Military Communications in the Future Battlefield 9781630813338

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Military Communications in the Future Battlefield

For a listing of recent titles in the Artech House Electronic Warfare Library, turn to the back of this book.

Military Communications in the Future Battlefield Marko Suojanen

Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the U.S. Library of Congress. British Library Cataloguing in Publication Data A catalog record for this book is available from the British Library.

ISBN-13:  978-1-63081-333-8 Cover design by John Gomes © 2018 Artech House 685 Canton Street Norwood, MA 02062 All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher. All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. 10 9 8 7 6 5 4 3 2 1

Contents Preface   13

1 Introduction   15 1.1  Information-Centric Warfare   15 1.1.1  Two-Sided War Games in the Development of Operational Excellence and Future Capability Requirements    16 1.1.2  Characteristics of Future Operating Environments    18

1.2  Implications of Technology Development on Command and Control Functionality   21 1.2.1  Implications of Cross-Cutting Technologies on Command and Control Functionality    22 1.2.2  Command and Control in Network-Centric Environment Challenged by Autonomous Systems and Cyber Activities    24

1.3  Contents of the Following Chapters in This Book   26 References   29

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2 Scenario-Based Capability Planning in C2 Context   31 2.1  C2-Related Definitions   32 2.2  C2 and Network-Centric Warfare    33 2.3  Capability-Based Planning and Threat-Based Planning   34 2.4  Capability-Based and Threat-Based Planning from the C2 Perspective   36 2.5  Key Military Definitions from an Operational Perspective   38 2.6  Joint Capability Areas   40 2.7  Joint Capability Areas in Identification of the Most Important Requirements   42 2.8  Military Communications Scenario in the Future Battlefield   43 2.8.1  Characteristics of a Military Communications Scenario in Scarcely Populated Areas   46 2.8.2  Characteristics of a Military Communications Scenario in Rural Areas;   47 2.8.3  Characteristics of a Military Communications Scenario in Suburban Areas   48 2.8.4  Characteristics of a Military Communications Scenario in Urban Areas   49 2.8.5  Description of Fictitious Military Communications Scenario in the Future Battlefield   50

References   60

3 Communications Systems   63 3.1  Requirements for Military Communications   63 3.1.1  Command-on-the-Move   64 3.1.2  Electromagnetic Spectrum   64 3.1.3  Importance of Redundancy, Radio Silence, and Several Communications Alternatives   65



Contents

3.2  Communications Chain   67 3.2.1  Communications Transmitters    71 3.2.2  Communications Receivers   72 3.2.3  Spread Spectrum Systems   73 3.2.4  Communications Antennas   75

3.3  Generic Parameters and Characteristics of Selected Civilian Communications Systems and Military Radios   77 3.3.1  Military Communications Systems   79 3.3.2  Short-Range Civilian Communications Systems   80 3.3.3  Long-Range Cellular Communications Systems   81

References   81

4 Situational and Context Awareness   83 4.1  Context Awareness   84 4.2  Interaction with Smart Objects in Location- and AR-Based Applications   86 4.2.1  Close-Range Interaction with Smart Objects   87 4.2.2  Short-Range Interaction with Smart Objects   87 4.2.3  Long-Range Interaction with Smart Objects   88

4.3  Location-Based AR Applications   89 4.4  Dual-Use AI-Supported Situational Awareness   90 4.5  Context-Aware Military AR Applications for Improved Situational Awareness   91 4.5.1  Situational Awareness Support Based on AR   91 4.5.2  AR Support for Finding Communications Opportunities   92

References   94

5 Radio Wave Propagation   95 5.1  RF Propagation Phenomena in Wireless Communications Media   96

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5.2  Trade-Offs Between Frequency, Antenna Size, and Node Mobility   97 5.3  Radio Horizon and Fresnel Zones   98 5.4  Receiver Sensitivity and Quality of Service as Measures of Performance   98 5.5  Coarse- and Fine-Grained Calculation of Radio Coverages   99 5.6  Selection of Radio Wave Propagation Equations and Models   100 5.6.1  Free-Space Path Loss    101 5.6.2  Plane Earth Propagation Model   101 5.6.3  Egli Propagation Model   102 5.6.4  Okumura-Hata Model   102 5.6.5  COST 231-Hata Model   103

References   104

6 Wireless Sensor Networks   107 6.1  Building Blocks of Sensor Networks   108 6.2  Sensor Types   109 6.3  Sensor Network Intelligence   110 6.3.1  WSN Example of Enemy Vehicle Detection   111 6.3.2  WSN Example of Data Collection in the Distributed WSN   112 6.3.3  Use of Several Sensors in Sensor Network Intelligence   112

6.4  Utilization of Information Collected by Sensor Networks in Commanding Various Actors on the Battlefield   113 6.5  Energy Issues of WSNs   115 6.6  Security, Robustness, and Reliability of WSNs   115 6.7  IoT’S Role in Both WSNs and Communications   116 6.7.1  Case Studies of IoT   117 6.7.2  Implications of Developments of Other Technologies on IoT   118 6.7.3  Energy Issues in IoT Networks    119 6.7.4  Military Procurement of IoT Type of Technologies   119 6.7.5  Big Data and Cyber Issues in IoT Networks   120

References   121



Contents

7 Software-Defined Radio and Cognitive Radio   123 7.1  Spectrum Management of Military and Civilian Users   123 7.2  Software-Defined Radio   124 7.3  System-On-Chip as Modern Software-Defined Radio and Cognitive Radio Platform   126 7.4  Cognitive Radio   127 7.5  Challenges on Software-Defined Radio Interoperability   128 7.6  Software-Defined Radio and Cognitive Radio Research and Development Directions   128 7.7  Military Software-Defined Radio   129 7.8  Military Cognitive Radio   129 References   130

8 Unmanned Aerial and Ground Platforms   131 8.1  Different Case Studies of Data Collection   132 8.2  Development of Unmanned Systems in the Medium Term   133 8.3  Unmanned Aerial Vehicles   133 8.3.1  Benefits of UAVs versus UGVs   134 8.3.2  ISR, Logistics, and Engagement Applications Using UAVs   134 8.3.3  Communications Applications Using UAVs   135

8.4  Unmanned Ground Vehicles   136 8.4.1  Communications Applications of UGVs   137 8.4.2  UGVs and Development of Robotics   137 8.4.3  Challenges in the Land Domain for UGVs   138

8.5  Examples of Unmanned Platforms with Generic Characteristics   139 8.5.1  Examples of UGV Characteristics   139 8.5.2  Examples of UAV Characteristics   140

8.6  Command and Control Cases   141

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8.7  Autonomy, Teaming, and Swarming of Unmanned Platforms   142 References   144

9 Analysis of Selected Communications Alternatives Related to Scenario   145 9.1  Examples of Military Communications Needs, Linkages to Capability Areas, and Operational Risks Due to Communications   146 9.2  Scenario-Based Iteration of Requirements of the Defense System   147 9.3  Introduction of Military Communications Alternatives   148 9.3.1  Wired Communications between Nodes Using Civilian Communications Networks   151 9.3.2  Wired Communications Between Nodes by Building Wired Military Communications Networks   152 9.3.3  Wired Communications from Sender to Radio Mast That Deliver Messages in the Air Using Radio Waves   154 9.3.4  Wired Communications from Sender to UAV Relay, Aerostat, or Balloon That Delivers Messages in the Air Using Radio Waves   155 9.3.5  Wireless Communications between Nodes Using Civilian Communications Networks   156 9.3.6  Wireless Communications between Nodes Using Military Communications Networks In Different Frequency Bands   157 9.3.7  Wireless Communications from Sender to UAV Relay, Aerostat, or Balloon   160 9.3.8  Wireless Optical Communications between Nodes Using Military Communications Networks in Different Wavelengths   161 9.3.9  Wireless Optical Communications from Sender to UAV Relay, Aerostat, or Balloon   162 9.3.10  Utilization of Heterogeneous Networks in the Transmission of Messages   163 9.3.11  Left-Behind Location-Specific Messages for the Second Phase of Blue Units   164 9.3.12  Physical Delivery of the Message from the Sender to Recipient by the Messenger   166



Contents

9.3.13  Physical Delivery of the Message from the Sender to Recipient by UAV Or UGV   166

9.4  Qualitative Factors in Evaluation of Communications Alternatives   167 9.4.1  Robustness Factor   168 9.4.2  Security Factor   169 9.4.3  Capacity Factor   169 9.4.4  Time Advance Factor   170 9.4.5  Discussion of Qualitative Factors   170 9.4.6  Importance of Operational Tempo in Evaluation of Communications Alternatives   173

9.5  Quantitative Estimation of Communications Ranges Based on Propagation Models and Public Sources   174 9.6  Analysis of Selected Communications Alternatives in Scenario   176 9.6.1  Analysis of Part 1   181 9.6.2  Analysis of Part 2   187 9.6.3  Analysis of Part 3   191 9.6.4  Further Steps for Improving Operational Trade-Off Analysis   196

10 Conclusion   199 10.1  Importance of Foresight in Capability Planning and the Role of Information   199 10.2  Evolving C2 in the Future Battlefield   200 10.3  Future Warfare and Nature of Battle   200 10.4  Coexistence of Legacy and Sophisticated Communications Systems   201 10.5  Understanding of Radio Wave Propagation in Operating Areas and Accurate Mapping of the Environment   201 10.6  Convergence of Sensors, Actors, and Communications Nodes   202 10.7  Spectrum Management and Sophisticated Forms of Military Radios   202

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10.8  Alternative Forms of Military Communications Need Input from Operational Excellence   203 10.9  Low-Power Military Communications and LPI Requirements   204 10.10  Unmanned Systems and Autonomy   205 10.11  Future Directions   206

Acronyms and Abbreviations   207 Bibliography   211 About the Author   217 Index   219

Preface This book presents an application-oriented view to communications in the future. The book is written with a hands-on approach by avoiding very theoretical presentation of the concepts. Theoretical issues are handled as well, but the goal is to serve both military and security technology experts and officers by giving insights that provide more common issues to discuss regarding long-term developments within the communications area. Technological alternatives to communicate in the battlefield in unexpected situations, environments, and unstructured formations of actors are considered using a holistic approach that takes other key capability requirements into consideration. There are many books available on wireless communications, but most of these are focusing on civilian applications. Military or defense-related technical books are quite often focused on electronic warfare or radar applications. This book represents a unique, futuristic, application-oriented approach by combining operational, communications, sensing, and mobility aspects under one title. The main message of the book is to prepare for the unexpected and to start building up agile, adaptive, and cognitive systems that are needed in future operating environments without forgetting time-tested methods of communications, both technologically and tactically, that serve as redundant ways to communicate if environments don’t allow the use of sophisticated technologies in carrying out command and control functionalities. 13

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Readers within the following areas may find the book interesting, although the conceptual, futuristic, and application-oriented approach may also be of interest in a wider range of readers. • Technology and business development managers in defense and security areas; • Military and security officers and technology experts within defense and security areas; • Technology experts within long-range technology foresight; • Post-graduate students in communications and defense-related research areas. The readers of this book are assumed to have basic knowledge of communications technology, recent developments on technologies on a wide scale, and operational knowledge on tactics, procedures, and the environments where military and security forces will be operating in the future. The author has written the book in such a way that previous knowledge of one of any three areas is enough to comprehend the contents. Perspectives, discussions, and analysis presented in this title are solely the author’s personal creations that do not reflect in any way the official views of Finnish Defence Forces, Finnish Defence Research Agency, and Ministry of Defence of Finland. Any details in this book that might be aligned with the official views of these organizations are pure coincidences. Classified information or classified references were not used in production of this title. Scenarios presented in this title are fictitious, generic, and they do not refer to any real nations, capabilities, or locations. The selection of presented topics, technologies, and capabilities is based on the author’s personal interests and duties during his early career in civilian organizations, with the generic approach of command and control in the military.

1 Introduction Information has always played a key role in battle. Without information on the environment and on the enemy carrying out and planning operations, execution of one’s own operations is a foggy and risky effort. Information may prove true or false, which results in very different actions based on the reliability of the information. Decision-makers may have several alternatives on the way battles progress in a mission that is based on the possession of reliable information. If the reliability of that information is challenged, this creates a need for new plans or improvisation by applying warfare expertise based on the decision-maker’s education, training, surrounding conditions, capabilities, and the resources available in the battlefield.

1.1  Information-Centric Warfare Although possession of reliable information sounds like the key to winning a battle it is not enough in most cases. One should pos15

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sess reliable information and have the necessary tools to distribute information on the battlefield so that every actor understands the information. Recipients of information should apply it on their own operational tasks in a way that preserves the commander’s intent regarding the goals of the mission. Every move on the battlefield changes the dynamics of the operation. Therefore, it is crucial that individual actors do not create their own realities which could hinder tasks that other actors are carrying out in the operation. In addition to the delivery and perception of information, information must be updated continuously. For the good of operational planning one must manage the trade-off between having information updated frequently and losing the latest data. There are different perceptions on the definition of information. On one hand, information may represent collected data filtered in a specific way to carry out analysis on information to make informed decisions. On the other hand, information may represent analyzed data that is directly applicable to decision-making. Information can also represent a description of real-world measurement data, events, and phenomena in a specific form. Information is processed in the digital domain that enables utilization of the most sophisticated information technologies and algorithmic tools. Current levels of these technologies enable the collection and processing of huge amounts of data (especially if the sources of data are connected to the internet.) If a phenomenon of interest is not accessible on the internet, it is more difficult and slower to observe these events and perform analysis based on non-internet sources. Then, as the data collection and analysis gets slower and more expensive, the utility of the information and its impact may diminish over time. 1.1.1  Two-Sided War Games in the Development of Operational Excellence and Future Capability Requirements

In the history of warfare there have been several well-known phases of development where industrialization, mass, air power, networkcentric, intelligence, surveillance and reconnaissance, and precision engagement capabilities have played an important role on the battlefield. The role of information, cyber, space, robotics, and autonomy is expected to affect the future battlefield on several fronts by decreasing the time spent in observe, orient, decide, act (OODA)



1.1  Information-Centric Warfare

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loops. These effects include delivering information on battlefield parameters to an increased number of users, pushing unmanned platforms into the frontline, and processing logistics streams to bring necessary resources to the right locations at the right time. Although there are many possible configurations of several actors in modern warfare, traditional approaches consider warfare as two-sided battles between friendly and hostile sides that are marked as Blue and Red. Opposing forces have specific operational goals that are described by mission requirements. Both sides have forces, units, systems, and resources whose locations and degrees of freedom in different phases of operation are considered against terrain characteristics, weather conditions, resources of the opponent, methods of the opponent to use the environment for their own good, and objectives of the opponent in the mission. Figure 1.1 presents an example of different military units and functions that might be used in a mission. Specific force elements have been trained to face similar force elements at the opposing side or trained to utilize countermeasures against opposing force elements in various ways. Various military tasks, a limited number of military systems, personnel and training, military technology investment and hierarchical organizations with various degrees of freedom at different levels of the organization limit the ability to carry out tasks very far from the main objectives in military missions.

Figure 1.1  Example of military units and functions that might be used in a mission.

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Battles in war can be considered as a game where actors on both sides have been preparing in order to be familiar with the relevant tools, forces, systems, environment, and opponents. Both sides prepare various alternative procedures in order to reach goals in the military mission. Different procedures have different priorities that changes in space and time as both actors update the situation on the battlefield, which can leave the previous incremental step outdated. Figure 1.2 presents an example of the military units and functions in the first phase of battle between Blue and Red. Units and functions of the Blue are on the left and units and functions of the Red are on the right. Positions of the units in the figure describe the order in time in which they are used in battle. For example, Blue has Special Forces and Red has ISR units in the front. 1.1.2  Characteristics of Future Operating Environments

It is often said that after the first action in the battle both sides must adapt since neither Blue nor Red will face the situation in the same way as was planned before the battle. Because there probably will be surprises for actors, adaptiveness, agility, and speed come into play. The one who has forecasted probable outcomes, collected information, analyzed different approaches to achieve goals of the mission, and performed them in exercises has higher expectations for achieving success in a mission. Military preparedness, mobility, a high speed of force projection, and maneuvers limit chances of a decision-maker to update and analyze a situation and perform short-term planning. If there is a continuous stream of events going on whose reliability and threat level must be verified and vali-

Figure 1.2  Example of two-sided battle between Blue and Red presenting units and functions in ordered phases.



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dated, the decision-maker is left focused on specific events instead of evolving the goals of the main mission. Therefore, the development of procedures and systems to collect, analyze, and deliver a situational picture is a continuous process. A few questions regarding achievement of the ideal situational picture are presented in the following: • Is this event credible and does it affect tasks in the mission? Does it indirectly affect the main mission? • If this event is not accounted for, what is the timeline of hostile events and activities that may be faced in the following phases of operation? • If this event is evaluated and mitigated, what other consequences emerge as a result of diminished focus on other issues? Does it limit alternatives to proceed with other tasks in the area of responsibility? • Is there a need for more thorough analysis of the situation before making decisions to act or to not act? Is there a need for additional information from the location of the event and is there a need for reallocation of resources to this task? This list makes clear that it is a decision-making challenge at every level of organization. Since military operations cover life and death situations, validity of information in space and time is often stressed in the planning. The use of different systems and force elements in battle requires both initiative and the timely and economic use of limited resources. If the mission takes longer than expected, military resources may diminish at a higher pace than expected. Resources must be allocated in order to provide protection for Blue forces, but, also have high preparedness to project resources and forces to key points that are considered vital for the success of mission. Timely and jointly focused effort on the key points may be needed to gain an upper hand in battle and a strong position in the final mission. There are several approaches to carrying out missions using fixed resources. The best one is hard to find beforehand, although the operations research and analysis community (with the support of modeling, simulation, and technology communities)

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are performing great studies and exercises. This book focuses on command and control (C2), communications, and emerging and disruptive technologies. As C2 is expected to be a lifeline of military operation in the long term, this discussion also focuses on communications. Military forces and security authorities have traditionally been organized in hierarchical and nonadaptive format. Forces at different levels of military organizations have varying ranges of responsibilities and freedom of action in missions. Widely adopted capability-based planning utilizes common situational awareness and joint operations. Timely projection and decentralization of forces are the key concepts of any successful military mission. There are ongoing discussions whether progress in new technologies has changed the nature of battle or warfare. It is expected that faster operational tempo and distributed allocation of forces will be utilized in the future instead of traditional projections of heavy forces with supporting units. Future military strategy may rely on more capable forces supported by superior situational awareness, transparent C2, and wide access to unmanned or even autonomous systems. Continuous progress of precision-guided weapons and utilization of unmanned platforms calls for protecting important systems by camouflage or decentralization of capabilities to reduce vulnerability of military formations. In fact, situational awareness and appropriate protection by both passive and active means are necessary factors for survival that should be attained before any actions focusing on communications or engagement. This poses requirements on smaller units that have to cope with any situation with their own assets without support from neighbor units. There may be situations where communication solutions must diverge from the chain of command to enable active initiative from the units that have the best knowledge of the local situation. There will be an increased need for ad hoc distributed methods of connectivity to make unforeseen connections as needed. The traditional approach separates sensing and communications, but, in the long-term these capabilities are expected to converge in the way different functions were integrated into smart phones in the 2010s. It is paradoxical that the decentralization of forces with the goal of protection in fact poses greater requirements for communications.



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On one hand, to accomplish common joint missions, each unit and warfighter needs information on emerging threats, locations of threats, civilians, friendly forces and important warehouses for battlefield logistics and critical capabilities that should be kept safe and undetectable at any time. On the other hand, the use of wireless communications might open a window of opportunity to hostile signal intelligence, surveillance, and reconnaissance (ISR) missions.

1.2  Implications of Technology Development on Command and Control Functionality Military C2 systems depend heavily on planned operations and operating environments. Therefore, continuous scanning of trends, developments, and disruptive events is important for understanding the environment. Technological progress has accelerated in recent years due to wider availability of enabling technologies (whose nonexistence in the past has hindered an application of specific concepts of operations). Key elements of this progress are the digitalization and networking of different functions. Awareness of new technologies, education, expertise, and innovation networks enables delivery of information at the global level. Due to the call for greater data capacity, transmission frequencies of many communication systems have moved to higher frequencies that require smaller distances between nodes and therefore smaller cell sizes in cellular mobile systems. Higher frequencies require line-of-sight (LoS) links where either mobile stations (MS), base stations (BS) or both are raised up utilizing high communications masts, elevated terrain or air-based systems. At the same time civilian frequencies are taking the upper hand over military frequencies which poses great requirements on military frequency planning. Increased urbanization and economic growth in cities attracts people to city centers from rural areas by providing better economic prospects for citizens. This forecasted increase of population in cities creates megacities that are expected to face challenges to offshore locations, networking, electricity, logistics, and maintenance related to provision of water, heating, ventilation, and waste management. Modern megacities are dependent on networking

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since many services will be managed through the cloud and the Internet-of-Things (IoT). 1.2.1  Implications of Cross-Cutting Technologies on Command and Control Functionality

Having examined several public technology foresight reports, roadmaps, and long-term strategic military reports, there are several emerging, radical and disruptive technologies that will have links to C2 capability. Information technology can be regarded as cross-cutting technology that has impact on most of the systems in the battlefield. Since C2 functionality forms the basis of leadership and management in the battlefield, this capability is needed in any operational task. The following list represents a snapshot of important technologies, methodologies, and systems that are regarded as having impact on performing operations in the long-term [1–7]. Long-term in this title is defined as a time period of 20–25 years from now to the future (2038–2043). • Autonomous systems; • Unmanned systems; • Deep learning; • Machine learning; • Artificial intelligence (AI); • Neural networks; • Cognitive systems; • Cognitive radio (CR); • Software-defined radio (SDR); • Cloud computing; • Augmented reality (AR); • Ubiquitous computing; • IoT; • Quantum computing; • Big data analytics; • Small satellites; • Nanotechnology;



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• Biotechnology; • Synthetic biology; • Additive manufacturing; • Robotics; • Multifunctional systems; • Multirole platforms. Progress in microelectronics is expected to continue although the limits of fabrication processes are seen on the horizon. Current common fabrication and material technologies need to develop to other fields by using different materials and methods. Nanotechnologies, biotechnologies, and quantum technologies seem promising, but, each of these needs new expertise, new ways of design and implementation, and reliable testing procedures to verify their capability. These new technologies require understanding of phenomena quite different from earlier ones. Transfer from matter to waves makes it difficult to isolate building blocks and keep achieved states of these systems unchanged. Understanding the interaction of these systems with the surrounding conditions is vital to keep these systems stable. In terms of networking, IoT may pose great challenges to cyber security, but, on the other hand it may create more opportunities to have more interconnected sensors, actuators, and communicators. Intelligence functions in the form of AI, deep learning, machine learning, neural networks, quantum computing, and cognitive systems are linked to the development in nanotechnologies, biotechnologies, additive manufacturing, and robotics. Examples of these developments are neuromorphic chip prototypes and nanostructures that perform interaction between electronic and optoelectronic components. Improved nanostructures and their beneficial characteristics of high switching and processing speeds, low power losses and miniaturization may open up new opportunities to develop highly sophisticated learning systems locally without the need of cloud-based infrastructure services. On one hand, reconfigurable systems guide the way to multifunctional systems and multirole platforms, but, on the other hand the development of swarming platforms may provide inexpensive solutions to form intelligent groups whose individual responsibilities change

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for the benefit of the whole swarm. Additive manufacturing may provide tools for local production of communications components. Synthesis of nanotechnology, biotechnology, synthetic biology, and learning capabilities may bring disruptions that are not completely understood and expected. Development in the cross-section of these technologies raises several ethical questions in addition to the technological ones. 1.2.2  Command and Control in Network-Centric Environment Challenged by Autonomous Systems and Cyber Activities

Although ethical and legal issues of autonomous systems have recently been under discussion, there are a lot of activities whose goal is improving sense and avoid systems, pattern recognition, analysis of big data, cognitive systems, and swarming. Autonomous systems may perform missions very efficiently compared to traditional approaches, and many current systems might appear obsolete in times of autonomous systems. If an autonomous platform or group of platforms has a very sophisticated knowledge of the versatile factors that affect its operations by adapting to current conditions, there is no need for communications from autonomous systems to control center or headquarters. Very elemental messages on aborting the mission and homing may be sent on very narrow bursts of data messages that could be relayed between autonomous systems. If the system is really self-contained there is no need for any communications to the platform. One way to control autonomous systems might be supervision of an unmanned mission from manned platform. Future autonomous systems could be independent systems aware of their environment and have all the capabilities needed for single actor operations. Another breed of autonomous systems is related to group and swarm intelligence, where the capability is built with several units that act in concert with each other. All these units carry out the main mission each having certain tasks that can be switched between different units if the units have the needed functions to carry out the tasks. Swarms could also have inherent deception capabilities meaning that some units of the group are only carrying out deception tasks to draw opponents’ interest in these artificial units to protect high-value targets (HVT). As previously



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mentioned, autonomous systems could improve military communications in several ways. Several swarming units could gather information on environmental and terrain conditions to optimize communication between geographical locations of the transmitter and receiver respectively. Optimization tasks could also be applied to rerouting communications via different nodes, by changing carrier frequencies, or diverting to wired connections or optical communications instead of using radio frequencies. Ultimately bits or bytes do not need to be sent through any media, if an autonomous platform has a capability to deliver the message physically from the origin to the intended recipient of the information. In the past warfare evolved along with the changes happening in societies, politics, economy, technology, ethics, globalization, and different alliances throughout the world. Although warfare as a concept and military preparations to develop the right capabilities, equipment, forces and training procedures to use them have always been classified to a large extent, warfare in general has not evolved in complete isolation. Defense is one elemental constituent of nation and society. Although the development of several technologies towards functional civilian or military systems will evidently affect the future battlefield, the core activity of the military throughout history still plays a major role in future developments. Virtual, cyber, or robotic wars do not represent the typical fight of will and sacrifices that a nation must be prepared for in order to protect its sovereignty and interests. Technological wars would probably still be fought to the point where material and financial resources were diminished and then boots on the ground would continue the fight. Although sacrifice is an unwanted phenomenon for most modern people, it is in the essence of warfare which virtual and robotic actors can’t overtake. Technologies could actually reduce suffering and sacrifice, for example, new types of weapons that are accurate and limit collateral damage to civilians and Blue forces. Cyber weapons might be located at the other end of the spectrum, since collateral damage might expand globally in the worst case scenario. Although direct consequences of wide unlimited cyber operations would at first be information-centric, indirect consequences could entail physical suffering and sacrifice as well in a networked and connected Earth. Military organizations

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have traditionally been preparing for expected critical changes in the battlefield by proactive and reactive means. Because the development of new capabilities is not a rapid process, militaries must have a capability to mitigate new challenges and develop operational and technological excellence after surprises in enemy strategy, operations, tactics and technological capabilities. More than ever this requires agility, adaptiveness, robustness, and resilience at all levels. Concepts of operations (CONOPS), research and development, and training must be developed in parallel with constant evaluation of lessons learned and reports of recent operations. In the technology area, the battle between technology and its countertechnology will continue. It wouldn’t be wise to leave technological research, innovations, and experiments completely for civilian actors. Different combinations of technologies in systems in addition to experimentation with several breeds of CONOPS may open up new unforeseen ways to use forces and assets in a clever manner [8]. Performing operations using a network-centric approach is as important as performing operations without the support of network-centric resources and services. One key question could be how much the military would be willing to reduce requirements for robustness if it would create excessive benefits within other areas. Robustness is embedded in the military requirements for military systems which is typically the explanation for the military use of military radios instead of civilian communications products [9–10].

1.3  Contents of the Following Chapters in This Book After introduction to the importance of information in the future battlefield, perspectives of technology forecasting in the long-term, and the character of future military operations and warfare in general, the contents of the following chapters in this book are presented below. Chapter 2 first introduces C2 in order to understand its elemental role in the portfolio of military capabilities. Military capability planning is introduced by comparing threat-based planning to capability-based planning in a C2 context. Capability planning can utilize both threat- and capability-based planning methodologies,



1.3  Contents of the Following Chapters in This Book

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although the latter has gained more ground in the western military capability planning. C2 and net-centric capabilities (e.g., in the U.S. Joint Capability Areas (JCA) model) are important capabilities considering military communications, but, from an operational analysis perspective, the elemental role of other capabilities becomes clear. Chapter 2 also introduces a fictitious military scenario that sets a baseline for evaluation of the communications technology alternatives in Chapter 9. Communications technology is introduced briefly in Chapter 3. Basic characteristics of the communication channel, transmitter, receiver, antennas, and spread spectrum (SS) communications systems are introduced. Different frequency bands are presented and generic parameters of both civilian and military communications technologies are introduced to be utilized later in Chapter 9. The importance of situational and context awareness in military operations is discussed in Chapter 4. C2 functionality requires upto-date situational awareness and the delivery of the situational picture is also a task of C2. Smart environments, location-based services, AR, ubiquitous computing, and man-machine interaction are also discussed in Chapter 4 with the goal to utilize new technologies to improve interaction of warfighters with each other and smart environments that might provide a new way to communicate through specific locations. Radio wave propagation is introduced in Chapter 5 with a view to basic phenomena in propagation and to simple propagation models that are utilized in Chapter 9 in communications range evaluations. As this book doesn’t present accurate 3-D terrain, object models, and real environments, propagation modeling is kept simple and at a coarse -grained level. Chapter 5 presents characteristics of free-space and plane-earth propagation as well as empirical models of Okumura-Hata, COST 231-Hata and Egli. Chapter 6 introduces wireless sensor networks (WSN) and focuses on emerged IoT concepts that fall between WSNs and communications networks in future 5G networks. WSNs could provide alternative communications paths for regular communications services and if messages were stored to one intermediate node, the concept comes close to the ideas of the left-behind location-based messaging presented in Chapter 4.

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Chapter 7 introduces SDR and CR that might provide solutions to the requirements of communications in the future battlefield. The promise of flexibility, adaptiveness, interoperability and multimode and multi-role characteristics of warfighter terminals has not been completely established, although these concepts have been under development for a long time. Recent technology development has resulted in new tools and solutions to utilize flexible processing options and wideband communications blocks together to implement SDRs that can operate legacy, narrowband, and wideband operating modes. Availability of spectrum will be challenged in the near and long-term that will require cooperative learning, and CRs that have awareness of spectrum in the operating environment. Unmanned systems and their utilization in providing communication services are introduced in Chapter 8. This chapter presents unmanned aerial vehicles (UAV), unmanned ground vehicles (UGV), robots, autonomous vehicles and swarms of unmanned systems. Technological progress brings utilization of the unmanned systems to the front in communications applications as well, since in the future autonomous systems might provide a nonemissive option for delivering messages from origin to destination. This will not only save spectrum and limit detectability of the platform, but, also reduce communications payload to extend flight time and remove the burden to design high-quality multiband antennas on the platform. Chapter 9 brings the contents of previous chapters together, where different options to communications in the battlefield are considered. The scenario developed in Chapter 2 is utilized as a framework to analyze C2 functionality in operational analysis by introducing the robustness factor, security factor, range factor, capacity factor, and time advance factor as measures of effectiveness (MOE) in communications. These factors are interrelated and selecting different communications alternatives has a great impact on tasks within a mission. Analysis in this chapter is related to the fictitious scenario, but, it introduces a list of procedures to go through in a scenario-based capability development process that might produce capability requirements of a total defense system as well.



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Finally, Chapter 10 looks back at the contents in Chapters 1–9 and draws conclusions on military communications in the future battlefield.

References [1]

Mathijsen, D., “DARPA: Inventing the Future of Military Technology,” Reinforced Plastics, Vol. 59, No. 5, September/October 2015, pp. 233–237.

[2]

Barno, D., and N. Bensahel, The Future of the Army: Today, Tomorrow and the Day after Tomorrow, Atlantic Council, September 2016.

[3]

Scheerder, J., R. Hoogerwerf, and S. De Wilde, Horizon Scan 2050: A Different View of the Future, The Netherlands Study Centre for Technology Trends, The Hague, 2014.

[4]

European Commission, A Digital Compass for Decision-Makers: Toolkit on Disruptive Technologies, Impact and Areas for Action, Recommendations of Strategic Policy Forum on Digital Entrepreneurship, European Union, July 2016.

[5]

Ivanova, K., and G. E. Gallash,, Analysis of Emerging Technologies and Trends for ADF Combat Service Support 2016, DST group, Department of Defence, Australian Government, Unclassified, Approved for public release, December 2016.

[6]

Office of the Deputy Assistant Secretary of the Army (Research & Technology), Emerging Science and Technology Trends: 2016–2045: A Synthesis of Leading Forecasts, US Army, April 2016.

[7]

Miller, D. T., Defense 2045: Assessing the Future Security Environment and Implications for Defense Policymakers, Center for Strategic & International Studies (CSIS), November 2015.

[8]

Burmaoglu, S., and O. Santas, “Changing Characteristics of Warfare and the Future of Military R&D,” Technological Foresight & Social Change, No. 116, 2017, pp. 151–161.

[9]

Chapin, J. M., and V. W. S. Chan, “The Next 10 Years of Wireless DOD Networking Research,” MILCOM 2011 Military Communications Conference, Baltimore, MD, 2011, pp. 2238–2245.

[10] Vassiliou, M. S., et al., “Crucial Differences between Commercial and Military Communications Needs: Why the Military still Needs Its Own Research,” MILCOM 2013 – 2013 IEEE Military Communications Conference, San Diego, CA, 2013, pp. 342–347.�

2 Scenario-Based Capability Planning in C2 Context C2 is one of the capability areas in many military capability frameworks. In a military context command refers to a commander’s right to use authority to give commands to the organization that he or she is responsible for. Often a mission is a top-level plan for an organization to reach its goals in an operational setting. A mission is divided into operations that are further divided into tasks. In military organizations missions are preplanned and the key duties of a military organization are to create plans for each expected mission and train for the execution of the mission by forces within the organization. It might be necessary to improve the plans after exercises and lessons-learned evaluations. Command also entails the delegation of command authority to lower levels, where officers are responsible for goals, resources, and the schedule of execution of operations. Control is a supervision of objectives given to the lower levels of a military organization in relation to the mis31

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sion goals along with orders to change objectives as circumstances change. Command is an act of decision-making. Control is feedback from lower levels of the organization that supports execution of the whole mission in the direction of the commander’s goals. These two factors are the typical constituents of C2, although many studies on organizational behavior have stressed the role of leadership in C2 as well.

2.1  C2-Related Definitions There are several definitions for abbreviations related to C2 capability such as command, control and communications (C3), and command, control, communications, and computers (C4). There are also abbreviations that add intelligence functions after C letters, such as intelligence, surveillance, and reconnaissance (C3ISR), as well as targeting functions, such as intelligence, surveillance, target acquisition and reconnaissance (C4ISTAR). C2 like any other military capability carries traditions from past wars and operations. As technology becomes more important, it is essential to understand that there is little experience with new technologies and military systems. This requires military organizations to stay on top of technology development and carry out their in-house military research and development (R&D) work. In parallel to technological R&D work, CONOPs against forces that fight with futuristic technologies have to be planned for and tested (at least in digital domains) with the support of operational analysis, modeling, and simulation. C2 systems are computing and communications technologies that enable C2 functions to be performed in the environments where military forces are operating. As C2 is such an important capability, C2 systems should be reliable, secure, adaptive, agile, scalable, support mobility of forces, support interoperability with national and international partners, support possible connectivity to nonmilitary networks, provide services without excessive costs, and provide necessary communications capacity along necessary communications distances between users [1]. Although this list of requirements is long, the messages transferred in the C2 systems should be welldefined and should be perceived uniquely by any user who is part of the C2 network.



2.2  C2 and Network-Centric Warfare

33

2.2  C2 and Network-Centric Warfare C2 systems operate using data, voice, pictures, and video. Due to developments in information and communications technology, networking of sensors, actors, and shooters was seen as a force multiplier in network-centric warfare (NCW) compared to platformcentric warfare. The importance of NCW is information superiority with respect to adversaries that enables decision-making based on accurate, timely, and reliable information. This superiority helps project Blue forces faster, as well dominate the spectrum by application of clever electromagnetic spectrum operations (EMSO). Current thinking in domains of warfare focuses on electromagnetic spectrum as the key domain where operations are prepared and secured. Electromagnetic spectrum management relates to cyber and space domains as well. The concept of NCW has been established but current progress in networking technologies and data analytics have improved the baseline of this concept. In addition to information superiority and information-based operations, the second important concept in NCW is joint operations, or the combination of forces from several branches. Joint operations may be a portfolio of capabilities used in parallel to achieve a common goal in the battlefield. Information superiority and a concept of joint operations work well together; actually each one of them amplifies the effects of the other. Information superiority is achieved by performing the continuous collection of data, filtering, classification, and analysis of data, as well as dissemination and delivery of data better than one’s adversaries. Unity of command, interoperability, and interconnectivity are issues closely related to information superiority since systems should be connected and messages should be understood in the same way irrespective of the user. Early research on NCW concepts clearly recognized the threat to NCW by offensive cyber operations as well as their power in engagement portfolios. This research also mentioned automation as an important goal in decision making but autonomous systems, such as vehicles or robots, were far in the future. The nature of warfare was transformed as a complex endeavor, where actors and assets could be utilized in various ways. Therefore, part of the benefits of NCW were lost

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since new operations were very complex compared to the previous ones.

2.3  Capability-Based Planning and Threat-Based Planning Threat-based planning is based on recognizing the most important threats and long-term planning is done creating countermeasures and mitigation strategies against these known threats. If the threat portfolio remains fairly static, threat-based planning might provide robust solutions to known threats but not necessarily to new and unknown threats. Since long-term military planning requires careful development of capabilities that are in service over several decades, evolving and new threats may pose challenges. Therefore new capabilities should be developed using a modular approach that enables integration and upgrade of new technologies. Figure 2.1 presents a dotted oval that shows threat-based planning that covers the most critical threats that are important baseline assumptions for the defense system. From Figure 2.1 one can conclude that the main focus of threat-based planning has been directed to countering primary and secondary threats. There are known threats B and C that are partly mitigated in defense planning but the defense system is not primarily focused on these threats. There is a known threat A that is evaluated to carry a certain level of surprise in the battlefield but it is eventually considered mostly irrelevant com-

Figure 2.1  Example of threat-based planning process in a complex threat space.



2.3  Capability-Based Planning and Threat-Based Planning

35

pared to the primary and secondary threats that are the most imporant threats to the military capability. Although planning is based on the understanding of primary and secondary threats, there are always parts of these threats that go beyond the planning space. There are also unknown threats that are not considered at all, since they are not recognized in the planning process. In contrast to threat-based planning, capability-based planning aims at creating generic capabilities that could be used in multiple conditions and versatile missions. In an evolving threat environment, capability-based planning may contain elements that can be adapted to different situations. If long-term capability-based decisions have created capabilities that do not cover new threats and the adaptibility of the capability portfolio is limited, the most important aspects of capability-based planning are lost. By definition, the capability-based approach may have better answers to unknown threats than threat-based approach. On the other hand, capability-based approach may not perform as well as threat-based planning, since the latter one is based on preparing for the most important (strategic) recognized threats. Figure 2.2 presents a dotted oval that shows coverage of capability-based planning for the most generic threats of the defense system. From Figure 2.2 it can be seen

Figure 2.2  Example of capability-based planning process in a complex threat space.

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Military Communications in the Future Battlefield

that capability-based planning mitigates generic threats to varying degrees. If the process is well-designed and iterated several times considering the validity of requirements of future missions, most of the generic threats might be mitigated. Capability-based planning may not cover the threats completely and there may still be unknown threats.

2.4  Capability-Based and Threat-Based Planning from the C2 Perspective Presentation of these two types of capability planning relates to C2 capability as well as military communications in many ways. Planning and implementation of a command chain is an essential factor in building up the total capability of the defense system. If military communications are based on threat-based planning, the communications and EW equipment of the most important threats are taken into account in preparing one’s own techniques, tactics and procedures (TTP) for operations in different scenarios. These technologies affect command chains on both sides and they must be analyzed with force structures. At first glance, threat-based planning of communications may seem static and monolithic, but in fact it may contain different and innovative ways to change structures and actions according to the situation at hand. If a military organization has missions in addition to preserving national defense, international operations, support to civilian society, and government security, authorities may have different requirements that don’t fit well with the capabilities developed for countering the most important threats. Capabilities are based on certain functionalities of systems and subsystems that have been implemented based on requirements that are typically defined by a scenario, a threat, a capability gap, or an opportunity. Communications technologies and concepts may be applicable to other domains (air force, navy, joint) as well, but this chapter describes the domain of land forces. As unclassified and publicly released, this book doesn’t refer to real force structures and specific defense materiel of any nation. The typical force structures presented here are generic in nature. Each nation has their own unique characteristics that are not analyzed in this book. Force structure



2.4  Capability-Based and Threat-Based Planning from the C2 Perspective

37

defines how a military is organized in terms of materiel and personnel in foreseen missions, operations, and tasks. Referring to defense capability planning models introduced earlier in this chapter, threat-based planning in communications could mean planning communication technologies to operate effectively in expected operations, operating environments, along with their different characteristics against hostile ISTAR and engagement operations in specific parts of the spectrum. Capability-based planning of C2 and communications technology means preparing for operations with different needs, supporting forces, threats, and operating environments. Although capability-based planning may include prioritizing features for the most important and probable operations, the basic idea is to deliver capabilities that are generic by nature in contrast to specific threats. The idea of generic capabilities could help in guiding capabilities to a variety of operational needs. In threat and capability-based planning unexpected changes in spectrum regulation could pose challenges for the efficient and long-term utilization of the military spectrum. Since military communications technologies have traditionally had long life cycles, this has led to the use of various legacy communications equipment supported by new equipment. Since different military units may use different technologies, it is necessary to bring these systems together by connecting them using interface equipment that supports different types of interfaces and standards These multitechnological communications have to be prepared using frequency management schemes and the forces have to be trained as well. There are several models or architectures for describing military activities. On one hand this is due to different functional military areas that are responsible for the development of assets, tasks, and command within those areas. On the other hand it’s due to frameworks created for specifying requirements and carrying out successful procurement processes and projects. In addition to capabilities and architectures, there are key items typically evaluated when considering the effects of procurement on military missions, tasks, assets, and forces. These items fall under the abbreviation of DOTMPLFI that is defined as doctrine, organization, training, materiel, personnel, leadership and education, facilities, and interoperability.

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There are alternative definitions that add a P at the end of DOTMLPFI (representing policy). In the end both of these capability planning models represent military requirements for every aspect of military activities, the goal of which is the comprehensive portfolio of forces and capabilities where the most critical shortfalls or capability gaps are covered or mitigated.

2.5  Key Military Definitions from an Operational Perspective A doctrine of a military organization provides a framework for the force structure that (in addition to operating environment) defines fundamental principles by which the forces guide their actions to support the goals of missions. An order of battle (OOB) contains the hierarchy of military organization, command chains, number of warfighters and materiel, and their specific units. OOB describes functional responsibilities of units in the command chain and the supporting roles of other units. Current OOB may be changed based on mission experience as requirements and threats evolve in performing mission objectives [2]. Military force structures are defined in terms of hierarchical groupings of units whose composition and linkages to other units have impact on communications solutions in the battlefield. Typical formations from the largest to the smallest are a division (10,000– 20,000 warfighters), a brigade (5,000 warfighters), a battalion (500 warfighters), a company (100 warfighters), a platoon (30 warfighters), and a squad (10 warfighters). Larger formations are built from a varying number of lower level units (e.g., a company could consist of four platoons). The structure of these units can differ a lot when comparing, for example, battalions of nation A to nation B. Not only do lower-level units differ from nation to nation, but the types of units that support the mission of a battalion differ regarding to functional responsibilities as well [3]. Figure 2.3 presents an example of the hierarchical structure of similar military organizations of Blue and Red. BRG represents the highest command level of a brigade, BTN represents one level lower, a battalion, and C represents a company. A company is further



2.5  Key Military Definitions from an Operational Perspective

39

Figure 2.3  Example of similar military organization structures of Blue and Red.

divided into lower level units, where the command line from the commanding officer is directed to one of the units in the company organization. Organic capabilities, units, or assets provide integrated function in the larger military unit that can be utilized effectively, since the organic element has been in previous missions and trained in military exercises. On one hand, if this static organization operates in versatile missions, where the organic units do not play as central a role as in other missions, organic units may complicate these latter missions. On the other hand, organic units may perform well in missions where their specialized capability can be utilized. In future complex missions, integration of several specialized military units will exhibit friction when carrying out joint operations, if participating units have not been previously trained in common exercises. Budget challenges on the development of military capabilities can result in limited use of organic capabilities with reduced numbers of warfighters in participating units, even though requirements for adaptiveness and flexibility in future operations will become more demanding. To maintain military capability in the future battlefield, technological solutions for operation demands will be needed. If technological alternatives are not thoroughly analyzed, new

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technological force multipliers may still bring additional organic units with them as well. An electronic order of battle (EOB) describes transmitters or emitters within an operational area with knowledge of location, movement, role in the military organization, network structure, and communications traffic between different nodes that may provide evidence of certain type of functionalities and responsibilities in specific nodes [2]. A chain of command refers to taking orders from higher rank officers and giving orders to lower rank officers and warfighters. Technological progress may create great challenges to the application of chain of command. This is clearer in circumstances where existing command chains are broken and there is limited adaptation to a new situation. Therefore, new communications technologies don’t necessarily provide remarkable improvements in military capability as long as traditional command structures control the range of possibilities to command the forces.

2.6  Joint Capability Areas Any mission that the military may face requires understanding of the environment, location of hostile forces, their capabilities and probable movements, location of one’s own forces, and the status of battle capability with knowledge of levels of ammunition, warfighter health level, supporting forces, and the logistic capability needed to execute the objectives. One key capability required in any mission is command of forces by means of communications and networking equipment. In addition to C2 several other capabilities needed for successful missions are listed below [4]: • Battlespace awareness or situational awareness is needed to detect key elements (geographical characteristics; locations of own/hostile/neutral actors in the surroundings, and locations of weapon systems that limit alternative approaches of operations) in the battlefield. • C2 represents a function to exercise authority and direction by a designated commander or a decision-maker over as-



2.6  Joint Capability Areas

41

signed and attached forces and resources in the execution of a mission. • Net-centric represents a function that provides a framework for human and technical connectivity and interoperability that allows users to perform timely information-sharing trustfully and in the correct format while preventing information from going to unintended parties. • Force support represents a function that provides procedures to establish, develop, maintain, and manage mission-ready forces. • Protection provides an ability to prevent and limit adverse effects of attacks on personnel and physical assets of forces and partners. • Force application integrates the use of maneuver and engagement in all environments to create the effects necessary for meeting the mission objectives. • Logistics projects and sustains logistical support to joint forces through sharing of national and multi-national resources in close and long-distance operations while providing the joint force commander the freedom of action necessary to meet mission objectives. • Building partnerships interact with partners, competitors or adversary leaders, military forces, or populations by developing and presenting information to affect their perceptions, will, behavior, and capabilities. These items represent functional joint capability areas adapted from the U.S. Department of Defense Joint Capability Areas (JCA) framework [4]. Several documents available on the internet refer to this framework in building military capabilities. The JCA framework divides each functional capability into more fine-grained military functionalities not discussed here. If one looks at the list of capability areas, C2, net-centric, and building partnerships relate best to military communications requirements. Since military operations are considered from the whole mission perspective, it is clear that other capability areas are important as well, especially

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if ground assumptions on operational tempo, battlespace awareness, force application, and protection are expected to change abruptly from the current assumptions and understanding of the commander.

2.7  Joint Capability Areas in Identification of the Most Important Requirements Capability frameworks help in grouping military tasks and functionalities into separate baskets. However, they may appear complex when linkages are formed between capability areas and actual battlefield systems because capability areas are not independent when a performance of an operational system is measured. Protection is one of the most elemental capability areas needed in every mission irrespective of the application area. Unless a company, a fighter jet, a military vehicle, a headquarters, a logistics warehouse, spectrum, or cyber is not secure, there is a high risk of failure in performing the main mission. Levels of required protection vary from operation to operation but in general there must be a certain level of protection to operate effectively and efficiently. Since military functions are organized in order-based style, C2 must be the next level after protection. There are several other great candidates, but each of the remaining capability areas needs C2 in order to utilize them effectively. One could argue whether it would still be so that protection must be managed from the top down. This is partly true, but protection can still be considered as a far-reaching generic capability that forms a baseline to perform military activities starting from the safe side. Since we have now protection and C2, would it be clear that we need a net-centric capability to extend command even to the farthest location in the battlefield? The ones who are in charge of C2 need, for example, information on Blue forces, hostile forces, environmental factors, and terrain profiles. The commander needs to know the battlefield; therefore battlespace awareness comes in third in the classification of capabilities. Since future military operations will be fast-paced, there is a need to inform forces dispersed in the battlefield of important events, changes, and to perform C2, resulting in the importance of net-centric being raised to the fourth capability.



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43

The remaining list of capabilities seemingly must be put in the fifth place. It is surprising that the key military capability of force application, including maneuver and engagement, comes last on the list. As force application includes using key assets it is clear that there must be awareness of situation in the battlefield and forces must be aware of their roles and tasks in the operation as well as recent changes made to the current operation plan. Force application requires extensive logistics capability in addition to partnerships, corporate management, and support that are heavily connected to the logistics chain. The logistics chain must be protected against kinetic and nonkinetic engagement, considering every national and foreign private company that is connected to the logistics chain. This brings us back to the beginning and clarifies why protection is raised to the top of the capability hierarchy. Even this order contains linkages between capability areas, since for example, maneuver and engagement under force application could be used for protective measures. One could separate a generic enabling protection as the first capability along with the form of protection related intimately to each capability area.

2.8  Military Communications Scenario in the Future Battlefield A scenario of military communications in the future battlefield (presented in Section 2.8.5) is used as a baseline to consider the technology alternatives in Chapter 9. An introduction to the military scenario represents a fictitious description of a primary threat that could be considered from a threat-based or capability-based perspective, and is therefore intimately related to the capability planning in a C2 context. It is important to note that although an example would be a primary threat, consideration of other scenarios is also needed, since there may not be an opportunity to procure different C2 systems for each mission. Scenario-based evaluation is a great tool to describe operational environments in the long-term. At their best scenario-based methods visualize important aspects and requirements for equipment to work in different operational environments. Where this type of consideration may fail is in future scenarios using only fixed and current force structures and units. Therefore, there should be some form of agility, adaptiveness, and

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scalability of force mix and structures in addition to technology developments. In conclusion, scenario-based evaluation should focus on two approaches: 1.

Evaluation of the force structures to be used in future operating environments and the implications of different technology alternatives used for commanding the forces;

2.

Evaluation of technology alternatives for single warfighters (or groups of warfighters) that have no fixed position in the military hierarchy or constant access to a secured network.

The first approach considers futuristic scenarios where most tasks in the operation go as planned and existing structures support operations in a fixed fashion. The second approach considers scenarios where a warfighter, a unit, or units encounter situations where they must operate in more agile fashion, connecting to other units and the supporting infrastructure in an ad hoc fashion. This book covers military operations in scarcely populated, rural, suburban, and urban areas while large cities and megacities are not covered. Many long-term forecasts indicate that urbanization is going to increase remarkably within the 20 years. Therefore, it is probable that future operations will occur in the urban environment. Since ground forces still have heavy ground platforms (such as battle tanks) not at their best in an urban environment, these should be focused in the scarcely populated area. Within the urban area there may be opportunities to utilize civilian cellular networks and cable connections, but the spectrum is probably very crowded. From a C2 perspective, there is a need to find opportunities to communicate with one’s own units if existing command chains are broken. These scenarios require innovative thinking from a futuristic and applied technology perspective. The evolving technology landscape provides opportunities to apply new technologies and use old technologies in innovative ways. C2 structures should be considered from a holistic point of view. Applying some communications technology imposes requirements on mobility, protection, data rate, range, and support. Different communications alternatives present a mix of functionalities that should fit the situation at hand within the operational scenarios



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45

the force is expected to face. Since the operating environment and technology are constantly changing, the need for adaptive, scalable, and cognitive systems becomes apparent. Until the cognitive systems reach their full operational capability, something has to be done to improve agility to prepare for the unexpected in the battlefield or in security operations. The following presents key points of unit communications that don’t have access to typical communication structures. These issues will be developed further in the subsequent chapters. Different groups of forces can be disconnected from each other. The forward group in the operation should provide information on the current tactical situation and operating environment to Blue forces approaching behind the first group. Key factors are • Availability of fixed communications infrastructure; • Availability of tactical data links to ground-based communications, aircrafts, unmanned aerial platforms, aerostats, or other forms of relay stations; • The level of direct or indirect threat to Blue forces; • The time available for transmission of information to other units (protection); • Availability of platforms that can deliver the message by going to the destination and back (air and land platforms) along with the level of risk compared to criticality of information; • Possibility to leave secured messages at specific locations where Blue units can detect and read messages (AR), the risk of Blue forces not detecting the message, or hostile forces receiving or corrupting the message (deception by cyber or EW means). Considering the above-mentioned operational environments, scenario elements are described here. First, the maximum area under consideration is 100 km × 40 km. Large operational areas may require extensive support from backbone terrestrial communications networks or satellite communications networks. When considering military organizations of a brigade or a unit of a lower number of warfighters, this area is well within the maximum number of

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warfighters. This book also examines smaller areas by dividing the operational area into three parts. With these smaller areas, different tasks and requirements for executing operations from a communications perspective are covered in Chapter 9. The scenario is analyzed from different perspectives using versatile environments features, different mobility parameters, different probabilities of detection, and threats of kinetic and nonkinetic engagement. The scenario doesn’t dive as deep as some readers would like but will raise important features and situations that leave room for communications discussions. The scenario description is fictitious and any similarities to real capabilities, country profiles, or geopolitics are purely coincidental. The scenario acts as a tool for bringing questions of operational analysis into the analysis of C2 as well as alternative forms of communications technology. It is also important to note that the description and analysis do not decide whether any actor will win in the end. The scenario is an application-oriented description that raises communications-related questions, requirements, possibilities, and threats in order to consider different alternatives to carry out C2 in these theoretical settings. From the communications perspective characteristics of military operations in different environments are described in Sections 2.8.1–2.8.4. The description of a theoretical military communications scenario in the future battlefield presented in Section 2.8.5 is the major tool in analyzing the communications alternatives in Chapter 9. 2.8.1  Characteristics of a Military Communications Scenario in Scarcely Populated Areas

Military operations in scarcely populated areas have the following characteristics: • A low number of civilians in the operating environment; • Red forces and terrorists have no possibility to hide among the crowd and perform their operations from hidden positions unless they are well camouflaged; • Very low communications traffic;



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47

• Good possibilities for spectrum operations due to the small number of civilian systems; • Military communications of Blue is detected by Red forces; • A high threat of electronic warfare; • Challenging propagation characteristics in communications; • Utilization of LoS communications links is dependent on the terrain and the situation at hand but selection of the best communications positions takes a long time; • Attacks on civilian infrastructure do not challenge freedom of movement or logistics operations unless operations are dependent on these civilian networks; • Hiding platforms, command centers, and other key units is a challenge compared to suburban and urban environments and it takes time to prepare positions; • Most often there is no possibility to utilize connectivity to civilian networks; • Challenges to hide engagement, surveillance, and protection systems; • Challenges to detect (civilian) UAVs behind terrain and other objects; • Long distances to logistics centers and the difficulty getting assets to end users due to remote locations (this imposes requirements on logistics vehicles in different terrain conditions); 2.8.2  Characteristics of a Military Communications Scenario in Rural Areas;

Military operations in rural areas have the following characteristics: • A low number of civilians in the operating environment; • Red forces and terrorists have little possibility to hide among the crowds and perform their operations from hidden positions (unless they are well camouflaged); • Low communications traffic; • Good possibility for spectrum operations due to a small number of civilian systems;

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• Military communications of Blue may be detected by Red forces; • High threat of electronic warfare; • Beneficial propagation channel characteristics; • LoS communications links are easily built up using, for example, temporary communications masts; • Attacks on civilian infrastructure do not greatly challenge freedom of movement or logistics operations unless operations are dependent on civilian networks; • Hiding platforms, command centers, and other key units is a challenge compared to suburban and urban environments and it takes a long time to prepare positions; • There are possibilities to utilize connectivity to civilian networks in some locations; • It’s a challenge to hide engagement, surveillance, and protection systems; • Visibility is decent for detection of (civilian) UAVs due to missing objects and buildings (terrain may still limit surveillance); • There might be long distances to logistics centers, but it is easier to get assets to the end users (this may still impose requirements on logistics vehicles in different terrain conditions); 2.8.3  Characteristics of a Military Communications Scenario in Suburban Areas

Military operations in suburban areas have the following characteristics: • A moderate number of civilians in the operating environment; • Red forces and terrorists have a moderate possibility to hide among crowds and perform their operations from hidden positions; • Moderate communications traffic; • Challenges for spectrum operations due to number of civilian systems;



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• Military communications of Blue is not easily detected by Red forces due to intense spectrum use; • Moderate threat of electronic warfare; • Challenging propagation channel characteristics; • Utilization of LoS communications links is a challenge, but communications locations are more secure than in rural areas; • Possible attacks on civilian infrastructure hinder freedom of movement or logistics operations due to traffic jams, massive crowds, accidents, and disasters; • Suburban environment offers the possibility to hide platforms, command centers, and other key units; • There is the possibility to utilize connectivity to civilian networks in most locations; • Challenges to hide engagement, surveillance, and protection systems; • Challenges to detect (civilian) UAVs between buildings; • Short distances to logistics centers, but it’s a challenge to get assets to end users if main roads are crowded or destroyed (this may still impose requirements on logistics vehicles in different terrain conditions); 2.8.4  Characteristics of a Military Communications Scenario in Urban Areas

Military operations in urban areas have the following characteristics: • A large number of civilians in the operating environment; • Red forces and terrorists have a greater possibility to hide among crowds and perform their operations from hidden positions; • High communications traffic; • Challenges for spectrum operations due to the large number of civilian systems; • Military communications of Blue is not easily detected by Red forces due to intense spectrum use; • Low threat of electronic warfare;

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• Very challenging propagation channel characteristics; • Utilization of LoS communications links is a great challenge, but communications locations are more secure than the rural areas; • Possible attacks on civilian infrastructure may greatly hinder freedom of movement or logistics operations due to traffic jams, massive crowds, accidents, and disasters; • Urban environment offers the possibility to hide platforms, command centers, and other key units; • There is the possibility to utilize connectivity to civilian networks from several locations; • Challenges to hide engagement, surveillance, and protection systems; • Challenges to detect (civilian) UAVs between buildings; • Short distances to logistics centers, but it’s a challenge to get assets to end users if main roads are crowded or destroyed (this may still impose requirements on logistics vehicles); 2.8.5  Description of Fictitious Military Communications Scenario in the Future Battlefield

This section introduces a fictitious military communications scenario that presents three countries A, B, and C. Country A represents Red, country B represents Blue, and country C represents Green. Countries A and B are geographically located side-by-side sharing a common border of 400 km. The terrain is very versatile along the border consisting of high hills in the north, lakes in the middle, and several rivers in the South. Country C is geographically located east from countries A and B sharing a common border with country A in the northwest, and sharing a common border with country B in the west and in the southwest. Figure 2.4 shows a large map of the area geography covering the territories of Red, Green, and Blue in addition to parts 1–3 and Blue city in the Blue’s territory central to the scenario description. Country A is a democratic nation, but appears to be transforming to an authoritarian regime. The head of the authoritarian party has had strong positions in the government and has succeeded



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Figure 2.4  Large map of the fictitious operating area, where the mission and operations are performed according to the scenario description.

in investing a great deal of money in military and security forces. Several private companies also have strong ties to the government with great knowledge of the government’s capability requirements, and to the current levels of defense in countries B and C. Country B is a democratic country that has extremist parties, but their activities are limited and do not pose immediate challenges to the unity of the nation. Country B has invested in defense and security continuously over the past years, but not in the same class as neighboring countries A and C. Country C is a democratic nation that has had challenges in the past with extremist groups and minorities from countries A and B that are opposing the current regime. Country C has invested greatly in military technology, but the size of the forces is limited compared to countries A and B. Country C has modern military capabilities that are expected to partially fill the gaps caused by limited number of forces. These societies are linked to security and military forces and there is a wide support for armed forces among citizens in countries A, B, and C. Security and military actors give support to society and vice versa. Tensions between countries A and B have emerged over the past months at several levels. Country A regards B and C as a potential threat. Due to several events in the information domain, at the border, and in media relations, country B has been alerted to defend its

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territory and spectrum from hostile actions from country A. There have been reports on a buildup of force in country A. According to reports there may be one brigade preparing to advance towards the land border between A and B, and another preparing to support the operation of the first brigade. Due to a late warning country B has prepared a limited battalion to be advanced to the border between A and B. By looking at plain numbers in the first phase, the partial battalion wouldn’t be strong enough to push the brigade back towards country A. The ground brigade of country A has assets including a mechanized tank company, ISR, and EW ground forces supported with air and space assets, a combat engineer company, artillery and missile forces, an unmanned ground and air company, and a logistics company as well as several other supporting units. Not only ISTAR pose challenges for defense operations, but also long-range missiles, air assets, and artillery along with cyber and EW capabilities limit freedom of operation of Blue in many ways. In part 1 of the territorial defense battle near the border of country A and B in country B’s territory, several illegal border crossings have been detected by Blue, and a buildup of Red forces has been ongoing for several days. Although the number of border security personnel has increased recently, people that have crossed the border have not been caught. Blue recognizes the possibility of a Red attack and speeds up preparation of forces to strengthen the defense to face an outnumbered opponent within a few days. Blue has quickly arranged several military exercises that have been limited with respect to the threat rising from the Red side. During Blue’s previous artillery exercise, logistics transportation to the artillery battery did not receive the intended destination but for some reason trucks had taken a much longer route and after the ammunition delivery had gotten to the final destination, a mismatch of material reports was recorded and recognized. The first impression was to blame the logistics cloud software of the delivery company that was part of the logistics chain. Later, there were reports of an accident in the Red’s area. Red sources reported that the Blue artillery battery had fired several artillery shells at the Red military communications mast which was severely damaged. Red regarded this event as a provocative act from the Blue side and announced in



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the local media that this appeared to be the first phase of the Blue operation to limit ISR and communications capabilities near the border. As the subsequent phases seem probable, Red has to resort to preemptive operations to prevent further hostile actions from the Blue forces. Blue had been trying to clarify things via diplomatic channels and media reports about lost and stolen artillery shells but Red had not been receptive to these explanations. Country C regards these events as surprising since they perceived country B as a civilized and peaceful country. As country C is not sure of the situation, they take a neutral perspective on the issue. Since they regard country A as more dangerous under escalation they start preparations of defense in the border of country A and C. As country C has limited forces, they are going to focus on surveillance using hightechnology platforms to be better informed on the current situation. 2.8.5.1  Day One

Last night Blue experienced network problems in civilian networks and also in military command networks. Data rates were below normal network capacities near the border of Red and Blue and in some regions network access was not at all possible. Inspections to solve networking problems were going on at several key points. Long-distance radar detected false targets not confirmed by other means. This has intimidated the forces analyzing the situational picture. They felt they couldn’t rely on the radar network. On the morning of day one, air strikes on several Blue radar stations damaged some of the radars in the direction of the Red forces. Country C provided details on the increase of Red forces near the Blue border with the help of satellite assets and their high-altitude UAV data collection assets. Within a few hours of the first air strikes that damaged radars, there were more air strikes on the main bridges and some points of the infrastructure that resulted in challenges for the buildup of Blue forces. Figure 2.5 describes affected communications networks near the border, targets of the air strikes, and the direction of roads to the Blue city. The arrow resembles the fastest and the most robust road surfaces to the Blue city that can carry the heaviest military vehicles. The distance from the Red–Blue border via the fastest route to the Blue city is approximately 100 km.

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Figure 2.5  Battle damage assessments of Blue forces in the Blue’s territory after day one.

2.8.5.2  Day Two

The morning after distributed engagement of the expected targets within the 30 km distance from the border by kinetic and nonkinetic means Red mechanized battalions supported by mobile artillery, ISR, and EW companies crossed the border between Red and Blue. Blue had succeeded in bringing two companies of infantry with anti-tank capabilities, mechanized battalion, field artillery, along with supporting engineering, ISR, and EW units into the operation. The army battle headquarters and logistics centers had been established on the safe side of the operational area and their air and ground defense has been effectively organized. Figure 2.6 shows the situation after day two. The lightly dotted oval (on the left) represents Red forces as a large formation, whereas dark dotted ovals to the right from Red formations represent Blue force units of various sizes. 2.8.5.3  Day Three

Blue and Red forces have had several battles in the operational area. Blue forces have succeeded in defense operations but they have not been able to build up force at the same pace as the Red forces did the previous day. Counterattacks on a large scale are not possible until more companies can be commanded to the battles. The main Blue forces have succeeded in slowing down the Red attack inland



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Figure 2.6  Locations of Red and Blue forces operating in the vicinity of border.

but some forces have been dispersed from the main direction of attack. The battle had not progressed the way Blue had planned, and battle organizations were missing some units needed for support of the operations. At the end of day three, Red was now in control of the narrow slice of Blue land 50 km from the border to the interior of Blue. Medium-sized operational level UAVs occasionally flew over the Blue territory. Most of the UAVs have ISR payloads but some of the platforms may carry kinetic or nonkinetic engagement payloads. Blue has the ability to limit operations of Red UAVs but training and arrangements for the following stages of Blue operation can’t be done in silence, since the surveillance in the sky has a wide coverage both in space and time. Figure 2.7 shows the situation of the Blue and Red forces after day three. 2.8.5.4  Day Four

In part 2 on the defensive retreat battles along the path from the border towards the central part of country B (Blue), the Blue is still lacking forces compared to the Red side and they need time for strengthening the defense. This would mean that the forces tied to the battle near the border have to retreat in execution of defensive battles and allow the Red to follow Blue towards the central part of the country.

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Figure 2.7  Blue and Red forces after day three.

New units of Blue are commanded in operations near the border away from the main direction of the attack of the Red forces. Their task is to observe the buildup of Red forces in the Blue side and perform limited attacks to the side of the forces from different distances. These Blue forces operating away from the Red main attack have to be aware of the current situation but they also have to be aware of current plans under execution along with short-term changes to them. On one hand they have to limit their communications to maintain the opportunity for surprise, but on the other hand their location is very good for engagement operations. Figure 2.8 shows a distribution of Blue forces in the operating area along with new ISR and smaller units operating away from the main direction of attack. Arrows show the directions the Blue units have been moving on day four. 2.8.5.5  Day Five

The Blue side can gain more time for military buildup by limiting the speed of the Red attack using several methods. An advancement of ground vehicles is dependent on the quality and number of paths available. If Blue succeeds in guiding the attack to the paths where they are being challenged, and to the paths where the movement stops completely, this will open up possibilities for counterat-



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Figure 2.8  Retreat of Blue forces and ISR capability buildup in the off track of the main attack direction.

tack. The best option would be to keep Blue forces on the fast track and keep Red forces busy on the slowest possible paths, reducing their capability and persistence to fight while moving toward their main mission goal. Therefore the role of both groups of Blue is elemental, since the second and third phase of the Red attack could find their way around preguided and blocked paths and advance to the Blue city at a higher speed than expected by the Blue side. Figure 2.9 shows Blue forces guiding Red forces to other than the fastest route using combat engineering capabilities and smart formations of forces at key points. ISR units moved to better positions to control the border and main road in case of advancement of subsequent Red forces. As the main philosophy of various Blue units is different, there are also different perspectives for using communications. Since the first phase of Red attack is now on Blue territory, Red cannot have unlimited capabilities available. Blue could use communications all the time, since ground-based electronic warfare capability can’t be used optimally in the current setting. Air-based EW is a completely different thing so one has to consider the probability of kinetic and nonkinetic engagement from air to ground. Since this is not an EW book, this presentation doesn’t dive too deeply into the subject and

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Figure 2.9  Blue forces direct the movement of Red units to unfavorable routes to limit the speed of advancement and enable counterattacks from the most favorable positions.

only considers general issues affecting communications in this type of scenario. 2.8.5.6  Day Six

Blue had not detected that there were several UGVs behind mechanized battalions. These UGVs had advanced to the Blue territory. Red also brought a UAV support company into the attack. Medium- and small-sized UAVs have been brought into the frontline to provide ISR and EW support for the detection of strengthening Blue forces as well as the main group of Blue forces retreating a couple of kilometers in front of the Red attack. UAVs have been used for tactical and operational purposes. Figure 2.10 shows the addition of Red UAV units to the operation at the frontline as well as advancement of Red UGV units over the border as a subsequent unit following the Red attack formation. 2.8.5.7  Day Seven

In part 3 on the defensive battle near the critical area and the swift change to offensive counteractions, Blue forces have retreated to the surroundings of an area essential for the Blue forces. This area contains logistics support centers with military training locations



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Figure 2.10  UAV and UGV units in Red operation.

in the surrounding area. As war between Blue and Red has been ongoing for a week, Blue has succeeded in bringing support forces to the area. Several land battles, rocket attacks, and air strikes have caused Blue forces to disperse throughout the area to protect from severe attacks. The position of various Blue units is not the same as in the original operational plans. The attack movement of the Red forces has been only partly guided to areas where the Blue forces had beneficial positions for counterattacks that could stop the movement of the Red forces. There is one brigade of Red forces in a narrow line in the Blue territory from the border to the center of country B. Country C has been active in surveillance of Red activities and ISR operations from the air, which has hindered the buildup of a second Red brigade from entering the Blue territory. Cyber operations against Blue infrastructure, military communications networks, and cellular mobile networks have created severe connectivity challenges near the area. Only half of the normal network capacity is available and networks are experiencing connectivity problems. Therefore, the normal data capacity of operations can’t be expected. Blue has succeeded in performing countermeasures against medium-sized operational level UAVs, but as Red forces

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Figure 2.11  Battle for the Blue city after one week from the beginning of the Red attack.

are approaching the central point of the Blue defense they have deployed small-sized tactical UAVs. These small-sized platforms can cooperate with similar assets using swarming techniques but can also team with other manned systems. They can advance silently and undetected in different environments (indoor and outdoor), which poses a challenge for Blue forces. However, these assets are of no use during moderate and high wind conditions. This is the final part of the scenario that brings the majority of the Red and Blue forces into the central part of the Blue area. The next phases of RedBlue battles in war-game fashion are omitted and the seven days described above will be analyzed in Chapter 9. Figure 2.11 shows an end phase of the Red attack operation since one week has passed and Blue has moved forces to defensive formations to protect the surroundings of the Blue city.

References [1]

Frater, M. R., and M. Ryan, Electronic Warfare for the Digitized Battlefield, Norwood, MA: Artech House, 2001.

[2]

Tolk, A. (ed.), Engineering Principles of Combat Modeling and Distributed Simulation, Hoboken, NJ: John Wiley & Sons Inc., 2012.

[3]

Bennett, R., Fighting Forces, London: Quarto Publishing plc, 2001.

[4]

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Office of the Secretary of Defense, Memorandum for the Vice Chairman of the Joint Chiefs of Staff: Joint Capability Area (JCA) 2010 Refinement, Department of Defense, Washington DC, April 8, 2011.

3 Communications Systems Communications technologies, systems, and supporting infrastructure form an essential element for effective C2 within any military or security mission. Although this book evaluates different alternatives to perform operations in versatile scenarios, it is important to present key characteristics of communications systems, and present examples of civilian and military communications systems used currently or in future deployment.

3.1  Requirements for Military Communications Military forces have traditionally needed dedicated tactical radio networks due to requirements for security and robustness. The drawback with military tactical networks is a lack of existing infrastructure at the tactical edge. Even if there were large-scale fixed military backbone networks, it is almost impossible commercially to extend the fixed-backbone networks to any location in the battlefield. 63

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3.1.1  Command-on-the-Move

Tactical military networks based on legacy systems do not often support mobility of the users in the battlefield. Deployment of C2 networks often relies on protection of prepared command posts and the movement of redundant command stations that extend coverage to areas where different force units are moving. Other solutions for commanding on the move have been used but with current military technology development, mobility is one of the key requirements for future networks. As future tactical radios need support for mobility there are opportunities to utilize commercial technologies in the form of cellular systems or forthcoming 5G systems that have a wide-scale coverage in the most inhabited areas. Civilian technology-based communications infrastructure is an appealing alternative for military forces as well if security and robustness of user terminals could be improved to reach military requirements. Military combat net radios often have FH modes that are not as common in civilian communications networks. Currently and in the near future different SS communications modes are the new normal of communications systems. SS-based communications have inherent security characteristics such as of pseudonoise (PN) codes and spreading transmission to the spectrum based on time, frequency, or space. The military environment poses severe requirements on communications equipment. However, not only military-specified functionalities will be needed in the future, since the demand for higher data rates has come from commercial applications. The primary focus of this book is directed to land forces, but there are ideas that could be applied to the air force and navy as well. Space dimension is not covered in this book, although it appears that the differences between space and air assets will be blurred in the coming decades. 3.1.2  Electromagnetic Spectrum

Electromagnetic spectrum is defined as frequencies extending from 3 Hz to 300 GHz. This range is again divided into two portions–– radio frequencies from 3 Hz to 3 GHz and microwave frequencies from 3 GHz to 300 GHz. The difference between radio and microwave frequencies is the refraction of radio waves from the lower atmosphere towards the Earth giving rise to the extension of wave



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distance from LoS path. This extended distance is called the radio horizon and is covered in Chapter 5. This type of refraction doesn’t happen for microwave frequencies, but microwaves follow LoS paths. Radio frequencies from 3 Hz to 300 GHz are further divided into different frequency bands that are named after commonly used abbreviations (e.g., VHF and UHF). World Radiocommunication conferences (WRC) are meetings for worldwide agreement on the use of the radio spectrum. They are organized every three to four years and the upcoming conference will be held in October 2019. The International Telecommunication Union (ITU) council has a key role in bringing new revisions to the agenda of the conference and along with considering recommendations made in previous WRCs. The conference aims at the efficient use of radio spectrum, taking radio spectrum needs from several application areas into account, and regulating access to the spectrum globally. WRC is an important event for exploring the spectrum needs for military applications since needs for increased spectrum for commercial use are still emerging. 3.1.3  Importance of Redundancy, Radio Silence, and Several Communications Alternatives

Although the civilian communications market is driving customers toward an always-connected state, for military it is still relevant to consider different ways to safely communicate using the lowest levels of RF emissions possible, or no emissions at all. The use of high transmission power levels at fixed frequencies poses risks on the freedom of operation in the spectrum; therefore, SS techniques may be used instead. Several approaches to communicate at low power levels can be utilized; for example, using active and passive RFID solutions, WSNs, deployable base stations, device-to-device communications (D2D), transmissions on several frequency bands in parallel (e.g., HF and UHF), and traditional wired connections. New and old approaches of communications may be used, such as optical communications, context-aware solutions (where a message is left at a certain geographical location without radiating the message in the air), and the use of unmanned platforms to deliver messages to a recipient without emissions.

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The main focus of this book is aimed at consideration of innovative and robust applications of military communications that form the basis of connectivity in unconventional and unforeseen situations. Hierarchical military networks have been planned for a specific purpose and are used according to agreed policies and network structures. To provide battle-proof communications links between agreed actors, some form of redundancy is typically built into the system (e.g., wired connections, satellite communications, or alternative communications solutions in different parts of the spectrum). These links require different equipment since presently SDR and CR solutions are not widely used within military organizations. In terms of wired communications, timely communication requires a fixed infrastructure that might be challenged by a limited number of routes between access points that may be damaged in the battlefield environment. Building wired connections ad hoc without existing infrastructure takes time, and the more reliable and battle-proof connections are built, the more time building the connections takes. There remain other options to create communications infrastructure using temporary relays in the air, stratosphere, or in space or optical LoS communications between communicating units. Each of these alternatives should be evaluated in terms of risks and performance. These values differ greatly based on the scenario at hand. Therefore different alternatives should be simulated in a set of probable scenarios that represent the main tasks of the force. Strategic wisdom calls for the preparation for the unexpected, but this is not possible in many cases due to limited defense budgets. There are several communications systems currently in use with different characteristics and performance based on the application. Typical wireless communications systems are cellular mobile systems, point-to-point systems, point-to-multipoint systems, multipoint-to-multipoint systems, WSNs, and mobile ad hoc networks (MANETs). Cellular mobile systems are based on a network of base stations along with the fixed infrastructure that provides access for mobile stations (MS) to network in the specific area mandated by BS coverage. Point-to-point and point-to-multipoint systems are typically microwave links that utilize directivity of transmission



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signals. BSs can also utilize these paradigms in addition to provision of coverage to mobile users. MIMO (multiple input multiple output) systems can be implemented either by sending different signals to different paths or by sending the same signals in parallel paths. Point-to-point systems can also be implemented within a cellular system where MSs have a direct communications link between each other in the form of D2D communications.

3.2  Communications Chain To deliver commands, messages, and reports over long distance by electromagnetic means, there must be a data source related to the transmitter and a data sink related to the receiver. One communications system delivers messages in one direction and is called one-way or simplex communications. Simple sensors or radio broadcasting systems are examples of simplex systems. A second communications system is half-duplex communications where there are communications channels in both directions, but only one direction can be active at a time. Personal mobile radios (PMRs) are an example of half-duplex systems. A full-duplex communications system enables communications in both directions at the same time. Current cellular mobile systems are examples of full-duplex systems. In half-duplex and full-duplex systems the sending block of communications is called the transceiver because it has the capability to operate as both transmitter and receiver. A communications system consists of a transmitter, a receiver, and communications media that connects the transmitter and receiver. Communications media is based on wired or wireless communications. Wired communications utilize copper lines, cables, twisted pairs, or optical fibers to deliver messages from the origin to the destination. Wireless communications can be implemented with different wavelengths that define the achievable performance in different conditions. As in wired communications, wireless communications systems can utilize the transmission of visible or nonvisible light from the origin to destination. This type of wireless communications systems is not common in military communications systems. However, they may have a key role in the long term if accurate pointing between transmitter and receiver can be

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arranged and the degradation of link quality in harsh weather conditions could be improved. Accurate pointing reduces the vulnerability of communications to eavesdropping and jamming similarly to directional antennas compared to typical omnidirectional antenna systems. A communications chain starts from the source that expresses the need to transmit information to the distant recipient(s), the destination of the transmitted data. Signals to be transmitted can be different types (e.g., data messages, voice commands, pictures, or videos). With the current technologies all these can be transmitted digitally in the data form. Communications devices can be divided into two parts that are baseband blocks and RF blocks. Signals that are processed in the baseband blocks cover the frequencies whose lower end starts from near 0 Hz whereas RF blocks process signals at the higher frequencies. Various types of signals use different widths of spectrum and have differing parameters regarding expected data rates and signal-to-noise (SNR) ratios; the wider the bandwidth the more noise is cumulated on top of the wanted signals. Signals are classified in two categories: narrowband (NB) and wideband (WB) signals. NB signals are typically audio signals or data signals that do not need such high data rates as WB signals. WB signals are typically video signals and the current generation of cellular 4G LTE systems mostly handle WB signals, with the increased demand for video streaming and data-extensive applications. Signals are driven through several digital signal processing steps that support the successful reception of the signal in the distant receiver as the communications channel has distorted the message and added noise signals to the signal on its way towards the receiver. These processing steps are proactive but there are also methods that require two-way communications between the transmitter and receiver to improve the quality of the transmission. In military applications, NB signals have several beneficial properties over WB signals. First, if messages are well-coded and sent in the standard form, these transmissions do not take wide parts of the spectrum from other data-intensive applications. Second, if these short messages are sent at different frequencies, this provides protection from interference from other transmissions.



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In terms of analog and digital separation, the signal may go through two conversions (A/D and D/A) on its way to the antenna. If the information source is analog by nature (e.g., microphones or sensors) measurements from physical quantities provided by sensing elements are converted to digital form. Accuracy of the information needed in the chain affects the volume of data, and increases the unit costs of the device, since high accuracy converters tend to be expensive. The second conversion happens at the edge of digital baseband and RF parts, where a digitally modulated signal is converted to an analog signal and mixed to higher frequencies suitable for transmitter antenna and propagation channel characteristics. Digital baseband blocks process the signals using source coding, channel coding, and symbol modulation blocks. Source coding encodes input bits in a more compact form that saves the amount of data and removes parts of the information from the input signal (e.g., in speech encoding the whole human audible spectrum is not regarded although parts of the spectrum are removed in the source coding process). Channel coding brings additional information to the signal by implementing error correction to overcome the added noise in the transmission media between the transmitter and receiver. A modulation block transforms the input data originated from the channel coder into specific waveforms that represent waveform parameters (e.g., frequency, phase and amplitude) instead of bits in the previous blocks. These symbol parameters are then consecutively guided through D/A conversion that outputs the analog waveform to radio-frequency blocks. Depending on the type of transmitter, the analog waveform is mixed up once or twice to a higher carrier frequency suitable for the transmitter antenna elements. In addition to these mixing functions to intermediate and carrier frequencies there are a lot of filtering blocks that remove the unnecessary parts of the spectrum in the transmission to limit interference to other receiver systems in the coverage area [1–2]. Due to limited frequency bands in the spectrum, new communications systems face a challenge of spectrum efficiency, which means a delivery of as many data elements as possible to the lowest bandwidth. The figure of merit representing this parameter is specified in units of b/s/Hz. Information to be delivered on top of the high-frequency carrier is modulated by changing the amplitude

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(AM, amplitude modulation), frequency (FM, frequency modulation) or phase (PM, phase modulation) of the carrier signal either using one of these modulation methods or several at the same time. AM uses twice the bandwidth of the highest frequency of the modulating signal. FM produces signals on several frequencies above and below the carrier signal depending on the deviation between two frequencies and time length of one bit. Synchronization methods of digital modulations and proper filtering limit the use of the excessive spectrum for signals. Binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) are examples of phase modulations that are spectrum efficient modulation methods [2]. The communications channel between the transmitter and receiver antennas is a challenging media where efficient operation needs several progressions in filtering, channel estimation, synchronization, timing, handling several concurrent subcarrier transmissions in MIMO systems, tolerance of interference, and noise processing functions. All these features together require great processing capability aided by developments in microelectronics in terms of miniaturization, memory capacities, operating frequencies, and energy efficiency. Large global markets and competition between mobile communications companies has limited the growth of unit costs of these sophisticated products. Wireless signals are affected differently in the communications media and at different frequencies. Radio signals are attenuated by the distance between the transmitter and receiver. In addition to attenuation there is ever present noise that is caused by the devices, weather conditions, and other terrestrial characteristics. Interference is caused unintentionally by devices that operate around the receiver and intentionally (referred as jamming in terms of military vocabulary). Figure 3.1 describes the situation where transmitter A is transmitting messages to receivers B and C. Because transmitter A is using an omnidirectional antenna, sent messages can be received by one-hop neighbors that are within the communication range of the transmitter A. The same figure can be considered from the other perspective as well, where transmitter A is transmitting messages to the intended recipient B but is not aware of the fact that unintended receiver C is also capable of receiving the message within the communication range. Since unintended receiver C might have more a sophisticated receiver system,



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Figure 3.1  Illustration of transmitter communications coverage using omnidirectional antenna to one-hop neighbors and possible unintended receivers B and C.

it might receive transmissions from transmitter A but from longer distances due to greater receiver sensitivity. 3.2.1  Communications Transmitters

A transmitter is the source of an RF wave that is governed by many different parameters due to the application at hand. Information (data) is delivered to the transmitter by baseband blocks and the transmitter generates appropriate carrier frequencies, modulates carrier waves with information, performs necessary filtering phases, and forwards an RF signal to the RF output raising the RF power level using an RF power amplifier. An antenna element attached to the RF output converts an incoming power signal to the RF wave radiated from the antenna to the communications media and affected by cable losses, interference and nonideal characteristics of the transmitter in general. Characteristics of the antenna define radiation patterns horizontally and vertically in the surroundings of the antenna. Antennas may be omnidirectional ideally radiating equal RF power levels to every direction or directional antennas that guide the radio waves to specific directions. Real omnidirectional antennas can’t produce equal levels of RF signals to every direction but approximate the ideal. Omnidirectional antennas are used in applications that require communications irrespective of the direction––one example of these is MANETs. Using directional antennas, an RF wave can be delivered to the specific direction with a high power level, but it requires mechanisms for accurately directing the transmit antenna towards a receive antenna. Transmitter antennas should have good selectivity properties to keep their radiation within the frequency range at hand without causing in-

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terference to the bands near the transmission frequencies. Figure 3.2 presents an illustration of an LoS link between two communications masts that are equipped with directional antennas [3]. 3.2.2  Communications Receivers

RF receivers have functional blocks that have different roles in the signal chain. The RF part receives an electromagnetic wave as a signal that is filtered and amplified for the subsequent blocks in the receiver chain. The following block separates the original information signal from the carrier wave using the functional downconversion parts of the receiver. RF receivers should have good selectivity properties to receive wanted frequency bandwidth and keep the selectivity characteristics of each narrow channel over the entire bandwidth as similar as possible. In practice, an exactly similar response to every channel cannot be achieved [3–5]. There are many types of receivers, but one of the most common is the superheterodyne receiver. Coming from typical distances, a wireless RF signal is attenuated along the propagation path to very a low RF power level (e.g., –90 dBm) when it arrives in the receiver antenna. The receiver antenna is connected to circuits that process the incoming RF signal (e.g., by limiting the received frequency range using filter structures). The expected range of the received frequencies is one of the requirements that specify the characteristics

Figure 3.2  Illustration of an LoS link between high communications masts that are equipped with directional antennas.



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of the receiver. Filtering enables the following RF amplifier to boost the low-level RF signal to a higher power level at the limited frequency range supported by the amplifier. As increased width to the frequency range of the RF receiver is implemented, the price of the RF amplifiers increases as well. Since all applications do not need WB performance, it is clever to use amplifiers that are fit for a purpose. Prestages before the RF amplifier may contain RF limiters that protect sensitive receiver components from possible unusually high RF power levels received in the antenna. A low-noise amplifier as an RF amplifier boosts the RF signal above the noise floor to improve SNR without injecting excessive noise to the signal chain. An amplified RF signal again goes through the second filter stage called the image filter. It has several requirements from attenuation of spurious receiver responses to suppression of harmonic frequencies to protect the following mixer stages from the excessive effects of harmonic frequencies. The receiver has a local oscillator that generates an RF signal at the frequency that produces intermediate frequency (IF) at the output of the mixer. The mixer produces the sum and difference of the RF signal and local oscillator signal. The resulting sum or difference component is filtered at the IF filter. A signal is then fed to the IF amplifier that amplifies it to the higher level in order to perform signal demodulation in the following stages of the signal path. The IF signal has the same characteristics as the RF signal but is shifted to a lower frequency in the mixer output. There may be another IF stage where the first IF signal is converted again to the lower IF. 3.2.3  Spread Spectrum Systems

Spread spectrum (SS) systems utilize wide frequency ranges in the transmission of communications signals compared to fixedfrequency (FF) systems. The bandwidth of SS signals is much wider than the bit rate of the SS channel. Using SS systems provides protection to communications signals by spreading the message that limits the power levels of communications signals resulting in timely detection of signals (low probability of intercept (LPI)). Different types of SS systems are a direct-sequence spread spectrum (DSSS), time-hopping spread spectrum (THSS), chirp spread spectrum (CSS), and frequency-hopping spread spectrum systems

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(FHSS). In DSSS the message modulates pseudorandom codes that create a WB DSSS signal due to a chip rate that is higher than the information data rate. Processing gain is achieved by spreading the signal over the wide spectrum that also improves the signalto-interference ratio (SINR) of the DSSS signals. DSSS is used in many systems, (e.g., in CDMA, IEEE 802.15.4) and in many satellite systems. For example, CDMA allows sharing of a frequency channel among different users if they are using different codes. Since pseudorandom codes are unique for every user in the spectrum, intended transmissions can be picked up by intended SS receivers. The receiver generates a local PN code and performs a crosscorrelation function with the received SS signal and with the local PN code [6–8]. FHSS generates communications signals that hop to different frequencies based on hopping patterns generated by different mechanisms (e.g., controlled by pseudorandom sequences). FHSS systems are classified as WB systems as well, since the whole spectrum where the range of hopping frequencies is located is very wide in contrast to typical FF systems. In FH systems, transmitters and receivers are synchronized to FH patterns known only by intended actors in the communications systems. Therefore, cybersecurity features have a great impact on the vulnerability level of the communications system. Since the communications channel is only active for a short period at the frequencies selected in pseudorandom fashion, it is challenging for unfriendly receivers to pick up the frequencies where the communications channel currently is, as well as to generate interference signals to the right channels in the time domain. The more hopping frequencies used and the more hops there are in the unit time, the more robust the communications system is against disturbances from the outside [6–8]. Pseudorandom codes make the signals in the time domain look like normal noise that is ubiquitous in every communication systems. SS systems have more tolerance against interference, jamming, and fading of the channel than FF systems (antijamming (AJ) capability). Security issues are typically connected to the generation of codes and logical frequencies. With the knowledge of security functions and codes, the SS receiver correlates the received noiselike WB SS signal and extracts the information from the signal. SS



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systems have good performance in multipath fading conditions, since delayed versions of signals do not correlate well with the original PN signal. Some types of receivers may utilize multipath components of received signals to improve receiver performance by setting weighing factors for the receiver [6–8]. 3.2.4  Communications Antennas

Since we have looked briefly at the characteristics of transmitters and receivers, the following text briefly introduces the characteristics of antennas. An antenna is an element made from conductive material that has a capability to transmit and receive electromagnetic waves. The size and structure of an antenna define electromagnetic characteristics that can be utilized in transmission and reception of electromagnetic waves. A voltage signal sourced to the antenna is transformed into an electromagnetic wave that has both electric field and magnetic field components perpendicular to each other and perpendicular to the direction of the propagating wave from the antenna as well. The same applies to the other direction where an incoming electromagnetic wave is transformed into a voltage or current in the antenna element. There are different types of antennas, the primary types being omnidirectional and directional antennas. Omnidirectional antennas radiate electromagnetic energy in many directions in the surroundings of an antenna. Directional antennas focus the energy of the electromagnetic wave to a certain direction or sector. An isotropic antenna is a theoretical concept where an antenna is supposed to radiate an equal amount of energy in every direction in the surroundings of an antenna. Antenna radiation patterns of real antennas can be drawn to both the horizontal and vertical plane. These radiation patterns are rarely symmetrical and often have a main beam that is the direction of the most emitted electromagnetic energy along with side beams and back beams. Side and back beams are generally unwanted characteristics of nonideal antennas, since all the energy consumed in the back and side beams could have been focused on the main beam to direct more energy to the wanted direction. Antennas are transmission lines, where voltage signals form patterns of increasing and decreasing energy that are changing based on the dimensions of antenna. In well-designed antennas, the maximum signal is guided

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to both ends of a half-wave dipole antenna, from which the electromagnetic energy radiates to the surroundings of an antenna. Antenna gains are typically expressed in dBi units; that is, decibels referred to the isotropic antenna. An isotropic antenna has a gain of one that corresponds to the value of 0 dB on a logarithmic scale. A half-dipole antenna has an antenna gain of 2.15 dBi in the perpendicular direction of the antenna length, and it falls gradually until the angle of the incoming wave is parallel to the antenna length. Sometimes antenna gains are expressed in a dBd unit, which means that the number in dBd values is referenced to the gain of dipole antenna. dBd values can be converted to dBi units by adding 2.15 dB to the number expressed in dBd. Antennas are reciprocal, which means the antenna can operate in both directions; the antenna is capable of transmitting communications signals and of receiving communications signals. Monopole antennas are straight antenna elements whose length is one quarter of the wavelength of the carrier signal (λ/4). These antennas have comfortable lengths at higher frequencies and they provide an omnidirectional electromagnetic radiation pattern around the antenna. At lower frequencies these antennas can be pretty long and need supporting structures to stand undamaged in any weather conditions. Folded dipole antennas and different forms of loop antennas are often used in applications where directivity of the radiation pattern is needed. Electromagnetic fields have complex properties from the antenna to the point where the near field changes to the far field. The distance from the antenna location to the far field is determined by physical dimensions of the antenna. Typically, RF measurements are performed at the distance that is located in the far field. The distance from transmitter antenna to the point where the near field changes to far field is defined by a Fraunhofer distance, which is defined by (3.1). To apply (3.1) correctly, conditions dFr >> D and dFr >> λ must be satisfied. The Fraunhofer distance must be much longer than antenna dimensions and the Fraunhofer distance must be much longer than the wavelength of the transmitted carrier signal [8].

dFr =

2D2

λ

dFr >> D and dFr >> λ

(3.1)

3.3  Generic Parameters and Characteristics of Selected Civilian Communications 77

where D is the largest dimension of the antenna or diameter of the antenna and λ is the wavelength of the transmission signal. There are many types of antennas and they have different characteristics that determine their applicability to different applications. Antenna gain doesn’t increase the intensity of the waves but instead focuses the energy in certain directions with the total radiated energy remaining the same. Frequency bandwidth of the antenna represents the range of frequencies that can be transmitted from or received to the antenna with the required performance (e.g., in terms of antenna gain, radiation pattern and voltage standing wave ratio (VSWR) performance). Polarization of the antenna refers to the plane where the electromagnetic wave is oscillating. Because antennas are sensitive to polarization, generally both transmit and receive antennas should have similar polarizations. If the polarization of the antenna with regard to an incoming electromagnetic wave is not aligned, the received signal level in the receive antenna doesn’t reach the maximum level, but the signal is reduced from the best level. Also, reflections along the path from the transmit antenna to the receive antenna change polarization of the electromagnetic wave [4].

3.3  Generic Parameters and Characteristics of Selected Civilian Communications Systems and Military Radios This section briefly introduces a few examples of communications systems to get an idea of the different characteristics of communications systems. LTE and WiMAX are examples of long-range cellular systems that can be utilized at shorter ranges as well. Tactical radio is introduced as a generic military radio that doesn’t represent any current system on the market. The generic data is collected from several public sources whose market names are not presented here. ZigBee is presented as an example of a short-range system that could be applied to WSNs or as an IoT platform. Modulation and coding have an effect on spectral efficiency, range, and achievable data rate in different channel conditions. Most current communications systems utilize adaptive modulation methods that can smoothly variate quality of service (QoS) parameters according to channel conditions. If several waveforms are supported, the sys-

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tem can use different frequency bands, NB or WB transmissions, and even transmit the same data at different frequencies to create robustness of transmissions, if certain frequencies appear unusable. In the future, there may be a need for horizontal information exchange between neighboring units in addition to typical vertical command structure. Increased tempo below the brigade level will require command-on-the-move functionality more than in the past. Therefore a change of command location between command posts and tactical headquarters is increasingly needed to enable effective command in situations when the main focus of the battle is on the different parts of the operational area. Typically, command paths between brigade and battalion headquarters require great communications capacity so they are implemented with existing wired communications infrastructure, satellite links, or microwave communications. Widely used IP-based communications is currently and in the near future the new norm in tactical communications, as data, video, and voice communications have been built on top of IP protocols. Former legacy-based military communications technologies do not provide the high data capacities that will be needed in future missions. Microwave links are directional by nature and provide protection since the traffic is not easily disrupted. To provide the LoS path between link stations, link antennas must be raised above the dominant obstructions (usually trees) using masts. If tactical LoS radios are mast-mounted, excessive cable losses can be avoided when compared to the situation where the radio is near the ground level and antenna is on the top of the mast. The roof of the building in an urban environment is a great place to locate the LoS link. VHF frequencies from 30 to 300 MHz have been used as transceiver frequencies for many tactical radios currently in the field due to better radio propagation characteristics than UHF bands. Older versions were not able to provide high data rates since security and robustness requirements limited the maximum achievable data rates. Military radios operating at HF frequencies can provide much longer communication ranges but varying channel conditions in the ionosphere require expertise in understanding the effect of those events on achievable performance. Increased data rate requirements (also in the military) have raised attractiveness

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of UHF radios from 300 to 3,000 MHz that can provide higher data rates than VHF radios. At UHF frequencies, antenna heights are lower than in VHF radios, but because radio wave propagation characteristics are worse than at VHF frequencies, in many cases UHF antennas need to be raised high on elevated terrain, masts, or flying platforms. At microwave frequencies from 3 to 6 GHz, elevated microwave radio links are typically used as LoS links that utilize directional antennas to improve the range and mitigate attenuation effects by the communication media. 3.3.1  Military Communications Systems

Tactical radios often appear as three basic versions: handheld radios, manpack radios, and vehicle-mounted radios. Handheld radios use lower transmission power and provide very limited communications coverage among a limited number of warfighters. Manpack radios use medium transmission power and provide communication ranges of couple of kilometers among warfighters. Vehiclemounted radios use high transmission power and as these are not limited by batteries carried by warfighters, can provide communication ranges of several kilometers. Vehicle-mounted radios may have several antenna options as well in contrast to handheld and manpack radios. At frequency ranges from 30 to 108 MHz, typical handheld and manpack radios have transmission power 5 to 10W with 2 to 5 km communication range with several data rate alternatives (e.g., 1.2, 2.4, 4.8, 9.6, and 16–60 kbits/s.) Vehicle-mounted versions of the same radio provide the same data rate options but with higher transmission power (50–100W) that provides communication range of 5 to 10 km. Some tactical radios are able to operate at wide range of frequencies, such as 30–900 MHz, handheld versions having 12.5- and 25kHz NB channels, and 500-kHz and 1.25-MHz WB channels. This handheld radio supports 5W of transmission power. At frequency ranges from 200 to 500 MHz, handheld and manpack radios have transmission power of 2 and 5W, respectively. A 2-W handheld radio provides a communication range of 1 to 2 km in open terrain. A 50-W vehicle-mounted version provides a communication range of 10 km in open terrain. These radios support

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5 MHz wide signal bandwidths. These radios can deliver 4 to 8 Mbits/s IP data rates. At frequency ranges from 1.35 to 2.7 GHz, a military radio has transmission power of 5W and is capable of delivering maximum data rate of 10 Mbits/s. Military LTE solutions can provide 150 Mbits/s data rates at maximum in downlink direction from the base station to mobile stations. At frequency ranges from 4.4 to 5 GHz, a military link is capable of providing 20 to 200 Mbits/s data rates over 20- to 40-km pointto-point connections. Links typically have antenna gains in excess of 15 dBi. Links often have several local connectivity options from wired to wireless technologies. Based on wide review of public sources, the minimum sensitivity generic receiver level is near -100 dBm level in communications applications. At the lowest sensitivity level (e.g., QPSK) modulation types can be used. In general, to achieve higher data rates and utilize more fine-grained modulations (e.g. M-QAM), 20 to 30 dB excess signal margin from the sensitivity level is needed in the receiver. Many military radios utilize FH modes as well and provide certain hopping rates that provide more protection for the radio. Radios operating at lower frequencies have a huge number of channels to choose from, since each channel is very narrow. Since there are a lot of different channels available, there is no need for the highest hopping rates at low frequencies. This book doesn’t delve deeper in the characteristics of military radios but focuses on characteristics presented here. 3.3.2  Short-Range Civilian Communications Systems

In addition to military radios, few characteristics of civilian communications systems are presented here, since these parameters will be utilized in Chapter 9. Of short-range wireless communications technologies, ZigBee could be utilized in the WSN and IoT applications. ZigBee operates in the ISM frequencies of 868 MHz, 915 MHz, and in the most common 2.4-GHz band. At lower frequencies, a 20-kbits/s data rate is achieved in contrast to 250 kbits/s at 2.4-GHz frequency. ZigBee’s transmission power alternatives are 1 and 100 mW, which provide

3.3  Generic Parameters and Characteristics of Selected Civilian Communications 81

a communications range of 10 to 100m. Bluetooth Low Energy (BLE) version 4 provides 1 Mbits/s data rate and 100m communications range. BLE version 5 provides 2 Mbits/s data rate and 200 to 400m communications range. Wi-Fi devices operating at 5 GHz frequency have a 50m communications range, whereas 2.4-GHz devices can have 150m communications ranges. Wi-Fi can provide data rates of dozens of megabits within its range. Five-gigahertz Wi-Fi uses a maximum transmission power of 20 dBm that is 100 mW, while 2.4-GHz Wi-Fi uses 14 dBm transmit power. 3.3.3  Long-Range Cellular Communications Systems

In the past WiMAX and LTE technologies were competing for the winning position of the fourth generation cellular system. Eventually LTE emerged as the dominant player but several WiMAX systems were developed in those days.� WiMAX BSs had transmission frequencies of 2.3, 2.5, 3.5, and 5.8 GHz. Transmission power of BS is 43 dBm that is 20W. WiMAX MS has transmission power of 23 dBm that is 200 mW. Typical communications ranges were within 10 km and data rates were 10 Mbits/s. LTE was previously mentioned in the tactical radio section but operating frequencies between 700 and 2,600 MHz provide many alternatives to build data capacity. LTE BS has transmission power typically between 61 and 64 dBm, whereas LTE MSs send uplink traffic using 23 dBm transmission power.

References [1]

Pu, D., and A. M Wyglinski,., Digital Communication Systems Engineering with Software-Defined Radio, Norwood, MA: Artech House, 2013.

[2]

Frenzel, L., Electronic Design Library Focus on Wireless Fundamentals for Electronic Engineers, Electronic Design, Penton Media Inc., 2017.

[3]

Winder, S., and J. Carr, Newnes Radio and RF Engineering Pocket Book, Third Edition, Woburn, MA: Newnes, 2002.

[4]

Dahlman, E., et al., Communications Engineering Desk Reference, San Diego, CA: Academic Press, Elsevier Inc., 2009.

[5]

Fette, B., et al., RF and Wireless Technologies – Know It All, Burlington, MA: Newnes, Elsevier Inc., 2008.

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[6]

Carlson, A. B., P. B.Crilly, and J. C. Rutledge, Communication systems An Introduction to Signals and Noise in Electrical Communication, Fourth Edition, New York: McGraw-Hill, 2002.

[7]

Proakis, J. G., Digital Communications, Fourth Edition, Singapore: McGrawHill Book Companies Inc., 2001.

[8]

Rappaport, T. S., Wireless Communications – Principles & Practice, Upper Saddle River, NJ: Prentice Hall Inc., 2002.

4 Situational and Context Awareness Situational awareness and context awareness are key terms and concepts closely related to capability planning, awareness of environment, actors and events in the battlefield, and to perception of the current situation based on analyzed information. Situational awareness has a counterpart of battlespace awareness in the JCA model that refers to similar capability. Situational awareness can be characterized as actions to understand what has happened in the area of interest, what type of actors there are (hostile, Blue, and neutral), in what locations, what capabilities they have, what the geographical characteristics are and how these along with different weather conditions affect the mobility and speed of different actors. Situational awareness therefore requires measurement data from sensors, the knowledge of techniques, tactics, and procedures of one’s own and opposing forces. This information, along with the forecasting of conditions and personal experience of the commanding officer, affects how well one succeeds in evaluating the next steps to be taken in the operation by the Blue and Red side. 83

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4.1  Context Awareness In contrast to situational awareness, context awareness is related more to the artificially and computationally implemented understanding of user or terminal behavior in different situations. The term is closely tied to the user interface research community. Current mobile phones are designed in a way that collects data from internal sensors to understand the context of the user and modifies the state of the phone according to decided context. The concept of context awareness originates from the research on ubiquitous computing by Mark Weiser [1]. The concept of context recognition is relevant in military applications in addition to many pioneering demonstrations that emerged in the 2000s. A context can be described as a perception of the situation at hand by the user device based on internal and external parameters as well as current and previous behavior of the user. The user device needs several information sources related to the situation. Examples of information sources that may be needed in implementation of context awareness are described in the following list: • Geographical location; • Past user behavior in the current location and/or in the close neighborhood of the location; • Presence of other users and objects in the neighborhood; • User preferences; • Date and time; • Available local and online information resources; • Requests of information and support to the online communities of interest; • User status (e.g., work or leisure); • High-level mission, operation, and planned tasks in the pool of operations; • Military support available; • Other military-related status information regarding situational awareness, early warning, and protection.



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If we look at this list of information sources related to the single warfighter in the field, it is clear that there is a need for a capable user device with good connections to the communications networks. To implement smooth, accurate, and low-latency context changes is more challenging. To limit the use of network connections in the formation of the context at hand, the user device needs to use local sensors, databases, and short-range connections to nearby devices while performing machine learning as an internal task, which requires a great deal of processing power and energy. Context changes could be implemented as external commands as well, but this may take extra time if the user device is obliged to negotiate with the originator of the context change command by providing the information regarding the internal status that might disable the context change command. Context awareness is not only the collection of data, but also the modeling, understanding, and delivery of information related to the context for the relevant participants. There are several levels of context. In some applications recognition of the movement mode of the user is the context (standing, walking, or running) whereas very complex contexts simultaneously need several parameter values to recognize the right context in, for example, future autonomous systems. The former type of context was recognized in several past studies by collecting data from several wearable sensors, whereas current technologies enables recognition of context using a single device equipped with several sensors. In fact, in military applications the user has a specific role in the operation or task that could be used as a filtering context that preserves and visualizes information related to that context from the situational picture. Context-aware applications characterize various states of the entities that can be warfighters, locations on the battlefield, smart machines, objects, or nonphysical virtual objects. Context-aware applications can be found currently in commercial applications and in virtual military training facilities but wide-scale use of AI-supported warfighters on the battlefield will take several years more. Context awareness in the military domain may present an important opportunity to improve situational awareness utilizing the personal training level, education, and experience of a warfighter, the status of warfighters on the same team, parameter databases,

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previous background data from the operational area, location, and local sensing of both actors and the environment. Threats in the cyber domain regarding AR- and AI-supported context awareness can be mitigated by preserving an opportunity to use various information sources and not to rely completely on one source of information. Hostile activities typically focus on one or a few information sources that leave other sources unaffected. Modern smart phones have an extensive set of integrated sensors, computational capabilities, and WB access to the network using various technologies. Smart phones therefore have been important drivers of user interface and context awareness research. In military applications, an extensive set of sensors in the warfighter terminal could be utilized for analysis of the warfighter state [2] as well as a locationspecific sensor node that provides more accurate location-specific details to assist the situational picture. For example acoustic, acceleration, and chemical, biological, radiological, and nuclear (CBRN) sensors would be valuable if sensor input from several warfighters could be collected and fused to the situational picture of a part of the operational area. An extensive survey of context-awareness in mobile sensing [3] presents important issues of future challenges that apply to the military applications as well.

4.2  Interaction with Smart Objects in Location- and AR-Based Applications User interface and interaction research progressed remarkably in parallel with the development of mobile communications although the value of this research had been recognized earlier. Wide-scale global penetration of mobile phones provided a good position as the most important terminal device of the user. Interaction research had earlier been limited by the fact that there were no widespread terminals that hindered research of consumers in the days of PDAs and computers. Current mobile phones have integrated sensors but commercial applications have guided the selection of built-in sensors to specific application areas. However, the current situation for interaction research is much improved from two decades ago. The author had an opportunity to work on ubiquitous computing, context awareness, and ambient awareness at Technical



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Research Centre of Finland in the 2000s. Measurements on user behavior, gestures, movement, and interaction were recognized as key issues in addition to networking in building smart environments. In those days, commercial applications in these areas seemed very farreaching. Various methods of interaction with smart environments, objects, or machines are introduced in the following description. 4.2.1  Close-Range Interaction with Smart Objects

Close-range interaction with smart objects can be implemented with various techniques, from direct operation on the user interface of the smart object to the close-range detection of the user presence near the object and provision of location-based services. Simple forms of interaction are implemented with RFID technologies that may be based on passive detection of an RFID tag in the user terminal and activation of interaction via other wireless communications technology. Smart objects may also contain RFID tags and the user terminal might have an RFID reader with local service delivery provided by cellular communications. In more sophisticated interactions, pattern recognition technology could be applied to both the user terminal and the smart object for recognition of human identity, gestures, commands, and movements along with visualization of smart objects on top of the display to easily locate them in the physical environment. If the smart object is not fixed in the infrastructure, the movement, tilting, shaking, and rotating of the object may change the contexts of interaction. Usually physical interaction with the object in close proximity is regarded as the most intuitive form of interaction since in that way the user has a real grasp on the item to be handled [4]. 4.2.2  Short-Range Interaction with Smart Objects

Short-range interaction with smart objects could also apply to the detection of user presence, but typically interaction happens from a longer distance than close-range interaction. This is the case when the user enters an area containing several smart objects and the user needs a straightforward way to select a certain object for interaction from several others. Selectivity implementation in radio frequencies can be applied using directional antennas but most of the tests

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were performed with optical connections. As TV users are used to pointing at their TVs with remote controls, the devices with beams of visual or infrared light would be a familiar form of interaction. The transmitter side needs a very narrow beam for great selectivity whereas smart objects in the environment need a wide angle of reception to effectively collect the user beams from different directions [5]. Pointing by the user could also be detected by pattern recognition capability integrated in the environment where a network of cameras analyze the direction that the user is pointing [4]. 4.2.3  Long-Range Interaction with Smart Objects

Long-range interaction may be implemented from longer distances than previous interaction methods. In this interaction form, the user operates an application that provides access to several smart objects irrespective of the distance between the user and the objects. This form of interaction needs networking resources to get access to the distant smart objects. The number of objects available in interaction may cause challenges to the user experience since the number of spaces available may cause information overload for the user. This type of interaction needs powerful filtering and analytics to limit the wide spectrum of available options. If the user has allowed profiling by network analytics, the application will know what the user is about to do in no time. The user could control the objects by limiting the options based on location, (e.g., the user could input a geographical location as a coordinate and select the right building from several buildings are located in the same coordinate.) The selected building provides several actions that can be performed remotely by simultaneously checking authorization information of the user for different functions to be performed. Again, the list of controllable items could get more fine-grained when the user moves to the lower level in the equipment lists. Finally, the user gets an access to the IoT device in the specific room of the selected building. Current hype around IoT covers these same elements but technological progress has already enabled improved development opportunities of these applications. The rise of the IoT requires energy sources to network even the smallest objects, cybersecurity, and analysis of data, which gets massive if a large number of physical objects



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report on their state and services via short-range and long-range communications.

4.3  Location-Based AR Applications Both situational awareness and context awareness form a baseline for location-based services and AR applications. AR brings virtual reality on top of the real physical environment and creates interactive functionalities, where the user is informed of services that are linked to the location. In addition to physical objects that are networked, the terminals that users are carrying may be interconnected. They can add value to applications by providing comments or more fine-grained information on applications at this location. To create more sophisticated crowd-sourcing applications, there must be enough willing users to contribute by allowing access to the user terminal in order to add value in the ever evolving user community. These applications require interaction with the physical and virtual environment. User interface research in the last decade was interested in applications of large displays at public places but this type of application did not emerge to the extent that was expected. As smart phones have become common in our society, locationbased applications have become very practical, for example, in the planning of routes in previously unknown locations. Different Global Navigation Satellite Systems (GNSSs) in space set the pace of modern society whether there are events in global supply chains, synchronization and timing of equipment connected to internet, or global monetary transactions. In fact, these systems have played a key role in information technology systems that control key functions in society. Dependency on space assets to keep society up and running is a risk that most nations have been willing to take, since the benefits of having near real-time awareness of different functions is seen to overcome risks of satellite system failures. Several parallel systems have been developed over the years to prepare for carrying out operations in GNSS-denied environments. Current technology has aided development of these systems but there are still challenges to find accurate, stable alternatives for GNSS systems. In ubiquitous computing and ambient intelligence research, there were visions of location-based services where the user was

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provided more information in the specific location and had interaction with the physical and digital worlds. The first forms of location-based awareness were advertisement tags that provided product information and possible connection to online shopping and support services. A main characteristic of this form of advertisement is the provision of services for every user who visits the location. More sophisticated location-based services could silently detect the user in the vicinity and perform authorization and security functions to resolve whether user could utilize services provided by the device in that location. This type of service could be used in the military with built-in security functions that allow only authorized users to use the classified services.

4.4  Dual-Use AI-Supported Situational Awareness Since sensors are important systems to produce data from the situations to be observed, they may be located in the environment, on the user, or embedded in the equipment of the warfighters. Different ways to interact with the environment of embedded smart devices were presented previously, but more sophisticated forms of interaction could be performed using gesture-based interaction with AI support. One interesting example of the utilization of network-based intelligence would be crowd-based applications, where wide-scale data collection from a large number of mobile users is performed using embedded sensors in their mobile terminals and network-based analytics and visualization tools to present the current situation from different perspectives. This is one example where commercial communications equipment could reveal their capabilities in contrast to similar approaches with military radios. First, the number of observations using commercial solutions would have to be very large to get enough samples to make analysis of a specific phenomenon. Second, desire for mobile users to allow access to the sensors of their mobile devices should be encouraged in some way. This could be a dual-use application that would inform citizens of important events in the community in addition to collecting important sensor data for military and security users. Analysis of information collected should only be done from limited areas in order to maintain computational performance at high level

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and to limit the privacy concerns of users committed to this application. In military and security applications, interest would be guided towards current or previous events in contrast to other scientific analyses that would be interested in long-term data as well.

4.5  Context-Aware Military AR Applications for Improved Situational Awareness Previous subjects covered were general issues of situational and context awareness. Military communications could really benefit from these applications but currently these applications are not fully mature. The concept of AR may increase the performance of warfighters and units in the future. The two directions of greatest importance are discussed next. 4.5.1  Situational Awareness Support Based on AR

First, AR could enrich visualization and perception of the operating environment by bringing virtual objects and markers into the display of the warfighter or platform. Objects and markers would pinpoint certain objects, actors, and locations in the layer that integrates both physical and virtual environment on the same screen. In a military mission, short latency of AR applications is a critical requirement. For example, recognition of enemy attack in the vicinity can take 20 seconds in the AR application, but decision support must be there in real-time. There are also events that don’t have as stringent real-time requirements. The lowest latencies cannot be met by the current technologies unless severe simplifications and limitations of functionalities are made. Therefore, typical network connectivity doesn’t support real-time requirements unless it is supported by high capacity networks. Enriched 3-D maps of an operational area with virtual information objects on static things could be downloaded to user terminals before the operation. However, limited capacity networks probably would not have the capability to update dynamic objects in real-time cases when users and systems are dismounted in the field. Within two decades it is probable that the first near-real-time and then real-time updates will be possible. Currently, warfighter terminals and platform terminals need

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computing capabilities from the network, since the development of energy technologies doesn’t allow for practical operating times and performance in order to put physical and fast virtual worlds together. Supporting network computing capabilities should reside in the local network since delays to access cloud-based services are too long to allow fast reactions to events. When operating in the field, dismounted warfighters have direct visibility and observations of the local environment. Therefore, collective enrichment of the local area of responsibility by a platoon or a company would present important functionality. As network-based operations always convey the potential of cyber threats, risk of tampering to the layer of virtual objects and events in the physical environment could be mitigated by checks between warfighter terminals in the same company. The challenge would be to recognize the time when AR becomes unreliable and instead only local observations of warfighters in the company ought to be used. This example clarifies the need for a redundant alternative for network-based AR. If AR was connected to engagement-capable autonomous platforms, a successful cyber offensive from the hostile side would be detrimental for missions governed by AR and autonomy. 4.5.2  AR Support for Finding Communications Opportunities

Second, AR could be the best choice to communicate with Blue forces by showing key points in the local environment with virtual objects that also show the identity of the potential destination as well as the location that provides the communications opportunity. As in the previous example, implementation of this functionality is far in the future since the computing burden is heavy for even current workstations. Some recent studies of 3-D mappings of local environments have been done in order to accurately predict behavior of very short wavelength communications technologies with limited coverage and which are easily blocked by an object, but are able to provide great communications capacities. This type of mapping does not fit well in outdoor environments, so certain approximations have to be made. To compute different opportunities for communications in the operational environment, several information sources are needed. A map of the area, terrain profiles, a city silhouette of at least dominant buildings, and characteristics of transmit-

4.5  Context-Aware Military AR Applications for Improved Situational Awareness 93

ters and receivers are needed. Requirements could also be extended by known hostile emitters and their characteristics, weather conditions, and status of communications equipment (e.g., whether they are running out of energy resources and whether typical capability is limited—only NB reception is possible at this time). Different alternative communications could be simulated and analyzed in terms of data capacity, communications range, the risk of losing data in transmission, time to deliver, and the risk of eavesdropping. Opportunities for communications could be using civilian LTE, military LTE, tactical radios with different communications bands, IoT connectivity or WSN communications in multi-hop fashion, aerostat communications or UAV relaying. These simulation tools typically focus on wireless communications but there may also be other alternatives to deliver messages from the operational analysis perspective. Similarly, this communications simulation support should also have a local mode that might be very helpful (e.g., in the case of CRs). Each radio would contain a database of licensed, unlicensed, and military frequencies within the operational area. The standard way CRs sense and use the spectrum (whether there is a current active primary user or the primary user is absent) in the future will be when there are several shared users and nonlicensed band users. Several users will compete for local use of the spectrum and well-known hidden terminal problems may result in congestion in the spectrum. Therefore, in the local operational environment the group of CR terminals could collectively create a local radio environment spectrum that is actively compared to the database of frequencies. The collective scanning of the spectrum not only has the opportunity to find hidden terminals but hostile terminals as well. This information is valuable for the detection and localization of hostile emitters along with the provision of information to occupy other parts of the spectrum to avoid hostile emitters. Since the terminal of a warfighter in the field will not be capable of sophisticated simulation before the 2030s due to computing, networking, and energy challenges, there will be a need for local environment scanning if network resources are needed for purposes other than communications opportunity simulations. Unmanned ground vehicles (UGVs) have found their first applications in logistics, explosive ordnance disposal (EOD), and ISR tasks. A UGV

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could also function as a local scanning, computing, and communications gateway that aids a warfighter to find the best communications options. A UGV might carry onboard an extendable antenna mast to communicate with other ground-based LoS radio links, or with a UAV relay or aerostat. If a UGV had a multisensor payload as well, it could locally scan the best positions for command posts.

References [1]

Weiser, M., “The Computer for the 21st Century,” Scientific American, Vol. 265, No. 3, Special Issue: Communications, Computers and Networks: How to Work, Play and Thrive in Cyberspace, September 1991, pp. 94–105.

[2]

Sadler, L., et al., A Distributed Value of Information (Vol)-Based Approach for Mission-Adaptive Context-Aware Information Management and Presentation, US Army Research Laboratory, ARL-TR-7674, May 2016.

[3]

Yürür, Ö., et al., “Context-Awareness for Mobile Sensing: A Survey and Future Directions,�” IEEE Communications Surveys & Tutorials, Vol. 18, No. 1, 2016, pp. 68–93.

[4]

Välkkynen, P., Physical Selection in Ubiquitous Computing, Helsinki, Finland: VTT Technical Research Centre of Finland, 2007.

[5]

Strömmer, E., and M. Suojanen, “Micropower IR-Tag - A New Technology for Ad-Hoc Interconnection between Handheld Terminals and Smart Objects,” Smart Objects Conference (SOC2003), Grenoble, France, 2003.

5 Radio Wave Propagation Chapter 3 presented the central building blocks of communications systems, but, this chapter takes a closer look at communications media to consider what happens to communications signals between antennas of a transmitter and receiver. Wireless communications transmitters, receivers, and transceivers need antennas as an interface to the outside world. Different antenna types have different antenna gains that are typically specified separately for the transmitting and receiving antennas. It is worth mentioning that antenna gain towards one receiver differs from antenna gain towards another receiver, since antennas have uniform antenna patterns only in theory. Every actual antenna is nonuniform in the antenna pattern. Omnidirectional antennas are often applied using a fixed antenna gain, whereas antennas with high directivity are prone to the orientation and alignment of the receiver and transmitter antennas. It is fundamental to this latter type of antenna to find the maximum gain to establish the longest achievable range for communications links. From an EW perspective the directivity of the links protects 95

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friendly links better than with omnidirectional antennas, since successful interception and jamming of links requires these systems be aligned with LoS links. Understanding of radio wave propagation mechanisms is important when planning efficient and robust radio networks. In principle the higher carrier frequency enables higher data rates. Systems operating at higher frequencies may have challenges regarding transmission power, non-line-of-sight (NLoS) communications paths, limited transmission range, and the need for a denser network of nodes.

5.1  RF Propagation Phenomena in Wireless Communications Media Electromagnetic waves are affected by several phenomena when they travel through communications media and meet different terrain objects, man-made objects, and materials. Reflections arise when the waves meet wide surfaces or objects much bigger than the wavelength of the propagating carrier signal. In diffraction phenomena the wave meets an impenetrable surface or sharp edges that diffract the signal from the original direction. Diffraction produces several diffracted waves that bypass the object which may enable reception of the signal although an LoS path does not exist between the transmitter and receiver. In scattering phenomena the incoming electromagnetic wave divides into many outgoing directions when it meets objects whose size is smaller or comparable to the propagating carrier signal. Scattering may enable reception of an RF signal from locations that would not be able to receive signals without this phenomenon. These three phenomena cause small-scale fading in the communications receiver whereas largescale fading increases when the distance between transmitter and receiver is increased. The cumulative effect of large and small-scale fading is hard to predict as the transmitter and receiver move in versatile environments causing different effects on received RF signal power levels. Different statistical and empirical models have been developed to predict radio wave propagation in different environments [1–2]. The receiving antenna receives the direct signal (LoS) and reflected signals (NLoS) that are superimposed on top of the direct



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signal. Depending on the phase of the reflected waves compared to a direct wave the total received signal can be increased or decreased from the original direct wave. Strong reflections with a certain delay as along with high mobility of the communicating devices may cause interference and deviations from typical performance. The communications channel can be described as a Rayleigh, Ricean, or Gaussian channel. A Rayleigh channel is characterized only by reflected waves (and not direct waves) whereas a Ricean channel contains both. A Gaussian channel is characterized by a dominant direct wave [2].

5.2  Trade-Offs Between Frequency, Antenna Size, and Node Mobility As these phenomena show, the wavelength of electromagnetic waves has a fundamental role in radio propagation. The wavelength of a radio wave is calculated by (5.1).

λ=

c f

(5.1)

where λ is wavelength in meters, c is the speed of light; 3 × 108 m/s, f is frequency in hertz. The higher the frequency, the smaller the objects that will affect the radio wave propagation. Small antenna systems provide greater user mobility but must deal with small-sized objects in the surroundings of the receiver. Communications systems operating at lower frequencies require large antennas due to long wavelengths and vice versa. Large antenna systems pose limitations on mobility (e.g., due to mast systems) but propagation of waves at these wavelengths is not hindered as it is at the upper frequency bands. Radio or microwave communications systems should provide proper communications ranges, power levels that don’t pose a heavy burden on batteries to be used, and proper channel capacity in addition to quality of the signals.

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The communications systems described in Chapter 3 are operate mostly in the VHF part of the spectrum that covers frequencies 30 to 300 MHz (wavelengths 10–1m) and in the UHF part of the spectrum 300 to 3000 MHz (wavelengths 1–0.1m). Studies on tactical communications do not often cover communications in SHF band, since in most cases the LoS links cannot be guaranteed. In contrast to HF frequency bands, the bands listed above have beneficial characteristics in terms of antenna size, achievable data rate, and propagation characteristics. Path losses at VHF and UHF frequencies are due mainly to terrain characteristics and obstructions in the environment whereas at SHF frequencies the weather and atmospheric conditions comes into play.

5.3  Radio Horizon and Fresnel Zones LoS paths are often described by calculation of radio horizon and Fresnel zones. Radio horizon calculation utilizes the radius of the Earth and doesn’t consider alternating terrain heights, man-made objects, or natural objects (e.g., hills, cliffs, mountains, forests, or vegetation). When looking at Frésnel ellipsoids to detect obstructions along the path between the transmitter and receiver, it is important to note that the effect of an obstruction near the transmitter or receiver is much greater. This can be utilized by placing a communications station behind the hill that greatly attenuates the interfering transmissions. If the communications path between the transmitter and the intended receiver is nearly free from disturbing objects, the selected position of the communications station has been a result of clever utilization of terrain characteristics. With the proper use of terrain, the limitations of communication systems can be partly mitigated, but in battle, picking up the best positions for communications, is very challenging due to opposition activities.

5.4  Receiver Sensitivity and Quality of Service as Measures of Performance As the communications distance is increased, the received communications signal level is decreased at the receiver. Each receiver has characteristics that result from design decisions made based



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on requirements specified for the communications application at hand. Modern communications systems utilize several QoS levels that define the limits of data rate and SNR performance. QoS is implemented with several modulations that are appropriate for the signal levels and channel conditions at hand. As distance between the transmitter and receiver is increased enough, even the most robust modulations can’t provide data transfer services. A communications link may still be established and run though data transfer is not possible. As the communications distance is increased, the transmitter and receiver cannot see each other in the spectrum. From a NCW perspective, in these conditions at the edge of the network the limits of the communications link should be detected and routed via other available paths. Receiver sensitivity is one of the key parameters of a receiver that is typically expressed in dBm units. The sensitivity parameter is the lowest power level at the receiver input that can be considered as a valid reception. There are different levels of receiver performance near the sensitivity limit, for example, detection of pilot messages, synchronization, formation of valid connection between transmitter and receiver, and sending different lengths of data successfully between transmitter and receiver. Any excess signal power level above the sensitivity level forms a receiver margin or link margin. The link margin varies between different communications systems due to requirements on link availability and to tradeoffs between different design parameters. Most often the specified sensitivity is the lowest limit of received power, but several vendors also specify sensitivity levels between different modulations. Unfortunately, neither known transmitter power nor receiver sensitivity reveal achievable communications ranges.

5.5  Coarse- and Fine-Grained Calculation of Radio Coverages One needs accurate information on antenna characteristics and path loss that is rarely known beforehand. In most cases there is no need for accurate path loss figures, but approximations with coarse deviations are suitable for estimating the operation of communication systems in versatile environments. 3-D modeling of the communications environment has gained ground recently in the mapping of

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indoor environments, although there are fine-grained modeling efforts regarding outdoor communications as well. As modeling and simulation details get more refined, the calculation time of radio coverages in typical areas gets very long. There are no technologies and systems available that allow near real-time communications performance estimation from the area. Communications receivers estimate channel characteristics and performance between the other end of communications link, but, they do not have knowledge of radio conditions from wide areas. Current communications simulation tools can provide fairly accurate path loss, as they can utilize several path loss models and mapping from geographical data gets more accurate. The simulation of radio wave coverages is a trade-off between simulation time and accurate description of the environment. For now, very accurate environment data libraries are not publicly available and are valid only for a certain time, since the communications environment is in constant change by man-made and natural events. Civilian efforts in communications modeling and simulation have focused on higher frequencies (e.g., in cellular and short-range systems especially in urban and indoor environments).

5.6  Selection of Radio Wave Propagation Equations and Models The end of this chapter presents several propagation models from simple to more complex used in the communications range approximations in Chapter 9. There is a great deal of literature that evaluates different propagation models and presents the results of several experimental measurement campaigns analyzed against analytical and numerical models. Accurate modeling of the operating environment provides a strong base for analysis of communications opportunities in the operating environment. However, in many cases military users need more straightforward and faster methods to evaluate radio coverages that need not to be as accurate as in fine-grained 3-D operating space modeling. Free-space loss and plane Earth models do not consider the effect of terrain, natural, and man-made objects on propagation, whereas Egli, Okumura-Hata and COST 231-Hata models include the effects of terrain and objects, respectively.



5.6  Selection of Radio Wave Propagation Equations and Models

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5.6.1  Free-Space Path Loss

Free-space path loss is the basic form of propagation that describes signal attenuation along LoS paths that are not interfered by objects or by reflections from objects along the path. It is often applied to model communications in a nonobstructed environment, and when the ends of the communications path are elevated from the ground (e.g., flying vehicles and high communications masts). It assumes using isotropic antennas at the transmitter and receiver. An isotropic antenna is an ideal antenna that radiates electromagnetic energy uniformly in every direction. The gain of the isotropic antenna is 1 in metric units that corresponds dB gain value of 0 dB. It is also assumed that there are no reflections of signals from the ground. Free-space path loss in decibels is calculated using (5.2) [3].

LdB = 32 + 20 log 10 dkm + 20 log 10 f MHz

(5.2)

where the constant represents geometric properties of the link using 1 dB accuracy, dkm represents distance in kilometers between transmitter and receiver, and fMHz represents transmission frequency given in MHz units. 5.6.2  Plane Earth Propagation Model

The plane earth propagation model considers reflections from the surface that may have a great effect on the received signal due to a 180-degree phase reversal that happens in the reflections. The reflected wave may reduce the cumulative signal seen by the receiver by subtracting the signal level of direct-path waves. If the distance between transmitter and receiver is assumed to be much longer than the height of the transmitter and receiver antennas, then the following (5.3) can be applied to calculate path loss [4].

LdB = 120 + 40 log 10 dkm − 20 log 10 hTx , m − 20 log 10 hRx , m

(5.3)

where dkm represents distance in kilometers between transmitter and receiver, and hTx,m and hRx,m represent antenna heights of a transmitter and receiver in meter units, respectively.

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5.6.3  Egli Propagation Model

The Egli propagation model can be used at frequencies 30 to 1000 MHz and communications distances 1 to 80 km. Communications path loss according to Egli model can be calculated using (5.4) and (5.5) depending on the height of the receiver antenna [5–6]. LRx 10 + = 85.9 + 20 log 10 ( f c ) + 40 log 10 ( d ) − 20 log 10 ( hTx ) − 20 log 10 ( hRx ) (5.4)

where fc represents the carrier frequency in MHz units, d represents distance between transmitter and receiver in km units, hTx represents height of the transmitter antenna in meters, and hRx represents height of the receiver antenna in meters. To apply (5.4), condition hRx > 10m must be satisfied.

LRx 10 − = 76.3 + 20 log 10 ( f c ) + 40 log 10 ( d ) − 20 log 10 ( hTx ) − 10 log 10 ( hRx )



(5.5)

where definitions of variables are similar to (5.4) but condition hRx ≤ 10m must be satisfied in (5.5). 5.6.4  Okumura-Hata Model

The Okumura-Hata model is one of the most used empirical models in radio propagation studies. It is based on measurements performed in Japan in 1968. The model is valid for the following ranges of parameters: [7–8] • Transmission frequencies from 150 MHz to 1.5 GHz; • Transmitter antenna height in the range of 30 to 200m; • Receiver antenna height in the range of 1 to 10m; • Distance between transmitter and receiver in the range of 1 to 10 km. Mean path loss LdB is calculated for three different cases using the following (5.6) to (5.8) and the parameters that are introduced below these equations.

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LdB = A + B log 10 R − E

(5.6)

LdB = A + B log 10 R − C

(5.7)

for urban areas,

for suburban areas, and

LdB = A + B log 10 R − D

(5.8)

for open areas Parameters used in (5.6) to (5.8) are presented below. Parameters for large cities are not presented here, since analysis in Chapter 9 deals only with small and medium sized cities [7–8]. A = 69.55 + 26.16log10 fc – 13.82log10 hb B = 44.9 – 6.55log10 hb C = 2(log10(fc/28))2 + 5.4 D = 4.78(log10 fc)2 + 18.33log10 fc + 40.94 E = (1.1log10 fc – 0.7)hm – (1.56log10fc – 0.8), for medium to small cities hm represents receiver antenna height from local terrain height in meters; hb represents transmitter antenna height from local terrain height in meters; R represents great circle distance between transmitter and receiver in kilometers; fc represents carrier frequency in MHz units. 5.6.5  COST 231-Hata Model

The COST 231-Hata model extends the Okumura-Hata model to cover the frequency range between 1.5 and 2 GHz by adjusting the model with F and G parameters as specified in (5.9). Parameters B, R, and E are calculated similarly as in the previous Okumura-Hata model. The model is valid for the following range of parameters [9]:

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• Transmission frequencies from 1.5 GHz to 2 GHz; • Transmitter antenna height in the range of 30 to 200m; • Receiver antenna height in the range of 1 to 10m; • Distance between transmitter and receiver in the range of 1 to 20 km.

LdB = F + B log 10 R − E − G

(5.9)

where F = 46.3 + 33.9log10 fc – 13.82log10hb and G = 0 dB for medium sized cities and suburban areas. This book doesn’t consider indoor propagation, but, focuses on outdoor propagation. The aim of the examination in this book is on conceptual design of communications alternatives and not on an accurate engineering approach.

References [1]

Andersen, J. B., T. S. Rappaport, and S. Yoshida, “Propagation Measurements and Models for Wireless Communications Channels,” IEEE Communications Magazine, January 1995, pp. 42–49.

[2]

Rohde, U. L., and D. P. Newkirk, RF/Microwave Circuit Design for Wireless Applications, New York: John Wiley and Sons, 2000.

[3]

Parsons, J. D., The Mobile Radio Propagation Channel, Chichester, England: John Wiley & Sons Ltd, 2000.

[4]

Adamy, D. L., EW 103 Tactical Battlefield Communications Electronic Warfare, Norwood, MA: Artech House, 2009.

[5]

Egli, J. J., “Radio Propagation Above 40 MC over Irregular Terrain,” Proceedings of the IRE, Vol. 45, Issue 10, October 1957, pp. 1383–1391.

[6]

Delisle, G. Y., J-P.Lefèvre, and M. Lecours, “Propagation Loss Prediction: A Comparative Study with Application to the Mobile Radio Channel,” IEEE Transactions on Vehicular Technology, Vol. VT-34, No. 2, May 1985, pp. 86–96.

[7]

Hata, M., “Empirical Formula for Propagation Loss in Land Mobile Radio Services,“ IEEE Transactions on Vehicular Technology, Vol. VT-29, Issue 3, August 1980, pp. 317–325.

[8]

Okumura, T., E. Ohmori, and K. Fukuda, “Field Strength and Its Variability in VHF and UHF Land Mobile Radio Service,“ Review of the Electrical Communication Laboratory, Vol. 16, No. 9–10, September–October 1968, pp. 825–873.

[9]

5.6  Selection of Radio Wave Propagation Equations and Models

105

European Cooperative in the Field of Science and Technical Research EUROCOST 231, Urban Transmission Loss Models for Mobile Radio in the 900 and 1800 MHz Bands, Revision 2, The Hague, September, 1991.

6 Wireless Sensor Networks Wireless sensor networks (WSNs) have been studied extensively in the past. Military organizations classify radar as one type of a sensor, since it detects whether or not a target is in the beam of a transmitted radar signal. In addition to radars, there are other important low-power sensors that may play an important role in the future battlefield and security operations. This chapter focuses on sensors that operate at lower frequency bands and have lower transmit power than radars usually have. Key elements of sensor networks are introduced in Section 6.1. Different types of sensors are presented in Section 6.2 along with the physical parameters that can be measured with them. Information analysis and situational awareness related to WSNs are presented in Section 6.3. Section 6.4 presents the utilization of data collected by sensors and actions that may be performed using actors or actor networks that operate in concert with WSNs. The energy issues of WSNs are presented in

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Section 6.5 and security, robustness, and reliability issues are covered in Section 6.6. Section 6.7 presents IoT as a future technology that may become a central part of WSNs and wireless communications networks.

6.1  Building Blocks of Sensor Networks There are various technologies used to implement sensor networks. This section deals mostly with WSNs due to the challenges that arise when using wired sensor networks on the battlefield. However, in circumstances where cable connections are used for communications purposes, it is possible to establish wired sensor networks on the same routes where communications lines are placed. A WSN consists of a number of sensor nodes that have different roles. Nodes can be used as passive data collectors, participants of continuous multihop communications, control nodes that manage specific domains in the WSN, or in large-scale networks, gateway nodes that connect traffic of low-end sensor nodes to more sophisticated and high-capacity networks. A WSN can be formed using various options, such as • Static gateway/control node that communicates with static sensor nodes; • Mobile gateway/control node that communicates with static sensor nodes; • Static gateway/control node that communicates with mobile sensor nodes; • Mobile gateway/control node that communicates with mobile sensor nodes; • Mobile and distributed sensor nodes that operate using collective intelligence where nodes can act as sensor and gateway/control nodes. It is clear that requirements on system design, WSN management, and the technologies used get more challenging toward the end of the list, especially in harsh environments. Seamless, infrastructure-independent internet working between fixed and mobile



6.2  Sensor Types

109

devices have been seen as critical and unique requirements on sensor networks [1]. Simple sensing systems rarely carry out measurements (e.g., once a day) and record measurements to the internal memory of a sensor node. Measurement data stored in the sensor node can be transmitted from the sensor to other sensor network elements by communications hardware, or it can be read to the sensor via cable locally by a connecting data collection device, optical link, or low-power wireless transceiver. Other types of sensors can collect data at very short intervals and transmit measurement data (often or rarely) grouped in larger blocks of measurement data. There are several limitations of sensor systems that impose requirements on their efficient utilization. Communications between sensor nodes can be implemented with technologies at different wavelengths, but as with tactical radios, VHF and UHF frequencies are beneficial for communications range and robustness. Most WSN literature consists of studies performed using ground-based WSNs due to energy-limited sensor nodes. As technology has progressed, in recent years air-based low-energy sensors have gained more attention.

6.2  Sensor Types A sensor is a device with sensing elements that measure a physical quantity in the environment in the neighborhood of sensor. These measurements are compared to preprogrammed reference levels and sometimes measurement data of other sensors to reveal false detections. Measured values are stored in the data memory of a sensor. It may be necessary to calibrate or correct stored sensor measurements if, for example, variable ambient temperature levels affect measurement functionality. Sensors should be sensitive to the phenomenon measured, while being able to prevent or minimize the unwanted effects of the surrounding conditions in the environment and in the sensor device. Necessary characteristics in sensor nodes include stability, sensitivity, accuracy, a high sampling rate, and a high dynamic range. Different types of sensors measure physical quantities and convert measurement events to electric signals that are easily processed by signal processing systems. Examples of phenomena that sensors might measure are as follows:

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• Acceleration; • Vibration; • Orientation; • Speed; • Movement; • Direction; • Sound; • Temperature; • Humidity; • Proximity; • Pressure; • Chemical and biological properties and characteristics of substances and gases; • Electric and magnetic fields; • Elasticity, and changes in the shape and size of objects. Using several sensors to collect data for decision-making on context changes or improved situational awareness may improve accuracy but at the cost of complex integration and straining systems-engineering. Sensor selections (e.g., in mobile phones) focus on specific applications, whereas specialized needs and a combination of different types of sensors call for more expensive equipment that is application-specific.

6.3  Sensor Network Intelligence Analysis of data gathered by sensor networks becomes very complicated if the WSN consists of all case studies presented in Section 6.1 and the WSN consists of a heterogeneous mix of different technologies [2] that might operate at different frequencies. As the number of nodes in the WSN increases, management of sensors becomes a challenge—especially if the WSN operates at frequency bands where it has to preserve access to the primary users by withdrawing from the spectrum [3]. Sections 6.3.1 and 6.3.2 present two



6.3  Sensor Network Intelligence

111

WSN case studies of military ISR. Section 6.3.3 covers the use of several sensors in military applications. 6.3.1  WSN Example of Enemy Vehicle Detection

Figure 6.1 on enemy vehicle detection shows a concept of the WSN in a surveillance and monitoring task, where several low-power wireless sensor nodes are distributed in the area of interest. There is also a distant data fusion center that collects detection information and data from sensor nodes that forward data via sensor-to-sensor routes in multihop fashion. Figure 6.1 shows a situation where in time T = 0 sensor A detects an event of vehicle presence in the vicinity of sensor A. Sensor A forwards the data originated from the detection event to the closest peer node B that forwards the message again along the B–C–D–E route to the data fusion center. At the moment of T = T1, sensor node C detects an event of vehicle presence in the vicinity of sensor C and forwards the message along the C–D–E route to the data fusion center. Similarly at the moment T = T2, sensor D forwards the message along the D–E route to the data fusion center. In this example sensor-to-sensor message delivery follows the same route––only the number of hops is different at times T = 0, T = T1, and T = T2. If sensor nodes C and D have a capability to store several messages of the previous events, this data can already be utilized in the WSN to analyze the probability of a false

Figure 6.1  Enemy vehicle detection.

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event and limit forwarding the false detection events to the data fusion center. Since sensor nodes may have different capabilities, the message might be an audio clip of the event, a still picture from a sensor node camera, a vibration sensor detection of heavy vehicle movement in the area, or detection of proximity sensors that detect blockage of the beam between two nodes. Some sophisticated sensor nodes may have an actuator capability to move within the area to get to a better position to observe the object. A similar concept of store and forward within a multihop WSN can be applied in the case where the warfighter’s communications terminal needs additional routes to perform communications in a limited spectrum despite the very low capacity provided by the WSN. In these applications, messages from warfighter’s communications terminal can be delivered from node to node in the WSN to the data fusion center which might have spectrum available to deliver the message via other channels. A second option would be to store the message at a certain intermediate sensor node waiting for better conditions to forward the message to the destination warfighter communications terminal or to the data fusion center, whichever is prioritized in the military networks. 6.3.2  WSN Example of Data Collection in the Distributed WSN

Figure 6.2 shows a concept of data collection in the distributed WSNs. Here wireless sensor nodes deliver data and status information to the mobile data collection vehicle which advances through different locations in the battlefield at times T = 0, T = T1, and T = T2. Although the concept is naturally related to the manned military vehicle, the data collection platform could also be a UGV or UAV. A mobile data collection vehicle can have capability similar to the data fusion center in the previous example or it could deliver the collected data to the more capable situational awareness center after the data collection mission. 6.3.3  Use of Several Sensors in Sensor Network Intelligence

Previous sections covered the use of a single sensor, but it is possible to integrate several sensors to create a multisensor node. In-



6.4  Utilization of Information Collected by Sensor Networks in Commanding 113

Figure 6.2  Blue sensor data collection concept.

dividual sensors may carry out their own measurement functions or several sensors can measure different physical quantities from the target environment where versatile collected data can be used for intelligent analysis. In the latter case one sensor may prove the detection decisions of other sensors false, which again underscores the need for the reliability of single sensors. If the sensors carry out their task in network structure, other multisensor devices in the neighborhood may provide important support for the decisionmaking in the other multisensor nodes. In the case of multisensors it may be beneficial to carry out multisensor analysis locally before sending results to the data collection device. The data of some sensors may be lost so a data collection device needs an extra communications cycle between the multisensor and data collection device. This is more important in the case of questionable reliability of the original multisensor by inquiries from other multisensor devices.

6.4  Utilization of Information Collected by Sensor Networks in Commanding Various Actors on the Battlefield As mentioned above, a sensor system or sensor network requires elements that receive data from sensors, command sensors, process and analyze the data received, and relay the data or results to other elements (e.g., data centers, user terminals, and peer data collection

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devices) in the network. Typically these intermediate data collection devices are called gateways, since in many sensor network applications there is a need to implement other types of communication links to the data analysis and transmitting side rather than in the field where (low-power) sensors are located. Data collection devices may transfer analyzed data using wired cable or fiber connections, optical links, or wireless communications that may be implemented at higher carrier frequencies to enable higher transmission rates. The elements described above form a system that allows the collection and analysis of sensor data and transmission of results to peer devices. By adding the location of sensors in the field to the measurement results, WSNs have an ability to provide situational awareness based on sensor data. So far the WSN has covered only three letters of the OODA loop: observe, orient, and decide. The fourth missing element of OODA loop (act) can be implemented with the addition of actuators to the system. The combined system can be described by the term wireless sensor and actuator networks (WSANs). An actuator represents one element of a system in the form of an actuator device that receives messages to initiate different actions based on commands and data embedded in the messages. Actuators come in many types. They can be separate devices in the systems or they may serve as sensor devices or data collection devices. A WSAN therefore forms a feedback loop, where actuators carry out actions based on analyzed sensor results, and sensor devices collect additional measurement results to enable decisions by the data collection device. This occurs whether the actions performed by the actuator were successful, unsuccessful, or there is a need to perform more fine-grained control on the actuators. More sophisticated WSANs can utilize mobile actuators for improving the reliability of situational awareness by performing specific surveillance missions on specific areas or by guiding actions based on situational awareness to specific operational areas. As WSANs develop, a WSAN could perform decision-making on the need to improve situational awareness by itself, and let unmanned assets perform autonomous surveillance missions [4]. Unmanned platforms could also connect two distant ground-based WSNs temporarily to exchange local situational pictures between these two WSNs.



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6.5  Energy Issues of WSNs Energy is a scarce resource that must be used in well-balanced way to extend the lifetime of a sensor battery. However, collection of current sensor data is important in applications that may not tolerate sensor data collection if seldom performed. If sensor data is processed locally in the sensor device, heavy processing requires energy which may limit the life cycle of the sensor node. If the measurements are sent to the data collection device by wireless transmission, the increased data rate, decreased data transmission intervals, and increased distances between sensor and data collection device shorten the life cycle of the sensor device.

6.6  Security, Robustness, and Reliability of WSNs Security, robustness, and reliability issues of sensor devices should not be discounted. On one hand more hops between sensors in a multihop network increases the burden placed on network management and reliability. On the other hand shorter hops between sensors in the network can be carried out using a lower transmission power level that conserves energy in sensor devices, reduces the detectability of the sensor network, and, therefore, poses challenges to hostile attacks against the sensor network. In terms of security the more measurement data is processed and analyzed locally in the sensor device the more the requirements to protect the sensor device against hostile tampering and cyber activities are increased. In addition, analyzed data must be transmitted to the data collection device, and in the case of a wireless transmission analyzed data appears vulnerable to hostile actions in the air. Therefore, with respect to security, it may be safer to only transmit raw data measurements to the data collection device and increase protection there. Again, the collection of analyzed results in one location may cause a single point of failure and a system bottleneck that must be mitigated by backup systems in order to create system redundancy.

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6.7  IoT’S Role in Both WSNs and Communications The IoT has brought a great deal of research from past decades back into the hottest topics in communications. IoT refers to a system similar to past research on ubiquitous computing, ambient intelligence, context awareness, and smart machines and objects. It is based on remarkable progress in technology and networking which enable applications only dreamed of in the past. However, concerns about cybersecurity have been raised once it was realized that every possible network access point represents vulnerability for security. IoT can be thought of as a communications solution, wireless sensor node, and as a smart object that relates to topics covered in Chapter 4 (situational and context awareness). Forthcoming 5G networks will contain both low-power nodes and high-speed communications terminals. The idea of bringing physical and virtual worlds together under a 5G umbrella is evident in the visions of many communications technology companies. The iterations of terminology used to cover this area is shown in the following list: • IoT; • Internet of Everything; • Internet of All; • Industrial Internet; • Internet of Smart Objects; • Ambient Intelligence; • Ubiquitous Computing; • WSANs. For each of these terms a definition can be found in the literature, but generally they all represent the same idea of an intelligent network of objects that have different capabilities of computing power, intelligence, sensors, interactive features and networking via the internet. The cognitive features and interoperability that are key in IoT are presented in Chapter 7 (which covers SDRs and CRs).



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6.7.1  Case Studies of IoT

IoT is about increasingly simple devices having access to the internet (or other networking solutions) enabling an interface to each device by which different functions can be performed remotely. The available network capacity, in addition to device and interface capabilities, can be different from application to application. Typical functions are reading the status of a device, software updates, and sending/receiving control and data messages between the device and an online user. In addition to online users, there could be network traffic between devices in the field without the supervision of an online user. Different devices can compare the status between devices and create collective intelligence of the situation happening in the surroundings of the IoT devices without human supervision. Advanced IoT devices can have several connections to WSANs, great computing capacity with embedded local databases, and high-speed connections to backbone networks. The most sophisticated IoT devices give tasks to actuators that support the main mission whether physically close to the tasking device or connected to a network receiving the task from the network. These types of devices are not very common currently. However, they represent the second or third wave of IoT applications where emerging autonomous and cognitive capabilities have the possibility to transform the IoT concept beyond the first wave function of reading the statuses of IoT devices. The building blocks of IoT systems are similar to wireless sensor systems and communications systems described previously. The most IoT-specific characteristics are using standard IP-based internetworking in network interfaces and a drive to extend this internetworking to very simple devices. These simple devices call for very energy-efficient solutions in order to be functional for convenient durations. Therefore, solving the energy challenge is essential for wide deployment of this type of devices. A key goal is the seamless interaction with the environment by sensors and actuators. Internetworking of a wide range of physical devices enables the integration of digital and physical worlds and serves a platform for the development of virtual, augmented, and artificial realities. In the

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first phase of development, location-aware, networked, and digital applications provide more information of the situation at hand for the user, but with future technology improvements, context-aware and ambient intelligence applications may achieve a state where the user cannot easily separate digital and physical worlds. From the military and security point of view this increases challenges such as deceptive applications that might alter the perception and awareness of the user. 6.7.2  Implications of Developments of Other Technologies on IoT

Concurrent developments in AI, microelectronics, and communications technologies also push the envelope of IoT applications in the defense arena. Communications between machines needs standard messages and a common understanding of the situations that happen to smart machines. In order to avoid the human need for continuous involvement in device actions, smart machines need sophisticated data collection, analysis, and intelligence capabilities in the first phase to guide their actions semiautonomously. The continuous development of autonomous features raises worries among defense experts, but in some tasks machines are more effective than humans. The most dangerous missions might be effectively carried out by machines without the need for supervision and human decision-making. Based on many discussions and reports, with the current level of systems these types of machines in security and defense applications may cause risks to friendly forces. Therefore, applications too simple for warfighters seem the best candidates for smart machines while waiting for more sophisticated applications to become available. Many international organizations are busy preparing legislation on autonomous machines in defense and security applications, so they may be banned in the future through international agreements if needed. With several systems operating in different layers in the air, not only will the spectrum be crowded, but the physical space as well. As technology develops, air, spectrum, space, and cyber domains may be the most visible ones providing information superiority opportunities to different systems. As the nature of future conflicts change the result will be that it is not easy to maintain information superiority for a long time, since there will be improved



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countermeasures available against NCW than against conventional warfare. 6.7.3  Energy Issues in IoT Networks

The role of energy consumption comes into play when thinking about the proper level of responsiveness of IoT systems. To save batteries, infrequent status queries and node wakeups are preferred. As increased real-time awareness and responsiveness is needed, greater focus should be placed on the energy-efficient design of IoT systems. Especially in high-risk environments, sudden changes in the systems surroundings may cause devastating effects on IoT systems. If nodes communicate infrequently, elevated risks may not be noticed in a timely fashion and normal functions continue when timely responses could have prevented decreased system performance. The limited performance and energy resources of the simplest IoT devices mean that the most important data should be identified and sent frequently to maintain a sufficient level of situational awareness. The equipment user interface connecting to the IoT networks and applications has a key role in providing improved capability for the warfighter. Due to checking the history and reference data from the network database if the response time of the user equipment to sudden events is too slow, it may not be approved by the frontline warfighters for use in the battlefield. In understanding the fast-changing battlefield phenomena, it is important to note the differences detected by different IoT devices, and to build mechanisms to draw conclusions about what detections are false, what are due to hostile engagement on IoT networks, and what are due to the methods of sensor fusion. 6.7.4  Military Procurement of IoT Type of Technologies

In contrast to SDR vendors, IoT technology may appear in many forms likely to pose challenges for military utilization. IP-based communications shares a common ground, but different technologies go through their lifecycles very rapidly. In order to use IoT systems, it is necessary for the military to change procurement procedures and develop new ways to build capabilities that rely partly

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on commercial technologies. At the core of capability planning is the question of whether applications should be widely distributed or strictly centralized. There is a need for full control of systems but also a need to improve the robustness of the system by applying redundant, battle-proof solutions in order to overcome single-pointof-failure situations. 6.7.5  Big Data and Cyber Issues in IoT Networks

A central concept in situational awareness is the relationship among data, location, capability, and the estimated behavior of the objects. The volume of information on the internet is massive even without simple IoT devices, but with simple devices this volume of information will reach new heights. There are several levels of information classification and requirements for interpretation of data among different users. For example, different communicating end devices reaching the necessary level of common understanding, the volume of data, and what form the data should be delivered to the other end. When devices with different capabilities are connected to the same network, this is a very important issue. Simple devices could be connected to more sophisticated ones via aggregator devices that transform the data in a way the destination has the impression that there are no differences in capabilities of the different devices. In the case of near real-time applications this might pose challenges. With a vast number of IoT systems, technology development may find ways to hide the role and location of a single object by storing location and data to the collective resource, where cloud-based analytics compute results for service inquiries quickly. Therefore, a single IoT object is no longer seen as a destination (where all parameters are controlled and read) and, the most important information is in the network. Every physical object used as a content provider increases the possibility of data overload in the network. It is important to consider different information consumers that are connected to the same network. Varying data presentation methods, as well as computing capacities, must be kept in mind when considering different information consumers such as cloud analytics engines, low-power coin-sized sensors, communications systems in military vehicles, or warfighter terminals on the battlefield. IoT systems with versatile capability levels



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should all recognize key parameters and information from the vast data space. This is where autonomy and self-learning techniques can provide solutions. Nevertheless, the recognition of the most important information from the big data may represent a severe vulnerability if cyber operations are aimed at the essence of information. Therefore, it may not be wise for decision-makers in security and defense to rush into making long-term decisions based on current technological progress without careful consideration of the consequences and interactions of technologies as well as changing future operational needs [5].

References [1]

Chong, C. -Y., and S. P. Kumar, “Sensor Networks: Evolution, Opportunities and Challenges,” Proceedings of the IEEE, Vol. 91, No. 8, August 2003, pp. 1247–1256.

[2]

Römer, K., and F. Mattern, “The Design Space of Wireless Sensor Networks,” IEEE Wireless Communications, December 2004, pp. 54–61.

[3]

Wu, Y., and M. Cardei, “Multi-Channel and Cognitive Radio Approaches for Wireless Sensor Networks,” Computer Communications, Vol. 94, 15 November 2016, pp. 30–45.

[4]

Nemeroff, J., et al., “Application of Sensor Network Communications,” 2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force, Vol. 1, 2001, pp. 336–341.

[5]

Kott, A., A. Swami, and B. J. West, “The Internet of Battle Things” Computer, the IEEE Computer Society, December 2016, pp. 70–75.

7 Software-Defined Radio and Cognitive Radio This chapter extends the introduction of communications technologies in Chapter 3 by introducing software-defined radios (SDR) and cognitive radios (CRs). The key issue of spectrum management that is intimately related to SDRs and CRs is introduced below.

7.1  Spectrum Management of Military and Civilian Users The proliferation of mobile cellular communications systems (from third generation to fourth generation cellular networks) has created the illusion of unlimited spectrum for mobile users. 4G networks can provide a good level of capacity for a single user, but during peak times data rates can’t be achieved. In fact, cellular systems (in addition to other consumer applications) exhibit an unlimited demand for ever increasing access to spectrum, whereas, the frequency bands reserved for military use have a tendency to shrink in the battle with commercial demands. The biannual World Radio communication conference is the event where the most important 123

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decisions on global spectrum use are made. To guarantee future military operations in a contested spectrum, military communities have various alternatives to consider, such as: • In addition to the military frequency bands in use, military users can utilize civilian spectrum by using commercial offthe-shelf (COTS) equipment and civilian applications. • Military frequencies are used in peacetime, but in wartime, some additional portion of the civilian spectrum is temporarily allocated to for military use. • Military frequencies are used in peacetime, but in wartime, spectrum is allocated using dynamic spectrum access and cognitive communications. The basic idea of dynamic spectrum access is to utilize licensed spectrum at times when primary users are inactive. It may be more convenient to allocate spectrum by military override methods if national security is severely threatened.

7.2  Software-Defined Radio The idea of software-defined radio (SDR) has existed for quite a while but only recent technological progress has enabled softwaredefined applications. Based on SDR principles, SDR is a communications platform, where the signal chain is digitized to the greatest extent. An ideal SDR would process signals in the digital domain as close to the antenna as possible, and digital-to-analog and analogto-digital conversions would be performed just before and after the transceiver antennas, respectively. The SDR paradigm has led to the initiation of international cooperation on the development of common waveforms and HW platforms. As most functionalities of SDR would be done in SW, this would result in benefits of interoperability, reconfigurability, and reprogrammability of SDR platforms. In the end, if HW platforms were designed according to common architectures, methodologies, and design patterns, SW-based functionalities could be installed or ported to any SDR HW platform on the market. The need for a paradigm shift in military communications arose from the multitude of legacy combat net radios and



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vendor-specific equipment not able to communicate with other legacy systems. The first goal of SDRs was to connect different legacy systems by implementing legacy waveforms as a tool to improve interoperability with different actors in joint operations. The second goal (still in the future) is to apply systems-based methods and common SW-defined platform development methods to create systems well-defined in their interfaces, widely adopted, and widely used in operations. The proper definition of HW and SW platforms should ease the development of communications systems by leveraging the flexibility of using different vendor packages without losing interoperability between vendors. If the SDR could be ideally implemented, customers could switch vendors in the middle of communications systems life cycles without excessive cost. At present there remain many vendor-specific characteristics and features in the SDR platforms to guide customers when selecting the second and later generations from the same vendor. SDR was coined by Mitola [2] and represents a vision of a generic HW platform with the capability to run any waveform implemented with SW. This concept creates a great need for portability, interoperability, generality, and adaptivity for SW and HW blocks of the system. The HW platform has to have all necessary external and internal building blocks to guide and control incoming and outgoing radio waves mandated by different waveforms. To fully implement Mitola’s vision, platforms should be all-digital to enable full reconfigurability and adaptiveness of the system. As technology progresses, the possibility exists to increase SW-based functionalities to the edge of the analog parts still to be used in radio frequency blocks near antenna elements. The idea to differentiate the HW platform and waveform SW, acquiring those from a selected vendor list has evolved, but achieving interoperability between SW and HW vendors has taken longer than expected. As in many cases in the communications community there have been several competing architectures aimed at the de facto position for SDR standards. Goeller [1] reviewed the history of SDRs focusing on a Joint Tactical Radio Systems (JTRS) program. He analyzed factors that affected the program which failed to achieve the original goals. JTRS

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was a massive group of projects aimed at replacing all legacy U.S. military communications systems and and solving the interoperability challenges by using SDRs that would support several waveforms. Based on Goeller’s findings, the challenges were due to following three different technology paths in the SDR development. In the early years of development, general purpose processors (GPPs) were considered as the heart of the waveform processing. After the GPP-based design approach, interest focused on field programmable gate array (FPGA)-based designs to improve the realtime performance of platforms. FPGAs are integrated circuits with programmable digital logic blocks and interconnects between the blocks. Digital blocks of the FPGA can be utilized to build processing functions, high-speed interface functions, digital signal processing, and SDRs.

7.3  System-On-Chip as Modern Software-Defined Radio and Cognitive Radio Platform System-on-chip (SOC) combines FPGA-based design with elements of integrated softcore processing that could be seen as reconfigurable processors with better real-time characteristics than the GPPs in early SDR development. GPP-based systems were thought to achieve high-level code development where SW could be implemented with a high-level programming language to improve interoperability between different systems. High-level language would then be compiled as a lower level language with HW specific compilers. FPGA-based platforms were designed with HW description languages that were not portable due to the specificity of the FPGA platform. The power budgets of FPGA systems were not competitive with DSP-based designs. Improved reconfigurability properties resulted in partial loss of interoperability and the use of high-level code [1]. Although better integration of functionalities has improved system performance compared to previous platforms, reconfigurability of these SOC platforms remains limited by the building blocks integrated inside these platforms. In addition, interoperability between SOC platform vendors is not sufficient and often directs customers using SOC platforms away from the same vendor. SOC



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platforms still show promise since the simultaneous progress of WB RF transceivers has enabled implementation of small-sized reconfigurable SDRs.

7.4  Cognitive Radio A pioneering publication by Mitola [2] in 1999 presented cognitive radios (CRs) as intelligent entities that have the capability to find the best ways to service users in various spectrum conditions without the user’s awareness of surrounding challenges. Awareness of the surrounding conditions could reduce unnecessary burden on the processors, and improve energy-efficiency of the user equipment. One of the most influential landmark papers on the future of CRs by Haykin [3] extended the concept of SDRs to CRs, and recognized the challenge of spectrum scarcity which at publication was not as pressing a challenge as it is now. Four major goals for the development of CRs are reliable communications irrespective of space and time, the efficient use of spectrum resources and the learning process of radios to perceive surroundings, the presence of users and their intentions, and the awareness of opportunities to operate in the spectrum. Part of the spectrum is globally licensed to certain users and part of the spectrum is unlicensed, but there remain many defined parameters that set limitations to using these bands. Market-driven spectrum licensing has taken major sections of the spectrum so security and military organizations must preserve their frequencies due to growing commercial spectrum demand. Since licensed spectrum is not in continuous use, there are opportunities to find free parts of spectrum––so called spectrum holes––in the space-time environment. That is, at a specific location at some point in time there might be the opportunity to utilize downtime of the primary users and prepare one’s own transmission. However, this requires the ability to detect the presence of primary users with very low latencies and avoid collision in the spectrum by retreating from the licensed user frequency bands. The cognition cycle described by Mitola and Haykin requires both receiver and transmitter functionalities. The receiver in the cognitive system needs to observe its radio environment. The computing part of the cognitive system needs intelligence to analyze characteristics

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sensed by the receiver, and to orient, plan, and decide actions that guide the transmitter. The transmitter in the cognitive system performs actions derived from the intelligence. The computing part also implements a learning process that looks at consecutive receive-compute-transmit cycles and stores characteristics of behavior in different situations to internal memory of the system. Analyzing this cycle from a more general perspective, CR operation is one type of AI with pattern recognition applied to RF communications [2–3].

7.5  Challenges on Software-Defined Radio Interoperability CORBA-based software communications architecture (SCA) was developed to define a mechanism between SW and RF HW to provide interoperability between different platforms by defining structures and application interfaces. The SW development would not refer to HW-specific features, thereby, creating universal functionalities that could be executed on versatile HW platforms. SCAbased mechanisms could result in portable waveforms running on GPP-based HW platforms, but because development has focused on FPGA-based SOC designs, the SCA-based approach is no longer efficient due to the amount of HW-specific code of SOC platforms. Efforts have been made to add extensions to SCA to improve lowlevel performance of SW to achieve better real-time capabilities [1].

7.6  Software-Defined Radio and Cognitive Radio Research and Development Directions SDR R&D have progressed lately though much of the focus has been on CR research. SDR establishes a baseline for spectrum sensing, intelligent and self-learning CRs. Current research on SDRs has expanded to different application areas; for example, software-defined networking. In principle SDRs and CRs can be differentiated on the basis of which characteristic features are the focus of these technologies and systems. Based on SDR research publications and SDR product marketing information, the main issues for SDRs are interoperability, reconfigurability, and separation of HW and SW to blocks that can be acquired from different vendors. With CRs,



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the main issues are spectrum sensing, coexistence with other users in the spectrum, flexibility, adaptability, and self-learning. Due to these features, CR finds common goals with machine learning, deep learning, and AI.

7.7  Military Software-Defined Radio In the military domain, SDRs are seen as a force multiplier in coalition missions where several nations can operate together using their national systems in concert with other coalition nations. In addition to coalition missions, upgrading military communications systems during their life cycle is thought to be easier compared to legacy systems when rules of SDR design are followed. In 2018 there are many products on the market advertised with the keywords SDR, but if analyzed more thoroughly, many products are not real SDRs in the strictest sense. Due to the long life cycles of legacy radios, vendors spend a great deal of time building interfaces to many families of legacy systems. The SDR concept will develop as long as new technologies are created with interoperability as a goal from the start, and SDR performance outpaces that of the legacy systems in the field. This is still debatable since from the vendors’ perspective it may be alluring to develop products with proprietary characteristics. SDR-based communications systems are expected to lower unit prices, so if customers want to buy specific, tailored legacy systems they will pay a premium. Better performance may result in losing interoperability. Different actors need to find the right balance between these trade-offs.

7.8  Military Cognitive Radio In the military domain, CRs are seen as a force multiplier in a congested spectrum where several cooperative and noncooperative users are operating. Since spectrum is scarce and will become more congested in the future, the CR concept is seen as a tool to maintain information and spectrum superiority. Progress doesn’t end there, when effective spectrum sensing is achieved, but the battle between cooperative and noncooperative users will continue until

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all actors achieve cognitive capabilities. Because whoever is first with deployed systems will have the upper hand in C2 capability, it is important to be within the state of the art of technology development in this area.

References [1]

Goeller, L., and D. Tate, “A Technical Review of Software Defined Radios: Vision, Reality and Current Status,” 2014 IEEE Military Communications Conference, 2014, pp. 1466–1470.

[2]

Mitola III, J., and G. C. Maguire, Jr, “Cognitive Radio: Making Software Radios More Personal,” IEEE Personal Communications, August 1999, pp. 13–18.

[3]

Haykin, S., “Cognitive Radio: Brain-Empowered Wireless Communications,” IEEE Journal of Selected Areas in Communications, Vol. 23, No. 2, February 2005, pp. 201–220.�

8 Unmanned Aerial and Ground Platforms There are many choices for human-controlled vehicles that handle message delivery between different organizations, units, and actors in the battlefield. This chapter focuses on understanding the role of robotics in the battlefield in the form of UAVs, UGVs, swarms, and cognitive units that may be disconnected from the military grid due to self-sustaining capabilities. Many military documents use the term unmanned aircraft systems or unmanned aerial systems (UAS) instead of UAVs to describe the need to have the system in addition to the flying platform. Unmanned vehicles in any domain should be regarded as systems of systems. A mobile platform males up just one part of the system. For example, a typical UAS is made up of: • Platforms; • Payloads; • Control centers; 131

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• Navigation systems; • Communications systems; • Take-off and landing systems; • Logistics systems; • Maintenance and repair systems. This chapter provides an overview to unmanned systems and robotics in air and ground domains. Since the focus is io ground forces, unmanned vehicles in the naval domain are not covered.

8.1  Different Case Studies of Data Collection Our focus in this discussion is on communications and the requirements of platforms and operating environments. There are different types of unmanned vehicles in communications. One type of unmanned vehicle doesn’t utilize communications on any tasks other than the delivery of commands between operator and unmanned vehicle. This type of unmanned vehicle may carry sophisticated sensors onboard collecting data using its payload during the flight but doesn’t send anything to the control center. In this type of vehicle and mission, all data is collected on the ground after the flight. A second type of unmanned vehicle performs tasks during the flight utilizing onboard sensors and transmits the collected data to the control center at certain intervals. From a cyber security perspective, these two types of operation have different threat levelswhen performing missions in hostile airspaces. A communications link could be intercepted in the latter case, but in the former, the whole platform and all the data can be lost if nothing is sent to the control center during the mission. One step further is an unmanned vehicle that can be reconfigured or reprogrammed in the air during an ongoing mission. One system relies on several vehicles (some manned and some unmanned) that act in concert performing the common mission. This type of system can bring the operator and control center closer to the unmanned vehicle than with a common ground-based control center. Another option brings autonomous features in play, where unmanned vehicles collect data from the



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surrounding operating environment, friendly and noncooperative vehicles and objects, create internal awareness and perception of the situation and then process the subsequent outcomes and possibilities of behaviors of the different actors and operating conditions. This could also be done in smaller units utilizing swarming behavior, with or without human decision-making.

8.2  Development of Unmanned Systems in the Medium Term A report written by the Center for Strategic and International Studies called for a strategy for unmanned systems. Although the United States is recognized as a key player in this technology, several other nations are developing their own unmanned systems since barriers for market entry are currently fairly low. CSIS also predicts that UASs will remain the most sophisticated unmanned systems through 2025 compared to ground and maritime applications. UASs are often compared to fighter jets, although in most cases this comparison is not adequate. There are a multitude of UAS types and they are different than other manned military systems. Increased human protection has been traded off for other performance characteristics by application of unmanned systems. This shouldn’t result in lower capability than other systems by any means [3].

8.3  Unmanned Aerial Vehicles There are many definitions of UAV types that commonly differ in terms of flight altitude, flight time, size, and the main functionality of the UAV. Typical UAV military tasks are (1) ISR, (2) C4, (3) Logistics, Transportation and Maintenance, (4) Protection of friendly forces, coalition partners, authorities and civilians by means of identification, early warning of close threats, acting as a decoy for incoming threats, and platform protection functions, and (5) Engagement by kinetic and nonkinetic means along with targeting and battle damage assessment. These functions can be more or less intertwined in future platforms, since future projects are moving to both multirole UAV systems and UAV swarms that may have sev-

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eral specialized UAVs with the capability to replace and take over tasks of other UAVs in the swarm. UAVs are often categorized under one term but in practice there are many platforms designed for specific tasks. Whatever type of UAVs is concerned the most challenging issues are size, weight and power, endurance or flight time, and the characteristics and capabilities of sensor payloads. With multirole UAV platforms there are more trade-offs, since general capability development affects performance measures more than designed-for-purpose platforms. Although there are several benefits of unmanned systems in military operations, for the foreseeable future UAV platforms will remain well deployed. 8.3.1  Benefits of UAVs versus UGVs

In practice similar categories can be made for UGVs as well, although the land domain poses additional challenges to UAS operations. For example, from the perspective of C4ISR and swarming, the effects of terrain, natural objects, and man-made objects severely limit the communication channel and freedom of operation not to mention the effects of weather conditions, temperatures, and season (winter vs. summer). 8.3.2  ISR, Logistics, and Engagement Applications Using UAVs

UAVs reduce the load on warfighters and increase operational efficiency by providing situational awareness, communications, and protection support to warfighters. Putting eyes in the sky not only provides a better situational picture from the air, but also improves communications capabilities with LoS links and increases time needed for the warfighters to prepare for the tasks at hand. Visibility from the ground of the surroundings is usually heavily blocked by elevation, terrain, and obstructions in the operating area. In the long-term, UAVs may be operating in strike missions with support provided by EW and kinetic engagement in cooperation with manned platforms, as an independent platform or a multifunctional swarm of platforms. UAVs may also have an increased role in battlefield logistics, although most logistics supply chains are still



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expected to roll on wheels near the areas of operations. The payload of the UAVs is usually limited but large UAVs may carry a sophisticated package of capabilities that make these platforms HVTs in the airspace. Platforms may carry sophisticated sensors (synthetic aperture radar, electro-optical, thermal and infrared sensors, SIGINT and GMTI systems). On top of these sensors, large platforms may have the capability to carry kinetic weapon systems onboard. UAV systems should not be seen merely as a force multiplier at the tactical level since they may also have a key role in information superiority. UAVs can perform several tasks simultaneously, therefore, regarding the large UAV platforms, there is a tendency towards multirole platforms as has happened with fighter jets. 8.3.3  Communications Applications Using UAVs

In communications applications UAV platforms can be used for relaying voice and data transmissions between nodes in the ground or in the air. UAV benefits from LoS connections and extends the connectivity of the ground-based user. In addition to radio waves, UAV could also use satellite or laser links for communications. Regarding communications, UAVs can be used for the following applications [1]: • Delivery of a situational picture to ground troops covering the area of operation; • Collection of status reports from Blue forces to create information analysis for an improved situational picture; • Operation as a communications relay station overcoming challenges of the terrain by transmitting voice and data in LoS paths; • Operation as a gateway to connect different communications systems together (also satellite); If a UAV is controlled remotely from the ground center, the communications channel between the center and UAV should be functional at all times. This information flow may break down due

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to malfunctions, exceeding the maximum communications range, blockage of signals due to obstructions in the environment, or to nonkinetic engagement directed to the UAV. Radio regulations impose requirements on the selection of communications frequencies of UASs. A selection of the downlink transmit frequency from a UAV to ground control station defines the applications that the UAV is performing in the air. If the UAV carries payloads that produce a large volume of data (e.g., high-resolution pictures and videos) the use of higher UHF band frequencies to guarantee a sufficient communications data rate between the UAV and ground station is required. Higher requirements on robustness, security, and reliability may make achievable data rates very low [2]. Three elemental features of UAV platforms regarding communications are described below: • Operating time or flight time of UAVs affects the length of the mission and ranges for control and communications purposes; • Energy capacity of UAVs is directly connected to the first item above but also defines how sophisticated a payload the UAVs could carry and what levels of transmit power can be used for communications; • Antenna solutions used in UAVs define the directional needs and services to different groups with different communications mechanisms. In the long term material and manufacturing development may provide important steps to integrate different antenna elements to UAVs without challenging performance.

8.4  Unmanned Ground Vehicles Platforms that operate at medium and high altitudes in the air are able to overcome challenges due to the terrain profile if the other end of communication path is free from blockages as well. UGVs experience challenges similar to other ground-based communications systems. Even though the average speed of UGVs is limited in



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contrast to UAVs they still provide some attractive features utilizing the unmanned concept. 8.4.1  Communications Applications of UGVs

As mast-based communications systems require unwanted preand post-operations to establish and detach to a communications station, UGV-based communications systems can serve as backup systems for other communication systems. UGVs-based systems can also speed up force maneuver by establishing communications services at times when regular communications stations are tied to pre- and post-operations. Their ability to advance in the terrain can create capability to establish short-term communication services by moving to higher terrain where they can maximize utilization of their limited heights antennas. From the protection perspective, unmanned communications stations would not tie important personnel to short-term communications services containing excessive risks. There are a number of UGV types. The smallest class of UGVs might serve as situational awareness tools in environments that do not require severe terrain advancement features. Severe terrain requirements lead to the use of bigger UGVs since, in addition to advancement capability, communications systems require electric power, sizeable antenna structures, and different sensor systems. Currently, it seems all-electric UGV systems are far off in the future, since they are not capable of reliable operation in harsh conditions. For even larger UGVs versatile communications services in unmanned form can take place, but with the size increase, energy consumption increases and the systems would be as vulnerable as regular trucks that need roads of good quality for logistics operations. 8.4.2  UGVs and Development of Robotics

Robotics is a wider application area that may contain all types of unmanned systems. Robotics have found their way into military applications such as ISR missions and engineering. The distinction between military robotics and UGVs is blurred. UGVs have been

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applied to engineering tasks such as explosive ordnance and in logistics tasks. The development path of UGVs follows a similar path as other domains although swarming on the ground has not been considered for UGVs as it is with the aerial, naval, and underwater counterparts. The early development focused on remote-controlled robots and vehicles with semiautonomous features and learning functionalities introduced in the mid- and long-term. Small formfactor UGVs may operate in ISR tasks in hostile areas providing visual information of the area (pictures, video clips, and different sensor data) before warfighters can enter. Different technologies may emerge to enable movement in harsh conditions, for exmple, systems capable of moving on stairs, crawling in uneven terrain, or rolling into caves and pipes where human observation would be impossible. Heavier UGVs may also have kinetic and nonkinetic payloads in addition to sensors used by the human operator with the aid of visual cameras, sensor data, and observations by other systems in the area. Since the human operator may not be in close vicinity to these systems, the decision to use lethal force must be taken after careful analysis of accurate and reliable information gathered from several sources. 8.4.3  Challenges in the Land Domain for UGVs

Although the challenges for unmanned systems in the air, sea, space, and cyber domains should not be underestimated, land is a very difficult element for route planning, obstacle avoidance, and analysis of unexpected situations. This is the main obstacle to the development of swarming features in land-based applications. Heavier UGVs have a capability to deliver fairly effective firepower without putting the human operator at risk in the battlefield. As their role is within high-risk missions maintenance support is not possible while they are operating on the frontline. Heavier UGVs have been considered in logistics applications and in providing protection for medical evacuation missions. They could also function as a first and last vehicle in convoys, taking first hits of possible landmines and bombs hidden along the path. Increased autonomy has caused discussions of the ethical, moral, legal, and political implications of using these systems in engagement tasks against human forces. As human lives are the most expensive losses in modern warfare



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increased use of unmanned robotics in the land domain seems evident in order to protect military forces. Regarding full autonomy, future challenges in the battlefield seem so complex that it is probable we won’t see full autonomy in engagement for most of the world’s armed forces. There might be countries or actors willing to do whatever it takes irrespective of the consequences in order to dominate the battlefield. Therefore each actor should be ready to develop systems to counter machine-based engagement systems even if they would not use the systems themselves.

8.5  Examples of Unmanned Platforms with Generic Characteristics Unmanned platforms will be covered from the communications perspective in the following chapter, but there is still a need to present examples of platform categories in order to analyze platform capabilities in the present scenario. 8.5.1  Examples of UGV Characteristics

The smallest categories of UGVs are not considered here, since they are not appropriate for these uses. Generic dimensions, weights, and speed estimates are presented in the following list: • UGV type A, length 8m, width 3m, height 3m, weight 40,000 kg, max speed in the best conditions 80 km/h, in easy terrain 30 km/h, and in the extreme terrain 5–10 km/h; • UGV type B, length 5m, width 2.5m, height 2.5m, weight 10,000 kg, max speed on road 50 km/h, in easy terrain 25 km/h, and in the extreme terrain 5–10 km/h; • UGV type C, length 2m, width 2m, height 1m, weight 2,000 kg, max speed on road 35 km/h, in easy terrain 20 km/h, and in the extreme terrain 5–10 km/h; • UGV type D, length 1.5m, width 1.5m, height 1m, weight 1,000 kg, max speed 20 km/h, in easy terrain 10 km/h, and in the extreme terrain 5 km/h.

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UGV types A and B have the benefit of higher speed and larger dimensions which allow for advancement over obstacles and higher payload capacity. However, they are also dependent on hard surfaces, robust bridges, and crossings. Wheeled UGVs have more limited advancement capability in rough terrain than tracked ones. UGV types C and D have the benefit of smaller dimensions allowing advancement between obstacles that would prevent larger ones from passing since they are unable to climb over the obstacles. They also have lower energy needs compared to types A and B. The lower weight of types C and D might allow advancement on softer surfaces that would cause types A and B to get stuck. UGV types C and D have much lower speed in good conditions, but the in most extreme conditions the speed of C and D is comparable to types A and B. The payload capacity of UGV types C and D is very limited compared to types A and B. 8.5.2  Examples of UAV Characteristics

For UAVs, the smallest categories are considered as they might be important, for example, in urban operations. Generic flight times, ranges, flight altitudes, and speed estimates of different UAV categories are presented in the following list: • UAV type A (nano), range up to 2 km, flight time 1 hour, max speed 20 km/h, flight altitude 100m, no additional payload options in addition to integrated sensors; • UAV type B (micro), range up to 15 km, flight time 2 hours, max speed 70 km/h, flight altitude up to 1 km, capable of carrying additional payloads of few kilograms; • UAV type C (tactical), range up to 150 km, flight time 10 hours, max speed 200 km/h, flight altitude up to 3 km, capable of carrying up to 100 kg payloads; • UAV type D (Medium-altitude long endurance (MALE)), range up to 300 km, flight time 20 hours, max speed 300 km/h, flight altitude up to 5 km, capable of carrying 300 kg payloads; • UAV type E (High-altitude long endurance (HALE)), strategic range, flight time 36 hours, max speed 800 km/h, flight altitude over 15 km, capable of carrying over 1,000 kg payloads.



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Considering the scenario presented in Chapter 2, UAV types D and E are left out of the discussion since these types are not needed in surveillance missions based on the distances presented in the scenario. UAV types A and B have more limitations due to environmental conditions and are not able to carry heavy payloads, but they have the benefit of silent operations and low detectability due to their small size. UAV type C has the capability to operate in the whole area along with the capability to carry heavier payloads. The speed of UAV type C is limited and it might be detected from the air; due to slow speed, it might be vulnerable for kinetic engagement.

8.6  Command and Control Cases Several cases can be defined using UAVs in a military mission from the C2 perspective. Ground-based sensors are distributed in the area under surveillance and gather data on hostile movement. The UAV unit acts as a data collector flying above the area and serving as an access point for ground-based sensors. The UAV can either store read data, travelling to headquarters for extraction of data locally, or serve as a gateway delivering the most critical data to other networks from the air. Ground-based nodes serve as data collection entities and flying UAV units use their sensors to store data from the area. When a UAV unit flies over the ground-based node, data is transferred along the LoS link between the UAV and ground node. A collection of UAV units operate as a swarm in the air creating a locally distributed network in the sky to serve local ground-based users. Each member of the swarm is able to find the best position to communicate with ground-based users and can also route traffic via the most appropriate routes in the air in terms of QoS, security, and possible interference. If the swarm is unable to find a good route to the destination, one unit can fly to the destination based on risk mitigation and quality of service measures. If the swarm has high performance assets on board, it can also provide computing capability to ground-based users with limited computing capacity. Data transfer between ground-based nodes and the UAV could be implemented by radio link, visible light communications, RFID

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connection, or by physical connection locally. The last two alternatives are time-consuming, because flying assets would need to be brought close to the ground. As with data transfer, these activities can be used for recognition of Blue forces presence and location in the battlefield. Some messages could be delivered as well under friendly force recognition, if needed. For the scenario and mission at hand, different ways to carry out C2 are considered. If military command posts and related communications stations are established in the appropriate locations, these have to be switched on and off in sync as battles evolve. There may be communications delays related to movement of communications stations if several versatile redundant communications are not used. A mast-based communications station may need several hours from the location arrival to the first message delivered, and the same time to take the station down and start movement to the next destination. Weather, time of the year, terrain, equipment, and skill level of the warfighters has an effect on the time it takes to establish and take down the station. If military units responsible for communications would use UGVs to support continuous communications service, some time establishing and detaching the station could be saved if these activities were carried out in parallel. In the meantime UGV equipped with a communications mast would take on the main provision of communications services as the manned communications station was taken down without interrupting communications services. Manned and unmanned communications stations wouldn’t have to be located next to each other but should be located in an appropriate distributed location where they could serve the same group of users. If the radio coverages are similar, the problem of a hidden terminal in CR uses can be addressed as well, since any primary user transmission missed from the first one could be caught by the second.

8.7  Autonomy, Teaming, and Swarming of Unmanned Platforms Chapter 2 provided perspective on future technology and considered the implications of those developments on communications technology. One key concept in future forecasts is the rising interest in autonomous technologies. Autonomy in its most mature form



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cannot be achieved quickly and requires several phases of development. The development path starts with remote-controlled unmanned vehicles, continuing to semiautonomous vehicles, manned and unmanned vehicles together, and finally may reach the level of cognitive, self-learning, self-organizing, and reproductive swarms of autonomous vehicles and objects. The speed of adoption varies between different application areas but many new innovations also spread out quite rapidly to other fields if there are no specific requirements that hinder the application of innovation. Defense industry and military organizations are often assumed to be in the forefront of autonomous applications but standard procurement processes do not make it easy to adopt breakthrough technologies. Military applications typically require interoperable, robust, proven technologies and systems that meet the most stringent requirements and have been effectively implemented before full operational capability (FOC) is reached. Until these requirements are fully met, new technologies can still be adopted for some applications, but in limited use along with the application of redundant systems for reliability. Implementation of autonomy at the level of human capability within a military context won’t likely happen in the mid-term, although systems with autonomous features may be fielded to provide value in operations such as ISR, C2, and protection tasks. Software-based functionalities extend from software-defined communications and networking to unmanned systems as well as those that offer better opportunities for interoperability, compatibility and upgradability. Moving towards full autonomy, teaming of unmanned systems, teaming of manned and unmanned systems, and collective intelligence of unmanned systems through learning and cognitive behavior must be developed. The latter comes close to swarming functionality, swarming tactics, and regenerative and replicative learning where systems are able to produce other systems and train them appropriately to the tasks given them. Previously mentioned NCW will be recovered with a totally new approach to autonomous NCW able to connect sensors, shooters, and decision-making without interrupting military command chains. It is clear that this type of system would improve total military capability but would also present complex legal, ethical, and political

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questions as well as increased levels of unacceptable risk. Although introduction of unmanned systems improves protection of human operators and forces, in the worst case immature full autonomy may eliminate all improved safety and protection for forces. Until the human operator is part of unmanned systems, control of versatile unmanned systems as a team or as a collaborative battle unit with versatile functionalities will require tremendous efforts of standardization, architecture development, and interoperability among different vendors. Otherwise unmanned teaming units must be procured as product families from a single vendor. The next steps would be learning and perception of the characteristics using cognitive capabilities of a mission in the air. Regarding use of lethal force, there is the requirement in many discussions for a man in the loop. Authority to use force during a mission must be delivered to the platform in some way, whether it be an uplink command channel or a preprogrammed authority to use force when specific conditions are met. With the possibility that these conditions are not correctly programmed, the system malfunctions cannot perform accurate recognition based on the collected patterns. These issues may be faced during a safe mission but possible countermeasures from an aerial platform make this type of mission more difficult. There is a high probability that autonomous features of unmanned systems will develop more quickly than currently projected. Forecasted in military terms, full operational capability for autonomous systems is predicted to occur in the long term due to challenges for existing force structures, integration, and cooperation with other actors.

References [1]

U.S. Army UAS Center of Excellence, “Eyes of the Army” Unmanned Aircraft Systems Roadmap 2010 – 2035, ADA518437, April 09 2010.

[2]

Austin, R., Unmanned Aircraft Systems UAVS Design, Development and Deployment, Chichester, United Kingdom: John Wiley & Sons Ltd., 2010.

[3]

Brannen, S. J., Sustaining the U.S. Lead in Unmanned Systems – Military and Homeland Considerations through 2025, A Report of the CSIS International Security Program, CSIS, Center for Strategic & International Studies, February 2014, 28 p.

9 Analysis of Selected Communications Alternatives Related to Scenario From a civilian perspective, society is now digitalized with easy access to network resources, social media, and all forms of information to assist the user very quickly. As user needs are immediate, easily accessible information supported by network applications may not always be critically examined. This creates a risk of forming perceptions based on misleading tips, disinformation, or deceptive applications. Many internet-based platforms provide helpful advice while creating a sense that other people have faced similar issues. Although these people are not directly connected to the user, input from the internet can lead to social support bringing users closer to the achieving tasks at hand than, for example, manuals that are increasingly online in any case. Therefore in civilian applications, low-latency communications, and the use of internet in everyday tasks is well established.

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From the military perspective, C2 is based on a very hierarchical structure with commands are given according to certain rules that each actor in the structure obeys. Depending on the mission and force elements that need to communicate with each other, there are different alternatives for communication between actors. Some actors can communicate openly at any time, but in the most demanding environments messages sent in the vicinity of forces need to be examined carefully, since which communications alternative chosen may impact the whole operation. As communications technologies have proliferated, there are fewer strict limitations for wireless communications as before. Still, this area must be understood thoroughly to command operations successfully.

9.1  Examples of Military Communications Needs, Linkages to Capability Areas, and Operational Risks Due to Communications In military applications, the need for communications arises from the following issues: • Important sensor events or an update of a situational picture for different actors (situational awareness); • Decision-making at the higher levels of command and commands to the lower levels (C2); • Reports from the lower levels of command to higher levels of command (C2); • Information updates between similar levels of command to create a more fine-grained situational picture in areas of responsibility (situational awareness and engagement); • Early warnings that are quick notifications of sudden changes in the mission area which might change the plan of operations (protection). For military communications, each message should be examined case by case, whether or not there is a real need for timely transmission of the message to the recipient. There are at least two reasons for this: (1) transmission of a message in some situations may endanger operational security and (2) unnecessary transmissions of



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messages limit network throughput, since spectrum resources are often both shared and limited. Commanding military missions is full of trade-offs to be managed by timely, resource-saving actions that match the right capabilities to the right locations and support while maintaining operational tempo and endurance.

9.2  Scenario-Based Iteration of Requirements of the Defense System Analysis of capability areas can be performed in general by starting a scenario-based study that is an iterative and cumulative process aimed at convergence of scenarios studied on a level that roughly corresponds to the required total capability in the expected missions and operations. This scenario-based approach makes it easier to start the iterative process compared to a process that considers capability requirements first. An example of the capability development process is described below: 1.

Create a scenario describing one of the most probable operations defense forces face within the forecasted timeframe.

2.

Estimate the current level of performance in the scenario above divided into clear constituents of total capability.

3.

Evaluate different systems alternatives to achieve the current level of performance in part 2 above. Do any positive or negative side-effects emerge based on different systems alternatives?

4.

Evaluate the functionalities and characteristics of different systems alternatives to perform the tasks of the mission in the scenario.

5.

List critical requirements for meeting the desired performance.

6.

Go through the list of critical technologies to evaluate the effectiveness of each technology in meeting requirements.

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Go back to the first step to create an additional scenario that represents one of the most probable operations and repeat numbers 2–6 for each scenario created in number 1. Continue as needed to reach the number of scenarios that cover the missions that could result in development of total long-term defense capability. The last step entails the most crucial issue which is fundamental in the discussion on threat-based versus capability-based planning in Chapter 2. What is the level of understanding of the global situation, resources, technologies, different actors, culture, society, and ways of life 20–30 years in the future? The development and procurement of complex systems commits resources to specific missions and force structures that may not be as flexible and adaptive as capability-based planning strives for. If the long-term vision is completely lost, the procurement could result in a real failure of the defense system. Although the number of procedures to perform scenario-based military capability planning includes scenarios that may reflect real capability gaps and requirements, this chapter only deals with one scenario presented in Chapter 2. In addition, the focus of this analysis is in C2 and net-centric capabilities, so other capability areas are not discussed as extensively as communications functionalities. However, since C2 is a mandatory capability that binds all other capability areas together, and to perform successfully requires all other capabilities to act in concert, considerations of other capabilities cannot be completely avoided in this examination.

9.3  Introduction of Military Communications Alternatives Having seen different constituents of military communications in the future battlefield, we are ready for analysis of different alternatives for implementing communications capabilities in versatile military tasks. As previously discussed, the need to send a one-way or two-way message arises from performing C2 tasks. C2 represents a far-reaching capability area that should be regarded as kind of glue that implements connections among every vehicle, system, actor, sensor, and warfighter. As such C2 represents features that are part of any military capability area. In this respect, C2 cannot be strictly isolated from other capability areas.



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One of the most important communications parameters is the distance between the sender and recipient. Even if distances between warfighters are short, message delivery from warfighter to warfighter in demanding conditions is prone to misunderstandings, even between warfighters in noisy environments with hearing protection equipment. Message delivery can be aided using visual codes to help message perception if the audible part is unclear. Visibility of these signs is heavily limited by weather and terrain as well as distance between warfighters. In this respect audible communications from warfighter to warfighter can’t be regarded as a reliable communications mode in the battlefield. If wired communications networks are implemented so that connections can be guaranteed using routes not affected by hostile events and are available in the area of operation, a great force multiplier is created. If the connections are based on civilian communications infrastructure they are often ubiquitous in urban and suburban areas. Civilian communications infrastructure may be severely affected by hostile activity which would require militarygrade options to back up lost civilian communications. When distances are long enough that audible delivery without carrier frequencies is not possible the options to deliver the message from sender to recipient are: 1.

Wired communications between nodes using civilian communications networks;

2.

Wired communications between nodes by building wired military communications networks from scratch (underground or just on top of ground without hiding it—which severely affects time used to build the networks);

3.

Building the network by walking;

4.

Building the network using motorcycles, snowmobiles, or other land-based vehicles;

5.

Building the network using UGVs or UAVs;

6.

Wired communications from sender to radio mast that delivers a message in the air using radio waves;

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7.

Wired communications from sender to UAV relay, aerostat, or balloon that delivers messages in the air using radio waves;

8.

Wireless communications between nodes using civilian communications networks, for example, cellular mobile networks

9.

Wireless communications between nodes using military communications networks in different frequency bands with radio masts, vehicles, and warfighters using different types of antennas (including SDRs and CRs);

10.

Wireless communications from sender to UAV relay, aerostat, or balloon that delivers messages in the air using radio waves;

11.

Wireless optical communications between nodes by using military communications networks in different wavelengths using masts, vehicles, and warfighters using directional beams;

12.

Wireless optical communications from sender to UAV relay, aerostat, or balloon that delivers messages in the air using radio waves;

13.

Utilization of heterogeneous networks in the transmission of messages, for example, routing the communications message through a WSN deployed widely in the area of operation;

14.

The force advancing at the front, leaves messages at a specific geographical location, whether into a WSN node, smart machine, or tag that can be read by Blue forces arriving later at the location (important cyber point since it shouldn’t be possible for Red forces to read and perceive the message);

15.

Physical delivery of the message from the sender to recipient by the messenger using walking, skiing, motorcycle, snowmobile, or other vehicle that suits the conditions or terrain (message is read using a physical connection to the messenger device or delivered on paper);



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16.

151

Physical delivery of the message from the sender to recipient by UAV or UGV autonomously or is guided to the destination using geographical location of the destination (message is read using physical connection to the vehicle).

The list above doesn’t represent a complete list of possibilities for message delivery. Many of these alternative approaches are connected to each other. For instance, utilization of UAVs for communications relays might take different forms in the future. Instead of using one relay in the air, there could be several that form a local network providing communications resources for ground-based users. Depending on possible restrictions on use of aerial relays there can be several alternatives. Relay routes can be selected in different ways; the transmitting power of the flying platforms can be controlled, or flying relays can move closer to provide more secure transmission between relays. Under threat, relaying could be implemented with delivery alternative number 13 from the above list. Increased autonomy could enable swarming of aerial relays where aerial relay platforms themselves decide the best way to deliver the message to the intended recipient. In some cases it would be beneficial to land to get the message physically from the originator and then take off again, but this is not applicable in every case––especially with heavy platforms that require prepared landing and take-off areas. Having seen various ways to deliver messages from sender to recipient, we consider these approaches regarding different environments (scarce-populated, rural, suburban, and urban setting), different distances, and different case studies (individual warfighter, group of mobile distributed warfighters and vehicles). Vehicles can be ground or air-based in this setting. 9.3.1  Wired Communications Between Nodes Using Civilian Communications Networks

Before the emergence of cellular systems—ADSL (Asymmetric digital subscriber line) and VDSL (Very-high-bit-rate digital subscriber line) systems—the coverage of wired telephone lines was wide whether in rural, suburban, or urban areas. As these telephone lines

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are still used widely for WB internet services, 4G LTE networks have become as cost-effective as providers of internet access with higher data rates and lower prices. If this trend continues, wired telephone lines could become obsolete. However, considering backup systems and resiliency from the military perspective the use of commercial wired telephone lines might provide an alternative for voice transmissions, data traffic, and independent systems used as a positioning network regardless of space-based assets. Scarcely populated areas may not have widespread coverage, but communications are available in those environments. On the one hand, civilian-wired communications are not vulnerable to EW activities, but on the other hand, they are difficult to protect from physical damages. With old-fashioned voice communications it is very difficult to analyze when the security of these lines is challenged or not. The appropriate data rate can be achieved by using telephone lines for ADSL data traffic. The distance between the sender and receiver doesn’t matter in this case because voice dialing can be arranged between any points that are lined. The drawback of this approach is a dependency on access to certain points to which these telephone lines can be connected, limiting coverage to certain points in geographic areas. If the area of operation is located far from the nearest point of access to telephone services, it doesn’t improve communications capability in terms of performance or resiliency if these points can’t be reached. 9.3.2  Wired Communications between Nodes by Building Wired Military Communications Networks

Since the previous alternative used old-fashioned commercial telephone services, the second option focuses on deploying military wired communications by building the lines from scratch or connecting communications assets to the existing wired military communications infrastructure. • Building the network by walking; • Building the network using motorcycles, snowmobiles, or other type of land-based vehicles; • Building the network using unmanned ground or air vehicles.



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The best operational situation for military forces would be to use existing military communications infrastructure, choosing wired or wireless access where available. Since there is a low probability of operations happening in preplanned environments, communications must be implemented based on immediate mission requirements. One drawback of wireless connections (especially in an otherwise largely silent spectrum) is the high probability of detection. Therefore, wired connections offer the opportunity to communicate between forces irrespective of EW, since wired connections can’t be easily disrupted by nonkinetic means. However, building these wired connections may take time; wired connections must be secured in order to prevent hostile forces from tampering with, cutting off, or eavesdropping on Blue communications. Also, since kinetic engagement may break important wired connections, there should be mitigation procedures in case of these events. There is a certain probability of wired connections to be affected by hostile forces depending on inventories of hostile assets, distances, OOB, environmental conditions, and the operating environment. In urban environments there may be several access points to military networks but implementation of wired connections by building cable routes from point A to point B is not easy, since cables on top of the streets are clearly visible and easily attacked by possible hostile units in the area. On the other hand, in urban environments building cable connections is fast because the surface is of good quality for warfighters and vehicles. If the area has been under air strikes or other forms of bombing, the conditions might be as bad as in the forest. In addition, if the urban area is heavily inhabited building cable connections is not easily detected. Using UAVs may not be a very good way of building wired cable connections in any environment, but these flying assets would be capable of implementing cable lines on the rooftops of tall buildings in urban and semi-urban settings as well as on top of trees and hills in rural and scarcely populated forest settings. If cable lines were lifted high on the roofs and trees, the possibility of detection and tampering with the communications lines would be limited. In case of explosions by kinetic assets, the cables could still be functional, if the engagement was focused on the surface level. To analyze these situations from the systems engineering and operational analysis perspective,

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one key element would be the time needed for building a redundant and looped-wired network within the operational area while taking the probability of detection and engagement into account. In a forest environment (especially in wintertime) building wired connections may be very slow even when using vehicles. There is also the opportunity to hide wired connections by burying cables underground or inserting them through drain pipes, but this severely affects the time to build the connections. In high-intensity scenarios these wired connections are treated as disposable, since there is no time to collect cables if the situation becomes worse from the Blue perspective. If there is a high risk of hostile forces to maintain possession of this area after Blue’s retreat, it is good to make the existing cable connections unusable for hostile forces. 9.3.3  Wired Communications from Sender to Radio Mast That Deliver Messages in the Air Using Radio Waves

This section deals with building wired connections to radio links or other radio equipment located high above ground level. Both commercial and military radio links are covered. The key benefit of using wired connections to radio links is that point-to-point links and sector antennas are by nature directional. Since directional radiation is beneficial in terms of electronic protection, there is usually no need to use omnidirectional radiating equipment for connecting to radio links. Although long cables attenuate signals severely, and very long cable connections are not practical, this alternative provides protection of communications for engagement and detection. High radio masts are heavy structures that exist within a specific area, whereas low-height radio masts can be mobile items built up based on the operational needs of the mission. It is not easy to connect by cable to a radio mast within a 100-meter distance. Time parameters are important within mobile radio mast implementation as well, since building the mast may take a long time in contrast with wired connections. Mobile radio masts are not disposable so the radio mast must be detached and taken with the forces when they head toward the next destination. Therefore, the time to build up the mast is T1, time to detach and pack the mast for the march is T2, time to build wired connections to the mast is T3, and the time to detach the wired connections to the mast is T4. All are vital for



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the success of operation, if operational tempo is increased to higher levels. In urban and suburban settings, the rooftops of high buildings might be intriguing positions for antennas, since wireless radio masts built on the ground experience challenges regarding LoS links and severe fading. Therefore, urban environments are not optimal locations for mobile radio masts, so in many cases these masts must be moved a short distance away from large buildings. On one hand the detection probability of mobile radio masts may increase in urban setting. On the other hand, there are a lot of signals in the spectrum in the urban area, so directional wireless communications gets mixed up in the traffic in the spectrum. Mobile radio masts can also be affected by tampering and engagement in the same way as in wired connections. In rural and scarcely populated forest areas, terrain can be used more effectively than in an urban setting but getting up to the elevated terrain positions may be challenging. A forest environment offers the possibility to limit detection, but due to rare movement in the environment, the location of the radio masts might be revealed to hostile forces. Although directional radio links are not easily detected, possible signals within the spectrum that are otherwise unused might reveal locations. In addition, the protection of cable connections and radio masts from other actors is easier than in the urban environments since the rural setting is not heavily inhabited. 9.3.4  Wired Communications from Sender to UAV Relay, Aerostat, or Balloon That Delivers Messages in the Air Using Radio Waves

This alternative form of communications is quite similar to the previous example, but here the radio link mast is replaced by a flying asset such as UAV, aerostat, or balloon which relays the radio signals in the air to the other end of communications which may be similar flying assets, radio masts, ground stations, or ground vehicles. The benefit of using flying or flowing assets in the sky is an extension of the LoS communications path, while at simultaneously avoiding the attenuation effect of different natural or man-made obstructions. The same issues of protection using cable connections to a flying asset apply here as well. It is worth mentioning that the higher the flying asset is lifted, the heavier the cable connecting the ground and air will get. This may have security implications for

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ground personnel if the heavy cable gets disconnected or cut at the time of flight. The clear benefit of using a flying asset compared to a ground-based radio mast option as a relay is the ability to quickly achieve altitude. An aerostat or balloon may be slower options than a UAV but detectability of all these airborne assets is low from a distance. From close distances, the ascent of these assets may be detected, and in sunny weather reflections from the surface may be seen from further distances as well. Due to the small size, the radar cross section of these objects is limited or nonexistent depending on the materials used in production. 9.3.5  Wireless Communications between Nodes Using Civilian Communications Networks

As different generations of cellular and short-range wireless communications systems have become an essential part of the modern society, utilization of these technologies in the military has become an attractive option. Since the commercial sector is leading the technological progress on many fronts, many military technologies are based on commercial technologies. Military-grade systems have more stringent requirements for security, protection, robustness, and reliability which lead the military technology development in certain directions. As security is not free, implementation of these security requirements results in lower data rates and limited use of frequencies. Therefore, civilian systems are attractive as backup communications systems and have higher data rate alternatives. Many security and military communications technology companies are currently offering communications products that have both hardened and commercial waveform in the same package. This represents a path toward SDRs and CRs (although these are not real SDRs by definition). Base stations of cellular mobile systems such as 4G LTE are built utilizing high masts that have long LoS paths and serve a great number of cellular mobile users within the coverage area. In most countries there is good coverage of cellular systems in inhabited areas, but cellular systems further from populated areas are not available. Handovers between base stations when mobile users move from one coverage area to another function smoothly with the current technologies in many areas. Urban and suburban areas have the best cellular connections although a large number



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of concurrent mobile users may severely affect achievable mobile data rates. Rural areas offer a moderate level of connections, but in scarcely populated areas users have to prepare to face disconnecting mobile services, and may need to move to better coverage areas for more reliable services. Based on many studies and forecasts, as urbanization is happening in the urban environments, the use of commercial technologies might be a good alternative for military users as well. A cellular system is vulnerable to many threats, but military use of the spectrum would be joined with civilian and government use which would lower the probability of detection. The current 4G system offers high-data rates for mobile users and maximum ranges of dozens of kilometers. Many LTE systems are under development such as LTE Advanced, IoT versions of LTE, and a form of 5G that fuses different technologies to extend connections deeper than ever before providing network connections to small objects as well as mobile terminals. Future 5G will require a smaller cell size and therefore several small base stations that could be owned by individuals. The business case for 5G is not clear at the time of writing this book. There are no clear civilian technologies to cover the range from 100 meters to several kilometers. WiFi access has become the dominant short-range access technology under 100m, but there are alternatives for shorter ranges such as Bluetooth, ANT, ZigBee, and several proprietary solutions. Wi-Fi technology provides the possibility to utilize high data rates over short ranges, but access is based on competition between users and freely accessible Wi-Fi connections are not very common. Several Wi-Fi access points require registration and a time or service quality based fee. In addition, public Wi-Fi access points may challenge connection security, since Wi-Fi has been the technology of choice of many reported cyber-attacks. 9.3.6  Wireless Communications between Nodes Using Military Communications Networks in Different Frequency Bands

This alternative focuses on wireless communications using several military communication technologies. It may have a wired backbone network and some redundant wired communication paths to improve robustness, but we will consider wireless connections in this setting. From an operational perspective, the use of military

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communications technologies leads to mission confidence since there is no need to worry about the shortcomings of commercial technologies that might be compromised due to environmental or hostile factors. Missions and tasks are well-planned though alternative plans may be required if the mission progresses differently than expected. The time dimension is very important in mission planning since it can’t be implemented effectively, if the situation moves rapidly. Many armed forces are dealing with maintenance of legacy systems along with new digital technologies that guide the path toward SDR and CR systems. When several technologies are in use and each functional unit has their own equipment, connectivity solutions are needed to ensure that different systems can communicate with each other. Forces need specific training for the communications equipment that they will be using in operations. Since future operations change, this training currently does not cover situations where the hierarchy of the forces must change based on the situation. This results in the need to train forces to use the communications equipment of other units as well as their own. Since training includes tasks other than communications, this may be a challenge for military education. One answer to this challenge could be a wide-ranging architecture, where armed forces communications are based on a common platform with extensions to the common platform based on the needs of specific units. The benefit of the common platform would be that any warfighter would have a basic understanding of the equipment and general functionalities. This would also speed up the use of specific extensions if they were implemented in a very intuitive and user-friendly fashion. This is the goal that the SDR community has been pursuing for a couple of decades. With civilian communications technologies there were both cellular mobile radio and short-range communications solutions. Regarding communications in future battlefields there will be requirements for better utilization of the local communications environment, since forecasts predict future operations being distributed, hybrid, fast-pace, and more challenging for the single warfighter. As a result even smaller units need a multitude of capabilities, communications being just one of many needs. To maintain or speed up force maneuver to high levels, smaller units can’t afford to bring



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their communications stations to high-intensity tasks and missions. One option for local communications would be direct communications between mobile military radios. Communications ranges between mobile radios would be limited compared to communications ranges between mobile radios and cellular base stations. Most connections between mobile military radios would be NLoS connections, and the radios would be very close to the ground without the help of radio masts to improve the conditions for wave propagation. Although civilian personal mobile radios achieve ranges of several kilometers, this would not be the case for WB mobile military radios with different transmit frequencies, limited transmit powers, and stringent requirements for energy consumption of mobile military radio batteries. One could then discuss several issues concerning direct communications between mobile military radios as follows: • What would be the maximum needed communications range between mobile military radios? • The range would be shorter for WB communications but longer for NB communications; • NB waveform that extends to longer ranges could provide Blue force tracking services and other situational information specific to the local environment; • Would there be need for a receive-and-forward feature that relays messages to every other participant in the group within range (group communications)? • Would there be a need for parallel waveforms able to access long-range military base stations, or would the same waveform be suitable for long-range communications since there could be LoS paths to military base stations from some locations? • Would there be a need to utilize direct communications as a spectrum sniffer as a first order spectrum awareness to utilize DSA and other CR features? Building a military communications network takes time, and in the future battlefield one function that should be improved is

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communications on-the-move. There is a need to use radio communications masts in the field, since communications infrastructure is never as robust as needed. Since future operations will be timelimited, there will be high requirements on the time to build up and detach communications masts in the field. In terms of communications performance, radio communications masts that extend over the top of trees or are placed at elevated terrain are highly respected but they may be considered a burden from an operational perspective. During high-intensity operations, the higher the communications masts the more movement of the units to the next destination is delayed. In many cases these communications systems are cut off from the network when they are built, detached, or when moving to the next destination. If there is a need to keep up the communications services operational until the moment when the first communications mast is detached, there could be a lighter mast that would be easier to detach and shorter than the main mast. This left-behind communications mast could be built on a mobile unmanned platform to provide wireless connections to the mast on the move. An unmanned platform would also reduce the risks of attack against manned communications stations. The communications masts on unmanned mobile communications stations must be fairly short on the move but they could still provide communications services reducing the communications downtime in movement of the stations. These backup masts, along with other mobile communications masts could be unmanned with the opportunity to lift masts higher when they are in position. It is obvious with current technologies that communications masts are shorter than static ones that do not support communications on-the-move. As sensors and AI develop strongly toward 2030 autonomous communications stations would know the best positions to establish a communications station, would be aware of every actor in the spectrum, and would know beforehand when to initiate movement to the next destination. 9.3.7  Wireless Communications from Sender to UAV Relay, Aerostat, or Balloon

In this alternative we consider wireless connections from the ground to UAV, aerostat, or balloon that relays in the air radio sig-



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nals to the other end of communications. This will reduce communications downtime during the transfer of communications system to the next destination. Utilization of aerostats and balloons doesn’t require as many support services as UAV, but it may take more time to raise them up and bring them back to the ground compared to UAVs. If there is time UAV can move to the following destination in the air. As most of the time there are LoS communications paths available in air-to-air, ground-to-air, and air-to-ground connections, this alternative is promising from the communications performance perspective. The clear benefit of using a flying asset as a relay compared to a ground-based radio mast is the fast ascent in the air. The detectability of these flying assets is low from a distance. Within close distances, the ascent of these assets may be detected, and in sunny weather surface reflections may be seen at further distances. As small-sized objects, the radar cross section of these assets is limited to nonexistent depending on the materials used in production. From a security perspective, the drawback of a connection to flying assets is the wireless nature of the signals that may be detected from a distance. This could be improved by using directional antennas in contrast to omnidirectional antennas in ground mobile radios. As technology progresses, the flight time of UAVs will improve to enable longer missions and perhaps autonomous transfer to the next operational area by providing communications services to Blue forces on the way to the next destination. Take-off, landing, and a new take-off is expected to take much shorter than the transfer of a ground-based communications mast to the next destination. Therefore, currently limits on flight time might not be as important an issue as it would seem at first. Although the use of unmanned assets requires a supporting organization it may be comparable to the personnel allocated to communications station support. 9.3.8  Wireless Optical Communications between Nodes Using Military Communications Networks in Different Wavelengths

Here we will discuss using optical communications. Since radio waves are affected by obstructions and distance along the communications path, using optical communications requires LoS paths.

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As wavelengths are very short, communications is severely affected by weather conditions. To achieve a greater level of beam density, optical communications systems are directional by nature and require accurate alignment of transmitter and receiver beams. For good selectivity transmission beams should be narrow in contrast to receivers that need to detect incoming beams for a greater range of arrival angles. There are also studies that utilize the diffraction of laser waves in the urban environment partly relieving the system from the need for LoS links. If the wave is dispersed and propagated as several beams, these systems cannot achieve the maximum rates that LoS systems can achieve. Optical communications on clear paths for short distances might work, but as a general C2 technology optical communications is too limited. Ground-toground communications in several communications environments and weather conditions is not reliable enough to allow it to be the only C2 technology for communication between the forces. To achieve the best performance for ground communications, transmitters, and receivers should be located on elevated terrain to have an undisturbed path between communications nodes. Even this wouldn’t be enough to provide high quality links, since mist, rain, and snow could jeopardize the functioning of the link. For short distances this form of communications has clear benefits because high data rates can be achieved, albeit with limited power, since short-distance data transfer doesn’t need high optical power. 9.3.9  Wireless Optical Communications from Sender to UAV Relay, Aerostat, or Balloon

We now consider delivery of messages to and from flying assets by optical means. Since the communications destination is in the air, some challenges of communications between ground nodes can be circumvented. However, obstructions can still block communications to the air, if the obstructions come in the way of communications path. Therefore, flying assets should be at high angles with respect to the ground node. Due to weather challenges, the flying assets should be flying or flowing at low heights in order to avoid sending waves through clouds. One clear benefit of this alternative would be a fast way to transmit and receive a great amount of data



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at high data rates between ground and air with low detectability due to the optical and directional form of communications. This form of communications could be a good alternative for Blue force tracking, and the collection and delivery of situational pictures for ground forces. This alternative assumes radio wave communication in the air between air platforms. As radio wave communication would rarely be omnidirectional in the air, the detectability of air-to-air communications is low. Therefore, there is no clear need for optical communications between aerial assets but it could be applied if needed. 9.3.10  Utilization of Heterogeneous Networks in the Transmission of Messages

Utilization of heterogeneous networks aligns with the previous alternatives because utilization of heterogeneous networks can mean: (a) the use of ground-based military communications radios (every form of radio, including SDRs); (b) the use of aerial platforms to relay transmissions over longer distances in the air; (c) the use of commercial civilian wired and wireless networks; (d) the use of local connectivity such as IoT equipment, RFID equipment, or location-based services; (e) the use of unconventional forms of communication (either military-specific or commercial sensor networks) as part of the communications network, and; (f) AI-supported communications technologies that have interoperability support of different types of waveforms, cognitive support to gain awareness of the surrounding spectrum, actors, and policies along with learning and agility functions to smoothly control the operation within heterogeneous networks. A few points should be noted to clarify the strict requirements for operation in heterogeneous networks. First, different military waveforms can be based on a common architecture making it easier to connect between technologies. Typically this has not been the case, since there are a great number of vendors with vendor-specific features in their products, and in many cases the products contain extra features on top of an otherwise basic platform. Second, several commercial communications technologies are well-proven but they may not be directly applicable to military use. In the past there was competition between 3GPP and WiMAX, and currently with

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IoT. The worst alternative would be implementation of one commercial technology for a military purpose that loses its dominant market position. Both solutions (military only versus a military/ commercial combination) pose risks for procurement. The former provides direct control for secure communications, but high costs for the number of units may be unsatisfactory from the capability perspective. The latter entails dependability on commercial technologies with the risk of picking the wrong product in the marketplace, but lower unit costs could achieve the desired number of units. If a solution that loses market share is chosen additional costs financed by the military may be incurred for support. Third, though picking the wrong solution would seem a mistake the loss of market share might result in improved security bringing it closer to a full-fledged military technology. 9.3.11  Left-Behind Location-Specific Messages for the Second Phase of Blue Units

In some cases radiation or movement of messengers is not allowed based on the possibility of detection and challenges to protection. Since messages cannot be delivered by waves or messengers, one alternative would be to leave them behind at specific locations for a second wave of forces to retrieve at a certain time. The forward force leaves messages at a certain geographical location, whether in WSN node, smart machine, or a tag that can be read by Blue forces that arrive in the same location later (important cyber point since it shouldn’t be possible for Red forces to read and perceive the message). As an example, company A has been stationed in the area OP A1 for the past day, and plans to move 10 kilometers south from that position. The forces have preplanned the tasks and unit progress and it is known that company B would advance to the OP A1 12 hours after company A has left toward OP A2 10 kilometers to the south from OP A1. Although company tasks are planned well beforehand, unexpected situations may change the plans of both companies A and B. Therefore due to circumstances, company B may not ever arrive in OP A1 and the message intended for company B may be lost for good. If we assume it is probable that company B succeeds in getting to OP A1, there is still a challenge to receive the message left behind by company A. For obvious reasons, the equip-



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ment left behind by company A should not initiate communications to prevent detection of the message by hostile forces. It should operate as a passive device that starts activity only in response to a message sent to it at close distance and with a code known only by the Blue forces. The equipment should be embedded in the environment but still be locatable for connection. There could also be several levels of security by using two or more devices where the first one acts as initiator and provides encoded hints to find the second device that contains the message from company A to company B. There is a trade-off with the transmit power of the equipment; the use of excessive power in finding the message from the OP A1 might be helpful but the power may act as a lighthouse for hostile systems scanning the spectrum. Directional transmissions decrease the probability of detection, but finding receivers in the area using very narrow beams may be slow and complicated. Therefore, some form of RFID systems may be the right answer to find the message of company A. An old-school approach to overcome most technological challenges is leaving a letter with encoded information at a certain location known by both companies. In conclusion, this form of communications doesn’t solve all C2 challenges but it presents a new (and at the same time old) paradigm where the message stands still but the transmitters and receivers are moving. Therefore this alternative could be called a location-based service. In the future, AR applications of company B warfighters could pinpoint an accurate location visible on the screen of the warfighter’s terminal. Communications between company B’s equipment and the embedded message equipment would take place in the background, the application would show the location from a distance and show the message when a warfighter comes within close-range of the equipment. This form of AR would enrich the real operational surroundings by providing information on objects, the map, and the terrain along with military messages left-behind. Many of these features would need WB access to network resources which opens a plethora of questions regarding cyber security and the possible danger of hacking the AR applications. This book is not focused on cyber issues, so these are raised only as a topic for further investigation.

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9.3.12  Physical Delivery of the Message from the Sender to Recipient by the Messenger

In the previous alternative the message was stationary but the transmitters and receivers were mobile. In this alternative form of communications we consider message delivery by messengers on foot or using any manned ground vehicles. Therefore, both the message and initiators of the message are moving but the object would be limiting communications by wireless or wired means. When a message is delivered personally from point A to point B, several technological challenges are mitigated. It is still worth noting that security could still be endangered even when using personal deliveries. Therefore, the probability of hostile gatherings or tampering with information on its way to the destination should be considered. As detection in the spectrum is not likely when transmissions are avoided, the movement of military vehicles could be detectable in an area of interest. In the previous alternatives, the message would be sent to the destination in very short time, if the radio masts and networks are already up and running. Depending on the average speed of the delivery due to traffic, vehicle type, driver, environment and terrain conditions, access and security procedures, delivery time could vary a lot. In some cases the physical delivery may be faster because the message can be delivered well before the military radio communications network is established. To maintain the idea of nonradiation over the whole communication chain, the message should be read at the destination via physical connections or by audiovisual means. 9.3.13  Physical Delivery of the Message from the Sender to Recipient by UAV or UGV

This alternative focuses on unmanned delivery of messages. UAVs are a faster alternative compared to UGVs when considering all terrain types which can pose challenges for the fast advance of ground vehicles. Unmanned platforms are remote-controlled and use both GNSS navigation and data from sensors of the unmanned platform. As long as unmanned systems have human operators, there is a need for a wireless connection between the operator and the vehicle. Wireless control can be implemented with radio or microwave technologies, the latter providing better capability for transmission



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of pictures and real-time video. Since the range of microwave signals is limited, the control station can’t be very far from the vehicle. For longer distances between the control station and vehicle, satellite communications must be used for control of the vehicle. Control via satellite communications is typically used for a bigger class of UAVs. The operational area considered in this book is limited to brigade-level and smaller military formations and satellite communications are not considered, so mid-range or lower classes of unmanned systems are considered here. Real-time video from the vehicle as well as a GNSS-based location are the most important factors for the operator to guide the vehicle to the destination and deliver the message to the recipient. In addition to GNSS, navigation could be done by signals from established ground stations or relative navigation between several unmanned vehicles. As autonomous technology develops in the future, navigation from the source coordinate to the destination coordinate could be possible. Control signals wouldn’t be needed in the case of autonomous aerial vehicles, decreasing the probability of detection of the control signals in addition to removing the limitations of distance from the control station to the vehicle. For now it seems autonomous systems would either need a GNSS signal to navigate to the destination or utilize onboard offline maps in concert with the analysis of data from different sensors onboard. The shortcoming to losing GNSS support is that vehicle itself must find the location on the map and the offline map can’t be as accurate as GNSS compared to sensor data from the environment.

9.4  Qualitative Factors in Evaluation of Communications Alternatives Different alternatives for military communications in different settings are evaluated using five factors that are defined in the Sections 9.4 and 9.5. • Range factor; • Security factor; • Robustness factor;

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• Capacity factor; • Time advance factor. The range factor is evaluated quantitatively using the radio wave propagation models discussed earlier. The security factor, robustness factor, capacity factor, and time advance factor are evaluated in the qualitative scale. In many cases, values of different factors move in opposite directions depending on the operational situation at hand. Tables 9.1–9.4 present scales of qualitative factors, respectively. 9.4.1  Robustness Factor

The robustness factor takes into account the level of how specific communications alternatives are affected by hostile activities or surrounding conditions. This parameter can have values according to the following scale presented in Table 9.1. Considering robustness, there is no need for military-grade robustness for single communications nodes, if the network consists of several nodes able to route traffic via different routes and capable of providing several redundant paths. Therefore, a military-grade system with few redundant paths and critical points of failure may have the same robustness factor value as a highly distributed multihop civilian system. Table 9.1 Robustness Factor Evaluation Value

0 1

2 3

Description

Civilian-based technology solution No specific protection against environmental conditions Is affected severely by engagement in the battle Military-grade system protected against environmental conditions and impacts in the battle System contains critical points of failure No built-in wide-scale redundancy in the system Distributed system built with civilian and/or military-grade components System provides several redundant paths to make system more battle-proof Distributed and redundant system designed for the most demanding environments Provides possibility for not easily detected operation



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9.4.2  Security Factor

The security factor takes into account the ease with which specific communications alternatives are detected and compromised. Considering the scenario presented in Section 2.4, revealing the Blue forces in the first phase (part 1) is not as important as in the two following phases (parts 2 and 3), since the build-up of Blue forces and possible locations for counter-attacks should be kept safe as long as possible. The security factor also considers whether key information can be collected, if the opposition gets access to the system in the communications path, and if the system is not protected. The security factor also considers the risk level for message delivery in the communications path, or in the physical delivery by manned or unmanned assets. This parameter can have values according to following scale presented in Table 9.2. 9.4.3  Capacity Factor

Capacity factor takes into account how much data can be delivered from the source to the destination using a specific communications alternative. In parts 1 and 2 of the scenario, the capacity to deliver information is necessary, but more important is the capability to transfer the most relevant information, whereas, in part 3 in an urban environment there may be more opportunities to utilize the existing wireline communications infrastructure. In evaluating communications alternatives, a longer communications range may be needed which might lower the achievable data capacity. The caTable 9.2 Security Factor Evaluation Value

0 1 2 3

Description

Chosen alternative of communications poses a high direct risk level for a communications path, messenger or indirect risk for the whole unit (squad, company, battalion) Chosen alternative of communications poses an intermediate direct risk level for a communications path, messenger or indirect risk for the whole unit (squad, company, battalion) Chosen alternative of communications contains minor risk level for a communications path, messenger or indirect risk for the whole unit (squad, company, battalion) Chosen alternative of communications is regarded secure enough from the operation’s perspective

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pacity factor may be more important, if flying platforms, high communications masts with directional antennas, wireline communication, and manned or unmanned physical data delivery are used. These parameter values are shown in Table 9.3. 9.4.4  Time Advance Factor

Time advance factor takes into account the time that needed to deliver a message from the source to the destination. These parameter values are shown in Table 9.4. Time is one of the most important variables in military missions, especially in high tempo operations. Blue forces need time to build up and prepare for counter-attacks and the defense of Blue city. Therefore time advance factor is very important in parts 1 and 2 of the scenario and not as important in the protection of Blue city in part 3. All methods that help to minimize communications delays and the movement of communications elements together with the fighting forces are relevant in the time advance factor. Minimization of communications delays can’t be done by compromising the security of the forces and operation. 9.4.5  Discussion of Qualitative Factors

The qualitative factors introduced in previous sections are interrelated. For example, if there is a limited data rate achievable using 50 kbits/s data rate, and one option would be the physical delivery by a messenger on a motorbike. The messenger delivers one terabyte of information from source to the destination in 5 minutes, and

Table 9.3 Capacity Factor Evaluation Value

0 1 2 3

Description

Capacity of the communications alternative doesn’t meet the needs of communications Capacity of the communications alternative is limited regarding the needs in the mission Capacity of the communications alternative is moderate and provides communications services for the most relevant messages Capacity of the communications alternative meets the needs of communications in the operation



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Table 9.4 Time Advance Factor Evaluation Value

0 1 2 3

Description

Operational speed of communications in the C2 chain is too slow regarding the operational tempo of Red forces Operational speed of communications in the C2 chain is limited and does not leave time for Blue forces to operate proactively regarding the operational tempo of Red forces Operational speed of communications in the C2 chain is moderate and may allow Blue forces to operate proactively regarding the operational tempo of Red forces Operational speed of communications in the C2 chain is fast enough to create time advancement and to operate proactively irrespective from high operational tempo of Red forces

the communications capacity delivers 50 kbits/s * 5 * 60 s = 15,000 kbits = 1.83 MB. The range factor is evaluated using a very basic radio wave propagation calculation. The goal is to have an idea of typical ranges for different systems in different environments rather than to perform accurate calculations. Radio wave propagation calculations using different models and methods provide a range of results, and since we are focused on a scenario in the future without accurate 3-D terrain and object models, there is no need for a high level of accuracy. Since the art of warfare contains unexpected events in different circumstances, it is not be useful to have highly accurate propagation modeling if other characteristics are not modeled accurately as well. Still, range factor is an important parameter, since it defines the length of path to the nearest communications node (either a destination or intermediate node.) A long communications range may be achieved in the lower VHF frequencies but the data rate might be limited (capacity factor) and high transmit power is required, which lowers the security factor due to the elevated level of communications detection. If a military radio is used, the robustness factor obtains values from the high end of the scale but the time advance factor may pose challenges if a limited volume of information can be delivered with military VHF radio system. In addition, elevated nonkinetic engagement on command stations along with the need to move locations of command posts increases communications blockages due to the time it

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takes to detach mast-based systems, move to the next destination, and reestablish them into operation. As stated previously, manned or unmanned physical delivery of information might be a good solution, since modern data storage systems can store several gigabytes of data in a very compact form. In this case the capacity factor gets a high value but it should still be compared to alternative solutions because in some cases warfighters might have a 100 Mbit/s wireline data connection near the origin of the information. If a wired connection was capable of delivering 100 Mbit/s throughput, the wired network delivery would take less than three minutes. Here again, range factor comes into play, as warfighters might have alternatives to perform physical delivery by walking, bicycle, motorcycle, or armored wheel vehicle. If the distance between the origin and destination is 5 kilometers, physical delivery of a message would take 60 minutes (walking), 30 minutes (bicycle), 6 minutes (armored wheel vehicle), and 4 minutes (motorcycle), respectively. If the distance is 20 kilometers, the physical delivery would take 240 minutes (walking), 120 minutes (bicycle), 24 minutes (armored wheel vehicle), and 16 minutes (motorcycle), respectively. Along with the effects of the range factor, the robustness factor gets different values according to the method of physical delivery. Although an armored vehicle would be the most robust compared to other alternatives, it may also be a target on the way to the destination, which again affects the robustness factor based on the elevated risk level. As detectability is also related to the security factor, it may have different values as well. It is assumed that performing a physical delivery, there is no need to radiate in the spectrum. As such, the platform always has a signature that affects the security factor. These scenarios are considered from different perspectives using features of versatile environments, using vehicles or advancing by foot, different mobility parameters, with different probabilities of detection, and threats of kinetic and nonkinetic engagement. Since there are no densely located wired military network access points, command stations must be established to connect local warfighters and long-range command stations to this access point. Considering an area of 30 km × 40 km, several command stations are needed in locations that are not directly under engagement.



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High masts with directional antennas and high transmit power can cover the area but the coverage of the local wireless connectivity may be limited. Based on calculations according to Egli models, the maximum ranges for typical 5W transmit power (BS height 30m, MS height 2m) are 6.8 km at 100 MHz, 3.4 km at 400 MHz, and 2.6 km at 700 MHz. Vehicle versions of military radios can utilize higher transmit power and higher antennas which allow longer communications ranges than warfighter radios. One effect of changing command station positions is the process of detachment of the station, movement to the next location, and reestablishment of the station. If detachment takes 90 minutes and establishment 60 minutes, and movement to the next destination is 15 km at the average speed of 40 km/h, the time delay of this specific command station is 90 + 23 + 60 = 173 min (approximately three hours). Whatever the numerical value of delay is, it depends clearly on the capability of personnel, conditions, platform, and the current phase of operation. In fast-paced operations, the delay for this station and for the forces to find redundant access points within the area might be too long. If the link throughput were 2 Mbit/s, the loss of information to be delivered would be 173 * 60 s * 1 Mbit/s = 10.38 Gbits = 1.3 GB. If the value of one of four factors is zero, and the estimated communications range is insufficient for the application, then this alternative contains elevated risk. In the evaluation of factors of parts 1–3, the sum of factors is presented in the tables as well. 9.4.6  Importance of Operational Tempo in Evaluation of Communications Alternatives

In evaluation of the time advance factors of different communications alternatives, the timetable of parts 1, 2, and 3 give an average speed that the Red front group and the main group advance. Table 9.5 presents average speeds of Red in their operation. As Table 9.5 describes, the main group of Red advances at about the same speed in parts 1 and 2 but speeds up in part 3. The front group advances at higher speed in parts 1 and 3, and accelerates to the highest level in part 3. In reality operations do not advance at the same speed during every time interval, but the average speed is an important consideration of the whole mission. The average speed of advancement seems very low, for example, the advancement of

174

Military Communications in the Future Battlefield Table 9.5 Average Speeds of Red Front and Main Groups in Different Parts of the Operation Phase of Red Operation

Average Speed of Red Front Group

Average Speed of Red Main Group

Part 1 Part 2

1.0 km/h 0.4 km/h

0.6 km/h 0.6 km/h

Part 3

1.7 km/h

0.8 km/h

a long-range engagement asset of 1.8 km in two hours might be a very important consideration. The rapid acceleration of the main group might be tenfold in the attack and instantaneous speed of the front group might be twentyfold in the best conditions.

9.5  Quantitative Estimation of Communications Ranges Based on Propagation Models and Public Sources As there are several alternative ways to communicate between senders and recipients, it is important to evaluate different antenna heights and the requirements they impose on communications. Ground-based sensors antenna heights can be below 2 meters. Deployable antennas carried by warfighters have typical heights of 2–3 meters, whereas vehicles may carry antennas of 4 meters. Communications stations or mobile base stations may have antenna heights of 25 meters if extended on top of trees. Fixed communications masts or cellular base stations may have heights of 100 meters. If the other end of communications path is close to ground level, a plane earth model is often used to take ground reflections into account. As the height of transmitter and receiver antennas is raised up to 30 meters from the ground, with the antennas having omnidirectional radiation patterns, ground reflections are still considered. If directional antennas are used in 30-meter masts, this LoS communications path can be evaluated with a free space model. Communications between aerostats and UAVs at high altitudes can be evaluated with a free space model, but if these platforms are communicating with ground-based users with low antenna heights ground reflections must be again taken into account. As the name plane earth indicates, a plane earth model does not include



9.5  Quantitative Estimation of Communications Ranges Based on Propagation 175

the effect of terrain variations in the form of hills, vegetation, and forests, or the effect of man-made obstacles in the form of buildings and structures. Since we are not using an accurate map, terrain, or 3-D building models in this presentation, the plane earth model only provides a coarse estimate of the communications range, but as it is applied to other alternatives, relations between different alternatives are treated in the same way. A free space model, plane earth model, and Egli models are applied to parts one and two in the scenario. Okumura-Hata and COST 231-Hata models are used in part 3 in addition to previous models, since part 3 is happening in the Blue city surroundings which can be classified as a medium or small-sized city. Therefore, these experimental models are used in part 3. Depending on the type of air assets used, several flying altitudes may be considered. In this section we will focus on the airspace below 2,000 meters. Range factor takes into account the range that can be achieved using a specific communications alternative. As mentioned in Chapter 3, the general parameter collected from several open sources for receiver sensitivity is –100 dBm. In range calculations the sensitivity dBm level (in addition to a 20-dB margin) is subtracted from the transmit power of transmitter and the maximum range is solved from the propagation equations. Depending on the application, common marginal values are between 5 abd 30 dB. In application of Okumura-Hata and COST 231-Hata models the 20dB margin is not subtracted, since transmitters in cellular systems use high power in elevated masts and do not normally face intentional interference. Free-space loss is utilized in communications between transceivers at high altitudes from the ground level, and ground-based antennas are elevated to overcome obstructions of the terrain and use directional antennas. The free-space loss equation does not contain antenna heights, but does contain the transmit power level and carrier frequency. The plane-earth loss considers flat ground without terrain effects but takes into account the ground reflections that occur when the other end of the path is at a low height. The plane-earth loss equation does not contain carrier frequency but does include transmit power and antenna heights. Egli, Okumura-Hata and COST 231-Hata path models include all of

176

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these parameters and require more effort to analyze different alternatives. It is important to note that the results of these calculations only give approximate guidance on the communications range using different frequencies and antenna heights, since characteristics of the real environment differ case by case. In some cases, for example, maximum communication ranges go beyond the range of Okumura-Hata model (1–20 km). There are many books available that go deeper into modeling of cellular systems and analyze differences of various models. If the free-space loss model for LoS connections is utilized in the calculation of a communications range using a 5W transmit power level and required reception signal level of –80 dBm, the free space model gives very optimistic results especially in the VHF frequency range. This is due to the equation that uses only transmit power and carrier frequency as input parameters. An effect of the height of the transmitter and receiver antennas is basic in calculation of the theoretical maximum communications range. Radio horizon calculations for different pairs of antenna heights are presented in Table 9.6 and show the fact that to achieve the longest communications ranges, both ends of the LoS communications paths must communicate at high altitudes. Radio waves tilt toward the Earth that makes it possible to achieve communications ranges longer than the visual LoS path would suggest. Radio horizon is indeed a theoretical range, since all sizable obstructions that exist on the path between the transmit and receive antennas, limit the achievable communications ranges. This was discussed previously in the Fresnel zone section.

9.6  Analysis of Selected Communications Alternatives in Scenario The scenario described in Chapter 2 created a timeline of events for one week where Red forces initiated an offensive mission in Blue’s territory. The goal of the mission was to bring one brigade near the border of Blue and Red, to strengthen the mission with another brigade, therefore allowing the first to advance to an important area from the Blue’s perspective. In this analysis, the scenario is considered in three parts that will occur in different environments. In the first part the territorial defense battle near the border of country



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177

Table 9.6 Radio Horizon Calculations for Different Pairs of Antenna Heights

Height of Tx Antenna [m]

2 4 4 10 10 10 30 30 30 100 100 100 100 300 300 1,000 1,000 2,000

Height of Rx Antenna [m]

2 2 4 2 4 10 2 4 30 2 4 30 100 4 30 4 300 2000

Maximum Theoretical Communications Range [km]

11.7 14.1 16.5 18.9 21.3 26.1 28.4 30.8 45.2 47.1 49.5 63.8 82.5 79.7 94.0 138.7 201.8 368.9

A and B in country B’s territory represents a battle in a scarcely populated, rural area. In the second part defensive retreat battles along the path from the border toward the central part of country B (Blue) represent more limited battles on the way to a retreat from the first phase of the Red operation covering both suburban and scarcely populated areas. Due to a lack of Blue defense forces and systems, the Red attack cannot be stopped but can be slowed down to build up more forces on the way to inland. The third and final part is a defensive battle near the critical area with swift changes to offensive counteractions to win. This scenario represents a battle in an urban environment in a situation where Blue has succeeded in building up forces from day one. In addition to these operational areas in three parts, the communications of Blue in the supporting areas is considered, since the line of advancing and defending forces is not the only topic of interest. Since the first part takes place in

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the vicinity of the border between Red and Blue, it imposes requirements on Blue communications. Red has many beneficial locations to perform ISTAR activities on Blue assets near the border. As the build-up of Blue forces and improved preparedness for Red actions must be kept in silence, C2 will focus on communications technologies that have limited radio coverage, satellite-based communications, wired communications, or the use of messengers. The use of civilian communications networks might be an option as well, but civilian networks should be protected and made redundant in order to achieve resilience in the cyber domain. Since the Red attack is eminent at the beginning of the scenario, the main focus of the Blue is the area and terrain that provides the best conditions for Red units to advance from the border inland. In addition to preparing for the defensive operation in the area, Blue has to perform surveillance in other areas near the border to be monitor illegal border crossings. As main part of the force has to focus on the defense mission, wide-scale ISTAR activities are considered to counter an unlimited number of warfighters in the area. A first option might be use of satellite or HF communications to perform C2 in the overall area but those technologies will not be considered here. The covered area is 100 km × 40 km requiring several nodes, warfighters, or mobile systems for effective surveillance and communications from the border to the command centers. Both the local defense mission and the surveillance mission in supporting areas would utilize any existing military backbone networks whether they are link-based, mast-based, fiber networks, or cable networks. Wide coverage of civilian cellular systems could be used as a part of the communications portfolio as well. Before the Red attack, the Blue civilian and military networks had been affected by cyber operations that limited network capacity below normal levels within areas near the border and other parts of the network as well. Some of the radars and infrastructure were damaged in air assaults performed by Red which caused challenges to coverage for situational awareness, communications networks, and logistics centers effectiveness. As described in this scenario, the Red side has an upper hand against Blue in terms of collection of systems and forces. Therefore, Blue has to carry out operations in a defensive fashion and limit the advancement of Red forces in order to buy time for supporting



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Table 9.7 Maximum Communications Range of a 5W Transmitter Based on Plane-Earth Model (Ground Reflections) Using Different Antenna Heights with –80-dBm Received Signal Level Target Tx Antenna Height [m]

2 4 4 10 10 10 15 15 15 15 150 150 150 150 300 300 300 300 1,000 1,000 1,000 1,000 2,000 2,000 2,000 2,000

Rx Antenna Height [m]

2 4 2 2 4 10 2 4 10 15 2 4 10 30 2 4 10 30 2 4 10 30 2 4 10 30

Maximum Communications Range [km]

1.7 3.4 2.4 3.8 5.3 8.4 4.6 6.5 10.3 12.6 14.6 20.6 32.6 56.4 20.6 29.1 46.0 79.8 37.6 53.2 84.1 145.7 53.2 75.3 119.0 206.1

Blue forces to establish systems and force structures for a stronger position in future battles. Blue needs to maintain command chains between headquarters, command posts, infantry companies, mechanized battalion, field artillery batteries, an engineer company, an ISR company, a EW company, and logistics centers. The closeness of Red formations affects the choice of communications, since Blue and Red are operating in the same area within 50 km depth near

180

Military Communications in the Future Battlefield Table 9.8 Maximum Communications Range of a 5W Transmitter at 100-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Egli Model (Irregular Terrain) Using Different Antenna Heights with –80-dBm Received Signal Level Target Tx Antenna Height [m]

10 30 50 150 300 10 30 50 150 300 10 30 50 150 300

Rx Antenna Height [m]

2 2 2 2 2 4 4 4 4 4 10 10 10 10 10

Maximum Communications Range [km]

3.9 6.8 8.8 15.2 21.4 4.7 8.1 10.4 18.0 25.5 5.9 10.1 13.1 22.7 32.1

the border between Blue and Red. Communications should be arranged within a wide area, but widely distributed ISR activities should also be considered. Communications under cyber, EW, ISR, and engagement threat require careful consideration. In addition, the performance and protection of logistics centers has been affected by air assaults, damage to the delivery routes, and limitations in the cyber domain. The main group of Blue forces has succeeded in slowing down the attack inland, but parts of the forces have been distributed off-track from the main direction of attack. Some Blue battle organizations that should have been supporting them in the operations were missing. Medium-sized operational level UAVs occasionally fly over the Blue territory. Most of the UAVs have ISR payloads, but some of the platforms may carry kinetic or nonkinetic engagement payloads. Blue has the ability to partly limit operations of Red UAVs, but the training and arrangements for upcoming stages of Blue operations can’t be done in silence, since eyes



9.6  Analysis of Selected Communications Alternatives in Scenario

181

Table 9.9 Maximum Communications Range of a 5W Transmitter at 400-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Egli Model (Irregular Terrain) Using Different Antenna Heights with –80-dBm Received Signal Level Target Tx Antenna Height [m]

10 30 50 150 300 10 30 50 150 300 10 30 50 150 300

Rx Antenna Height [m]

2 2 2 2 2 4 4 4 4 4 10 10 10 10 10

Maximum Communications Range [km]

2.0 3.4 4.4 7.6 10.7 2.3 4.0 5.2 9.0 12.8 2.9 5.1 6.6 11.3 16.0

in the sky have a wide coverage. Three parts of the scenario are defined by the straight line distance from the Blue-Red border to the Blue city along the best routes to take for the heaviest military vehicles. The first part covers 30 km from the border to the Blue city, followed by the 40 km retreat phase in part 2, and finally the last 30 km to the Blue city in part 3. The direct path from the border to the Blue city is important as well as the width of 20 km of the main path in order to perform possible ISR tasks and counter-attacks. When considering different communications alternatives there is a need at several key points to receive and forward messages, since HF and satellites are not covered here. 9.6.1  Analysis of Part 1

Part 1 considers the advancement of Red forces from the border 50 km inland toward Blue to get control of a narrow strip of Blue (50 km from the border) near the fastest route toward Blue city (100 km

182

Military Communications in the Future Battlefield Table 9.10 Maximum Communications Range of a 5W Transmitter at 700-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Egli Model (Irregular Terrain) Using Different Antenna Heights with –80-dBm Received Signal Level Target Tx Antenna Height [m]

10 30 50 150 300 10 30 50 150 300 10 30 50 150 300

Rx Antenna Height [m]

2 2 2 2 2 4 4 4 4 4 10 10 10 10 10

Maximum Communications Range [km]

1.5 2.6 3.3 5.7 8.1 1.8 3.0 3.9 6.8 9.6 2.2 3.8 4.9 8.6 12.1

from the border.) At the end of this part, the main Red forces have advanced 30 km in two days, whereas the forward group of Red forces has advanced 50 km in two days. Advancement of the Red forces forced Blue to retreat and distribute along the attack route. The main Blue forces utilize existing wired connections available at points in the infrastructure. This part is taking place in a suburban area where connections to the fixed backbone networks are not as good as in the urban areas. The main Blue forces will utilize command stations established at specific locations to support the Blue operation in the best way. Wired connections, messengers, and directional links between units are favored when using radio communications at the frontline. Command stations with masts elevated over the top of terrain and equipped with directional antennas, provide protection for detection and interference. This scenario description contained hostile medium-sized operational level UAVs that cannot operate safely at low altitudes. Therefore, the use of



9.6  Analysis of Selected Communications Alternatives in Scenario

183

Table 9.11 Maximum Communications Range of a 25W Transmitter at 400-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Okumura-Hata Model Using Different Antenna Heights with –100-dBm Received Signal Level Target

Tx Antenna Height [m]

30 30 30 100 100 100 150 150 150

Rx Antenna Height [m]

2 4 10 2 4 10 2 4 10

Maximum Communications Range [km], Smallor Medium-Sized City

6.8 9.0 21.0 14.0 19.2 49.1 18.6 25.8 68.3

Maximum Communications Range [km], Suburban Area

11.5 15.2 35.5 25.2 34.4 88.0 34.1 47.2 125.2

tactical radio links is favored in part 1. This would be different if there were small-sized tactical UAVs with a window of opportunity to advance between the LoS path between command stations and interfere with the traffic. As battles emerge and Red succeeds in moving forward, it is necessary for Blue forces to change command stations positions along the retreat operation. If operational tempo were increased, the timely detachment, transfer, and establishment of communication stations would become more important. Therefore, the time advance factor should be considered. There may not be enough time available to collect existing wired cable or fiber connections when command stations need to move to future destinations. The question arises whether there is a need for provision of communications services with the major part of forces moving to the following key area. As previously discussed, UGVs equipped with a communications station and an extendable mast may provide one alternative to maintain communications services after the main forces have left for the next destination. Also, mast-based communications stations do not support command-on-the-move concepts well since the most capable masts need fixed position to communicate efficiently. To mitigate this challenge, Blue UAVs (as relay stations in the air) could be connected with VHF, UHF or SHF band communications terminals from the vehicles when

184

Military Communications in the Future Battlefield Table 9.12 Maximum Communications Range of a 25W Transmitter at 700-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Okumura-Hata Model Using Different Antenna Heights with –100-dBm Received Signal Level Target

Tx Antenna Height [m]

30 30 30 100 100 100 150 150 150

Rx Antenna Height [m]

2 4 10 2 4 10 2 4 10

Maximum Communications Range [km], Smallor Medium-Sized City

4.5 6.2 16.1 9.0 12.7 36.6 11.7 16.8 50.3

Maximum Communications Range [km], Suburban Area

8.3 11.4 29.6 17.6 25.0 71.8 23.5 33.9 101.3

moving to the next destination. A similar concept could be applied with civilian or secure LTE technologies, where a UAV relay could represent a LTE mobile station or deployable LTE base station. If a ground-based LTE base station serving the operational area gets destroyed, a plain LTE mobile station mode in UAV would remove ground-based service as long as there were no other redundant communications alternatives. If UAV contained a deployable LTE base station, LTE services for ground-based users could be provided during those hours when LTE UAV relays were undamaged. Ground-based WSNs, for example, in the form of IoT, could prove beneficial in ISR tasks and in monitoring the key areas. However, operational tempo in part 1 is so high that it may be best if WSNs were prepared for important areas well before the conflict began. Cases introduced in Chapter 4 on context awareness are not applicable , since leaving a message behind at certain locations to secure operations includes several risks: • Red attacks so quickly that using these smart devices for local information storage for Blue units maynever be read by Blue, but might be compromised by Red forces increasing risk to the operation.



9.6  Analysis of Selected Communications Alternatives in Scenario

185

Table 9.13 Maximum Communications Range of a 25W Transmitter at 1350-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on Okumura-Hata Model Using Different Antenna Heights with –100-dBm Received Signal Level Target

Tx Antenna Height [m]

30 30 30 100 100 100 150 150 150

Rx Antenna Height [m]

2 4 10 2 4 10 2 4 10

Maximum Communications Range [km], Smallor Medium-Sized City

2.8 4.0 11.8 5.3 7.9 25.9 6.8 10.2 35.2

Maximum Communications Range [km], Suburban Area

5.8 8.3 24.3 11.8 17.5 57.7 15.5 23.5 80.8

• It would be very difficult to determine the proper locations for smart devices, unless the movements of Blue units were known in advance, which is rarely the case. • One key characteristic of smart devices is locality of information to avoid coverage over a long distance. Extending the communications range to find smart devices more easily would not be a good option considering the main purpose. This could be mitigated by prior agreement among Blue units on the possible geographical coordinates for local information storage to ease finding smart devices in the environment. • Access to smart device should be restricted to Blue terminals to protect the information. The main direction of the Red attack is vital for Blue forces, but also important is the distributed off-track Red forces advancement along with large-area monitoring of other possible routes to the Blue city. One key requirement is the capability to establish communications from distant areas without the help of support units that would normally be there. Possible solutions might be using satellite or HF communications. Tactical communications command stations could also be a solution for distributed and distant forces, but thise would be challenging without enough forces to secure

186

Military Communications in the Future Battlefield Table 9.14 Maximum Communications Range of a 25W Transmitter at 1800-MHz Carrier Frequency (Antenna Gain 0 dBi) Based on COST 231-Hata Model Using Different Antenna Heights with –100-dBm Received Signal Level Target Tx Antenna Height [m]

30 30 30 100 100 100 150 150 150

Rx Antenna Height [m]

2 4 10 2 4 10 2 4 10

Maximum Communications Range [km]

2.2 3.2 10.0 4.1 6.2 21.7 5.2 8.0 29.3

the locations as silently as possible. The utilization of fixed civilian or military communications infrastructure from specific locations could be applied, but these may not be close to distant areas and distributed warfighters. Therefore different alternatives to deliver messages to these access points must be considered. LTE networks in most countries covers most inhabited areas well, so civilian or secure LTE would be one solution to deliver. Short- or medium-range MANET communications between warfighters could be applied as well, but routing of information from the source to the destination needs undisrupted connections between different hops. Groups of warfighters in the same unit often operate within short distances from each other. Therefore the MANET alternative carries some benefits including low transmission power levels that do not radiate far from the transmitter. Possible MANET disconnections might be mitigated by finding positions of the nearest Blue warfighters and moving closer to each other to establish connections. MANET nodes should store current positions such as GPS coordinates and maintain the list of neighboring nodes and their coordinates. Since MANET nodes are aware of the previous locations of neighboring nodes, they have the possibility to estimate current unknown positions of neighboring nodes. Other ways to find the positions of Blue warfighters could be a temporarily airlifted aerostat or UAV



9.6  Analysis of Selected Communications Alternatives in Scenario

187

that may fly across the distant area where distributed forces are operating. If the locations of warfighters cannot be detected by Blue ground-based nodes, it would not be effective using aerial assets to locate Blue forces, but these assets may provide communication services for distant warfighters. Although there are no continuous LoS communications from ground to air, occasional visibility is enough to obtain locations at time intervals. Aerostat would have a lower capability to detect locations from the fixed position, but doesn’t require as extensive a support organization as UAV requires. UAV may cover a larger area with better capability for detecting Blue positions, but it has limited operating time and needs more support. Since distributed warfighters are not operating in the direction of the main Red attack forces, the use of flying assets is not as insecure in these positions as at the frontline. If aerostat or UAV were used, the best way to deliver messages would be relaying them in the air to the distant aerostat or UAV counterparts. The altitude of a flying communications system defines the limits on the ways and how wide a coverage area is achieved among the ground-based users, but it is important to be aware of the varying performance of the air-ground path due to obstructions. As seen in Table 9.15, deployable military LTE communications, and physical delivery with manned platforms get the highest evaluation scores, followed by physical delivery with medium-sized UAV. Although aerostat is capable of providing long ranges, security and capacity factors are evaluated lower than with deployable military LTE. Concerning the high intensity in the first part, physical delivery with manned ground platforms is considered more robust and reliable than with UAVs. 9.6.2  Analysis of Part 2

The second part defensive retreat battles along the path from the border toward the central part of country B has the main goal of slowing down the speed of the Red attack and the movement of Blue forces inland where battles can’t continue due to lack of Blue. At the end of part 2, the main Red forces have advanced 40 km from the end position of part 1 in three days (70 km from the border) whereas the forward group of Red has advanced 30 km (80 km from the border). The main Blue forces have few alternatives

Physical delivery manned vehicle Physical delivery UGV Physical delivery UAV, small Physical delivery UAV, medium

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (30m) Wireless tactical 400 MHz 5W radios (30m) Wireless tactical radios 5W (2m warfighter) Deployable military 25W LTE BS 15m Wireless sensor node 100 mW, 2,400 MHz

Transmitter

Military LTE (2m warfighter) Wireless sensor node 100 mW, 2,400 MHz Physical delivery manned vehicle Physical delivery UGV Physical delivery UAV, small Physical delivery UAV, medium

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 400 MHz 5W radios (2m warfighter) Aerostat at 150m altitude

Receiver

N/A N/A N/A N/A

+10 +10 2 15

0.1

N/A

14.6

N/A

N/A

3.4

5–8

8

6.8

5–9

2

Range from Public Sources [km]

1.7

Range Estimation [km]

1

0

1

2

2

1

1

2

2

2

Robustness Factor

1

0

1

1

1

3

1

2

2

2

Security Factor

Table 9.15 Characteristics of Communications Alternatives in Part 1

3

3

3

3

0

3

1

2

1

1

Capacity Factor

3 (70 km/h

2 (20 km/h)

2 (30 km/h)

3 (50 km/h)

0

2

2

1

1

1

Time Advance Factor

8

5

7

9

3

9

5

7

6

6

Sum of Factors

188 Military Communications in the Future Battlefield



9.6  Analysis of Selected Communications Alternatives in Scenario

189

to approach inland because systems must maintain capability with the possibility to move quickly toward the Blue city. In addition, some forces may distribute along the main roads, but they cannot continue counterattacks over a long time, since they don’t have supporting units at all times. From the border to the Blue city is characterized by a mix of suburban and scarcely populated areas. Since the need for retreat of Blue forces is mandatory, there is a need for maintaining the communication and command chains between different units. Units may have to rely on rarely used ways to communicate, since several battles might have forced Blue forces to distribute into formations that are not favorable from the Blue perspective. The nonconnectedness of units, the lack of regular supporting force elements, and the increased level of engagement hinder freedom to maneuver in ways the Blue side wants. The terrain may provide opportunities and threats that must be utilized in maintaining coordination of Blue forces, although in unfamiliar organizational settings. As intelligence units were performing surveillance in a wide area near the border, new forces have succeeded in advancing to the border where they can engage advancing Red units in a limited way. With more Blue forces near the border, Blue has an increased capability to collect situational awareness data from the border, but they will need to deliver the information to the main forces on the move and forces in the Blue city. The Blue forces away from the main direction of attack must be kept secure as long as possible which affects the delivery of information. The speed of the Blue forces advance toward the Blue city should be maximized, but the speed of Red should be minimized, Red movement halted completely, or Red movement guided to paths most unfavorable from the Red perspective. The main Blue forces must now use their communications, since the OOB of forces is already known and they have to be aware of the situation in the previous location and near the border. The challenges of continuous movement on communications are great as there are few locations where command stations can be installed methodically. Since Red has succeeded in using unmanned assets in the Blue’s territory, Blue has to be prepared for surveillance, targeting, and engagement from the mid- and small-sized UAVs that are part of Red operations. This defensive retreat operation requires increased speed and mobility

190

Military Communications in the Future Battlefield

in contrast to the first part, since a powerful convoy of Red forces is advancing along the major roads toward the Blue city. The Blue side still needs time to build up forces to protect the outer perimeter of the Blue city, and must slow down the advancing Red units along the major routes. As in the part 1 forces performing ISR in wide areas apply to this part as well. As the main Red forces are focus on the major paths leading to the Blue city, tactical command stations can be utilized in wide area surveillance since there are less strict requirements to move command stations to other locations. UGVbased command stations could be applied here as well. Access to the optimal locations for sending and receiving messages to other stations might require the capability to advance in rough terrain. Wheel-based UGVs could be used along paths of varying quality resulting in greater mobility, but at the expense of picking less than ideal locations for command stations. Command stations might only be active at certain times previously agreed upon. Access to the fixed military communication infrastructure and backbone networks may be limited in these distant areas. Civilian or secure LTE communications has a required range for distant areas that might be utilized in sending some messages. To achieve the lowest path losses in communications, UAVs or aerostats could be used in communications between wide-area ISR units and command posts. One challenge for units operating in distant areas is limited support for UAV- or aerostat-based communications and the elevated probability of detection. Therefore, the size of the UAV or aerostat must be limited which shortens the operating time, payload, and capability to fly in varying weather conditions. Smaller platforms can utilize the blockage of terrain to limit detectability and they have the ability to operate at low altitudes. Again, lower altitudes limit the visibility of the platform to ground-based users and the use of LoS paths between warfighter terminals and UAVs. Also, lower flying altitude results in shorter areal coverage to groundbased users. If an aerostat or UAV were used, the best way to deliver messages would be to relay them in the air to distant aerostat or UAV counterparts. If the use of air-to-air relaying is not possible, the physical delivery of messages between source and destination could be carried out by UAVs, UGVs, or in the future autonomous unmanned systems that do not require radiation of communica-



9.6  Analysis of Selected Communications Alternatives in Scenario

191

tions signals from the platform. Distances between source and destination mandate the capability requirements for the type and size of the unmanned aerial system. The smaller breed of UAVs might be appropriate for performing missions in ideal conditions, but the weather and time of year must be considered, for example, moderate wind may severely affect the performance of the smaller range of UAVs. Using manned physical delivery of messages from a source to the destination should be considered as well, since this alternative maintains a physical human presence along the whole path. A human presence circumvents many vulnerabilities regarding functioning and reliability of technologies and can verify the arrival of the platform at the destination or if any damage occurred along the way. In the event of kinetic engagement, a human is more vulnerable in contrast to the small-sized UAV, but nonkinetic engagement has a fairly low impact on a warfighter if he or she is not in the middle of receiving signals during engagement. Therefore, weighing different alternatives to perform missions is not only a communications or C2 issue but an operational analysis issue as well. Choosing different solutions poses many direct and indirect consequences on the ability to carry out the main mission. As seen in Table 9.16, deployable military LTE communications, tactical military radios, and physical delivery with manned and unmanned platforms receive the highest evaluation scores. Time advance and capacity factors get higher values when using physical delivery. Since conditions in part 2 are different than part 1, the aerostat alternative may prove valuable due to its extended range. 9.6.3  Analysis of Part 3

The part 3 defensive battle near the critical area and swift change to offensive counteractions to win the battle is the final phase of the scenario from the communications perspective that takes place in the urban, suburban, and scarcely populated areas where parts of the Blue forces are distributed. By the end of this part, the main Red forces have advanced 10 km from the final position of part 2 in one day (80 km from the border), whereas the forward Red group has reached the Blue city (100 km from the border). The Blue city is important for Blue as it provides the communications infrastructure as along with appropriate locations for logistics centers and trans-

Receiver

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 400 Wireless tactical MHz 5W radios (30m) 400 MHz 5W radios (2m warfighter) Wireless tactical radios Aerostat at 150m 5W (2m warfighter) altitude Deployable military Military LTE (2m 25W LTE BS 15m warfighter) Wireless sensor node Wireless sensor 100 mW, 2,400 MHz node 100 mW, 2,400 MHz Physical delivery Physical delivery manned vehicle manned vehicle Physical delivery UGV Physical delivery UGV Physical delivery UAV, Physical delivery small UAV, small Physical delivery UAV, Physical delivery medium UAV, medium

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (30m)

Transmitter

2 8 N/A N/A 5–8 0.1 N/A N/A N/A N/A

6.8 3.4 14.6 5–9 N/A +10 +10 2 15

1

0

2

2

2

1

2

3

3

3

Range from Public Sources Robustness [km] Factor

1.7

Range Estimation [km]

2

0

2

2

1

3

2

3

3

3

Security Factor

Table 9.16 Characteristics of Communication Alternatives in Part 2

3

3

3

3

0

3

1

1

1

1

Capacity Factor

3 (70 km/h

0 (20 km/h)

1 (30 km/h)

2 (50 km/h)

0

2

3

2

2

2

9

3

8

9

3

9

8

9

9

9

Time Advance Sum of Factor Factors

192 Military Communications in the Future Battlefield



9.6  Analysis of Selected Communications Alternatives in Scenario

193

portation routes, but includes a number of civilians to be protected. Severe Red engagement has forced the Blue forces to take positions dictated by circumstance and regular military communications services have not been fully established. The Blue force has succeeded in bringing supporting forces to the perimeter of Blue city to strengthen protection. Red has managed to bring one brigade whose key capabilities have reached the perimeter of Blue city. Blue forces away from the main roads are observing the build-up of Red forces near the border to determine whether Red will succeed in bringing a second brigade to the Blue territory. Cyber operations have caused a reduction of Blue network capacity to half of normal capacity. Military and civilian networks are available approximately 50% of the time. Red forces have taken small-sized swarming tactical UAVs into use. Cooperation of UAVs with manned assets along with their capability to advance silently and undetected in different environments poses a challenge for Blue forces. Urbanization has been recognized as a long term global trend with many consequences for societies, the environment, and economies. Since a primary task of the military is to protect a nation’s territory against armed assault, the trend toward urbanization must be dealt with in the military planning as well. Based on the principles of warfare, the offensive side in the battle clearly requires more force to improve the probability of battlefield success compared to the defending side. In the past, military operations in urban environments have been challenging for the offensive side leading to the conclusion that more power is needed in urban environments than in others. This means military power in relative measures. Although the urban environment seems to favor the defending side, the defender is challenged by large civilian populations, vulnerable infrastructure, and limited ways to minimize collateral damage. As an urban environment gets damaged by an attack, there will be a need for usable paths, for example, for maintenance, logistics, and the functioning of normal city life. From the environmental perspective part 3 offers the best possibilities to utilize civilian or military infrastructure. The normal capacity of communications networks cannot be achieved, and beyond the lack of services there are cyber operations going on that change network use. Still, there is a need for maintaining

194

Military Communications in the Future Battlefield

communications between Blue city, ISR wide area surveillance, the units along the path toward the Blue city, and units near the border of Blue and Red. In the Blue city perimeter there are suburban locations where the existing communications infrastructure can be utilized. Within the Blue city area, there are many possibilities to perform maintenance tasks. With more Blue forces available, unmanned systems can be better utilized than in parts 1 and 2. Since the Blue forces must be prepared for a major attack near and in the city, there remains limited support for using several unmanned systems in the air. Military command stations with mast-based antennas are challenging in the urban environment––especially if there are dense formations of high buildings. The rooftops of high buildings are good locations for microcell devices or deployable communications solutions, for example, in the form of LTE or IoT access points. With suitable antennas attached to the rooftops, tactical military radios could be deployed to the buildings, but mast-based VHF antennas don not fit well into this environment. LoS ground-to-ground military communications are challenging. Therefore air-based relaying by UAVs or aerostats might provide possibilities for delivering messages from the ground to distant recipients and wired connections in the communications infrastructure. In an urban environment, a large number of civilian spectrum users, used frequencies, and limited data capacity call for spectrum awareness and agility to find frequencies of opportunity. On one hand CR features may show their real capability in this type of environment better than in part 2. On the other hand, spectrum awareness requires several sensors able to pick up emitters from databases or beneficial locations that limit the presence of hidden terminals. Since the spectrum may be very limited, the capability of CR to tune to a wide range of frequencies, reduce information to a minimum, and send it through several channels simultaneously or consecutively, will be valuable. The capability to operate cognitively based on learning in the spectrum, from the HF up to millimeter waves and optical waves, provides several paths to deliver messages. This could provide a wide range of spectrum blocks, but could also force a limited range of communications in the shortest wavelength.

Receiver

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 400 Wireless tactical 400 MHz 5W radios (30m) MHz 5W radios (2m warfighter) Wireless tactical Aerostat at 150m radios 5W (2m altitude warfighter) Deployable military Military LTE (2m 25W LTE BS 15m warfighter) Wireless sensor node Wireless sensor node 100 mW, 2,400 MHz 100 mW, 2,400 MHz Physical delivery Physical delivery manned vehicle manned vehicle Physical delivery UGV Physical delivery UGV Physical delivery Physical delivery UAV, UAV, small small Physical delivery Physical delivery UAV, UAV, medium medium

Wireless tactical 100 MHz 5W radios (2m warfighter) Wireless tactical 100 MHz 5W radios (30m)

Transmitter

2 N/A N/A N/A N/A 0.1 N/A N/A N/A N/A

6.8 4.5 14.6 1–5 N/A +10 +10 2 15

Range from Public Sources [km]

1.7

Range Estimation [km]

1

1 0

2

1

1

2

3

3

3

Robustness Factor

2

2 2

2

1

2

2

3

3

3

Security Factor

Table 9.17 Characteristics of Communications Alternatives in Part 3

3

3 3

3

0

2

0

1

0

0

2

8

7

8

7

7

2 (70 km/h

8

2 (30 km/h) 8 2 (20 km/h) 7

3 (50 km/h) 10

0

3

3

1

1

1

Capacity Time Advance Sum of Factor Factor Factors

9.6  Analysis of Selected Communications Alternatives in Scenario 195

196

Military Communications in the Future Battlefield

As seen in Table 9.17, deployable military LTE communications, tactical military radios, and physical delivery with manned and unmanned platforms get the highest evaluation scores. Time advance and robustness factors get higher values when using physical delivery with manned platforms. The urban environment doesn’t provide the best possibility to utilize the high speed of mediumsized UAVs. Since the Red force has both UGV and UAV assets supporting the attack near the Blue city, physical delivery with manned platforms gets the highest score. Tactical military radios as well as aerostats may prove valuable for enabling long-distance transmissions between Blue units surrounding the Blue city. Different capabilities between Blue and Red guide the choice of the communications alternative, operational tempo, and the importance of the time advance factor. In different operations, range, robustness, security, capacity and time advance factors have different values that may be weighed differently. It should be noted that only the subset of different communications alternatives presented previously was used in the evaluation of qualitative and quantitative factors. Certain changes to scenario parts, Blue and Red capabilities, operational areas, distances, and the number of data deliveries could set the factors to different values. For example, UAV relaying was not utilized in the calculation which might be a key capability in some operations. In this scenario, utilization of medium-sized UAVs in the Blue side would have tied limited forces to support UAV operations that would have had a great impact on the success of the Blue side in part 1 and part 2. 9.6.4  Further Steps for Improving Operational Trade-Off Analysis

The evaluation of qualitative factors was carried out by the author in three parts of this fictitious scenario. The range factor was calculated with propagation models and compared to parameters of products from public sources. If experts from various fields took part in the evaluation of qualitative factors; and accurate, measurement-based parameters would be used for range calculation with accurately modeled operational environments, this would result in important trade-offs in operations. Because the battlefield contains surprises and the need for adaptiveness beyond fixed plans, the evaluation of scenarios from different angles is an important tool



9.6  Analysis of Selected Communications Alternatives in Scenario

197

to prepare for paths that the future might hold. The quantitative consideration of communications ranges does not provide all the answers to C2 questions without considering all other (qualitative) factors that have effect on operations.

10 Conclusion This book introduced several aspects of military communications and provided future-focused analysis of C2 specifically focusing on communications. Several communications technologies, including commercial ones were covered underscoring the traditional military procurement approach consisting of long lifecycle products used in many countries.

10.1  Importance of Foresight in Capability Planning and the Role of Information Future projections, technology trends, technology roadmaps, and technology foresight describe critical, emerging, and disruptive technologies that contain elements that can be linked to the innovations and development of information technology. The role of information in the future battlefield is fundamental with linkages to traditional, cyber, and space domains. The long-term development of military capabilities, utilizing threat-based or capability-based 199

200

Military Communications in the Future Battlefield

planning, needs to keep C2 and network-centric capabilities high on the priority list, since these have a major impact on comprehensive operations and interoperability.

10.2  Evolving C2 in the Future Battlefield Since military hierarchy-based C2 is expected to prevail in the future operations of military organizations, the development of redundant and securing methods is needed, especially if wide-range connectivity between military and civilian actors appears as an alternative to connect sensors and shooters. In addition to providing hierarchy-based command chains, future systems will need the ability to establish ad hoc communications groups vertically and horizontally, irrespective of functionality, and for analytics-based information support to help actors at every level of organization. However, based on international discussions on this topic, it seems clear that future analytics-based systems will serve militaries in a supporting role, which will lessen the information burden of commanders, but not in autonomous decision-making roles. As the fundamental role of communications in C2 has been recognized, the increasing enthusiasm to connect every node to the military information domain may pose risks to future operations.

10.3  Future Warfare and Nature of Battle As the main constituents of the nature of warfare will be preserved in the future, several changes will happen to the nature of battle. The author shares a view of the future that sees warfare as a human endeavor with several changes at the tactical and operational level. The role of human as the decision-making actor will be supported by versatile technology and systems that allow commanders to focus on mission priorities. Systems with varying levels of autonomy will be used with the goal to protect forces and increase their capability. Physical safety, the reduction of cognitive burden, and the capability to operate in an analytics-augmented environment may allow warfighters to focus on their main tasks leaving the most hostile activities to machines. This will require different approaches to educate and train forces for future missions. Furthermore, since the



10.4  Coexistence of Legacy and Sophisticated Communications Systems

201

main elements current warfare will exist into the future, established ways to fight cannot be ignored. This leads back to threat- or capability-based planning whether future operations deal with robotics, conventional, asymmetric, or hybrid war, to name but a few.

10.4  Coexistence of Legacy and Sophisticated Communications Systems Military organizations use legacy systems and sophisticated wireless technology solutions in communications applications. As the commercial sector has become dominant in wireless communication technology development, military-grade communications equipment will follow by improving the best communications technology solutions security and robustness. A wide range of different communications solutions provide technology and system alternatives for military organizations. Military organizations need to find optimal and cost-effective equipment which may contain both civilian and military-grade equipment. Requirements for scalability, agility, interoperability, multifunctionality, mobility, and adaptive communications capacity may result in the simultaneous use of short lifecycle hardened civilian and long lifecycle military SDR or CR operating in heterogeneous networks with a combination of new and legacy systems.

10.5  Understanding of Radio Wave Propagation in Operating Areas and Accurate Mapping of the Environment Understanding radio wave propagation in different frequency bands and different communications environments requires simulation studies and field tests for better estimation of performance in future operations. Sensing and communications will be tightly interrelated having the potential for improved capability when used in combination with AI-based analytics and autonomous actors. Unmanned systems could play an important role in 3-D mapping of the environment, as aerial or ground-based relay stations, enabling local networking, and in physical delivery of messages between distant locations.

202

Military Communications in the Future Battlefield

10.6  Convergence of Sensors, Actors, and Communications Nodes IoT is developing into a modern sensor network and communications infrastructure that will contain high-speed and low latency, as well as low-speed and low-power consumption operation modes. If standardization leaves room for next generation applications, the 5G concept of IoT may prove successful in the long term. Man-machine teaming, interaction with smart machines, and augmented reality technologies create new opportunities to implement location-based services, force mixes consisting of robotic systems, and information-enriched situational picture applications expected to revolutionize the battlefield in the 2030s. These technologies will clearly affect the future battlefield, but with current understanding we can’t tell whether impacts will be negative or positive. We will need to train for new forms of operations with or without augmentation, if forces are going to be ready for information-centric warfare in the long term.

10.7  Spectrum Management and Sophisticated Forms of Military Radios SDR and more sophisticated CR technologies guide the way to future military communications. As scarce radio spectrum becomes congested, new ways to find windows of opportunity in the spectrum will be needed. Different actors in the spectrum must be collected from existing radio databases, as well as locally through local radio environment maps that list and detect emitters in the neighborhood. Although commercial demand is pushing military users to limited spectrum bands, there may be modes of operation that ensure military spectrum access in certain circumstances. These methods require careful preplanning and training to ensure the functioning of these mechanisms. With spectrum crowding there are shared spectrum users along with licensed primary users whose access to the spectrum has to be managed to avoid using the same frequency and time spots. Most up-to-date spectrum awareness requires spectrum usage observations from several locations. There is a need to develop equal opportunities for spectrum use among shared spectrum users. Spectrum usage may be governed



10.8  Alternative Forms of Military Communications Need Input

203

by the policies where certain users have low data rate spectrum access and other users may purchase spatiotemporally higher data capacities. Along with cost-based models there should be mechanisms for pinpointing spectrum for military users in specific situations. This requires communications technologies of civilian users, security users, and military users be based on cognitive and learning radios supported by infrastructure services. Low-power transmissions allow freer use of the spectrum as potential interference is very limited for other users. A limited range of high-speed wireless technologies (such as millimeter wave communications) and accurate orientation of optical waves enable implementations of local high data rate areas that might be connected to wired communications. In the long-term, if wireless infrastructure is based on CRs and ubiquitous IoT sensors, there will still be a need for different communications technologies at different frequency bands, since focusing communications to certain interoperable frequency ranges poses risks from EW and cyber perspectives.

10.8  Alternative Forms of Military Communications Need Input from Operational Excellence This book presented several alternative ways to communicate in the scenario developed in Chapter 2. The key takeaway from the analysis in Chapter 9 is that although there are visible paths to bring sophisticated and high-performance communications equipment to the battlefield, different alternatives must be carefully considered. Not only communications functionality, but all other factors that have consequences in military operations must be considered. Location-based first stored and later delivered messages may prove valuable in situations where forward and following units need to communicate with limited emissions via planned geographical locations. This may apply when one’s own emissions are restricted, and air-based relays can’t be used, but contains risk if in the fog of operation the following unit never achieves the position where the stored message is located. In addition, it may take too long between the store and delivery of the message, which might make the message inapplicable to the current situation.

204

Military Communications in the Future Battlefield

10.9  Low-Power Military Communications and LPI Requirements Just as spectrum is a scarce resource, it would be beneficial to use low transmission power while maintaining the range requirements for military units to maximize energy sources and detectability of communications. Two alternatives to implement this requirement are using LoS communications paths (raising ground-based communication masts high in elevated terrain) or using air-based assets that might also utilize aerial mobility. Ground-based communications using masts is slower than using air-based assets for future fast-paced operations. As tempo increases, these ground-based LOS communication assets must be brought back and to the side of the frontline. Air-based assets provide better mobility for fast-paced operations, but have limited operating time as well. Both alternatives require a large number of forces for signals operations support. When operated in hostile environments, air-based assets are under kinetic and nonkinetic threats. Therefore, air-based message delivery in a UAV-hostile environment cannot be the only communications alternative. Air-lifted aerostats such as LoS communications assets fall between UAV and ground-based communications. The takeoff and landing of aerostat assets takes a long time, and elevation heights are more limited than with typical UAVs, which results in shorter coverages. Aerostats require supporting forces as well, but there is a need for information when an aerostat at the other end of the LoS path is elevated to establish the best LoS link between the two aerostats. In addition to air-based relays, UAVs, and UGVs may be used as redundant communications path providers that extend the time the network can be maintained while traditional communications stations move to the next destination. Unmanned assets could provide command on-the-move functionalities temporarily to specific focus areas. MANETs have been in the core of tactical communications for several decades. D2D communications with or without backbone support (BS) may find its way via communications between warfighter user devices or via communications between warfighter user devices and any available infrastructure support whether cellular communications, Wi-Fi access nodes, or low-power WSNs



10.10  Unmanned Systems and Autonomy

205

that deliver a warfighter’s message over several hops in the dense WSNs. It is important to note that communications within the WSNs might allow temporary message storage to a specific node on way to the destination and the ability to forward it again to the destination as a result of a specific event (e.g., detected interference on every path to the destination and forwarding the message after the channel is released). Low-power distributed WSNs typically have very limited performance so messages intended for WSN delivery must be kept simple and small as an opposed to the current trend toward delivery of high-definition videos.

10.10  Unmanned Systems and Autonomy As unmanned systems develop toward higher levels of autonomy, unmanned systems can carry out physical delivery of messages from the origin to the destination. As autonomous features develop, radiation of antenna may be eliminated as there will be no need to control the flight by remote control. There are many efforts to develop different navigation mechanisms for autonomous platforms based on GNSS signals, beacon signals, relative navigation, correlation between image sensors, and stored terrain models and maps. Since there would be no emissions from communications, an autonomous platform could silently deliver a great volume of information from origin to destination. Again, in a hostile environment autonomous message delivery may face kinetic engagement, but wouldn’t be as vulnerable to nonkinetic engagement with no parts receiving high-power signals. If the receive function of the autonomous air system was a desired characteristic, the receiver antenna(s) could be directional antennas that would only receive from high angles from the ground up. Another way the autonomous air-based asset could receive ground-based messages would be to use optical communications. This is where the air receiver would contain wide-angle optics and the ground-based warfighter user devices would have very narrow beams for selective pointing when there might be several autonomous assets in the air simultaneously.

206

Military Communications in the Future Battlefield

10.11  Future Directions Whatever the future holds for military communications, it is certain that elements of past, current, and emerging systems must act in concert and also provide redundant paths if operations don’t go as planned. Future military communications may utilize several domains in parallel. Military communications must adapt in real-time to events in the spectrum to find optimal ways to deliver messages to the destination. Depending on the situation, spectrum availability, and the time-sensitivity of message delivery, messages could be routed through complex paths to avoid interference or temporarily stand still in a trusted, secure location on the way to the destination. Or, for preserving redundancy and reliable delivery, messages could be sent on several parallel paths, with time delays that would deviate from each other. Some paths would rely on physical delivery as well as wireless and wired transmissions. AI-based analytics would pinpoint paths affected by hostile activities that could be used in subsequent planning of message delivery.

Acronyms and Abbreviations ADSL

Asymmetric digital subscriber line

AI

Artificial intelligence

AJ

Anti-jamming

AM

Amplitude modulation

AR

Augmented reality

BPSK

Binary phase shift keying

BS

Base station

CBP

Capability-based planning

CBRN

Chemical, biological, radiological, and nuclear

CDMA

Code division multiple access

CONOPS

Concept of operations

CSS

Chirp spread spectrum

C2

Command and control

C3

Command, control, and communications

C3ISR

Command, control, communications, intelligence, surveillance, and reconnaissance

207

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Military Communications in the Future Battlefield

C4ISTAR

Command, control, communications, computers, intelligence, surveillance, target acquisition, and reconnaissance

C4

Command, control, communications, and computers

DOTMLPFI Doctrine, organization, training, materiel, leadership and education, personnel, facilities, and infrastructure DSSS

Direct-sequence spread spectrum

D2D

Device-to-device

EOB

Electronic order of battle

EOD

Explosive ordnance disposal

EMSO

Electromagnetic spectrum operations

EW

Electronic warfare

FHSS

Frequency-hopping spread spectrum

FM

Frequency modulation

FPGA

Field programmable gate array

GMTI

Ground moving target indicator

GNSS

Global navigation satellite systems

GPP

General purpose processor

HF

High frequency

HVT

High-value target

HW

Hardware

IF

Intermediate frequency

IoT

Internet of Things

ISR

Intelligence, surveillance, and reconnaissance

ITU

International Telecommunication Union

JCA

Joint Capability Areas

LoS

Line-of-sight

LPI

Low probability of intercept



Acroynms and Abbreviations

LTE

Long Term Evolution

MANET

Mobile ad hoc networks

MIMO

Multiple input multiple output

MOE

Measures of effectiveness

MS

Mobile station

NB

Narrowband

NCW

Network-centric warfare

NLoS

Non-line-of-sight

OOB

Order of battle

OODA

Object, orient, decide, and act

OPSEC

Operational security

PM

Phase modulation

PMR

Personal mobile radio

PN

Pseudo noise

QPSK

Quadrature phase shift keying

RF

Radio frequency

RFID

Radio frequency identification

R&D

Research and development

SCA

Software communications architecture

SDR

Software-defined radio

SIGINT

Signal intelligence

SINR

Signal to interference and noise ratio

SNR

Signal-to-noise ratio

SOC

System-on-chip

SS

Spread spectrum

SW

Software

SWaP

Size, weight, and power

209

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Military Communications in the Future Battlefield

THSS

Time-hopping spread spectrum

TTP

Tactics, techniques, and procedures

UAS

Unmanned aerial systems

UAV

Unmanned aerial vehicle

UGV

Unmanned ground vehicle

UHF

Ultrahigh frequency

VDSL

Very-high-bit-rate digital subscriber line

VHF

Very high frequency

VSWR

Voltage standing wave ratio

WB

Wideband

WRC

World Radiocommunication Conferences

WSAN

Wireless sensor and actuator networks

WSN

Wireless sensor networks

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About the Author Mr. Marko Suojanen received his M.Sc. degree in electrical engineering in 2002 at Tampere University of Technology with major studies in microelectronics and minor studies in communications circuits and industrial management. He has worked in research and R&D projects in several areas at Tampere University of Technology, Technical Research Centre of Finland, technology companies, and most recently at Finnish Defence Research Agency. His research interests include wireless communications, technology foresight, systems engineering, and operational analysis. Mr. Suojanen has been active in several international cooperation efforts and conferences. He has authored or coauthored several publications on high-voltage electromagnetic field modeling and simulation, lowpower wireless technologies, wireless sensor networks, technology foresight, war-gaming, and future military communications. He has been an active reviewer in the technical committees of the International Conference on Military Communications and Information Systems (ICMCIS) in 2013–2015, the International Conference on Advances in Cognitive Radio (COCORA) in 2015–2016 and the IEEE Systems conference (SYSCON) in 2015–2018. He has chaired technical sessions in relevant areas at COCORA 2014 and IEEE SYSCON 2015 conferences. The author participated in an international task group that was awarded with a Scientific Achievement Award in 2014.� 217

Index A Actuators IoT networks, 23, 117 mobile, 116 See also Wireless sensor and actuator networks Antennas characteristics, 71, 75, 95 dBd, 76 dBi, 76 dipole, 76 directional, 68, 71-72, 75, 79, 87-88, 95-96, 161, 170-75, 182, 205 far field, 76 Fraunhofer distance, 76 gain, 76, 80, 95 height, 174-97 in LoS links, 78-80, 95-96 in SDR, 124 in UAVs, 136 in the communications chain, 69 isotropic, 75-76, 101 monopole, 76 near field, 76

219

omnidirectional, 68, 71, 75, 95-96 polarizations, 75, 77 radiation patterns, 71, 75, 77, 205 receiver, 72, 95-96 sector, 154 size of, 97-98 transmitter, 71, 95 Anti-jamming, 68, 74 See also Electronic Warfare, and Non-kinetic engagement Artificial intelligence analytics in sensing and communications, 201, 206 communications stations, 160 cyber threats, 86 in cognitive radio, 128-29 in IoT networks, 118 in technology foresight, 22-24 situational awareness support, 90 support to warfighters, 85 See also Augmented reality, and Autonomous systems Augmented reality convergence of sensors, actors and communications, 202

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Augmented reality (continued) cyber threats, 86 in future warfare, 200 in interaction with smart objects, 86-89 in IoT networks, 117 location-specific messages and services, 45, 89-90, 150, 165 situational awareness support, 9092 support for finding communications opportunities, 92-94 See also Artificial intelligence Autonomous systems cyber threats, 92 development of, 142-44 ethical issues of, 118 in communications, 24-25, 33 in IoT networks, 117 in physical delivery of messages, 151, 160, 167, 190-91, 205 in technology foresight, 20, 22, 24 recognition of context, 85 self-improved situational awareness, 114, 132-33 See also Unmanned aerial systems, Unmanned aerial vehicles, Unmanned ground vehicles, and Robotics

B Base station, 21, 66-67, 80-81, 156-59, 173-74, 184, 204 See also Mobile station



See also Robustness factor, Security factor, Range factor, and Time Advance factor Chain of command, 20, 40 Coexistence, 128-29, 201 Cognition cycle, 127 Cognitive radio, 22, 126-30 See also Spectrum management, and Spectrum sensing Command and control as capability area, 31-32 definitions, 32 in capability-based and threatbased planning, 36-38, 146-48 in future warfare, 20-22, 200 in joint capability areas, 40-43 in network-centric warfare, 33-34 in scenario-based approach, 43-46 in unmanned systems, 141-42 Command-on-the-move, 64, 78, 183 Concept of operations, 21, 26, 32 Context awareness, 65, 83-86, 89-91, 116-18 See also Situational Awareness Control center, 24, 131-32 COST 231 – Hata model, 100, 103-04

D Digital signal processing, 68, 126 Disinformation, 145 See also Information, and Information superiority Disruptive technology, 21-22, 199 Doctrine, 37-38 Dynamic spectrum access, 124, 159

C Capability-based planning, 20, 34-38, 43, 148, 199-201 See also Threat-based planning Capacity factor, 168-72, 187, 191

E Egli model, 100, 102, 173-76 Electronic order of battle, 40 See also Order of battle



Index

Electronic warfare future military radios, 203 in different operating environments, 46-50 in relation to antenna type, 95-96 in scenario description, 52, 54, 5758, 179-80 in threat- and capability-based planning, 36 in UAV applications, 134 trade-offs in emission control, 15253

F Field programmable gate array, 125-28 Flight time, 133-34, 140, 161 See also Operating time Force multiplier, 33, 39-40, 129-30, 135, 149 Free-space loss, 100-01, 174-76 See also Line-of-sight Freedom of operation, 52, 65, 134

G General purpose processor, 126, 128

H High-value target, 24-25, 135

I Information in communications channel disruptions, 45 in future warfare, 18-21, 199-200 in horizontal and vertical delivery, 78 in information superiority and information-based operations, 33-34 in information warfare, 15-18

221



in IoT networks, 120-21 in processing, 69 in situational awareness, 83-86, 8994, 111-15, 202 role in command and control, 21-26, 169-73 Information superiority, 33, 118-19, 135 Internet of things cyber issues, 120-22 in heterogeneous networks, 163-64, 194, 202-03 in selected civilian communications systems, 77, 80, 157 in situational awareness, 108, 11619, 184 in smart objects, 88 in technology foresight, 22-23 Interoperability, 32-33, 37, 41, 124-30, 143-44, 163, 199-201

J Joint Capability Areas, 40-43 See also Capability-based planning Joint Tactical Radio Systems, 125-26

K Kinetic engagement in scenario, 46, 54-57 in unmanned vehicles, 133-35, 138, 141, 180-81, 191 requirements, 43, 153, 172, 204-05 See also Non-kinetic engagement

L Latency, 85, 91, 145, 202 Legacy systems, 37, 64, 78, 124-26, 129, 158, 201 Line-of-sight communications links at higher transmission frequencies, 21, 71-72, 96

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Line-of-sight (continued) free-space loss, 64-66, 98, 101, 13435, 141, 155-56, 174-76 in different operating environments, 47-50, 78-79 in relaying, 160-61, 183, 187, 190, 194, 204 Low probability of intercept, 73, 204

P

M

R

Mobile station, 21, 66-67, 80, 81, 173, 184

Radar, 53, 107, 135, 156, 161, 178 Range factor, 167-68, 171-73, 175-76, 196-97 See also Robustness factor, Security factor, Capacity factor, and Time Advance factor Receiver characteristics, 72-75 fading, 96-97 in cognitive cycle, 127-28 in communications chain, 67-71 sensitivity, 80, 98-100 Relaying air-based, 45, 66, 93-94, 135, 150-51, 155-56, 159-63, 183-84, 187, 190, 194, 196 between autonomous systems, 24 challenges of, 201, 203-04 in wireless sensor networks, 113-14 Robotics, 16, 23, 131-32, 137-39, 200-01 Robustness factor, 167-68, 171-72, 196 See also Security factor, Capacity factor, Range factor, and Time Advance factor

N Network-centric warfare, 33-34, 99, 118-19, 143 Non-kinetic engagement in scenario, 46, 54-57 in unmanned vehicles, 133-36, 138, 141, 180-81, 191 requirements, 43, 153, 171-72, 20405 See also Kinetic engagement

O Okumura-Hata model, 100, 102-03, 175-76, 183-85 Operating area, 51, 56, 134, 201 Operating time, 91-92, 136, 187, 190, 204 Operational security, 146-47 Operational tempo characteristics of military operations, 41-42, 78, 147, 154-55 consequences for communications, 170-74, 183-84, 196, 204 in future warfare, 20 Order of battle, 38, 153, 189

Payload, 55, 93-94, 131-38, 140-41, 180, 190 Physical delivery, 150-51, 166-67, 16973, 187-88, 190-96, 201, 205-06 Plane earth model, 100-01, 174-76, 179 Primary user, 93-94, 110-11, 124, 127-28, 142, 202-03

S Scenario-based approach, 43-44, 147-48 Security factor, 167-69, 171-72 See also Robustness factor, Capacity factor, Range factor, and Time Advance factor



Index

Self-learning, 121, 128-29, 143 Sensor data collection, 67, 69, 83-86, 90, 107-08 in Network-centric warfare, 33 multisensors, 94, 112-13, 119, 194, 200 payloads, 132-35, 140-41, 166-67, 205 related to communications, 146, 148, 160, 163, 174, 202-03 types, 107-09 Situational awareness based on sensor data collection, 107, 110, 112, 114, 119-20 battlespace awareness, 40 communications perspective, 146, 159, 163 in augmented reality applications, 89-94 in capability-based planning and operations, 19-20, 83-86, 202 in scenario, 53, 178, 189 using unmanned systems, 134, 135, 137 Smart object, 86-88, 116 Software Communications Architecture, 128 Software-defined radio, 22, 119-20, 12329, 150, 158, 201-02 Spectrum management, 33, 123, 202-03 Spectrum sensing, 128-29 Swarm in scenario, 60, 193 in technology foresight, 23-25 in unmanned systems, 131, 133-34, 137-39, 141-44, 151 See also Autonomous systems and Robotics System-on-chip, 126-27

223

T Threat-based planning, 34-37, 43, 148, 199-200 See also Capability-based planning Time advance factor, 167-68, 170-73, 183, 196 See also Robustness factor, Security factor, Range factor, and Capacity factor Transmitter characteristics, 74-76, 95-96, 98-99, 162, 165-66, 186 in cognitive radio, 127-28 in communications chain, 25, 67-72, 175-76 in electronic order of battle, 40

U Ubiquitous computing, 22, 27, 84, 8687, 89, 116, 203 Unmanned aerial systems, 131-32, 13334, 136� Unmanned aerial vehicles characteristics of operating environments, 47-50 communications, 135-37, 140-44, 149-51, 155-56, 160-62, 193-94, 196 in scenario, 53, 55, 58-60, 180, 18284, 186-87, 189-91 types of, 112, 133-35 using physical delivery, 166-67, 204 Unmanned ground vehicles characteristics, 134, 138-39 in communications, 93-94, 136-38, 142, 149-51, 183, 190, 204 in scenario, 58-59 types of, 138-40 using physical delivery, 166-67, 196

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W Waveform, 69, 77-78, 124-26, 128, 156, 159, 163 Wireless sensor networks characteristics of, 107-15, 184 in communications, 93, 150, 164, 204-05



in selected civilian communications systems, 77-78, 80-81 low probability of intercept, 65-66 Wireless sensor and actuator networks, 114, 116-17