to about 70% of the telecom towers in India. The Railwire Wi-Fi project also aims to connect 200 designated rural railway stations close to the inhabited villages across India as an effort to partially bridge the digital divide. Despite these government efforts and investments, lack of micro-operator ecosystem, lack of capacity to absorb technologies, and governance issues at the local level are going to be major hurdles to internet adoption.

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With the projected broadening of rural–urban digital divide in India in the 5G/B5G era, greater challenges lie ahead to develop advanced and cost-effective solutions to improve the broadband connectivity, network coverage, and QoS in the rural India.

1.1.3 Future Aspects The OFC being deployed under BharatNet connects to 4G base station towers; however, in the 5G/B5G era, the wireless network architecture will be consisting of dense deployment of macro cells and small cells. Further, the population density of rural and urban areas differs significantly, which requires research to be conducted on various technology options to be considered for providing 5G/B5G connectivity in the rural India. Given the differences between population density of rural and urban regions and that between different regions of the world, the solutions to be developed, spectrum handling and licensing, network and device technologies used, and operator ecosystem will be different for rural and urban regions in the upcoming 6G era. In addition to the networking challenges, it is necessary that the developed solutions be affordable, easy-to-use, and secured enough for use by the digitally disadvantaged people living in rural and remote areas of India, especially the digitally illiterate and non-tech-savvy citizens including women and elderly. To achieve 6G connectivity for sustainable development of rural and remote communities, the existing ICT infrastructure, especially the OFC backhaul deployed under BharatNet, should be leveraged to minimize the CAPEX. The research focus should be on affordable wireless broadband Internet backhaul for rural and remote areas to achieve most of the selected sustainability goals defined by the United Nations (UN) sustainable development goals (SDGs) [21] so as not to repeat the mistakes of the past in not including the requirements of the under- and un-connected regions of the world in the objectives of the previous generations of mobile technologies, including up to 5G. It is imperative that such requirements be publicized and highlighted as the standards work for 6G networks begins. The promising technologies to achieve B5G/6G connectivity using advanced wireless technologies such as multiple-input multiple-output (MIMO) and beamforming, exploring unlicensed spectrum, licensed spectrum sharing, and spectrum refarming are mentioned in Sect. 3.1. Further, to improve the network coverage and to reach the remotest areas, the increasing power distribution network can be leveraged to deploy backhaul network using overhead OFC. The ever-increasing bandwidth requirements and diverse service requirements will necessitate capacity enhancement and technology upgradation in backhaul OFC networks as mentioned in Sect. 3.2. To achieve UN SDGs for 2030 such as healthcare, quality education, gender equality, and poverty eradication, it is necessary to develop easy-to-use HCI technologies especially designed for elderly, women, and digitally illiterate people living in rural and remote areas. Section 3.3 mentions such HCI technology options for enabling digitally disadvantaged people to use the facilities such as e-commerce,

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e-health, e-agriculture, distance-education, online banking, mobile payments, and Internet of Things (IoT) for rural regions such as Internet of Cows [22], and others. The storage, encryption, and authentication technologies will affect the security of data and records of rural citizens, as these people are more vulnerable to cyberattacks. The security and storage technologies to be considered are mentioned in Sects. 3.4 and 3.5. Depending on the technologies used, future service requirements, and the resources available, the business opportunities and role of local operators will vary requiring certain key factors to be considered from the operators’ perspective as well along with the users’ perspective (mentioned in Chap. 2) for a sustainable microoperator ecosystem. To prevent broadening of digital divide in the future, and to keep the micro-operator ecosystem sustainable and profitable, it is necessary to maintain and upgrade the deployed solutions and migrate to new technologies by conducting periodic assessment based on changing service requirements, demographics, and demand forecasting in rural and remote areas.

1.2 The World In this section, the current state, major ongoing projects, and future aspects of access to Internet in the developed countries of Europe, North and South America, African countries, and Japan are described.

1.2.1 Current State As per the Digital Economy and Society Index (DESI) 2020 report on connectivity in Europe, broadband coverage in the rural areas is still a challenge as 10% of the rural households are not covered by any fixed network and 41% of the rural households are not covered by any next generation access (NGA) technology [23]. 4G networks are available to almost entire European population [23]; however, the digital divide is anticipated to remain in Europe as only 17 member states of the European Union (EU) have assigned the 5G spectrum bands until the end of 2020, with Finland, Germany, Italy, and Hungary being the most 5G ready countries currently. Thus, to highlight the aspects of connectivity in the developed countries of Europe, in the next sections of this chapter, example of Finland is taken as Finland has been among the leading European countries in terms advancements in ICT research, development, and implementation, and it was also the first country in the world to make broadband a legal right from July 1, 2010 with a right to access to a 1 Mpbs broadband connection for all its citizens [24]. In 2010, about 96% of the population was already online in Finland [24], with 76% households having broadband internet access [25]. The Government of Finland (GoF) vowed to connect everyone to a 100 Mbps connection by 2015 [24]. Furthermore, Finland has been a leader in the development of mobile technologies, services, and

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equipment to be used as an illustration. Interestingly, Finland has launched a multibillion-euro project, called 6G Flagship [26], managed and run by the University of Oulu, which has one of the goals to connect the remaining 3.5 billion people (residing mostly in rural regions) in the world who are not yet connected to the Internet. At the end of the year 2018, 93% of the households in Finland had access to the Internet via broadband connection [25] with about 60% of them having access to a fixed broadband network with the speed of at least 100 Mbps [27]. The broadband connections in Finland are mostly wired, based on cable modem connections that use the cable television network and OFC connections [27]. By the end of the year 2018, 33% of the households in Finland were connected to 100 Mbps OFC broadband connections [27]. The OFC deployment is increasing every year in Finland. Though a major region of Finland has access to broadband connection, Lapland, the northernmost region of Finland has limited Internet connectivity. Lapland is a sparsely populated area consisting of 21 municipalities with population density as low as 0.17/km2 . Efforts have been made recently to improve Internet connectivity in northern Finland. The European agricultural fund for rural development (EAFRD) funded project titled ‘High Speed Broadband Network in the North (HSBNN)’ [28] recently won the 2019 Rural Inspiration Award. Under the HSBNN project, 31 villages in Lapland gained access to high-speed internet that connected over 3000 people. Under the 2019 smartest village competition [29], 33 villages located in different parts of Finland with as low as 100 inhabitants competed with the objectives such as improvement in village communication, optical fiber network, digitalization, among others. Japan, being an Island country, has about 6,852 islands, of which about 421 islands are inhabited [30]. Majority of the Japan’s population live in the five mainland islands, namely, Hokkaid¯o, Honsh¯u, Shikoku, Ky¯ush¯u, and Okinawa Island, with about 80% of the Japan’s population living on the Honsh¯u Island. The islands other than the five mainland islands are called remote islands. Out of about 131.1 million population of Japan in 2020, 0.6 million people (less than 0.5% of the total population) live on the 416 inhabited remote islands, with about 70% of the remote islands having a population of 500 inhabitants or less [30]. Japan is among the heavily forested countries of the world and most of its regions are mountainous. The geography of Japan makes it difficult to install telecommunications networks. Moreover, the frequent earthquakes, tsunamis, and typhoons make the maintenance and restoration of telecommunications infrastructure more challenging. Despite these challenges, Japan has been among the leading countries of the world in terms of internet connectivity. Many people in Japan have multiple mobile phone connections, and hence, as of February 2021, the number of total mobile connections in Japan is about 159.3% of its population [31]. Japan has a low (~8%) rural population and almost all the inhabited regions of Japan have internet coverage. Despite the coverage, about 7– 9% of the population is still unconnected to the Internet due to varying degree of internet penetration among the users that differs with age, income level, and rural and urban regions [31, 32]. This indicates the importance of several other factors to be addressed to close the digital divide, such as affordability and the users’ ability to access the technology, among others, that have been described in the later chapters.

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With the launch of 5G in Japan, the Ministry of Communications of Japan is considering charging the internet users with additional fee to fund the OFC infrastructure to support 5G connectivity in rural and uneconomic regions of Japan [33]. According to the Federal Communications Commission (FCC) estimates, more than 21 million people in the United States do not have internet connectivity and that number grows significantly to 163 million when access to broadband (25 Mbps downstream and 3 Mbps upstream is taken into consideration) [34]. The extent of the challenge is similar in Canada [35]. Like everywhere else, in North America as a whole, these high numbers primarily come from the rural segment of the population. The Internet penetration in the Caribbean is about 48%, in Central America 61%, and in South America 72%. However, a significant number of users lack broadband connectivity and only receive the speeds of 3G or less and fall under the category of under-connected. A majority of those unconnected generally reside in rural and remote areas. Africa has the least internet penetration in the world with only about 22% of the continent having access to the internet [36, 8]. Most of the African countries have a high share of rural population, and only about 6% of the rural population of Africa had internet access at home until 2019, whereas in urban Africa, about 28% of the population has internet access at home [8]. Furthermore, Africa has the highest percentage of 2G and 3G users as compared to the other continents, and only about 44% of the total mobile network users are using 4G, as per the ITU Facts and Figures 2020 report on measuring digital development [8]. Out of the total 4G users in Africa, 77% are from urban regions and only 22% are from the rural regions of Africa. The primary reason behind this is the lack of backbone and backhaul telecom infrastructure. Another crucial factor is the access to computer at home in Africa, which is the lowest in the world with only 2% and 17% of the rural and urban population, respectively. Thus, as compared to the other parts of the world, greater challenges lie ahead to provide internet connectivity in Africa.

1.2.2 Ongoing Projects As per the ‘Digital Infrastructure Strategy’ [37] published in October 2018 by the Ministry of Transport and Communications of GoF, Finland aims to achieve 100 Mbps for all households by 2025 with the possibility to increase it to 1 Gbps in future. A balanced co-development of fixed and wireless connections will be implemented as per the strategy. Measures for promoting the implementation of 5G and supporting OFC construction have been identified in the strategy in line with global development trends, such as augmented reality, the growing role of artificial intelligence (AI), automation, IoT, machine to machine (M2M) communication, robotization, and virtual reality in future applications and services. For the construction of 5G networks, the 3.5 GHz (3400–3800 MHz) and 26 GHz (24.25–27.5 GHz) radio spectrum have been specified [37]. The measures proposed in the strategy also involve, among other things, streamlining the network permit

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and construction procedures for cost-efficient construction of OFC networks with the drafting of the Highways Act. In Japan, testing of 5G systems in actual deployments began in 2019 with mobile operators providing pre-services such as high-definition video streaming, multi-angle viewing experiences of sports and entertainment, among others, in the region. The roll-out of commercial 5G services started in March 2020 and is planned to be deployed in almost all the regions across Japan [38]. Moreover, Japan is among the frontrunners of 6G research and development with the country aiming to develop the technology for 6G systems by 2025 and to commercially launch 6G by 2030. Japan’s Beyond 5G Consortium has signed an agreement with the 6G Flagship Programme to conduct joint research on 6G. There are numerous initiatives that started since the onset of the COVID-19 pandemic in the year 2020 by many states in the United States [39], totaling in investments in billions of dollars [39, 40]. Those living in sparsely populated remote countryside are typically served via satellite, mobile broadband, or microwave backhaul networks. The network architectures being proposed or implemented are no different than those proposed in other parts of the world and discussed in Chap. 4. Microsoft’s Airband Initiative is pursuing the television white space (TVWS) approach, Tesla is looking into high altitude platforms (HAPs), and the mobile operators are considering 5G and B5G technologies to reach the rural population. From the network architecture perspective, to reach the rural population in Latin America, there is a significant interest in the TVWS and satellite technologies. Some operators are interested in deploying open radio access networks (O-RAN) compliant architecture to deliver 4G services in rural areas [41–43]. Otherwise, all the other architectures discussed in Chap. 4 are good candidates for Latin America as well depending on the local geography, use cases and backhaul technologies that may be available and affordable.

1.2.3 Future Aspects With the arrival of 5G in Finland, it is necessary to take measures for bridging the digital divide between urban and rural/sparsely populated regions of Finland in the B5G/6G era. The OFC backhaul networks in Finland may require technology migration in PON as well as the core network to support the ever-increasing bandwidth demands in the access networks. The status of broadband network evolution in other developed countries is along the same lines, but with different timelines and network architectures. Due to the factors such as aging population, decline in population and birthrate, Japan aims to use 5G to improve the quality of life and employment, and labor productivity in the country. Pan-Japan 5G deployment is planned, however, ensuring the feasibility of business, which might leave some of the remote islands without 5G services. Moreover, the population in the remote islands is gradually decreasing. For instance, the town of ‘Ama’, consisting of an island of about 33.4 km2 had

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about 2,672 inhabitants in the year 2000, and gradually decreased to about 2,353 inhabitants in 2015 despite having a good ICT infrastructure in the town, where fiber to the home (FTTH) broadband became available across the entire town in 2011 [44]. With the arrival of 5G, a major challenge in Japan is to ensure there is no digital divide between the mainland and the remote islands, to promote ICT for empowerment of the population living in the remote islands through 5G/6G, and to improve internet penetration in the regions where ICT services are already available by focusing on technical, economical, and socio-cultural aspects.

References 1. Measuring the digital divide in the Asia-Pacific region for the United Nations economic and social commission for Asia and the Pacific (ESCAP), October 2019. https://www.une scap.org/sites/default/files/Measuring%20the%20Digital%20Divide%20in%20the%20AsiaPacific%20Region%20for%20the%20United%20Nations%20Economic%20and%20Social% 20Commission%20for%20Asia%20and%20the%20Pacific_0.pdf. Last Accessed 20 May 2021. (Online) 2. How to measure the digital divide? (2004). https://www.itu.int/osg/spu/ni/digitalbridges/pre sentations/02-Cho-Background.pdf. Last Accessed 20 May 2021. (Online) 3. WHO director-general’s opening remarks at the media briefing on COVID19, March 2020. 4. De R, Pandey N, Pal A (2020) Impact of digital surge during Covid-19 pandemic: a viewpoint on research and practice. Int J Inf Manag 55 5. Rural population (% of total population), The world bank. https://data.worldbank.org/indica tor/SP.RUR.TOTL.ZS. Last Accessed 31 Mar 2021. (Online) 6. Countries in the world by population (2021), Worldometer. https://www.worldometers.info/ world-population/population-by-country/. Last Accessed 31 Mar 2021. (Online) 7. The world bank data: rural population (2017). https://data.worldbank.org/indicator/SP.RUR. TOTL.ZS. Last Accessed 28 July 2019. (Online) 8. Measuring digital development: facts and figures (2020). https://www.itu.int/en/ITU-D/Statis tics/Documents/facts/FactsFigures2020.pdf. Last Accessed 30 Apr 2021. (Online) 9. The Indian telecom services performance indicators, Telecom regulatory authority of India (TRAI), 10 July 2019. https://www.trai.gov.in/sites/default/files/PIR_10072019.pdf. Last Accessed 28 July 2019. (Online) 10. Bharat sanchar nigam limited (BSNL. https://www.bsnl.co.in/. (Online) 11. RailTel corporation. https://www.railtelindia.com/. (Online) 12. POWERTEL. https://www.powergridindia.com/telecom. (Online) 13. National knowledge network. http://nkn.gov.in. (Online) 14. Railwire: RailTel’s express network. https://www.railwire.co.in. (Online) 15. Jio GigaFiber. https://jiofiber.org/. (Online) 16. Tejas networks. https://www.tejasnetworks.com/. (Online) 17. Sterlite technologis limited. https://www.stl.tech/. (Online) 18. Planning for BharatNet phase-II, Sep 2016. http://bbnl.nic.in/WriteReadData/LINKS/Rpt_ Nw_Plg_tool6cad24a7-eea8-4adc-91ff-468d7119eeb0.pdf. Last Accessed 31 July 2019. (Online) 19. Bharat broadband network limited. http://bbnl.nic.in. (Online) 20. PM-WANI central registry, Department of telecommunications. https://pmwani.cdot.in/wani. Last Accessed 20 May 2021. (Online) 21. United Nations sustainable development goals. https://sdgs.un.org/goals. (Online) 22. Huawei: connected cow. https://www.huawei.com/en/technology-insights/industry-insights/ outlook/mobile-broadband/wireless-for-sustainability/cases/game-changer-for-china-dairyfarmers. Last Accessed 31 July 2019. (Online)

References

15

23. Digital economy and society index report 2020—connectivity (2020). https://digital-strategy. ec.europa.eu/en/policies/desi-connectivity. Last Accessed 25 May 2021. (Online) 24. Finland makes broadband a ‘legal right’, 1 July 2010. https://www.bbc.com/news/10461048. Last Accessed 31 July 2019. (Online) 25. Share of households with broadband internet access in Finland from 2003–2018, 10 July 2019. https://www.statista.com/statistics/702541/broadband-internet-household-penetrationfinland/. Last Accessed 31 July 2019. (Online) 26. 6G flagship. https://www.oulu.fi/6gflagship/. (Online) 27. 100Mb broadband available in nearly 60% of households, 17 Apr 2019. https://www.traficom. fi/en/news/100mb-broadband-available-nearly-60-households. Last Accessed 31 July 2019. (Online) 28. Kuitua pohjoiseen—High-speed broadband network in the north, 13 Feb 2019. https://enrd.ec. europa.eu/projects-practice/kuitua-pohjoiseen-high-speed-broadband-network-north_en. Last Accessed 31 July 2019. (Online) 29. Smart villages in Finland. https://www.maaseutu.fi/en/the-rural-network/smart-villages/. Accessed 31 July 2019. (Online) 30. Japan: A Nation of Nearly 7,000 Islands, Nippon, 11 September 2020. https://www.nippon. com/en/japan-data/h00806/. Accessed 5 June 2021. (Online) 31. DIGITAL 2021: JAPAN, Feb 2021. https://datareportal.com/reports/digital-2021-japan. Accessed 5 June 2021. (Online) 32. Internet usage in Japan - statistics & facts, 6 Aug 2020. https://www.statista.com/topics/2361/ internet-usage-in-japan/. Accessed 20 May 2021. (Online) 33. Rural broadband: Japan eyes 5G, while Oz seeks more NBN cash, 2020. https://www.lightread ing.com/asia/rural-broadband-japan-eyes-5g-while-oz-seeks-more-nbn-cash/d/d-id/757249. Accessed 23 May 2021. (Online) 34. America’s Digital Divide, PEW Trust Magazine, 26 July 2019. https://www.pewtrusts.org/en/ trust/archive/summer-2019/americas-digital-divide. Accessed 28 June 2021. (Online) 35. T. Chapman, Poor connection: Examining Canada’s digital divide, McGILL POLICY ASSOCIATION, 10 Nov 2020. https://mcgillpolicyassociation.com/journal/2020/11/10/poor-connec tion-examining-canadas-digital-divide. Accessed 28 June 2021. (Online) 36. Bringing Africa Up to High Speed, International Finance Corporation: World Bank Group. https://www.ifc.org/wps/wcm/connect/news_ext_content/ifc_external_corporate_site/ news+and+events/news/cm-stories/cm-connecting-africa. Accessed 26 May 2021. (Online) 37. Digital infrastructure strategy: Turning Finland into the world leader in communications networks, 02 10 2018. https://www.lvm.fi/en/-/digital-infrastructure-strategy-turning-finlandinto-the-world-leader-in-communications-networks-985076. Accessed 31 Jul 2019. (Online) 38. White Paper: Information and Communications in Japan 2020, 2020. https://www.soumu.go. jp/main_sosiki/joho_tsusin/eng/whitepaper/index.html. Accessed 5 June 2021. (Online) 39. Governors Start 2021 by Expanding Access to Broadband, National Governors Association, 16 Feb 2021. https://www.nga.org/news/commentary/governors-expanding-access-bro adband-2021/. Accessed 28 June 2021. (Online) 40. Rural Broadband Network Solutions, Cisco. https://www.cisco.com/c/en/us/solutions/serviceprovider/rural-broadband.html. Accessed 28 June 2021. (Online) 41. Millicom to deploy O-RAN with Parallel Wireless in Latin America, FIERCE Wireless, 13 May 2021. https://www.fiercewireless.com/operators/millicom-to-deploy-o-ran-parallelwireless-latin-america. Accessed 28 June 2021. (Online) 42. Tigo Colombia will deploy Open RAN in 362 rural sites, TowerOne Wireless, 14 May 2021. https://toweronewireless.com/tigo-colombia-will-deploy-open-ran-in-362-ruralsites/. Accessed 28 June 2021. (Online) 43. Open Access Architecture for Rural Broadband Networks, Cisco. https://www.cisco.com/c/en/ us/solutions/service-provider/rural-broadband/white-paper-sp-open-access.html. Accessed 28 June 2021. (Online) 44. H. Kammura, Utilization of ICT for industrial promotion on a japanese remote island, NETCOM, 2019.

Chapter 2

Key Considerations to Achieve 5G and B5G Connectivity in Rural Areas

In rural regions, various factors may affect network planning and deployment, such as demographics, architectural structure, geomorphic and topographical features of land, current state of development, economic status, and education, among others. For cost-efficient and sustainable realization of B5G/6G connectivity in the rural areas, several factors need to be considered from the perspective of both the users and the network operators. However, a positive aspect of 5G is that it supports a multitude of wireless technologies and standards, working cooperatively, and offering a lot of flexibility in building most affordable radio access networks that also enable highest network performance. It gets even better as the evolution toward B5G and 6G gains momentum as the 6G is being discussed to meet the societal needs as the main driver rather than to meet the stringent engineering performance objectives as in the previous generations of mobile standards.

2.1 Users’ Perspective The network usage and QoS requirements of rural population may vary depending on the enterprises being run in that region, the age of people, devices to be used, and services being offered or planned to be offered in that region. Some of the key considerations to achieve B5G/6G connectivity in rural and remote regions from the users’ perspective are mentioned below. Another important aspect which must be considered is to be sensitive to local culture, traditions, needs, and earn the confidence and trust of the local community.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_2

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2 Key Considerations to Achieve 5G and B5G Connectivity …

2.1.1 Affordability One of the most important factors for successful realization of B5G/6G connectivity in rural and remote regions is the cost of the services to be offered in various regions. Thus, it is necessary to develop solutions that require low-cost of deployment and operation. The regional operators will play a major role in the implementation of the connectivity services in various rural regions. For sustainable implementation, revenue generation models need to be carefully designed so that the residents of rural regions can be attracted to serve as the local operators and accelerate the adoption by the users while maintaining the QoS in their region. Providing declining subsidies to the local operators is one of the possible solutions to initiate the communications and networking services in the rural and remote regions. Some promising technology options for low-cost realization of B5G/6G connectivity in rural regions of the world in general and India in particular are described in Sects. 3.1 and 3.2. Increasing network capabilities, accompanied by increasing cost of service, must be carefully balanced with the resulting increase in value provided and thus charging more for the services.

2.1.2 Ease-of-Use Another major challenge along with the implementation of telecommunications connectivity is to develop user-friendly and easy-to-use gadgets, applications, and user interfaces to enable the residents of rural and remote regions derive maximum benefits of the deployed technology. To achieve the advantages of the B5G/6G connectivity for the maximum numbers of residents such as elderly, challenged, or illiterate people having diverse requirements, special focus needs to be laid on the HCI technology, as described in Sect. 3.3. Moving away from text input–output and point and click seems to be the way forward. The emphasis needs to be on empowerment of individuals so that socioeconomically disadvantaged sections of the society can effectively use ICT. Regardless of ensuring accessibility to the technology, if potential users find the digital services and products difficult to use, they will continue to be most susceptible to digital exclusion. Removal of this obstacle will lead to facilitating effect, and it will go a long way in preparing digital readiness of the target users towards democratization of ICT.

2.1.3 Security In this era of digitalization, where it is expected that the rural regions will be provided with facilities such as online banking, mobile payments, e-verification, biometric

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security, the security of stored data as well as the data transmission need to be ensured. Further, elderly and illiterate people are more prone to be the victim of financial frauds, such as password theft on fake calls. Thus, HCI technology based authentication systems need to be developed for high security. Applying block chain technology with full audit trail for rural population remains an unexplored opportunity.

2.1.4 Services and Applications To achieve faster adoption of Internet, it is important that the relevant applications and services be offered that affect the daily lives of the rural population, and these should be in local language(s). Content generation and curation should be enabled to the local community and preferably managed through local servers but with controls residing at some centralized location(s) for regulatory compliance.

2.2 Operators’ Perspective The leading telcos and service providers may not provide coverage in all the rural and remote regions. Thus, the regional micro-operators will be required to provide last-mile connectivity. This implies lighter regulatory requirements for such rural operators and a supportive government regime. The factors to be considered by the micro-operators and some major challenges for them to provide services in rural and remote regions are detailed below.

2.2.1 Power Issues The communication network technology and infrastructure are highly dependent on the availability of power. Figure 2.1 shows a map indicating the access to electricity in different parts of the world. Although this map shows the country-wide statistics, it can be observed that Africa is the continent with least access to electricity. Moreover, some other countries of the world such as Papua New Guinea, French Guiana, among others, also lack access to electricity. Thus, in the regions with non-availability or limited availability of electricity, efforts for renewable energy generation and consumption must be accelerated to support the communication infrastructure such as the Everything on Tower (EoT) infrastructure mentioned in Chap. 4. Access to electricity and availability of electricity are two different aspects, i.e., even if electrification of a particular region is done, the availability of electricity in a day might be too less to support the energy requirements of communication networks. For instance, in India, 100% village electrification has been achieved recently [3]; however, with the definition that at least 10% of households in every village are

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Fig. 2.1 Share of the population with access to electricity until 2019 [1, 2]

connected to the electric grid. Further, the availability of electricity is about 50% of the time in a day. Nevertheless, efforts are being made to improve both the coverage of electrification and the availability. Figure 2.2 shows the map of photovoltaic power potential in different parts of the world. It can be observed from this map that Africa is one of the most promising

Fig. 2.2 Solar resource map indicating the photovoltaic power potential in different parts of the world [4]

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Fig. 2.3 Wind resource map indicating the mean wind speed in different parts of the world [5]

continents to generate solar energy and to develop solar-powered network solutions to realize a sustainable communication network in the future. Similarly, the potential of wind energy is higher in coastal and hilly regions, as shown in Fig. 2.3. Thus, wind energy-supported ICT solutions such as cable landing stations (CLS), submarine cables, and wet datacenters (DCs) can be deployed in the coastal regions, and the wireless network infrastructure deployed in hilly regions can be supported by wind energy. Besides generating renewable energy, efforts to develop low-power, and renewable energy dependent products must also be taken. While efforts are being made globally to generate renewable and clean energy given the factors such as limited fossil fuels, and climate change, it is necessary to focus on the renewable energy based devices and machines in parallel. For instance, Costa Rica produces nearly 100% renewable energy, however, about 70% of the total energy consumption in Costa Rica comes from oil and gases. To support the communication networks, subsidized or aggressive promotion of renewable energy sources (solar, wind) can help a lot to supplement the distribution through the normal electric grid. Given the present scenario of electrification, it is a major challenge to ensure high availability of communication networks in the rural and remote regions since critical applications such as web-based authentication, online banking, and other electronic services require high availability. Electric supply planning using power backups, lowpower equipment, and leveraging renewable sources of energy, need to be done. In addition to providing all the technical support, the community involvement and leveraging their physical facilities will go a long way to improve the availability metric. Participation of the local community to generate renewable power and volunteering to support the energy requirements of the local network infrastructure could be a big game changer both to reduce cost and to increase service availability.

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2.2.2 Interference Interference management for the wireless communication systems is a big challenge that lies ahead for network and technology planning to achieve B5G/6G connectivity in the rural and remote regions. Foliage losses are one of the major concerns in the rural environment. Depending on the geography, the interference management solutions to be employed in different regions may differ on the basis of weather conditions. Nevertheless, radio interference management in rural areas is much less a problem than in densely populated urban or suburban areas.

2.2.3 Maintenance To ensure high QoS for the services being provided, the operators and the local community should be made skilled enough to maintain and repair the equipment used in the deployed technology. Skill improvement workshops and training sessions need to be provided periodically to generate skilled professionals in the local region. Further, they should be made aware of the latest products and trends in technology, and near-future upgradation requirements. They should view learning digital technologies as pathways to better employment and well-being for themselves and the community.

2.2.4 Resilience Failures are inevitable in communications networks either due to man-made errors or due to the natural calamities such as earthquakes, floods, landslides, and storms. The communication networks should be resilient and survivable against small-scale failures such as a fiber-cut or power supply failures. Further, the restoration times need to be decreased. Network planning to reduce and restore network connectivity against natural disasters must be made on the basis of geomorphic and topographical features of land and weather conditions. As a general rule wired interconnects and backhauls should be avoided and increased emphasis should be on wireless and mesh networks with automatic reconfiguration, including device to device (D2D) and ad hoc networking.

2.2.5 Risk There is a risk associated with the financial investment being made by the local operators, depending on the deployed technology. Thus, the economic planning for

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micro-operator ecosystem needs to ensure the sustainability and profitability of the operators. To encourage local operators, subsidies may be provided to them with minimum income guarantees or reduced tax burden but this must accompany with their performance monitoring through such parameters as the number of subscribers, annual growth rates, and data consumption. Allowing play for the industry verticals, such as healthcare, banking, financial services and insurance (BFSI), agriculture (seeds, fertilizers, and pesticides), and education, can enable micro-operators to generate additional revenues and/or attracting Corporate Social Responsibility (CSR) funds from companies.

2.2.6 Scalability With the introduction of telecommunications connectivity in rural and remote regions, the coverage and user base is expected to increase. Further, the technological regulations and upgrades may affect the type and cost of equipment. With changes in traffic demands and service types resulting from the village empowerment and significant growth subsequent to the deployment of network services, the local operators should be able to accommodate the increasing requirements in their existing infrastructure. Scalablity in the rural environment also means inter-connecting cluster of villages to bring down the CAPEX and OPEX of the infrastructure (for both physical and services platforms).

References 1. Access to Energy, 2019. https://ourworldindata.org/energy-access. Accessed 21 March 2021 2. World Development Indicators, Access to electricity (% of population), 2019. https://databank. worldbank.org/reports.aspx?dsid=2&series=EG.ELC.ACCS.ZS. Accessed 21 March 2021 3. Rural Electrification In India: Customer Behaviour and Demand, https://www.rockefellerfoun dation.org/wp-content/uploads/Rural-Electrification-in-India-Customer-Behaviour-and-Dem and.pdf. Accessed 30 June 2020 4. Global Solar Atlas, Oct 2019. https://globalsolaratlas.info/download/world. Accessed 16 July 2021 5. Global Wind Atlas, 2019. https://s3-eu-west-1.amazonaws.com/globalwindatlas3/HR_posters/ ws_World.pdf. Accessed 16 July 2021

Chapter 3

Technology Drivers for 6G

All generations of mobile and networking solutions have been driven by technology innovations, stringent performance requirements and demanding user expectations. For example, multimedia applications and video streaming proved to be the killer applications for 4G/long-term evolution (LTE) mobile services, and IoT/M2M and ultra-reliable/low latency applications are the key drivers of 5G networks. Therefore, we need to study the potential impact of technologies for B5G and 6G connectivity in rural and remote areas, which is the focus of this chapter. Also, we should look into their relevance to reaching out to these communities.

3.1 Wireless Technology 3.1.1 Multiple-Input Multiple-Output (MIMO) The performance of any wireless communication system is limited by the spectrum availability, laws of electromagnetic propagation, and the principles of information theory. The efficiency of a wireless network may be improved by (1) deploying access points more densely, (2) using more spectrum, (3) increasing the spectral efficiency both in the spectral and temporal dimensions, (4) exploiting spatial diversity, and (5) utilizing adaptive reconfigurability. Use of multiple antennas, known as MIMO technology, is a viable solution for the improvement of spectral efficiency. MIMO technology can be classified as point-to-point MIMO, multiuser MIMO, and massive (M)-MIMO [1, 2]. Applying MIMO to rural connectivity is a novel concept and offers tremendous opportunity to deliver the required capacity and coverage. Coherent superposition of signals is the underlying principle of M-MIMO. Emitted signals add constructively at the intended location and reduce their strength everywhere else [3]. Thus, spatial multiplexing at a base station (BS) enabled with © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_3

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M-MIMO increases capacity many times [4]. M-MIMO is a scalable version of multiuser MIMO. There are some differences between M-MIMO and conventional multiuser MIMO. First, only the base station learns the channel matrix between base station and users. Second, the number of antennas of the base station is typically much larger than the number of antennas on the user device. Third, simple linear signal processing is used for both uplink and downlink. The usage of large number of antennas at the base station not only increases the spectral efficiency of a cell, but also provides good services to many terminals or users simultaneously [1]. Signal processing and resource allocation are also simplified by using a large number of antennas, owing to the phenomenon known as channel hardening. The channel hardening implies that small-scale fading and frequency dependence disappear for a large number of antennas [5]. Another benefit of channel hardening on M-MIMO is that the effective channel seen by each user is like additive white Gaussian noise (AWGN) channel and hence standard channel coding and modulation used for AWGN channel tend to work well in case of M-MIMO [6]. M-MIMO is an enabling technology for enhancing the energy and spectral efficiency, reliability, security, and robustness of future broadband networks. However, in spite of numerous benefits of M-MIMO, its implementation has several challenges such as the need for simple, linear, and real-time processing of the huge amount of generated baseband data [7], need for new and realistic channel characterization and modeling which includes geometry and distribution of antennas, need for accurate channel state information acquisition and feedback mechanism to combat pilot contamination [8].

3.1.2 TV White Space With the exponential increase in the number of wireless devices, the limited licensed spectrum poses a great challenge. Several researchers around the world have found that most licensed bands are either unused or underused [9]. In [10], researchers have shown that in rural and remote areas, the majority of television (TV) spectrum is vacant. These vacant TV bands are referred to as TVWS [11, 12]. Further, newer TV bands have been made vacant after digital switch over in the United Kingdom (UK), Germany, Australia, Singapore [13], and other countries. The powerful propagation characteristics of very high frequency (VHF)/ultra-high frequency (UHF) signals make them ideal for use in rural areas where wired infrastructure is not cost-effective to be deployed, and vegetation makes line-of-sight wireless solutions unreliable. In 2004, the Institute of Electrical and Electronics Engineers (IEEE) 802.22 working group was created, which published the functional requirements for the wireless radio access network (WRAN) system in September 2006 [14]. Later, an amendment was made in 2011 in the physical layer of IEEE 802.22–2011 standards to support enhanced broadband services and monitoring applications [15], and further enhancement to this evolving standard is in draft mode [16]. In [17], the performance of IEEE 802.22–2011 network has been evaluated in the presence of a wireless microphone. Apart from IEEE 802.22, different working groups such as

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IEEE 802.15.4 m and IEEE 802.19.1 of IEEE 802 family have proposed standards for TVWS communication [18]. Additionally, the IEEE Dyspan standards committee has proposed IEEE 1900.x standard for TVWS communication [18]. TVWS can be used for several applications, namely, smart grid and monitoring, broadband service extension, environmental monitoring, critical infrastructure and monitoring, homeland security, smart traffic management, emergency broadband infrastructure, remote medical services, marine broadband services, etc. In other parts of the world, the overall usage of the spectrum in the range of 470– 590 MHz is as low as 4.54% in Singapore, 6.2% in Auckland, 17.4% in Chicago, and 22.57% in Barcelona. In India, according to the Indian National Frequency Allocation Plan (NFAP) 2011 [19], the spectrum band from 400 to 900 MHz is mainly being used for Fixed, Mobile, and Broadcasting services. The digital broadcasting services are operated in the 585–698 MHz. Currently, 470–590 MHz band is used in analog TV transmission [20]. Currently, state broadcaster ‘Doordarshan’ has more than 1400 terrestrial transmitters [21]. The operating frequency of Doordarshan is characterized in three bands: VHF Band-I, VHF Band-II, and UHF Band-IV [21]. Doordarshan plans to completely convert its transmission from analog to digital as telecom regulatory authority of India (TRAI) recommends shutting down of analog transmission by 2023. These bands are likely to be either unlicensed, as in the UK and in Africa, where the regulators have made these bands unlicensed, or lightly licensed. In the Indian context, an investigation of TVWS has been done in Delhi [20] and Southern India. In Maharashtra, India, based on measurements, 80–85% TV band has been found to be vacant in rural areas [20]. The availability of TVWS from 400 to 900 MHz at different times in a day has been measured in Indore, India. The readings were taken at suburban and rural areas around Indore, which represents a significant area of Central India. There are about 650 villages and rural communities which are sparsely populated in distributed communities over a coverage area of 4500 square kilometers. The study shows that 92–98% bands are available with a maximum contiguous bandwidth from 140 to 160 MHz. Hence, there is a vast availability of white space bands that may be utilized for wireless communications for rural broadband.

3.1.3 mmWave There are various ways to increase the capacity of wireless networks that includes more spectrum usage. A huge amount of bandwidth is available in the millimeter wave (mmWave) band, which requires reduced cell sizes and enhanced signal processing techniques to fulfil the demand of capacity for the next decade [22]. The frequency band ranging from 30 GHz to 300 GHz is termed as mmWave spectrum, since it has a wavelength range from 1 to 10 mm. The mmWave band has abundant amount of bandwidth of up to 252 GHz. About 23 GHz bandwidth is being identified for mmWave cellular in the 30–100 GHz bands, excluding the 57–64 GHz oxygen absorption

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band which is best suited for indoor fixed wireless communications [23]. mmWave communications exploit large-scale antenna arrays due to short wavelengths. Thus, highly directional narrow beams are exploited to cut down the interference. mmWave wireless connectivity offers extremely high data rates to support many applications such as short-range communications, vehicular networks, and wireless in-band fronthauling/backhauling, among others [8]. The mm-wave spectrum has already been employed in many applications, for example, radio astronomy [24], radars, military [25], satellite communications [26], and point-to-point communication applications [27], but not for commercial wireless networks. Communication at mmWave frequencies promises to deliver a unifying connectivity fabric virtually to everyone and for everything, and is depicted in Fig. 3.1. The applications of mmWave are immense: wireless local and personal area networks in the unlicensed band, 5G cellular systems, vehicular area networks, ad hoc networks, and wearables’ increased network capacity by aggregating unlicensed spectrum opportunistically, but also to enable new deployment models, such as enterprise mobile broadband or private IoT networks. mmWave spectrum that could simultaneously support mobile communications and backhaul, with the possible convergence of cellular and Wi-Fi services for densely distributed small cells in urban environments for delivering extreme data speeds and capacity, will reshape the mobile experience. Due to spectrum sharing, mmWave co-exists with other users such as satellite operators, military. Due to highly directional beams, spectrum reuse is also explored. By exploring unlicensed spectrum and utilizing mmWaves, both spectrum efficiency and coverage will be enhanced, especially through device-to-device communications. The extended coverage area in mmWave communications is illustrated in Fig. 3.2. mmWave could be used to enable high data rate low latency connections to clouds that permit remote driving of vehicles through new mmWave vehicle-toinfrastructure applications. mmWave is also of interest for high-speed wearable networks that connect cell phones, smartwatches, augmented reality glasses, and

Fig. 3.1 mmWave connectivity fabric [28]

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Fig. 3.2 mmWave coverage in shared spectrum [28]

virtual reality headsets [29, 30]. The outdoor connectivity of mmWave communications is depicted in Fig. 3.3. There are some challenges for cellular communication in mmWave band: 1.

The propagation characteristics of mmWave band are completely different from those in the conventional sub-3-GHz band; hence it requires further efforts for modeling the mmWave channel [32]. The channel characteristics of indoor, outdoor, cellular, fronthaul, and backhaul systems must be modeled carefully. Further, mmWave signals are more prone to high path loss, high penetration loss, severe atmospheric absorption, and more attenuation due to the rain [33]. Thus, these effects must be considered while characterizing mmWave channel.

Fig. 3.3 Outdoor mmWave applications [31]

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2.

Due to extremely low wavelengths, high density of antennas is explored in mmWave communication. Thus, to leverage them, highly precise intelligent beamforming, steering, and tracking techniques should be developed that do not cause interference. Medium access control (MAC) protocols should be redesigned to support highly directional transmission links, extreme low latencies, and high peak data rates. mmWave communications are vulnerable to wiretapping. Hence, highly directive gain antennas should be employed to reduce the leakage to eavesdroppers. The channel state information acquisition becomes very difficult with M-MIMO because of limited radio frequency chain. mmWave voltage-controlled oscillator encounters several design challenges due to very high operating frequency.

3. 4. 5. 6.

3.1.4 Beamforming Beamforming is a spatial filtering operation using antennas to capture or radiate energy in a specific direction over its aperture. It improves the transmit/receive gain as compared to omnidirectional transmission/reception [34]. Advanced communication systems deploy smart antenna systems, which combine array gain with diversity gain along with interference mitigation to further increase the capacity of the communication systems. This is achieved by electronic beam steering using a phased array, which is a multi-element radiation device with a specific geometric configuration. The output spatial power distribution, termed as the array radiation pattern, is determined by the vector sum of the fields radiated by individual elements. It can be expressed in terms of the individual element radiation pattern and the array factor, which is a function of the array geometry and amplitude/phase shifts applied to individual elements [35]. Beamforming can be classified as fixed weight beamforming, and adaptive weight beamforming. In fixed weight beamforming, constant weights (amplitude/phase) are applied in analog or digital domain to steer the beam direction. In adaptive weight beamforming, adaptive weights are applied, which are based on the time-varying direction of arrival (DoA) in analog or digital domain [36]. In temporal domain, the weights can be applied using time delay or equivalently using phase shifter in the analog domain. In digital domain, processing for beamforming is done by using a digital signal processor. Digital domain beamforming provides greater flexibility with more degrees of freedom to implement efficient beamforming algorithms [37]. In frequency domain beamforming, the processing is entirely done in the frequency domain using some transform techniques [37]. The beamforming techniques to be adopted for a given application mainly depends on the capability of transmitter and receiver. At the transmitter, beamforming can be employed between the source and the radiating elements to direct the resulting electromagnetic field in three-dimensional space based on receiver localization, a process known as transmit beamforming. In receivers, beamforming can be employed between the antenna arrays and receiver modules to control the

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spatial directivity of the antenna to signals in its capture range, a technique known as receive beamforming, which generally requires DoA estimation [34]. In a multipath environment, open-loop and closed-loop beamforming can be employed to calculate antenna steering vector. In open-loop beamforming, the transmitter performs channel sounding based on channel reciprocity assumption in order to calculate the elements of the steering matrix. In closed-loop beamforming, the receiver estimates the channel, and information is fed back to the transmitter to obtain steering matrix [38]. The beam patterns are shown in Fig. 3.4 for a typical M-MIMO mmWave setup. The same can be extended for ultra-massive (UM)-MIMO and THz bands for 6G. In Fig. 3.4, on the transmitter side, there are multiple data streams as the input to the baseband precoding block. Digital to analog converters (DACs) and radio frequency (RF) chains are used and their outputs are combined in the RF precoding block. On the receiver side, each signal from the antenna is connected to multiple phase shifters or switches, each for one RF chain and the corresponding analog-to-digital converters (ADCs). The signals from all or some of the antennas are combined to each RF chain separately. Similarly, there could be multiple data streams from the outputs of the baseband decoding block. There are some challenges for beamforming [39]: 1.

2.

3.

4.

Finding the optimal number of RF chains, analog phase shifters, and antenna elements. The objective is to find the optimal capacity under constraints such as hardware complexity and power consumption. Joint design of baseband and RF precoders based on sum rate maximization under the constraint of constant amplitude and quantized phase of analog phase shifter. Optimal beamforming requires full knowledge of the channel state information. However, the limited number of RF chains as compared to the antenna elements is the bottleneck. Thus, the channel estimation for beamforming is an optimization problem, where optimal analog RF transmit-receive beam pairs are determined. In order to reduce the training and feedback overhead, reference signal for joint baseband and RF beamforming must be designed optimally.

3.1.5 Spectrum Refarming Spectrum refarming refers to repurposing spectrum allocated in the past to new generation of wireless technologies to increase its more efficient use and to newer services. For example, the spectrum bands that have been refarmed from 2G and 3G for 4G (LTE) are 850, 900, 1800, 1900/2100, and 2100 MHz. For rural communities, refarming and reuse is a lot easier due to almost absent interference from neighboring cell sites. The coverage-cost conundrum is easily addressed by allowing an increase in the transmit powers of antennas (see Sects. 3.1.1 to 3.1.4). The co-existence of mmWave small cells for local coverage for capacity building and macro-cell for backhaul and long-range coverage is a lot easier for villages than for urban areas.

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Fig. 3.4 Hybrid-beamforming transmitter–receiver architecture for UM-MIMO system

The regulatory regime must be relaxed for extending broadband wireless to villages such that the cost is more affordable and OPEX is minimized. This includes actively exploring the use of the TVWS for backhaul to reach remote areas where population density is sparse and the terrain is difficult to reach (Fig. 3.5).

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Fig. 3.5 Spectrum availability for mobile broadband and sections of spectrum unsuitable for information transfer

3.2 Fiber Optics Currently, optical fiber is the only medium of transmission that can carry the massive amount of data generated globally over long distances. Optical fibers form the backbone of the Internet carry about 99% of the global Internet traffic currently. Figure 3.6 shows the ITU interactive transmission map [40], representing the submarine and terrestrial OFCs deployed worldwide to enable long-distance communication. Until recently, the line rates supported by the standard single-mode fiber (SSMF) equipped wavelength division multiplexing (WDM) networks were sufficient to satisfy the bandwidth demands in the core network. The incessant growth in the global Internet traffic (as shown in Fig. 3.7) has caused ‘capacity crunch’ in the core optical network, and it is a general consensus in the research community that the currently deployed WDM networks will not be able to support line rates above

Fig. 3.6 ITU interactive transmission map [40]

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Fig. 3.7 The predicted growth of global Internet traffic as per the Cisco Visual Networking Index (VNI) forecast 2017–2022 [42]

100 Gbps, which is insufficient in this Zettabyte era [41]. Increasing the number of OFCs is not a feasible solution to this capacity crunch due to high CAPEX associated with the excavation and installation. Moreover, the mechanical factors limit the fiber count per cable. Thus, the spectrum efficiency of core networks is of utmost concern, without which the increased capacity provided by the new OFC deployment will be used up more quickly. Moreover, the existing OFC infrastructure, wherever available, should be leveraged to increase the Internet coverage in the remote regions. Optical networks also serve as a substrate to support inter-DC networking. Some of the nodes of optical networks are connected to the submarine fiber cables. The traffic generated through the access and metro wireless/wired networks is aggregated to the terrestrial optical networks for long-distance communication. Thus, in a telecom-cloud infrastructure as shown in Fig. 3.8, the optical network plays a major role. As the wireless communications technology is advancing to deliver bitrates comparable to the currently deployed optical communications technology, the capacity of backhaul and backbone optical networks need to be increased manifold. The increasing bandwidth demands and diverse QoS requirements in the 5G and beyond wireless communication era necessitate the need of spectrum efficient and dynamic next-generation optical networks. Since the optical networks carry voluminous traffic generated by metro/access networks, DCs, and submarine cables, a network component (node/link) failure results in huge economic losses and disruption of services. Thus, optical network survivability is also an important factor to be considered during network planning, deployment, and operation. The OPEX of optical networks depends significantly on the length of lightpaths. The cost of Internet bandwidth is ~5X times the cost of local bandwidth as the Internet traffic has to traverse through the submarine cables, terrestrial BONs, PONs, and then the wireless network towards the end-user, involving several stages of signal processing and switching and, criss-crossing the networks owned by multiple operators. The core optical networks are reaching the capacity bottleneck

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Fig. 3.8 Role of optical networks in a Telecom-Cloud Infrastructure [43]

and several research efforts are underway to increase the capacity supported by them by exploiting time, frequency, phase, and spatial domains as well as increasing the OFC deployment. On the other hand, the currently deployed metro/access PON (that connects the wireless network to the core optical network) is mainly based on the GPON technology. However, efforts are being made to increase the capacity supported by the PONs (such as next-generation PON (NG-PON) and 10-gigabit symmetrical PON (XGS-PON), given the 5G network densification, thus necessitating PON densification as well as capacity enhancement. Moreover, the advancements in the core optical network technology can be utilized for PONs as well by reconsidering the access network topology given the advantages of edge storage, fog computing, low-cost of local bandwidth, while leveraging the opportunity of fiber densification in the access networks. In the long term, the PON technology migration and topological reconsiderations are required, whereas, to provide connectivity in the unconnected regions, the existing OFC infrastructure must be utilized as well as non-telecom infrastructure may be explored to provide connectivity in the rural and remote regions.

3.2.1 Leveraging the Deployed Optical Fiber Network The NOFN of India, reconceptualized and renamed as BharatNet which will connect all the 2,50,000 GPs of India through OFC will provide middle-mile connectivity for the rural and remote regions of India. Figure 3.9 shows the initial concept of BharatNet, where the existing terrestrial optical networks owned by NLD operators

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Fig. 3.9 Concept diagram of rural connectivity under BharatNet [44]

are being used to extend the coverage towards the rural and remote regions. Additional OFC is being deployed to connect the GPs with the existing NLD networks; and point of presence (PoP) and point of interconnection (PoI) are being established at the block and GP levels under the Bharat Broadband Network Limited (BBNL) domain, i.e., under the BharatNet project. To connect a GP level PoP/PoI to the access provider POP and to the base transceiver station (BTS) for wireless transmission, the access domain is open for private service providers. However, as per the BharatNet Phase2, to provide basic telecommunications connectivity, 3 Wi-Fi APs per GP are being deployed at the government-owned facilities, and 2 Wi-Fi APs as per the choice of the local service provider. Though the BharatNet aims to provide middle-mile connectivity to all the ~6,40,000 villages of India, it is observed that the rural population living in hamlets around the villages will be missed. For instance, a village named Musapuri is located at 21.51°N 75.56°E in the Bhagwanpura block of the Khargone district of Madhya Pradesh. There are about 40 kutcha (i.e., mud) houses in this village (as shown in Fig. 3.10), and there is no telecommunications connectivity at present. The OFC deployment plan in the Bhagwanpura block under the BharatNet project is shown in Fig. 3.11. It can be observed that the small and clustered establishments such as Musapuri (located between Pipaljhopa and Sirwel near the Khaparjamli village) will need additional network deployment to connect them with the OFC being deployed under the BharatNet. A dense OFC infrastructure will be an asset for a nation in the 5G/B5G era. As the studies suggest, a 10% increase in broadband penetration leads to ~1.38%

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Fig. 3.10 Musapuri village in the Bhagwanpura block of Khargone, Madhya Pradesh

Fig. 3.11 OFC deployed/proposed in the Bhagwanpura block under BharatNet [45]

increase in the nation’s gross domestic product (GDP) in developing countries [46]. OFC deployment is increasing globally and is one of the important drivers for the broadband speed at a particular location. For instance, the UK broadband speed was ranked as one of the slowest in Europe as per a recent survey [47], and the primary reason for which is the slow roll-out of OFC in the UK. One of the main challenges in OFC deployment is the cost, time, and obtaining permissions for excavation and duct laying (as shown in Fig. 3.12). Thus, the Pan-India dense deployment of OFC being carried out under the BharatNet project, under which more than 4,52,000 km of OFC has been laid as of September 15, 2020, must be leveraged for connecting the unconnected rural and remote regions. Moreover, the existing GPON technology (shown in Fig. 3.12) adopted under the BharatNet might be migrated to the recently developed

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Fig. 3.12 Duct laying and GPON installation under the BharatNet [48]

NG-PON and XGS-PON technologies along with several possible long-term modifications as described later in Sect. 6.3.2. With the middle-mile connectivity enabled by BharatNet, rural population living in hamlets, and difficult terrain conditions in remote regions, wireless network deployment is unavoidable in the access region to connect the end users. Moreover, in difficult terrain conditions, wireless backhaul is the most suitable and cost-efficient solution. Thus, OFC and wireless network infrastructures positively complement each other and will play an important role in defining the QoS and QoE of connectivity of a region in the 5G/B5G era.

3.2.2 Exploiting the Power Distribution Network POWERGRID is one of the largest transmission utilities of the world and is the only telecom service provider in India having Pan India overhead OFC network. POWERGRID’s telecom network is referred to as POWERTEL. It has a Pan-India OFC network of 60,000+ km, where OFCs are installed on its extra high voltage transmission lines. POWERTEL provides coverage in remote and far-flung areas of India, such as Jammu and Kashmir, and the North-Eastern states. Moreover, POWERTEL is increasing its footprints in Africa, South Asian Association for Regional Cooperation (SAARC) countries, and Gulf countries. Rural electrification has been on the ‘to-do-list’ of the Government much before the rural broadband connectivity. To achieve 100% rural electrification in India, significant efforts have been made to provide electricity in the rural and remote regions including those having difficult terrain and extreme weather conditions. Figure 3.13 shows the transmission lines installed by POWERGRID in the remote and hilly regions of India. Similar power distribution infrastructure is available in various parts of India and other countries. The power distribution network installed in the rural and remote regions can be leveraged to provide broadband connectivity in those regions using the technology adopted by POWERTEL. The most widely used method of overhead OFC deployment is optical ground wire (OPGW) installation, where ground wire of existing transmission lines are replaced by a new type of cable,

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(a)

(b) Fig. 3.13 Transmission lines installed in the hilly regions of a Jammu and Kashmir [49] and b North—East region of India

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Fig. 3.14 Overhead OPGW installation in POWERTEL [50]

viz, OPGW cable having fibers inside and aluminum conductor steel-reinforced (ACSR) ground wires outside, as shown in Fig. 3.14. OPGW installation has several advantages over the conventional underground OFC deployment. OPGW has readily available ‘right of way’ as no forest clearance is required for OPGW installation along the existing transmission lines and towers. Moreover, faster roll-out and easy maintenance are among the main features of OPGW communication networks. Along with the OPGW, the power distribution infrastructure can also be explored as a colocation facility for BTS/radio unit (RU). The migration of overhead power distribution cables to underground cables can be leveraged to reduce the cost of laying duct and additional clearance requirement for underground OFC deployment. Since power availability is necessary to realize true digital connectivity in rural and remote regions with high QoS, for instance, to power the signal transmission equipment and end-user devices, simultaneous roll-out of transmission lines and OFC in the unelectrified regions may be considered.

3.3 Technologies for Human–Computer Interaction At the beginning of the technical advancement of computing, just exceptionally trained personnel could utilize computers, and these were massive and expensive machines only found in specialized industry and research settings. Today, computers are pervasive and the scope of information consumed by users is wide. At the same time, there are increasingly diverse users across nook and corner of the world. Such transformation brings varieties of choices for users to have interactive experience with respect to day-to-day activities, operation of complex systems, and specialized services. For instance, everything starting from the local grocery store to a university course on another continent is just a few clicks away. Unlike few decades back, most of the computer users these days are not given formal training to operate a computer or a handheld device. HCI as a specialized field has emerged to be a body of scientific study encompassing anything that involves an interaction between a user and a system associated with computing technology. In general, it lies in the

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Fig. 3.15 An illustration of the power of multi-mode HCI on user experience. (Courtesy HP Labs India)

intersection between psychology on the one hand, and computer science on the other. The idea of HCI has also evolved and it is not restricted to using a desktop computer or a laptop computer. Current generation of users will find it surreal if they think about massive computer units that used to be the size of an office room the thought of which is rather surprising and intimidating. The field is bound to continue to be a host of interdisciplinary outlooks as there is a growing recognition that understanding human aspects is critical in system design as opposed to considering only engineering (Fig. 3.15). Smart devices today come with gyros and an impressive array of interactionenabling sensors, such as touch-enabled screens, cameras that can potentially recognize hand gestures, handwritten text and symbols and follow gaze, microphone to enable speech-based command and control, speakers to play text with voice, etc. The gyros can easily be trained to recognize how the device is maneuovered (tilt, rotate, shaking, move up or down). What is actually needed is to integrate these interaction modalities with the plethora of applications already available today on smart devices through Google Play and others. Most present-day applications use text, point-and-click, and audio/visual input–output methods to interact with the applications. These interaction modalities would need to be changed or upgraded for the digitally disadvantaged users who are sometimes not literate.

3.3.1 Users in Rural Regions and the Associated Challenges One of the most important concerns for rural communities is the extensive efforts required for digital inclusion. There are three distinctive characteristics in this

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context: (a) digital divide where a section of the society does not have access to ICT, (b) the digital inequality where people are not digitally literate, and (c) lack of infrastructure such as electricity, water, transportation, connectivity [51–54]. Another critical factor is that there is no clear-cut distinction between a group of people having access to ICT and others not having access to it. Instead, the boundary is blurred, and people are situated in multiple groups which are not well-connected to make them function as a system with desired outcomes. For instance, in the villages of Khargone district (Madhya Pradesh state, India), people live in hamlets at a distance of about 3–4 kms from one house to another in the same village. Because of the geographical isolation, residents need to travel from one place to the other where network connectivity is available. People often walk or use bullock carts as the most common mode of transport (Fig. 3.16). This reflects the current condition of digital divide. Existing social structure also plays a role in giving rise to the problem of affordability. In general, the villagers belong to the poorer section of the population and they live in mud houses (Fig. 3.17). The head of the village can get a router installed at his/her home to access internet through government schemes. Such option is a privilege and it is not available for the general public of the village or restricted to the people the head wants to incorporate. Apart from the prevalence of issues related

Fig. 3.16 People riding on bullock cart in Musapuri

Fig. 3.17 A representative kutcha house at Musapuri

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to (un)preferential treatments, the situation implies a lack of awareness among local bodies about the rights and facilities that they are entitled to. On the whole, there is undesirable social reality operating in a much more complex manner which calls for extra efforts at various levels (researchers, community members, non-governmental organizations (NGOs), government bodies, etc.).

3.3.2 Touch and Display Touch is a very well-understood user interface (UI) for app interaction and is combined for the digitally disadvantaged rural users. Since it has also been costoptimized, this UI is perfect for the users who are unable to afford expensive devices.

3.3.3 Speech and Gesture-Based Inputs Similar to touch and speech, it is quite advantageous to integrate both gyro-based gestures with voice commands without any increase in the price of the smart devices since they are already built into them. Visual gestures can also be leveraged by the built-in camera to enable biometric authentication and device/app sign-on. Interactive voice response (IVR) is an important aspect of modern devices. Voice is very natural and easily accessible medium for people in a rural community having almost none or limited training in formal education and digital literacy. It is also useful in conveying the information to visually challenged people. A field study titled, Avaaj Otalo (literally, ‘voice stoop’) conducted in Gujarat used an interactive voice application accessible through basic mobile phone for small-scale farmers [55]. It allowed them to receive relevant information about agriculture, weather, animal husbandry, government schemes. They could also record and post agriculturerelated queries on a question-and-answer forum and receive answers from fellow farmers. Other similar studies on voice user interface for the low-literacy population investigated interaction design issues [56, 57], and compared touchtone to speech [58–60]. In another initiative in Madhya Pradesh, Gyandoot Project linked villagers and government through information kiosks where people had access to multiple government services, and could also file complaints. This project was a pioneer in establishing the idea of rural telecentres in India, establishing itself in more than 600 villages; it also improved digital awareness in rural areas [61]. Similar studies on phone-based systems explored the issues on navigation and adoption of voice-based content and proposed guidelines for successful deployment of voice sites like understanding social context, gaining users’ trust, and providing relevant and concise content [62–64]. Another comprehensive study in Karnataka used HCI and Spoken Web to develop a voice-based employment platform to address rural unemployment

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and concluded that the rural candidates are open to using voice-based technology provided it matches their tendencies [65].

3.3.4 HCI for People with Disability Though it may or may not be immediately apparent, all humans have limitations and capabilities. When it comes to designing systems from the HCI perspective, there is a section of our society which has certain limitations due to their existing condition of disability. This issue is very important in the context of inclusive approach since the impairments they struggle with are of different kinds (e.g., it could be poor vision or movement disability like quadriplegia or tetraplegia). Therefore, the aspect of assistive technology in HCI and prolific development of the sub-field is important in order to overcome the difficulties posed by the disabilities keeping in mind that these users come from all the age groups with diverse requirements. Hence, the task is challenging and requires interdisciplinary and collaborative efforts. Eye detection and tracking is one of the advanced techniques with potential applications used for HCI system interaction, where a camera is mounted over a user’s head and a camera is in front of the user’s eyes [66]. It involves processing of eyeball movements, blinking rate, etc., where the person interacts and operates computers through eye movements. Another interesting approach is that of wearable devices in which a computer is operated using Electroencephalogram (EEG) signals from the brain of the person with severe disability controls movement to perform various functions like control robots, move wheelchair, among others [67]. Gesture-based communication has promising results in the context of HCI where the users rely on sign language/gestures in using interactive devices thus bridging the gap between deaf and dumb [68].

3.3.5 HCI for Children Traditionally, HCI research has focused on the adults in the working environment, but the gradual penetration of technology into our day-to-day life has expanded its scope of relevance. It covers people from almost all age groups, millennials, and post-millennials being the first generation to use computers from early childhood. It is essential to study the context and environment to understand the needs of the young emerging users. This requirement is giving rise to a new area of HCI, i.e., Computer-Support for Collaborative Learning (CSCL) environments [69]. The study of interaction with children and information technology has developed in a research area named Child–Computer Interaction (CCI) [70] which deals with design, evaluation, and usability of interactive systems developed for children [71]. It studies the influence of technology and society. Since games have immersive properties, and they also generate a sense of flow, making the player feel being inside it, they are children’s gateway to learn things as

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well. Thus, it can be incorporated with HCI to make learning engaging and inculcate educational principles [72]. Azim Premji Foundation, a non-governmental organization and another study deployed computer games in the rural area of India and found that e-learning games are beneficial in teaching the rural children English as a second language and other subjects as well [73, 74]. Another longitudinal randomized experiment was conducted by Abhijeet Banerjee, the Nobel laureate in Economics, wherein over more than two years with over 10,000 urban slum students of India were studied by Pratham, a non-governmental organization. The results demonstrated significant gains in mathematics test scores from playing computer games that target mathematics learning [75]. Considering over 65% of the Indian population still reside in rural areas, and most children work in agriculture fields to support the family and do not attend school regularly, HCI can be a necessary tool to teach children by making the education accessible through e-learning. It should also be taken into account that they cannot be taught by only providing computer devices because necessary skills to operate the computer and digital literacy is crucial to help them adapt with a very western concept of e-learning through mobile games. Few studies recognized that games played by urban students are not engaging enough for rural students [76], so they designed and translated the traditional games into videogames keeping the local culture in consideration, and concluded that traditional games aid in learning [77]. Being in technologically advanced times, digital parenting is another critical area where HCI plays a significant role. It is used to observe the physiological parameters like breathing, body temperature, and heartbeats of a toddler to keep the well-being in check [78]. It is also valuable when it comes to the safety and privacy of children at home and especially on the internet as it requires an understanding of digital ethics [79]. Children learn in many ways depending on their needs, interests, and available sources but their development gets hampered if they get affected by any disability or disorders. So, HCI is incorporated using assistive technologies to keep the learning process unhindered. It takes unique approaches to address multiple problems depending on the situation; for example, a child suffering from movement issues will require different methods compared to another child having visual or hearing impairment or a child with neurological dysfunction. Various studies working with deaf children used digital storytelling [80] and used didactic materials in teaching natural sciences [81]. For children’s rehabilitation, Sandlund et al. proposed ‘interactive computer play’ where they can interact and play with the virtual object in a computer-generated environment [82]. It was used in a study for post-operative rehabilitation of children with cerebral palsy and found it to be beneficial as children had better muscle control [83].

3.3.6 Consideration for Elderly Population Elderly people, with their advancing age, face various challenges. The life-span changes related to aging include changes in cognitive-motor coordination such as

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sensory, perceptual, and motor performance. In other words, with aging, there is compromise in the ability to operate in the world effectively. What is important is an orientation of putting extra efforts in investigating the implications of these changes in the contexts of everyday tasks and activities under natural conditions apart from laboratory studies. This will provide better scientific understanding and encourage development of better interfaces for devices and services. Irrespective of rural or urban contexts, there is a need to take care of aging adults. In general, increased life expectancy means we have a larger segment of population older than 65 years of age. It is both socially valuable and cost-effective to support the independence of this aging population in as many of the aspects of their day-to-day activities as possible. Efforts catering to the needs for these citizens in the field of HCI will translate into better autonomy, sense of agency, and dignity in their day-to-day lives. Particularly in the Indian context, it is important to highlight that a large percentage of the elderly population in rural and remote areas of the country needs to be part of the digital inclusion programs.

3.3.7 Summary Social, economic, and cultural factors play a vital role in defining the convenience of accessibility, affordability, and acceptance of technology in daily routine. HCI covers a broad spectrum which takes the personal, social, political, and ethical issues into consideration while designing for humans such as privacy, trust issues, adoption, global usability, and accessibility. HCI professionals aim at designing computers keeping the needs of subpopulation like children, elderly, persons with disabilities, or gender-based requirements in consideration. The culture too plays an essential role in the designing processes, which is evident in the cross-cultural studies in the organizational and global software engineering literature by Hofstede [84, 85]. A survey conducted by Biswas and Langdon [86] on elderly users in Mandi district of Himachal Pradesh suggested that most elderly have never used a computer or a smart TV but most were able to use basic mobiles to make calls and reach to their favorite TV channel as well. They suggested that they are open to technological intervention provided it is interesting and easy to use, like preferring big font size. In the context of Information and Communication Technology for Development (ICT4D), Medhi and others [87] found that irrespective of how efficient a system is, a trustworthy human intermediary is necessary for overall user acceptance. They also reported importance on building skills within the community, a need for a strong value proposition for the services, and the requirement of technological literacy. Likewise, Smyth and others [88] found that user motivation towards a given goal is a necessity in successful ICT4D projects.

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3.4 Security Information related to intelligence, defence, banking, and finance is vulnerable to cyberattacks. Moreover, individuals are subject to identity theft and monetary loss as well. Figure 3.18 shows the number of consumers affected by cybercrimes in ten different countries in the year 2019 [89]. India and the United States had very high number of cybercrime victims in 2019. It has been found that on average, 43% of the consumers affected by cybercrimes in 2019 lost their money. It is estimated that the cyberattacks will result in a global loss of $6 trillion annually by 2021 [90]. Thus, it is the utmost concern of the network operators to secure the critical and confidential information carried over communication networks. Among the various types of cyberattacks, ransomware attacks are the most probable type of attacks that can target the rural community. Ransomware attacks threaten the victim to publish their data or perpetually block access to it unless they pay a ransom. Figure 3.19 shows the top five countries of the world that were affected by ransomware attacks in the third quarter (Q3) of 2020, where it can be seen that India was the most affected by the ransomware attacks followed by the United States. Moreover, a rapid increase in the incidents of ransomware attacks has been observed from Q2 to Q3, as can be seen in Fig. 3.19, where an increase of 436% was observed in Sri Lanka. To prevent the rural users from ransomware attacks, the foremost step is to educate them with the identification and avoidance of ransomware attacks and related practices. Moreover, device level security, network protection, and data encryption

Fig. 3.18 Cybercrime victims in different countries in 2019 [89]

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Fig. 3.19 Top 5 countries affected by ransomware attacks in the Q3 of 2020 [90]

are necessary to be employed in the communication systems with continuous data backups.

3.4.1 Biometric Authentication Biometric-based authentication of an individual is considered as a cornerstone of many security applications. There are several physiological traits (like a fingerprint, deoxyribonucleic acid (DNA), iris, retina, face, etc.) and behavioral traits (like a signature, typing rhythm, voice, etc.), that are unique to an individual and can be used as a biometric signature [91]. The present technological evolution has allowed the use of biometrics in many diverse environments, such as in research laboratories, national security, defense, security printing and minting corporations, surveillance, e-commerce, etc. Nowadays, even devices such as laptops, mobile phones, tablets use fingerprint biometric sensors for individual’s authentication, as these devices contain sensitive information regarding bank account, personal identification number, etc. In today’s world, over 3.4 billion population resides in rural areas [92]. In these areas, often different fraudulent attacks occur by taking advantage of digital illiteracy and lack of awareness of rural people [93]. For government employment schemes, incidents of fake claims have been observed where a person is not eligible under the scheme, but still taking the benefits. In such cases, biometric-based authentication systems can provide a solution that supports the accurate calculation of wages and ensuring that payouts are transferred to the right beneficiary account. Banking and

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finance is also one of the most sensitive sectors where enhancement of security is essential in rural areas. There are different cases of illegal online as well as offline banking transactions where a genuine person is cheated by fraudsters. Most of the existing systems for these transactions are secured by either personal identification number (PIN) or one time password (OTP), which can be easily stolen when a device has been stolen or the owner is asleep or intoxicated. Utilization of biometric-based authentication for such transactions can be a stepping stone to mitigate such types of security threats. As these systems will require biometric trait of every individual in place of PIN/OTP, hence transactions cannot be performed without physical presence of the customers. There is a serious and debilitating scarcity of banking infrastructure in rural areas. This insufficiency indeed hinders the rural population towards utilizing the banking facilities with ease. Due to unavailability of adequate number of branches, villagers get stuck in long queues and struggling for availing their banking facility. As an alternative to conventional banking system, biometric-based mobile banking can also be utilized to provide fraud-resistant and safer mode of digital financial transaction experience to the rural customers. Secure authentication of individuals for proper implementation of different Government schemes and financial transactions in rural areas will contribute to the overall growth of the country. One of the main challenges in majority of the biometric identification frameworks is the possibility to recognize different types of spoofing attacks. In such attacks, the stolen biometrics records can be easily exploited and mimicked by impostors to get unauthorized access to the biometric system, without consent of the genuine user. To prevent such attacks and strengthen the security of conventional biometric sensors, several robust spoof-proof biometric sensing mechanisms are being developed utilizing optical coherence tomography [94], biospeckle analysis [95], pulse oximetry [96], infrared imaging, live speech utterances, and other technologies. In future, these foolproof biometric technologies can be well utilized to enhance the security and transparency in different domains of rural development. Lastly, multiple biometric inputs could be fused to arrive at granting authorizations while thwarting attempts to conduct fraud. In summary, biometric authentication is well suited for the rural population who may be deficient of digital literacy or cannot read and write.

3.5 Data Storage 3.5.1 Cloud Storage Cloud storage is the newest paradigm in distributed computing. Cloud storage can accelerate social and economic development in rural areas. Cloud storage results in shared pool of computing resources and applications and hence will result in less expensive and highly efficient communication. Its low setup cost makes it a viable solution in rural areas. Further the expenses on education, health, and other services can be reduced to a great extent. Cloud storage can help the farmers communicate

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with agricultural experts and also provide sufficient database to improve the decisionmaking. Cloud storage can fill in the gap between health services of urban and rural areas by providing equal access to healthcare facilities and efficient handling of patients’ records by storing them in the cloud. Thus, cloud storage can be seen as a tool to bridge the gap between the urban and rural communities. It can be leveraged to improve the quality of life by providing access to better education, healthcare, and other social programs. Figure 3.20 shows how cloud storage can enhance the overall welfare of the rural region. During the low peak time, the data can be stored in the cloud and hence can be effectively transferred to the users during the high peak periods. In a rural area, the users can be a group of students, individual staff, health worker, or a farmer. A sharing model is used where a trusted third party is not required. The users can upload the data in the cloud as well as share the outsourced data with others. In rural areas, a strong network of computing devices is necessary to establish the benefits of cloud storage. This means a constant internet connection is required; otherwise, it would hamper important processes. When data is accessed from far away locations (not from a local server), it will be necessary to provision high bandwidth backhaul connections (including mid-haul connectivity). Since the data is stored online it has a larger threat of theft and hacking, but this issue has been adequately addressed. There is a notion of distributed knowledge platform where the data repository is distributed at a central site, state level, district level, and village level (including cluster of villages). It is somewhat synonymous with edge storage.

Fig. 3.20 Illustration of cloud storage in rural areas

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The next section discusses how latency can be further reduced by bringing the data closer to the end user (i.e., edge storage).

3.5.2 Edge Storage Due to the massive number of connected devices, even the fifth-generation wireless networks will have stringent data rates and latency requirements. In addition to the vast mobile data generated, the limited spectrum especially in the wireless link, due to the extensive use of smartphones and other devices, ultimately leads to congestion in the backhaul links. The salient features of 5G wireless network: low latency and immense throughput requires the deployment of small and dense small base stations (SBSs); however, this does not solve the bottleneck issue. The huge amount of traffic imposes a larger workload on the already congested backhaul and the mobile networks. It is challenging for the networks to provide a balance between a user’s Quality-of-Experience and handling of the mobile data traffic. Edge storage combined with Artificial Intelligence (AI) will be an important factor for future 6G networks and is proposed as a solution in reducing the burden of the backhaul. Edge storage is similar to cloud storage, albeit it moves the data from the cloud to the edge network nodes. Since, in a community, people will have similar interests, therefore, pre-fetching of popular content and storing them at the edge nodes during off-peak hours would help in avoiding congestion. While providing wireless coverage in a particular area in a rural region, edge storage can be an important key in providing uninterrupted services with minimum delay. Based on the architecture of the wireless network, edge storage can be classified into two different categories: (1) SBS caching and (2) D2D caching [97]. The system model for SBS caching is shown in Fig. 3.21. The SBS can store F contents of equal sizes from a catalog of contents C: = {1,2,…., F}. A distributed caching strategy can be deployed at the SBS such as federated learning or transfer learning to train the model. The end user devices would generate huge data and such data will be at a risk of privacy leakage. In such scenarios, federated learning can play an important role as privacy-friendly distributed training algorithm. As shown in Fig. 3.22, D2D caching provides direct communication between devices, without the data being transferred from SBS. Usually, a central SBS controls the devices or they coordinate by themselves in a distributed manner. Thus, in a D2D communication, the users are enabled to connect directly with each other without having any connectivity with the backhaul. With coordinated small-cell systems, considerable gain can be achieved. In a multi-agent setting, where the behavior of other users is unknown, the users can learn from each other using AI techniques and hence significantly improve the performance of the system. While edge storage results in better real-time communication, they could be inefficient in terms of energy consumption, storage requirements, data freshness, and privacy concerns. For higher reliability on edge devices, robust coordination within the network is required and hence it may suffer when the communication links and

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Fig. 3.21 Illustration of an edge storage-enabled cellular network

Fig. 3.22 System model for device-to-device storage

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network dynamics in the rural region keep fluctuating; for example, in hard-to-reach areas such as a boat or a hilltop. Hence, connectivity is an important component in determining the effectiveness of the edge storage algorithms. Also, it is essential to identify the network dynamics while designing AI-based distributed algorithms. Edge storage also faces the issue of privacy and is also exposed to threats from the outsiders. Therefore, secured distributed algorithms are crucial to ensure data integrity and user authentication.

References 1. Marzetta TL, Ngo HQ (2016) Fundamentals of massive MIMO. Cambridge University Press 2. Datta A, Mandloi M, Bhatia V (2021) Minimum error pursuit algorithm for symbol detection in MBM massive-MIMO. IEEE Commun Lett 25(2):627–631 3. Larsson EG, Edfors O, Tufvesson F, Marzetta TL (2014) Massive MIMO for next generation wireless systems. IEEE Commun Mag 52:186–195 4. Lu L, Li GY, Swindlehurst AL, Ashikhmin A, Zhang R (2014) An overview of massive MIMO: benefits and challenges. IEEE J Sel Top Signal Process 8:742–758 5. Agiwal M, Roy A, Saxena N (2016) Next generation 5G wireless networks: a comprehensive survey. IEEE Commun Surv Tutor 18:1617–1655 6. Gupta A, Jha RK (2015) A survey of 5G network: architecture and emerging technologies. IEEE Access 3:1206–1232 7. Chin WH, Fan Z, Haines R (2014) Emerging technologies and research challenges for 5G wireless networks. IEEE Wirel Commun 21:106–112 8. Busari SA, Huq KMS, Mumtaz S, Dai L, Rodriguez J (2017) Millimeter-wave massive MIMO communication for future wireless systems: a survey. IEEE Commun Surv Tutor 20:836–869 9. Mishra AK, Johnson DL (2014) White space communication: advances, developments and engineering challenges. Springer 10. Regulatory requirements for white space device in the UHF TV band, technical report, OFCOM (2012) 11. Bishnu A, Bhatia V (2018) Receiver for IEEE 802.11ah in interference limited environments. IEEE Internet Things J 5(5):4109–4118 12. Bishnu A, Bhatia V (2018) Grassmann manifold-based spectrum sensing for TV white spaces. IEEE Trans Cogn Commun Netw 4(3):462–472 13. Nekovee M (2009) Quantifying the availability of TV white spaces for cognitive radio operation in the UK. In: 2009 IEEE International Conference on Communications Workshops 14. IEEE working group on wireless regional area networks (2005). Functional requirements for the 802.22 WRAN, Doc: IEEE 802.22–05/0007r46, technical report. IEEE 15. IEEE working group on wireless regional area networks (2011) Cognitive wireless RAN medium access control (MAC) and physical layer (PHY) specifications: policies and procedures for operation in the TV bands amendment: enhancement for broadband services and monitoring applications, technical report. IEEE 16. IEEE working group on wireless regional area networks (2014). Standard for spectrum characterization and occupancy sensing, technical report. IEEE 17. Gronsund P, Pawelczak P, Park J, Cabric D (2014) System level performance of IEEE 802.222011 with sensing-based detection of wireless microphones. IEEE Commun Mag 52:200–209 18. Harada H (2014) White space communication systems: an overview of regulation, standardization and trial. IEICE Trans Commun 97:261–274 19. Department of telecommunication, Government of India. National Frequency Allocation Plan 2011, WPC

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20. Naik G, Singhal S, Kumar A, Karandikar A (2014) Quantitative assessment of TV white space in India. In: 2014 Twentieth national conference on communications (NCC) 21. Kumar P, Rakheja N, Sarswat A, Varshney H, Bhatia P, Goli SR, Ribeiro VJ, Sharma M (2013) White space detection and spectrum characterization in urban and rural India. In: 2013 IEEE 14th international symposium on a world of wireless, mobile and multimedia networks (WoWMoM) 22. Hemadeh IA, Satyanarayana K, El-Hajjar M, Hanzo L (2017) Millimeter-wave communications: physical channel models, design considerations, antenna constructions, and link-budget. IEEE Commun Surv Tutor 20:870–913 23. Khan F, Pi Z (2011) mmWave mobile broadband (MMB): unleashing the 3–300GHz spectrum. In: 34th IEEE sarnoff symposium 24. Hoffman LA, Hurlbut KH, Kind DE, Wintroub HJ (1969) A 94-GHz radar for space object identification. IEEE Trans Microw Theory Tech 17:1145–1149 25. Meinel HH (1988) System design, applications and development trends in the millimeter-wave range. In: 1988 18th European microwave conference 26. Dees JW, Wangler RJ, Wiltse JC (1966) System considerations for millimeter wave satellite communications. IEEE Trans Aerosp Electron Syst 195–213 27. Natarajan A, Komijani A, Guan X, Babakhani A, Hajimiri A (2006) A 77-GHz phased-array transceiver with on-chip antennas in silicon: transmitter and local LO-path phase shifting. IEEE J Solid-State Circuits 41:2807–2819 28. Qualcomm, Making 5G NR a reality (2016). https://www.qualcomm.com/media/documents/ files/whitepaper-making-5g-nr-a-reality.pdf. Last Accessed 22 Mar 2021. (Online) 29. Pyattaev A, Johnsson K, Andreev S, Koucheryavy Y (2015) Communication challenges in high-density deployments of wearable wireless devices. IEEE Wirel Commun Lett 22(1):12–18 30. Wiesbeck C, Sturm W (2011) Waveform design and signal processing aspects for fusion of wireless communications and radar sensing. In: Proceedings of IEEE 31. Brown G (2016) White paper: exploring the potential of mmWave for 5G mobile access (2016). https://www.qualcomm.com/media/documents/files/heavy-reading-whitepaper-explor ing-the-potential-of-mmwave-for-5g-mobile-access.pdf. Last Accessed 31 May 2021. (Online) 32. Zhang H, Venkateswaran S, Madhow U (2010) Channel modeling and MIMO capacity for outdoor millimeter wave links. In: 2010 IEEE wireless communication and networking conference 33. Pi Z, Khan F (2011) An introduction to millimeter-wave mobile broadband systems. IEEE Commun Mag 49:101–107 34. Kutty S, Sen D (2015) Beamforming for millimeter wave communications: an inclusive survey. IEEE Commun Surv Tutor 18:949–973 35. Balanis CA (2016) Antenna theory: analysis and design. Wiley & Sons 36. Krim H, Viberg M (1996) Two decades of array signal processing research: the parametric approach. IEEE Signal Process Mag 13:67–94 37. Johnson DH, Dudgeon DE (1992) Array signal processing: concepts and techniques. Simon & Schuster, Inc. 38. Clerckx B, Kim G, Choi J, Hong Y-J (2010) Explicit versus implicit feedback for SU and MU-MIMO. In: 2010 IEEE global telecommunications conference GLOBECOM 2010 39. Alkhateeb A, Mo J, Gonzalez-Prelcic N, Heath RW (2014) MIMO precoding and combining solutions for millimeter-wave systems. IEEE Commun Mag 52:122–131 40. ITU interactive transmission map, ITU. https://www.itu.int/itu-d/tnd-map-public/. Last Accessed Oct 2020. (Online) 41. Barnett T (2020) Cisco: the Zettabyte era officially begins (How Much is That?). https://blogs. cisco.com/sp/the-zettabyte-era-officially-begins-how-much-is-that. Last Accessed Nov 2020. (Online) 42. Cisco Visual Networking Index (VNI) complete forecast update, 2017–2022. https://www. cisco.com/c/dam/m/en_us/network-intelligence/service-provider/digital-transformation/kno wledge-network-webinars/pdfs/1213-business-services-ckn.pdf. Last Accessed Spet 2020. (Online)

References

55

43. Agrawal A, Bhatia V, Prakash S (2019) Network and risk modeling for disaster survivability analysis of backbone optical communication networks. J Lightw Technol 37:2352–2362 44. NOFN concept diagram: bharat broadband network limited. http://bbnl.nic.in/index1.aspx? lsid=253&lev=2&lid=22&langid=1. Last Accessed Nov 2020. (Online) 45. Know your fiber: bharat braodband network limited: Khargone: Bhagwanpura block. http:// bbnl.nic.in//WriteReadData/datafiles/NOFN_Survey_Format_BHGWANPURA_Block_2___ 1_46656ff4-a280-4a2f-ad27-4655e5308211.pdf. (Online) 46. Digital globalization: the new era of global flows (2016). https://www.mckinsey.com/~/media/ McKinsey/Business%20Functions/McKinsey%20Digital/Our%20Insights/Digital%20globali zation%20The%20new%20era%20of%20global%20flows/MGI-Digital-globalization-Fullreport.ashx. Last Accessed 31 May 2021. (Online) 47. Britain’s woeful broadband: UK drops to 47th place in global speed leagues due to slow rollout of pure fibre networks (2020). https://www.dailymail.co.uk/sciencetech/article-8685409/UKdrops-47th-place-global-speed-leagues-slow-rollout-pure-fibre-networks.html. Last Accessed 20 Jan 2021. (Online) 48. Photo gallery: bharat broadband network limited. http://bbnl.nic.in/pgcat.aspx?lang=1. Last Accessed Aug 2020. (Online) 49. OFC network in India: POWERGRID’s perspective (2015). http://workshop.nkn.in/2014/ima ges/presentation/2015/Connectivity%20in%20North-East.pdf. Last Accessed 5 June 2021. (Online) 50. NKN workshop: OFC network in India: POWERGRID’s perspective. http://workshop.nkn. in/2014/images/presentation/2015/Connectivity%20in%20North-East.pdf. Last Accessed 21 Mar 2021. (Online) 51. Ahmed SI, Mim NJ, Jackson SJ (2015) Residual mobilities: infrastructural displacement and post-colonial computing in Bangladesh. In: Proceedings of the 33rd annual ACM conference on human factors in computing systems 52. DiMaggio P, Hargittai E, Celeste C, Shafer S (2004) From unequal access to differentiated use: a literature review and agenda for research on digital inequality. Soc Inequal 1:355–400 53. Rebecca EG, Michael LB, Edwards WK, Elizabeth D (2010) Mynatt, computing at the margins: report from NSF sponsored workshop, Atlanta, Georgia. http://www.computing-margins.org/. (Online) 54. Hargittai E (2002) Second-level digital divide: differences in people’s online skills. http://fir stmonday.org/ojs/index.php/fm/article/view/942/864. Last Accessed 25 Mar 2021. (Online) 55. Patel N, Chittamuru D, Jain A, Dave P, Parikh TS (2010) Avaaj otalo: a field study of an interactive voice forum for small farmers in rural india. In: Proceedings of the SIGCHI conference on human factors in computing systems 56. Plauche M, Nallasamy U, Pal J, Wooters C, Ramachandran D (2006) Speech recognition for illiterate access to information and technology. In: 2006 International conference on information and communication technologies and development 57. Sherwani J, Ali N, Mirza S, Fatma A, Memon Y, Karim M, Tongia R, Rosenfeld R (2007) Healthline: speech-based access to health information by low-literate users. In 2007 International conference on information and communication technologies and development 58. Patel N, Agarwal S, Rajput N, Nanavati A, Dave P, Parikh TS (2009) A comparative study of speech and dialed input voice interfaces in rural India. In: Proceedings of the SIGCHI conference on human factors in computing systems 59. Grover AS, Plauché M, Barnard E, Kuun C (2009) HIV health information access using spoken dialogue systems: Touchtone versus speech. In: 2009 International conference on information and communication technologies and development (ICTD) 60. Sherwani J, Palijo S, Mirza S, Ahmed T, Ali N, Rosenfeld R (2009) Speech vs. touch-tone: telephony interfaces for information access by low literate users. In 2009 International conference on information and communication technologies and development (ICTD) 61. Bhatnagar S, Dewan A, Moreno Torres M, Kanungo P (2003) Gyandoot project: ICT initiative in the district of Dhar, Madhya Pradesh (English). https://documents.worldbank.org/en/pub lication/documents-reports/documentdetail/621851468267614396/gyandoot-project-ict-initia tive-in-the-district-of-dhar-madhya-pradesh. Last Accessed 25 Mar 2021. (Online)

56

3 Technology Drivers for 6G

62. Dhanesha KA, Rajput N, Srivastava K (2010) User driven audio content navigation for spoken web In: Proceedings of the 18th ACM international conference on multimedia 63. Diao M, Mukherjea S, Rajput N, Srivastava K (2010) Faceted search and browsing of audio content on spoken web. In: Proceedings of the 19th ACM international conference on Information and knowledge management 64. Agarwal SK, Dhanesha K, Jain A, Kumar S, Menon S, Rajput N, Srivastava K, Srivastava S (2010) Organizational, social and operational implications in delivering ICT solutions: a telecom web case-study. In: Proceedings of the 4th ACM/IEEE international conference on information and communication technologies and development 65. White J, Duggirala M, Kummamuru K and S. Srivastava (2012) Designing a voice-based employment exchange for rural India. In: Proceedings of the fifth international conference on information and communication technologies and development 66. Zia MS, Ansari U, Jamil M, Gillani O, Ayaz Y (2014) Face and eye detection in images using skin color segmentation and circular Hough transform. In: 2014 International conference on robotics and emerging allied technologies in engineering (iCREATE) 67. Jang WA, Lee SM, Lee DH (2014) Development BCI for individuals with severely disability using EMOTIV EEG headset and robot. In: 2014 International winter workshop on braincomputer interface (BCI) 68. Chattoraj S, Vishwakarma K, Paul T (2017) Assistive system for physically disabled people using gesture recognition. In: 2017 IEEE 2nd international conference on signal and image processing (ICSIP) 69. Inkpen K (1997) Three important research agendas for educational multimedia: learning, children, and gender. In: AACE world conference on educational multimedia and hypermedia 70. Mazzone E, Read JC, Beale R (2011) Towards a framework of co-design sessions with children. In: IFIP conference on human-computer interaction 71. Markopoulos P, Read J, Hoÿsniemi J, MacFarlane S (2008) Child computer interaction: advances in methodological research. Springer 72. Gee JP (2003) What video games have to teach us about learning and literacy. Comput Entertain (CIE) 1:20–20 73. A. P. Foundation, Impact of computer aided learning on learning achievements: a study in Karnataka and Andhra Pradesh, 2004 74. Kam M, Agarwal A, Kumar A, Lal S, Mathur A, Tewari A, Canny J (2008) Designing e-learning games for rural children in India: a format for balancing learning with fun. In: Proceedings of the 7th ACM conference on designing interactive systems 75. Banerjee AV, Cole S, Duflo E, Linden L (2007) Remedying education: Evidence from two randomized experiments in India. Q J Econ 122:1235–1264 76. Kam M, Rudraraju V, Tewari A, Canny JF (2007) Mobile Gaming with Children in Rural India: Contextual Factors in the Use of Game Design Patterns. In: DiGRA conference 77. Kam M, Mathur A, Kumar A, Canny J (2009) Designing digital games for rural children: a study of traditional village games in India. In: Proceedings of the SIGCHI conference on Human factors in computing systems 78. Hemalatha P, Matilda S (2018) Smart digital parenting using Internet of Things. In: 2018 International conference on soft-computing and network security (ICSNS) 79. Rode JA (2009) Digital parenting: designing children’s safety. In: People and computers XXIII celebrating people and technology, pp 244–251 80. Elahi AN, Mahmood Z, Shazadi M, Jamshed S (2015) Digital storytelling: a powerful educational tool for primary school student. In: 2015 International conference on information and communication technologies (ICICT) 81. Pérez D, Pérez AI, Sánchez R (2013) El cuento como recurso didáctico. 3Ciencias, 1–29. Recuperado de http://dialnet.unirioja.es/descarga/articulo/4817922.pdf 82. Sandlund M, McDonough S and Häger-Ross C (2009) Interactive computer play in rehabilitation of children with sensorimotor disorders: a systematic review. Dev Med Child Neurol 51:173–179

References

57

83. Sharan D, Ajeesh PS, Rameshkumar R, Mathankumar M, Paulina RJ, Manjula M (2012) Virtual reality based therapy for post operative rehabilitation of children with cerebral palsy. Work 41:3612–3615 84. Hofstede G, Hofstede GH (1991) McGRAW-HILL Book Company Europe 85. Hofstede G (2002) Dimensions do not exist: a reply to Brendan McSweeney. Hum Relat 55:1355–1361 86. Biswas P, Langdon PM (2014) An HCI survey on elderly users in India. In: Inclusive designing. Springer, pp 3–12 87. Medhi I, Menon G, Toyama K (2008) Challenges in computerized job search for the developing world. In: CHI’08 extended abstracts on human factors in computing systems, pp 2079–2094 88. Smyth TN, Kumar S, Medhi I, Toyama K (2010) Where there’s a will there’s a way: mobile media sharing in urban india. In: Proceedings of the SIGCHI conference on human factors in computing systems 89. 2019 Norton Cyber Security Insights Report (2019). https://www.nortonlifelock.com/con tent/dam/nortonlifelock/docs/reports/2019-nortonlifelock%20-cyber-safety-insights-reportglobal-results-en.pdf. Last Accessed 10 Dec 2020. (Online) 90. Global Surges in Ransomware Attacks (2020). https://blog.checkpoint.com/2020/10/06/ study-global-rise-in-ransomware-attacks/?fbclid=IwAR2nR2L9mwRo6-1-vuPixxcWY93P eo3RMCJD_dM6ZwNiuVImHAtdL7PC5O4. Last Accessed 5 Jan 2021. (Online) 91. Hawthorne M (2017) Fingerprints: analysis and understanding. CRC Press 92. U. N. Department of Economic and Social Affairs, World’s population increasingly urban with more than half living in urban areas, 10 July 2014. https://www.un.org/development/desa/en/ news/population/world-urbanization-prospects.html. Last Accessed 20 Mar 2021. (Online) 93. Yang W, Wang S, Hu J, Zheng G, Valli C (2019) Security and accuracy of fingerprint-based biometrics: A review. Symmetry 11:141 94. Cheng Y, Larin KV (2006) Artificial fingerprint recognition by using optical coherence tomography with autocorrelation analysis. Appl Opt 45:9238–9245 95. Chatterjee A, Bhatia V, Prakash S (2017) Anti-spoof touchless 3D fingerprint recognition system using single shot fringe projection and biospeckle analysis. Opt Lasers Eng 95:1–7 96. Reddy PV, Kumar A, Rahman SMK, Mundra TS (2008) A new antispoofing approach for biometric devices. IEEE Trans Biomed Circuits Syst 2:328–337 97. Krishnendu S, Bharath BN, Bhatia V (2019) Cache Enabled Cellular Network: Algorithm for Cache Placement and Guarantees. IEEE Wirel Commun Lett 8(6):1550–1554

Chapter 4

Systems Architecture and Major Global Initiatives

In the previous chapters, several technical and non-technical aspects of rural and remote connectivity have been discussed such as the non-availability of backhaul communications infrastructure, affordability, power issues, HCI, among others. In this chapter, various systems architectures for establishing connectivity in the remote and rural regions are elucidated. Furthermore, the major ongoing initiatives around the world to connect the unconnected are summarized with their mission, vision, and core areas of research and development.

4.1 Architecture for Connectivity in Rural Regions The architecture for establishing connectivity in the rural and remote regions depends on the technology employed. The choice of technology is rather region and location specific and depends on various factors. Though the intercontinental communication and intracontinental/national core networks are supported by terrestrial and submarine OFCs, several network architectures are possible for establishing the middlemile and last-mile connectivity in rural and remote regions. A few architectures have been proposed for the middle-mile/last-mile solutions considering wired (i.e., OFCs) as well as wireless technology options. The absence of backhaul network is one of the major challenges to connect the unconnected population, primarily because the mobile network operators (MNOs) are not attracted to invest in infrastructure deployment in these sparse and clustered settlements. The most common and widely known backhaul options are shown in Fig. 4.1, where fiber backhaul is the most desired and common in the urban environment. However, for the rural and remote regions, deployment of fiber backhaul may not be either feasible or cost-effective. Thus, multi-hop microwave link backhaul and lower-orbit satellite based backhaul might be preferred in such cases. Along with these backhaul options, several other options have been proposed to cover the © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_4

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Fig. 4.1 Most common backhaul options to provide connectivity in rural/remote regions: a Fiber backhaul, b Microwave backhaul, and c Satellite backhaul

unconnected or under-connected regions, depending on the absence or presence of telecommunications network infrastructure in the nearby regions, as discussed below.

4.1.1 Remote Regions with no Infrastructure In the remote regions with no existing infrastructure, some of the possible technology options and architectures are shown in Fig. 4.2. It is noteworthy that in these remote regions, network coverage should be provided at as low a cost as possible since the population density in such regions may be too low, such as the polar areas (where, most of the existing satellite systems do not provide coverage) or the mobile users in the ships (where, deployment of fixed infrastructure is difficult). Hence, return on investment (RoI) in such regions is not attractive even in the long-term, as opposed to the permanent rural establishments. To cover sparse and clustered populations in remote regions with no existing infrastructure, satellites in desired orbits may be established for backhaul connectivity, or balloon base station networks may be deployed. Further, wireless relay network may be used to enhance the terrestrial link range. For mobile remote users, such as those on a ship, drones may be used as moving access points. Cognitive highfrequency (HF) radio (3–30 MHz) based solutions for providing/extending coverage in the remote regions have also shown promise [1].

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Fig. 4.2 Technology options to connect remote regions with no infrastructure [1]

4.1.2 Regions with Limited Infrastructure To provide or improve coverage in the regions with limited existing infrastructure is less challenging as compared to the remote regions with no existing infrastructure. The regions where fiber backhaul are present or wireless network coverage is available in the nearby regions, the already available technology can be utilized easily to connect the unconnected or under-connected regions, as described below.

4.1.2.1

Filling Coverage Holes

The regions where network coverage is available in most of the locations, however, some spots are left uncovered creating coverage holes, either due to poor network infrastructure planning/deployment or due to no or low demand in these locations, such as the tourist spots, mountains, farmlands, remote factories, sparsely populated regions between well-identified villages (such as the Musapuri village, mentioned in Chap. 3), or any other place that has no permanent residence. It is important to be connected in such regions, especially for emergency and surveillance. Such coverage

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Fig. 4.3 Solution to extend coverage in the holes using small cells [1]

holes can be filled with small cells, as shown in Fig. 4.3. Here, umbrella cells covering a large area with few base stations utilizing TV broadcast infrastructure are shown. TV antenna masts are much taller than the mobile radio towers and hence can cover a larger area.

4.1.2.2

Backhaul in Clustered Settlements Using Directed Beams

To connect the clustered settlements in the regions having fiber PoP, the TV infrastructure can be repurposed, as shown in Fig. 4.4, to provide backhaul connectivity in different clusters using the beamforming technique discussed in Chap. 3. MIMO technology can be utilized here to increase the capacity in such TV mast based large backhaul coverage regions.

4.1.2.3

Frugal 5G

The architectures discussed above are mainly for the regions where limited infrastructure is available and TV broadcast infrastructure combined with the latest wireless communication technologies such as MIMO, beamforming, and small cell network can be used to provide coverage in large regions or several clustered establishments in large regions. In the regions where fiber-based middle-mile connectivity is available or planned to be deployed soon, such as in India, under the BharatNet project, the only challenge is to develop and deploy access network architecture to provide last-mile connectivity in the clustered rural regions from the nearby fiber PoP (optical network terminal (ONT)/optical network unit (ONU)).

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Fig. 4.4 Connecting the rural clustered establishments using beamforming [1]

Frugal 5G [2] infrastructure is designed to extend the coverage in the villages lying under a GP (as mentioned in Chaps. 1 and 3) from the fiber PoP being made available at GP-level under the BharatNet project. The GPON network being deployed under BharatNet aims to connect all the villages, however, due to difficulty in excavation and installation of OFCs, right-of-way (RoW) policies, terrain conditions, costineffectiveness, or other infeasibilities, it is not possible to connect all the rural establishments in India by OFC, and hence the Frugal 5G architecture, shown in Figs. 4.5 and 4.6, that brings together software defined networking (SDN), Network Function

Fig. 4.5 Basic concept of Frugal 5G [2]

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Fig. 4.6 Architecture of Frugal 5G [2]

Virtualization (NFV), Fog networking, among others, can be used to connect such rural regions wirelessly. The Frugal 5G architecture is similar to the microwave link backhaul architecture shown in Figs. 4.1 and 4.4; however, the difference being that it complements the OFC infrastructure of BharatNet (or any other PON infrastructure in the world) and is designed to cover clustered establishments spread in smaller regions.

4.1.2.4

Bluetown’s Architecture for Rural and Remote Connectivity

Bluetown [3] is a private organization that provides low-cost and sustainable Wi-Fi solutions to connect rural populations with the Internet. Bluetown provides last-mile as a service using microwave links for backhauling from the fiber PoP and Wi-Fi Hot-Spot for access. They partner with village level entrepreneurs (VLEs), who are responsible for taking care of the Hot-Spot, and selling prepaid broadband coupons. The solutions provided by Bluetown can be deployed in semi-urban, rural, and remote regions. The company’s concept of everything on tower (EoT), as shown in Fig. 4.7, enables the deployment of their solutions in the rural regions, particularly for the developing world, where power-grid is not available, and low-power transceivers working primarily on solar/wind energy are necessary. The unwired rural EoT masts obtain backhaul using either of the options shown in Fig. 4.1.

4.1 Architecture for Connectivity in Rural Regions

Fig. 4.7 The concept of EoT [3, 4]

Fig. 4.8 Bluetown’s microwave backhaul mesh network [3, 4]

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The architecture of Bluetown’s backhaul network, as shown in Fig. 4.8, is similar to that of the Frugal 5G and belongs to the microwave link backhaul approach shown in Fig. 4.1. Here, the towers/masts deployed in the rural regions are mesh-connected with each other using microwave links (operating in the unlicensed band) and the aggregated traffic terminates at the nearest OFC PoP.

4.2 Architectures for Enabling Affordable Service Provisioning in Rural Regions While most of the technology required to establish network infrastructure to connect the unconnected rural and remote regions is available and can be used straightaway using one or more options described in Sect. 4.1, a bigger challenge is to develop service provisioning methods in rural regions in an affordable and effective manner for positive uses and with sufficient QoS to the users who have almost no skills or experience in consuming digital services being provided by the telecommunication networks. An architecture using Long-Range Wi-Fi or TVWS as the middle-mile option for connecting with ONT (or satellite backhaul in case of difficult terrains) is given in [5]. Here, several options for providing access to end-users through public data office (PDO), Wi-Fi hotspot, among others are proposed, as shown in Fig. 4.9. However, it does not address the major issue of affordable service provisioning and the use-cases to ensure that the connectivity being provided is put to useful purpose, thus bringing the envisioned rural empowerment through it, which is the main motivation to connect the unconnected population of the world and to meet the UN SDGs through 5G/6G communication networks. An affordable service provisioning model that employs content-level differentiability to provide free access to digital public goods (DPGs) to rural users, has been introduced under the ‘Non-discriminating access for Digital Inclusion (DigI)’ project of the Basic Internet Foundation [6]. Access to DPGs is an economic challenge as per the UN High-level Panel on Digital Co-operation [7] since traditional internet connectivity might not be affordable by the rural residents, especially in the lower income countries. Under the DigI project, it is suggested to split the architecture and the access to DPGs into two parts, namely, Lite bandwidth (referred to as L-DPG) and Heavy bandwidth (referred to as H-DPG) [5]. L-DPGs refer to the useful service provided through text and picture content, whereas H-DPGs refer to the video and streaming services, which is a paid premium service. The concept of this Freemium (Free + Premium) model is shown in Fig. 4.10, where L-DPGs can be provided for free as they consume only about 2–3% of the internet bandwidth, and H-DPGs may be subscribed by the users who can afford it and might as well attract other users in the future once the rural population becomes familiar with the internet connectivity and its features, which can improve the RoI.

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Fig. 4.9 Architecture for rural connectivity by C-DOT [5]

In addition to free L-DPGs, the H-DPGs that are stored on local servers like fog DCs or micro DCs (mDCs) can also be accessed for free since the content is being consumed locally and do not consume the internet backhaul bandwidth. Figure 4.11 shows a rural connectivity infrastructure that combines the approach of DigI and the architecture shown in Fig. 4.9 that can be used to provide freemium service in the rural regions, especially, the large rural population in the developing countries. Local content creation and free access to that local content has been suggested as per the DigI project. However, H-DPGs such as video lectures, online education, and professional networking platforms, among others are also necessary for global digital inclusion which should be available to the rural users in an affordable manner. Premium services may be obtained by the local microoperators to provide H-DPGs from the internet to their regional users. Educational and other useful videos may be stored locally from the Internet during the non-busy hours, such as during the night, which can be accessed later for free. In addition to this, to promote the local content

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Fig. 4.10 Freemium model for access to heavy and lite bandwidth by rural consumers

Fig. 4.11 A holistic view of rural connectivity infrastructure with freemium service

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Fig. 4.12 Popular regional content sharing during low congestion in a preemptive way

(culture, production, services) of rural and remote regions and store the content in large DCs (to be accessed by the Internet users around the world), traffic scheduling during non-busy hours or using preemptible traffic model can be done, as depicted in Fig. 4.12, which can also be a source of employment generation in the rural regions. Local can be the next global and such content sharing will help in the dissemination and increasing popularity of several region-specific content, products, and services around the world.

4.3 Global Initiatives for Rural and Remote Connectivity Several initiatives are ongoing around the world to connect the unconnected rural and remote populations and to improve connectivity in the under-connected regions. Efforts are being made by the researchers from the academia as well as the industry to address the challenges in establishing rural and remote connectivity. Due to the heterogeneity of region-specific challenges, several national projects are ongoing and planned in different countries by the government as well as private organizations to bridge the digital divide in their regions, as discussed in Chap. 1. However, international efforts are required to bridge the global digital divide. Some of the major global initiatives that aim to contribute technically, politically, and/or financially towards establishing connectivity in the rural and regions of different countries of the world are mentioned in this section along with their main objectives and activities.

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4.3.1 6G Flagship The 6G Flagship [8] program led by the University of Oulu, Finland, and launched by the Academy of Finland, a governmental funding agency for scientific research, is a research and co-creation ecosystem for 5G adoption and 6G innovation. The main goals of 6G Flagship program, among others, are to support industry in finalization of 5G, to develop the fundamental technology needed to enable 6G, and to speed up digitalization in the society. Towards the digitalization for all, the first 6G white paper [9] published in 2019 mentions rural and remote connectivity as one of the most important factors towards the fulfilment of 2030 UN SDGs [10]. The 6G Flagship, under its 6G Research Visions White Paper series of 12 white papers, each focusing on the most crucial aspects of 6G research, has published a topical white paper on connectivity for remote areas in June 2020. The 6G white paper on connectivity for remote areas [11] describes the technoeconomic challenges in closing the digital divide including terrestrial and nonterrestrial solutions, need for local operators, and spectrum issues. Global challenges in achieving the rural and remote connectivity have been discussed that should be considered for 6G research from the beginning such that 6G could be the first mobile connectivity generation to close the digital divide. In the rural and remote regions, network deployment using conventional approaches might be difficult due to difficult terrains that might hinder the deployment of OFC between cellular stations. Thus, integrated access and backhaul (IAB) has been presented as a promising solution in this white paper to enable rural and remote connectivity. In IAB, only few BSs connect to OFC, and other BSs wirelessly relay the backhaul traffic. Non-terrestrial network solutions such as satellite communication, HAPs, unmanned aerial vehicles (UAVs), and balloons can provide several benefits to remote connectivity, including resiliency, energy-efficient connectivity, and QoS enhancement, among others, as highlighted in the 6G white paper on connectivity for remote areas. Along with the network technologies, microoperator ecosystem and radio frequency-related issues have also been discussed for affordable and sustainable rural and remote connectivity.

4.3.2 Basic Internet Foundation The Basic Internet Foundation (BIF) [6], headquartered in Norway, aims at providing “free access to basic information on the Internet for everyone in the world”. BIF was established in December 2014 as a collaboration between The University Graduate Centre (UNIK) and Kjeller Innovasjon AS. The foundation is a global partnership among the technology leaders, local communities, non-profits, and experts with a common objective to bring the Internet to about half of the world’s population that is currently unconnected.

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BIF makes digital inclusion happen by providing free access to the internet and its basic information to every single human on this planet to improve his/her life. The information that must be available for every human being is referred to as DPGs (as described in Sect. 4.2), and thus the goal of BIF is to provide free access to these DPGs to everyone. This goal is being achieved through a freemium model for access, where Internet lite technology is being used to provide free access to text, pictures, and local content (including video) with emphasis on education and health. The projects of BIF mainly focus on connecting the villages, schools, and women empowerment towards the fulfilment of UN SDGs.

4.3.3 Broadband Commission for Sustainable Development The Broadband Commission for Sustainable Development [12] was established in 2010 as a joint initiative by the ITU and the United Nations Educational, Scientific and Cultural Organization (UNESCO) to promote Internet access to help achieve United Nations development goals. The Commission was established with the aim of boosting the importance of broadband on the international policy agenda and expanding broadband access in every country as key to accelerating progress towards national and international development targets. In 2018, given the shift towards new UN development Agenda 2030 and new challenges of a digital world, the Commission re-evaluated and launched new framework of Targets 2025 in support of “Connecting the Other Half” of the world’s population.

4.3.4 IEEE International Network Generations Roadmap The IEEE International Network Generations Roadmap (INGR) [13] is an activity of the IEEE Future Networks Initiative launched by the IEEE Future Directions in 2016 that aims to stimulate an industry-wide dialogue to address the many facets and challenges of the development and deployment of 5G in a well-coordinated and comprehensive manner, while also looking beyond 5G. INGR has a number of technical working groups that focus on different crucial aspects of future network technologies (energy efficiency, security, satellite, mmwave, system optimization, connecting the unconnected (CTU), AI/machine learning (ML), edge automation, M-MIMO, etc.). One of the working groups of INGR focuses on CTU that identifies the research challenges and the solutions to provide affordable access to Internet in rural and remote regions of the world. Recently, a white paper [5] on Connecting the Unconnected was published by the IEEE INGR CTU working group that provides various technological as well as economical perspectives to enable broadband connectivity in rural and remote regions with a roadmap timeline with 3-year, 5-year, and 10-year horizons.

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4.3.5 Wireless World Research Forum The Wireless World Research Forum (WWRF) [14] works towards the exploration and development of the research challenges for beyond current 5G deployments. The WWRF is a global wireless research community with over 50 members from industry and academia across 4 continents. The WWRF has different working groups to address a variety of challenges that confront us in realizing 5G and beyond 5G connectivity. Among others, the WWRF working group on 6G Vision and Technologies focuses on research that looks five to ten years ahead in order to meet the requirements of the networks in the year 2030 timeframe. The group also focuses on developing business models and addressing regulatory issues along with the technological issues in rural and remote areas.

4.3.6 World Bank Digital Development Initiative The World Bank Digital Development [15] Global Practice works with the governments of different countries in creating strong foundations for the growth of digital economy. Closing the Digital Divide is among the main focus areas of the World Bank Digital Development Initiative, where several ongoing projects focus on providing Internet connectivity in the unconnected regions of the lower and middle-economic countries.

4.3.7 Internet Society—Wireless for Communities The Wireless for Communities (W4C) program [16] initiated in 2010 by the Internet Society Asia–Pacific Bureau provides last-mile connectivity to rural and remote areas of the Indo-Pacific using wireless technologies. The program in India was piloted in the village of Chanderi in Madhya Pradesh. W4C has established 146 access points in 38 districts of 18 states in India. The program uses line-of-sight methods, wireless technologies, low-cost Wi-Fi equipment, and unlicensed spectrum—2.4 GHz and 5.8 GHz—to create community-owned and community-operated wireless networks in rural and remote locations of India to provide Internet access to all. In 2015, W4C was launched in Nepal and Pakistan and is rapidly expanding. The W4C program aims to provide Internet connectivity by utilizing low-cost Wi-Fi-based equipment to connect rural and underserved communities.

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4.3.8 SMART Africa SMART Africa [17] is an innovative commitment from the African Heads of State and Governments to accelerate sustainable socio-economic development in Africa. The SMART Africa Manifesto was endorsed by all Heads of State and Governments of the African Union in January 2014. The SMART Africa alliance currently includes 30 African countries and is bringing all African countries as per their manifesto represented by the African Union (AU), the ITU, World Bank, ECA, African Development Bank (AfDB), the Global System for Mobile Communications Association (GSMA), the Internet Corporation for Assigned Names and Numbers (ICANN), and the private sector. The vision of SMART Africa is to ‘transform Africa into a single digital market’. The main manifesto principles of SMART Africa include leveraging ICT to promote sustainable development, to put private sector first, to put ICT at the center of national social-economic development agenda, and to improve access to broadband internet. Large-scale investments in fiber-optic networks, mobile networks, DCs, satellites, among others have been planned. The need of strong partnerships among the government, academia, industry, civil society, and citizens has been emphasized to achieve the goals of SMART Africa.

4.3.9 Organization for Economic Co-Operation and Development The organization for economic co-operation and development (OECD) [18] addresses the economic, social, and environmental challenges of globalization. The OECD in its Rural 3.0 policy has laid emphasis on the diverse and distinct need of the rural areas with the associated challenges in rural regions inside metropolitan areas, near metropolitan areas, and remote rural areas. One of the megatrends mentioned in the policy that will drive the change in rural regions is the ‘technological breakthroughs’ such as digital connectivity, cloud computing, IoT, AI, drones, e-health, e-education, among others that will transform the way people access goods and services in rural regions as well as open up new production possibilities enabled by smart solutions in agriculture, forestry, and mining.

References 1. Pirinen P et al (2019) Wireless connectivity for remote and arctic areas—food for thought. In: ISWCS 2. Khaturia M et al (2020) Connecting the unconnected: toward frugal 5g network architecture and standardization. IEEE Commun Stand Mag 4(2):64–71 3. BLUETOWN. https://bluetown.com/. Accessed 26 June 2021

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4. Satya N Gupta et al (2020) WWRF online seminars, 17 Nov 2020. https://www.wwrf.ch/eve nts/wwrf-online-seminars/articles/wwrf-online-seminars-3.html. Accessed 26 June 2021 5. INGR Connecting the Unconnected 1st Edition White Paper, 2020. https://futurenetworks.ieee. org/roadmap. Accessed 15 May 2021 6. Basic Internet Foundation, https://basicinternet.org/. Accessed 20 May 2021 7. United Natons Secretary-General’s High-level Panel on Digital Cooperation, 11 June 2020. https://www.un.org/en/sg-digital-cooperation-panel. Accessed 29 June 2021 8. 6G Flagship. https://www.oulu.fi/6gflagship/ 9. Key Drivers and Research Challenges for 6G Ubiquitous Wireless Intelligence. http://jultika. oulu.fi/Record/isbn978-952-62-2354-4. Accessed 16 Mar 2021 10. United Nations Sustainable Development Goals. https://sdgs.un.org/goals 11. 6G White Paper on Connectivity for Remote Areas, June 2020. https://www.6gchannel.com/ items/6g-white-paper-connectivity-remote-areas/. Accessed 15 May 2021 12. Broadband Commission for Sustainable Development. https://www.broadbandcommission. org/. Accessed 16 June 2021 13. IEEE International Network Generations Roadmap (INGR). https://futurenetworks.ieee.org/ roadmap. Accessed 20 June 2021 14. Wireless World Research Forum. https://www.wwrf.ch/. Accessed 21 June 2021 15. The World Bank: Digital development. https://www.worldbank.org/en/topic/digitaldevel opment. Accessed 27 June 2021 16. Wireless For Communities. https://www.internetsociety.org/projects/w4c/. Accessed 12 June 2021 17. Smart Africa. https://smartafrica.org/. Accessed 14 June 2021 18. The Organisation for Economic Co-operation and Development. https://www.oecd.org/about/. Accessed 5 June 2021

Chapter 5

Techno-economic Challenges

Without business sustainability, no technological innovation or solution is feasible in the long-term. The business viability may come from complex free market forces, from government subsidies, or combination of the two, and for 6G, this needs to be addressed from the very beginning. In the event the government considers access to broadband Internet at par with access to clean water, roads, electricity, public hospitals, it becomes another public investment whose returns are better measured in social impact, GDP growth, etc., which may also be translated into money. Since there are discussions on the objectives of 6G, one of them being social impact, it is important to also consider key performance indicators (KPIs) of 6G related to societal considerations. These could be measured by such parameters as increase in life expectancy due to increased consumption of healthcare information and improved environment; increased literacy rates in rural and remote areas; reduction in unemployment rate; gender equality, and good governance.

5.1 Economic Estimates for Future Communication Technologies The emerging communication technologies that have the potential to almost completely change the current communication network architecture in the future and their estimated market are among the crucial issues that might affect the economics of the rural networks in the future. Quantum communications should be one such major consideration to plan the future networks. The difference in the fundamental unit of information between the classical communications and the quantum communications, bit and qubit, respectively, might completely change the communications infrastructure in the future. Moreover, quantum communication is not a higher class of services but an essential service that should be provided to each individual user irrespective of the rural and urban users to provide privacy and security to all the users © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_5

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in the quantum computing era. Due to lack of digital literacy and lack of awareness to dangers of compromised privacy and security, people living in rural and remote areas require even better solution to protect them from the fraudsters who may prey on them from other parts of the world.

5.1.1 Quantum Communication Technology Funds for several quantum initiatives around the world have been declared to focus on several quantum technologies, multidisciplinary research aspects, and numerous possible applications. Quantum efforts of close to $25 billion have been estimated as of mid-2021 [1] and China as the frontrunner with funding of ~$10 billion followed by Germany and France (Fig. 5.1). The rapid progress of quantum computing technology is an approaching threat to the existing classical communication networks. Hence, quantum communication is an important technology to be aware of and should be discussed. As of now, Quantum Key Distribution (QKD) is the most practical solution available to realize quantum communication. An exponential market growth for QKD systems has been predicted with the total expected market of ~$7.5 billion by 2028 [2] (Fig. 5.2).

Fig. 5.1 Funding for quantum initiatives around the world [1]

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Fig. 5.2 Market growth forecast for QKD systems [2]

5.2 CAPEX CAPEX is probably the most important cost to implementing the village infrastructure. In case of the availability of the broadband fiber termination in a GP, the backhaul network cost becomes negligible. In cases where it is not the case, it could constitute a significant part of the overall investment required. The cost to provide coverage to the village population residing in clusters is not very high, especially if the population volunteers to share their resources (power, cabling, and access points) in return for credit to their monthly subscription charges. Of course, they would need to be bound by providing some service guarantees that are continuously monitored to be eligible for the credits. It is estimated that to implement one access point, it would cost about $200, including the required external antennas, routers, and any additional electronics. Multiple access points when mesh networked can not only reduce the cost of coverage but improve the QoS for all users in the neighborhood. Positioning of antenna masts at hilltops and/or high-rise buildings with multi-beam coverage and beamforming technology can bring down the cost of deployment (CAPEX) while increasing the coverage extending to multiple nearby hamlets or village settlements. Micro-operators (who are typically local entrepreneurs, i.e., VLEs) can play a very important role as they know the local ecosystem and have the needed contacts to bring down both the CAPEX and OPEX. Potentially, micro-operators can revive the old practice of bartering local commodities (such as agricultural) in return for capital investment and subscription fees, similar to the urban population paying with their profiles and usage data in return for the use of free email and social networking applications.

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5.3 OPEX OPEX can be reduced by community involvement in running the network and utilizing user’s homes, equipment, and solar power. In return, those offering their facilities can be compensated by providing service credits and other incentives to maintain high availability. Community ownership also enables safety and security of the infrastructure not to mention of the incentive to grow the customer base. Utilizing cloud-based network management and operations of the local network will make it possible to select and deploy low-cost equipment and reduce OPEX. Remote firmware and software updates must be automated to reduce personnel costs and improve the availability and reliability of the Internet for use by the local population.

5.4 Micro-operator Ecosystem Agile new players in the ecosystem inevitably accelerate fast digitalization of the society and thus huge economic growth. Micro-operators fall in this category. They build indoor and outdoor networks and offer local services while also interconnecting with the large service providers beyond the local domain. Some of the technical building blocks they utilize are small and large cells, network virtualization, mobile edge-computing, higher spectrum frequencies, and share spectrum and management techniques. Some of the regulatory building blocks are availability of the spectrum that is affordable, right to install and build networks, right to collect and use data, and rules to cooperate and/or compete with other mobile network operators. The micro-operator model must be promoted and enabled for the successful deployment and operation of the access networks to the rural community. Micro-operators differentiate themselves from the virtual operators who do not own their own infrastructure but have their own customer base. The micro-operators are just the opposite; they own the infrastructure but not necessarily the subscriber base. The micro-operator concept and ecosystem is illustrated in detail in Fig. 5.3. It touches all the stakeholders in one way or the other. The enablement of the virtual and micro-operators requires significant government intervention and relaxation of the telecommunications policy and regulations not to mention training and encouragement of the potential entrepreneurs. Training will definitely help the new operators to develop appropriate relationships with the stakeholders and configure suitable business models.

5.4.1 Sustainability The concept of sustainability is somewhat different between the urban and rural population and should be considered in the context of the local culture. Preservation

5.4 Micro-operator Ecosystem

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Fig. 5.3 Micro-operator concept and ecosystem [3]

of local culture and traditions should be taken under consideration when making information available from the worldwide sources through access to Internet, which could be destabilizing, create tensions, and slow down its acceptance. Imagine being exposed to everything from the flip of a button, which even in urban areas has traditionally experienced slow adoption of the new trends and social norms. The rural population generally is well-versed in recycling and that should be preserved than turning into a throw-away society where garbage collection and recycling is virtually non-existent. When considering energy sources for powering electronic devices, renewable sources must be given priority as the rural population is not accustomed to power grid and adoption of renewables could be much easier by skipping to the next generation of power that the world is already aspiring to achieve. Access to Internet can and should play a critical role in achieving the 17 SDGs defined by the United Nations. That route is much faster and cheaper than building physical infrastructures and in keeping with the global trend. Access to information and knowledge motivates and enables individuals on their own and promotes selfreliance than dependence on the government which generally functions slowly and inefficiently. Recently, with the global changes in the environment, sustainability has

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picked up momentum where every country and every human being is impacted in some way such that this challenge has become an equalizer.

5.4.2 Profitability While keeping CAPEX and OPEX low, community involvement and meeting user needs with embedded trust will help the ICT services to be profitable. If regulatory changes are made such that there are less restrictive regulations for the rural areas, that will bring down the cost of service, such as free spectrum awards, higher transmit powers, allowing sharing of network equipment from user’s homes, sharing of revenues, free right of ways, and sharing of energy sources including local villagewide renewable energy grids controlled and managed by the local population. Use of renewable energy would not only leap-frog the rural communication but will reduce the cost of energy for the service provider.

5.5 Licenses and Permissions Along with exploration of unlicensed higher frequency bands, leveraging underutilized licensed bands like TVWS in rural environments via the lightly licensed approach can turn out to be more promising [4]. In lightly licensed approach, the unlicensed radio bands require cognitive radio (CR) and spectrum sensing to ensure the presence/absence of the primary/licensed users [5]. The regulators need to adopt lightweight licensing regime, but these must be strictly controlled and enforced to deter the urban mobile operators from abusing them in semi-urban and rural areas primarily meant to promote the micro-operators.

References 1. Overview on quantum initiatives worldwide—update mid 2021. QURECA, 19 July 2021. https:// www.qureca.com/overview-on-quantum-initiatives-worldwide-update-mid-2021/. Accessed 23 July 2021 2. Gasman L (2021) The future of the quantum internet: a commercialization perspective. In: ITU workshop on quantum information technology for networks, Shanghai 3. uO5G—Micro operator concept for boosting local service delivery in 5G. https://www.oulu.fi/ uo5g/. Accessed 24 Mar 2021 4. Shetty S et al (2010) Proposal for TV white space towards national frequency allocation plan (NFAP). IIT Bombay 5. Bishnu A, Bhatia V (2018) LogDet covariance based spectrum sensing under colored noise. IEEE Trans Veh Technol 67(7):6716–6720

Chapter 6

Future Challenges

In the previous five chapters, various technical, economic, social, and cultural aspects of B5G and 6G connectivity in the unconnected rural regions have been discussed. Though most of the technology required to bridge the digital divide as of now is available [1] currently, it is important to note that the urban communication networks in the developed regions are going through a paradigm shift with the development and implementation of 5G and B5G communication networks [2–4]. Thus, in the future, the rural and remote connectivity solutions [5, 6] being discussed in the literature at present might not be able to bridge the digital divide and we might observe a new kind of digital divide where everyone might be connected to the communication networks, but with a huge differentiation in the types of services offered, QoS, and use-cases between the rural and urban users might be observed. Some of the main factors behind this type of probable digital divide in the future include technology migration [7– 10], difference in the network architecture of rural and urban environment, imperfect region-specific planning, limited non-technical considerations, among others. Thus, along with the efforts to bridge the digital divide, it is important to consider the aspects of service differentiation models, demand forecasting, effect of advanced communications technologies, and socio-cultural progress, and then plan the future networks accordingly to prevent the digital divide from broadening in the future.

6.1 Differentiated Service Under a common network and region, to support a variety of services demanded by different users, a differentiated service model should be employed to improve the QoS of different classes of service (CoS) as well as to improve the network resource efficiency. Differentiated service refers to provisioning different types and/or quality of service to different users as per their requirements. Thus, a differentiated service model can improve the customer satisfaction as well as the network operator’s © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dixit et al., 6G: Sustainable Development for Rural and Remote Communities, Lecture Notes in Networks and Systems 416, https://doi.org/10.1007/978-981-19-0339-7_6

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revenue. To provide differentiated services in a region, the design of service level agreements (SLAs) plays a major role to offer different service plans at different costs, to monitor the network performance (both by the user and the operator), and it allows the operators to deploy, manage, configure, and upgrade their network accordingly. The service requirements and use-cases in rural regions are expected to be different. For example, the bandwidth and latency sensitive services like Internet Protocol Television (IPTV) and online gaming are not expected, at least during the initial years of enabling connectivity in an unconnected region, either due to the user demands or due to non-affordability. Since the rural services are quite price sensitive, it would be desirable to be able to support a range of QoS classes from best effort (lowest cost) to latency controlled (highest cost for critical services, such as healthcare, security, and safety). Although not presently being actively promoted for rural communities, the concept of network slicing must be investigated which is already well developed for 5G and B5G networks.

6.2 Demand Forecasting 6.2.1 Urbanization It is anticipated that as broadband digital connectivity extends to rural areas, reverse migration might happen resulting in the urbanization of villages. This would require more accurate forecasting of the data demand. It seems that there is a lack of reliable demand forecasting for the rural areas which is affecting the proper design and planning of the network infrastructure. It is further hampered not knowing how fast the adoption of the digital services would happen.

6.2.2 First Responder Services How to quickly rollout a broadband wireless network for first responders at random places in active use-cases continues to be a challenge in every part of the world. Such networks need to be elastic and adaptable as the situation changes and the availability of the access and backhaul technologies. The scenario becomes even more challenging in rural areas where the networking (and physical) infrastructure is poor to begin with.

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6.3 Technology Migration 6.3.1 Wireless 6.3.1.1

Full-Duplex Communication

In half-duplex (HD)-CR, transmission of secondary users (SUs) is divided into two time slots. In the first time slot also known as sensing slot, the SUs sense the presence of the primary user (PU), and in the second time slot also known as data transmission slot, the communication between SUs takes place. This approach has two limitations. First it reduces the throughput of SUs since SUs communicate only in the data transmission slot, and second it also interferes with the PUs operation if PUs reappear in the data transmission slot. These limitations lead to the emergence of full-duplex (FD)-CR, where SUs concurrently sense the available spectrum and transmit [11] (Fig. 6.1). In HD-CR, the SUs cause interference to PUs in data transmission mode because in this mode SUs do not sense the available spectrum. In contrast, full-duplex cognitive radio (FD-CR), concurrent sensing and transmission cause less interference to PUs because of continuous monitoring of the spectrum. FD-CR improves the spectralefficiency due to continuous searching for available white space and hence FD-CR identifies large number of white spaces as compared to HD-CR. FD-CR improves the throughput of SUs because of continuous data transmission as compared to HDCR, where SUs only transmit in data transmission slot. Collision of SUs in data transmission mode can greatly affect system performance of HD-CR [12]. However, by employing FD in CR, the collision probability can be reduced without interrupting

Fig. 6.1 a Interweave CR scenario and b Underlay CR scenario

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the data transmission of SUs. Energy Efficiency is also the crucial entity for future wireless networks. In HD-CR, energy harvesting from external source results in the interruption of both data transmission and sensing slot for SUs [13]. However, in FDCR, the SUs do not suspend its sensing and data transmission for energy harvesting. FD-CR undoubtedly increases throughput and spectrum efficiency compared to HDCR. Thus, FD-CR in conjunction with advanced wireless networks can fulfil the demand of spectrum efficiency and throughput of various wireless applications.

6.3.1.2

Intelligent Reflecting Surfaces

Improved spectrum efficiency, energy efficiency, and low communication latency are some of the key requirements in the future beyond 5G and 6G wireless networks that aim to deploy several demanding applications like autonomous cars, telemedicine, smart homes, etc. In this context, given the recent advancements in the area of electromagnetic (EM) metamaterials, the concept of the man-made intelligent reflecting surface (IRS) (also referred to as reconfigurable intelligent surface) has emerged as a smart and an attractive solution and thus has drawn significant research attention from both industry as well as academia [14, 15]. An IRS is a thin two-dimensional (2D) planar structure of EM material that contains a large array of passive reflecting elements, known as meta-atoms, whose size is comparatively smaller than the signal wavelength. Each meta-atom can be dynamically controlled in a software-defined manner in order to change the EM properties (like phase shift, amplitude, frequency, and polarization) of the incident RF signal so that the elements can coherently focus the waves with ideally any desired radiation pattern. This further enables the deployment of smart wireless environments, leading to a new wireless communication paradigm. The number of elements in IRS can range from tens to hundreds. Also, the IRS can be in any shape and thus can be easily embedded into and removed from buildings, indoor walls, ceilings, and surface of large vehicles, etc. (Fig. 6.2). In addition to the aforementioned features, due to the passive reflecting nature of the meta-atoms, IRS has the potential to exhibit a negligible energy consumption, unlike the power-hungry active components of conventional RF chains that involve complex decoding, encoding, and signal processing algorithms. Therefore, IRS can be battery-less and wirelessly powered by RF-based energy harvesting and thus is an extraordinary green resolve scheme. Additionally, unlike an FD relaying system, as the IRSs do not require a dedicated energy source to retransmit the signals, it enables them to work in a full-duplex cooperative mode without being affected by self-interference and noise amplification. Further, by optimizing the IRS’s reflection coefficients (i.e., passive beamforming), signal beams can be formed to enhance the performance of an intended receiver, mitigating interference from other devices and also completely nulling out the information leakage at an eavesdropper. Some of the recent works [17–19] have proposed IRS to be incorporated into various wireless technologies that include M-MIMO systems, non-orthogonal

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Fig. 6.2 IRS system model [16]

multiple access (NOMA) [20], energy harvesting, optical communications [21– 26], etc. Further, current research aims to explore the potentials of using the IRS in various other aspects like wireless power transfer, mobile edge-computing, and UAV communications. Therefore, IRS promises to be a revolutionizing technology, integrating which into the existing wireless communication infrastructure can bring unprecedented enhancement in the spectral and energy efficiency at an ultra-low-cost.

6.3.1.3

High Altitude Platform Station

A High Altitude Platform Station (HAPS) is a network node that operates in the stratosphere at an altitude of around 20 km and is instrumental for providing communication services. HAPS is an integral component for the full realization of the vision of Vertical Heterogeneous Network (VHetNet). Due to the unique properties of the stratosphere, a HAPS can stay at quasi-stationary position, providing significant benefits to the ubiquitous connectivity goal. The use of HAPS as a new promising platform can catalyze advanced mobile wireless communication services with ultrawide coverage and high-capacity. Although the choice of energy source was considered as a fundamental issue in HAPS, solar power coupled with energy storage has been regarded as the primary means of providing energy for HAPS since they have large surfaces suitable to accommodate solar panel films [27]. Due to low-delay characteristics in comparison with the emerging satellite networks, a HAPS can provide wireless services directly to the users of the terrestrial networks [28]. The HAPS layer performing as a large-scale intelligent entity enables fast, reliable, and efficient long-distance communication between the satellites, bypassing the need for the installation of millions of the ground relay stations and/or vessels/ships offshore [29]. Satellites help the HAPS layer in improving the handoff performance. HAPS

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layer is responsible to manage the mobility of swarm of UAV via providing edge intelligence, offloading the heavy computations, and handling large-scale sensing and monitoring, which are useful for cargo delivery and monitoring systems. The HAPS layer provides fast Internet access and wireless communication services, such as IoT and distributed ML, to urban, sub-urban, and remote areas, reducing the reliance on the terrestrial and satellite networks. Low altitude deployment with favorable channel conditions (400–2000 km), favorable link budget, and a high signal-to-noise ratio (SNR) for the downlink provide a coverage advantage. The uplink connectivity with relatively low path loss enables the use of user equipment (UE) as the terminals which have limited transmit power levels, without the need for specialized ground equipment. Relatively stationary position of HAPS systems prevents a waste of capacity and avoids the introduction of a significant Doppler shift. Smaller footprint due to low altitudes provides a higher area throughput. Due to its large volume, (a) HAPS is suitable for MIMO and M-MIMO deployments, (b) Generate highly directional 3D beams with narrow beamwidths that improve the signal to interference and noise ratio (SINR) for all users, and (c) Larger volume of HAPS systems can be equipped with huge solar panels and energy storage systems. HAPS systems also have reduced round-trip delay—relatively low altitude of HAPS systems corresponds to a round trip delay of 0.13–0.33 ms, enabling ultra-reliable low-latency communication (URLLC) applications. Costs and risks of launching are less in the case of HAPS compared to Low Earth Orbit (LEO) (Fig. 6.3).

Fig. 6.3 Various use-cases for the HAPS

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6.3.2 Fiber Optics 6.3.2.1

Capacity

Fiber optics play a crucial role in long-distance communication. Though rural and remote connectivity can be achieved by using the existing OFC infrastructure, greater challenges lie ahead to provide high-bandwidth and QoS, as expected in the 6G era, using the existing fiber optics resources and associated technologies. In Fig. 6.4, the role of optical networks, their structure, and the topology for supporting various types of services are shown. Optical networks support the mobile services as well as the fixed-line residential and business services. The factors necessitating the need of capacity enhancement of optical networks are discussed below. Mobile Services and Wireless Network Densification The traffic generated from the wireless metro/access networks is aggregated to the optical networks through PON [30]. PONs have inverted tree topology, where OFC connects the optical line terminals (OLTs) deployed at the district/town-level to various end-nodes, called ONU or ONT. Passive splitters split the downlink traffic incoming from the OLT, which is then transmitted to various ONUs connected to the fixed-line and mobile services. The uplink traffic is aggregated at the OLT, which is connected by OFC to one of the nodes of the mesh-connected terrestrial BONs. In Fig. 6.4, a 19-node mesh-connected BON of RailTel [31] is shown that interconnects various locations of India. Due to the increasing mobile broadband speeds, increasing number of users of mobile services, emerging applications such as self-driving vehicles and IoT, efforts are being made to enhance the capacity of wireless networks, as described

Fig. 6.4 Factors necessitating the need of capacity enhancement of optical networks

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in Sect. 6.3.1. Since the traffic generated by the mobile services is to be transported through OFCs, the increased capacity of wireless networks enforces the needed capacity enhancement of optical networks. Moreover, for efficient optical spectrum utilization, the existing time division multiplexing (TDM)/WDM based optical networks that are mostly static and pre-planned, need to be migrated to the next-generation, high-capacity, and dynamic optical network technologies, namely, elastic optical network (EON) [32] and spectrally-spatially flexible optical network (SS-FON) [33–37]. Rural and Remote Connectivity As rural and remote connectivity is one of the most important goals of B5G/6G era, efforts are being made around the world to connect the unconnected population. For instance, in India, the BharatNet project aims to provide broadband connectivity in all the villages, as described in Sects. 1.1.2 and 3.2.1. The OFC being deployed under BharatNet will serve as the middle-mile network and wireless access networks will enable the last-mile connectivity except for the FTTH services. Moreover, under this project, the existing OFC infrastructure of NLD providers is being used and additional OFC is being deployed using GPON technology to connect the villages of India to the BONs of NLD providers. Thus, the number of OLTs connected to each of the nodes of the BONs is being increased under the BharatNet. To handle the excessive traffic that will be aggregated through the newly deployed OLTs, the capacity of the BONs needs to be increased manifold [38]. To support the increased bandwidth demands, continuous new OFC deployment is expensive as well as impractical. Thus, the BONs will need to be migrated to the next-generation technology, i.e., EON and SS-FON. Inter-Datacenter Networks Optical fiber network is the only feasible technology option to support networking among DCs, given the high-bandwidth and low-latency requirements of inter-DC communication [39]. With the increasing data services including cloud computing, cloud storage, cloud-based content recovery, among others, the number of DCs is continuously increasing. Moreover, videos being uploaded on the cloud is one of the most important factors that is responsible for the exponentially increasing bandwidth demands, and hence increasing number of DCs around the world. Currently, DCs are connected to some of the nodes of the BONs. However, it is expected that with the increasing number of DCs, multiple DCs will be connected to each of the nodes of the BONs in future. Moreover, fog/edge-computing and storage will increase the number of mDCs which will need to be interconnected with other DCs and mDCs through metro and backbone optical networks [40, 41]. Thus, it is necessary to enhance the capacity of existing optical networks to support cloud and fog services in the future. Due to the critical aspects highlighted above, there will be a need of increased capacity and dynamicity in the future optical networks including the PON, terrestrial BONs, and the inter-continental submarine OFCs. In Fig. 6.5, let us assume that the incremental width of lines representing OFCs, denote the increased capacity requirement in OFCs. Due to the increasing bandwidth demands in mobile services

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Fig. 6.5 Increased capacity requirement in the B5G/6G era for submarine, terrestrial backbone, and middle/last-mile optical networks

and the number of ONUs per OLT, there will be increased traffic on the OFCs connecting OLTs with the nodes of BON. Due to the increased traffic in PONs and the cloud services, the nation-wide terrestrial BONs will be most crucial for researchers to improve their capacity and dynamicity. Obviously, to support the increased Internet traffic, the submarine cables need to be migrated to the latest high-capacity optical communication and network technologies at first [42]. The most promising and widely accepted near-term and long-term optical network technologies to support the increasing bandwidth demands, viz. EON, and SS-FON are described below. Elastic Optical Network Elastic optical network (EON) [32, 43] has been introduced as a promising technology alternative to WDM networks to satisfy the bandwidth demands in the near future. The term ‘elastic’ in EON refers to the spectral flexibility which makes it possible to assign the spectrum to a lightpath as per the bit-rate requirements as well as to dynamically adjust the spectrum allocation with time-varying traffic. EON enables spectral flexibility and bit-rate adaptive spectrum allocation due to its flexible grid structure. EON supports increased dynamicity enabled by distance adaptive modulation (DAM) [44], bit-rate variable transceivers, subcarrier multiplexing, among others, thus improving the network resource utilization (Fig. 6.6).

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Fig. 6.6 WDM fixed grid versus EON flexible grid

Space Division Multiplexing EON has been widely accepted as a near-term solution to the capacity crunch, whereas space division multiplexing (SDM) [37, 45] is envisioned as a long-term solution to the increasing bandwidth demands. SDM exploits the spatial-domain using multicore fiber (MCF) and/or multimode fiber (MMF) [45]. The optical network supported by both the EON and SDM is commonly known as SS-FON or SDM-EON [33–36]. EON requires technology migration at the nodes only, while utilizing the existing SSMFs, whereas SS-FON equipped with MCF will require the existing fibers to be replaced (Fig. 6.7). Margin Reduction The currently deployed optical networks are mostly static and pre-planned. Thus, they operate at high margins. Margins can be classified as unallocated (U)-margins, system (S)-margins, and design (D)-margins [46]. Ideally, the margins should be reduced to as minimum as possible for low-cost and spectrum-efficient optical networks; however, they depend on the optical network technology as well as the resource

Fig. 6.7 Multicore fibers

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provisioning schemes being used. For instance, the current WDM networks use fixedmodulation format for all the source–destination pairs in a mesh optical network having OFC links of different lengths, which necessitates the use of low spectralefficiency modulation schemes, and hence several lightpaths operate at high optical signal-to-noise ratio (OSNR)/distance/spectrum margins. As we progress towards the deployment of EON and SS-FON, there is a huge potential to reduce the margins leveraging the spectral and spatial flexibility of EON and SS-FON, thereby resulting in additional capacity enhancement of future optical networks.

6.3.2.2

Security

The two common beliefs with respect to the fiber-optic communication are as follows: (i) optical fiber can handle any amount of traffic being aggregated to it from the metro/access wireless communication networks and DCs; and (ii) optical fibers are highly secure because of the inherent isolation of the optical signals inside the fiber medium. However, none of them are true now. There have been numerous recent incidents of lightpath attacks, such as eavesdropping, jamming, and data interception that have affected millions of customers around the world, and have shaken the confidence of believing optical fibers as the highly secure media. Furthermore, the existing optical encryption techniques rely on the computational complexity, which the quantum computers can easily crack. Thus, the security of optical networks is a growing concern with the development of quantum computers. AI/ML Based Prevention from Physical Layer Attacks The common types of (optical path/lightpath) attacks in optical networks include eavesdropping, signal degradation attacks, and physical infrastructure attacks. These attacks can either lead to failure of communication or stealing of crucial information. While the communication failures may be restored by rerouting the traffic through alternate paths, the stolen information might be a great threat to the communicating parties that cannot detect such an incident in the current infrastructure. For infrastructure failures such as fiber-cuts and large-scale failures caused by natural disasters or man-made attacks like weapons of mass destruction (WMD) attacks, appropriate schemes for content placement and backup in edge or core DCs can be designed. ML based approaches have recently shown promise in monitoring and improving the optical network security, where several types of attacks on optical networks can be detected along with the location of harmful connection/ breached link by supervised learning (SL), semi-supervised learning (SSL), and unsupervised learning (UL) [47]. Blockchain based virtual network function (VNF) placement has also been explored to improve the security of optical networks [48]. However, all of the above methods mainly depend on the computational complexity involved and cannot guarantee unconditional security as that provided by the QKD systems.

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QKD Secured Optical Networks QKD is envisioned as a promising technology to realize secure communication networks in future. QKD is a cryptographic protocol that enables generation and sharing of secret keys between two end-nodes based on the principles of quantum mechanics, viz., the quantum no-cloning theorem, and the Heisenberg’s uncertainty principle, due to which the quantum bit (qubit) cannot be copied, and any attempt of copying can be detected [48]. Thus, using QKD, any two remote nodes can establish secure communication. Successful experimental demonstrations of QKD secured communication over both the optical fiber and free space have been done. The preliminary experiments on QKD secured optical fiber communication used dedicated dark fibers; however, it has now been widely accepted that the integration of QKD with the existing global optical network is a cost-efficient way to realize quantum communication [49], and hence the quantum and classical signals will coexist in the future optical network enabling the Quantum Internet [50]. The difference between classical and QKD secured communication is shown in Fig. 6.8, where the two end users, namely, Alice and Bob, communicate with each

Fig. 6.8 Difference between classical communication and QKD secured communication

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other, and an unauthenticated user/ eavesdropper, known as Eve, tries to steal or modify the information being transmitted between Alice and Bob. The cryptography methods used in the classical communication at present, such as public key cryptography, are based on the computation complexity involved in such methods. However, with the development of faster processing chips and quantum computers, these conventional cryptography schemes will become useless as the Eve can easily crack the complexity to hack the end-user devices or tap the classical channel through which the information is being transmitted. With QKD, communication between Alice and Bob will be secure in the quantum computing era since QKD is not based on the computational complexity, but on the laws of quantum mechanics. In classical internet, information is encoded into the classical bits, i.e., 0 or 1, whereas in the quantum internet, information will be encoded into the quantum bits (qubits), where qubits can be in a superposition of 0 or 1 simultaneously. Quantum signals are weak (few countable photons per pulse), and they cannot travel too far (usually