Preface xi Acronyms xiii 1 Introduction 1 1.1 Background 1 1.2 Relationship with Green Communications 2 1.3 Potential Applications 3 1.3.1 Energy Harvesting for 5G 3 1.4 Outline of Chapters 4 2 Energy Sources 5 2.1 Introduction 5 2.2 Types of Sources 6 2.2.1 Mechanical Energy 6 2.2.2 Solar/Light Energy 8 2.2.3 Electromagnetic Energy 9 2.3 Predictive Models of Sources 9 2.3.1 Solar Energy Modeling 10 2.3.2 Ambient RF Energy Modeling 12 2.4 Summary 16 3 Energy Harvesters 19 3.1 Introduction 19 3.2 Photovoltaic Panels 19 3.2.1 Principles 20 3.2.2 Models 22 3.3 Radio Frequency Energy Harvester 25 3.3.1 Principles 26 3.3.2 Efficiencies 28 3.4 Overall Models 31 3.5 Battery and Supercapacitor 35 3.5.1 Battery 35 3.5.2 Supercapacitor 36 3.6 Summary 36 4 Physical Layer Techniques 39 4.1 Introduction 39 4.2 Effect of Energy Harvesting 40 4.2.1 Distribution of Transmission Power 41 4.2.2 Transmission Delay and Probability 43 4.2.3 Bit Error Rate 47 4.2.4 Achievable Rate 52 4.2.5 General Information Theoretic Limits 54 4.3 Energy Harvesting Detection 55 4.4 Energy Harvesting Estimation 61 4.4.1 With Relaying 62 4.4.1.1 Scheme 1 62 4.4.1.2 Scheme 2 66 4.4.1.3 Scheme 3 68 4.4.1.4 Scheme 4 70 4.4.1.5 Scheme 5 71 4.4.1.6 Scheme 6 72 4.4.2 Without Relaying 79 4.5 Energy Transmission Waveform 83 4.5.1 Scenario 84 4.5.2 Energy Waveform Optimization 85 4.5.2.1 Linear Harvester 85 4.5.2.2 Non-Linear Harvester 86 4.6 Other Issues and Techniques 88 4.6.1 Circuit Power Consumption 88 4.6.2 Physical Layer Security 89 4.6.3 Non-orthogonal Multiple Access 91 4.6.4 Joint Detection and Estimation 92 4.7 Summary 98 5 Upper Layer Techniques 101 5.1 Introduction 101 5.2 Media Access Control Protocols 102 5.2.1 Duty Cycling 102 5.2.1.1 Wireless Power Transfer 103 5.2.1.2 Ambient Energy Harvesting 107 5.2.2 Other Issues in MAC Protocols 110 5.3 Routing Protocols 111 5.3.1 Ambient Energy Harvesting 112 5.3.2 Wireless Power Transfer 117 5.4 Other Issues in the Upper Layers 118 5.4.1 Scheduling 118 5.4.2 Effective Capacity 121 5.5 Summary 123 6 Wireless Powered Communications 125 6.1 Introduction 125 6.2 Types of Wireless Powered Communications 126 6.3 Simultaneous Wireless Information and Power Transfer 127 6.3.1 Ideal Implementations 128 6.3.2 Practical Implementations 130 6.3.2.1 Time Switching 130 6.3.2.2 Power Splitting 132 6.3.2.3 General Scheme 134 6.4 Hybrid Access Point 135 6.4.1 Rate-Energy Tradeoff 135 6.4.2 Fairness Issue 138 6.4.3 Channel Knowledge Issue 138 6.4.3.1 Average Achievable Rate 139 6.4.3.2 Average BER 141 6.4.3.3 Numerical Examples 144 6.5 Power Beacon 150 6.5.1 System and Design Problem 150 6.5.2 More Notes 152 6.6 Other Issues 153 6.6.1 Effect of Interference onWireless Power 153 6.6.1.1 System and Assumptions 153 6.6.1.2 Performances with Interference 154 6.6.1.3 Performances without Interference 155 6.6.1.4 Numerical Examples 155 6.6.2 Effect of Interference byWireless Power 157 6.6.2.1 System and Assumptions 158 6.6.2.2 Average Interference Power 159 6.6.2.3 Rate 159 6.6.2.4 Numerical Examples 161 6.6.3 Exploitation of Interference 163 6.6.4 Multiple Antennas 169 6.7 An Example: Wireless Powered Sensor Networks 172 6.8 Summary 172 7 Energy Harvesting Cognitive Radios 175 7.1 Introduction 175 7.1.1 Cognitive Radio 175 7.1.2 Cognitive Radio Functions 177 7.1.3 Spectrum Sensing 177 7.1.4 Energy Harvesting Cognitive Radio 178 7.2 Conventional Cognitive Radio 180 7.2.1 Different Types of Cognitive Radio Systems 180 7.2.2 Spectrum Sensing Methods 182 7.2.2.1 Energy Detection 182 7.2.2.2 Feature Detection 186 7.3 Types of Energy Harvesting Cognitive Radio 189 7.3.1 Protocols 189 7.3.2 Energy Sources 190 7.4 From the Secondary Base Station 192 7.5 From the Primary User 198 7.5.1 Conventional PU 198 7.5.2 Wireless Powered PU 204 7.6 From the Ambient Environment 210 7.7 Information Energy Cooperation 215 7.8 Other Important Issues 217 7.9 Summary 218 8 Energy Harvesting Relaying 221 8.1 Introduction 221 8.1.1 Wireless Relaying 221 8.1.2 Relaying Protocols 222 8.1.3 Energy Harvesting Relaying 223 8.2 Conventional Relaying 224 8.2.1 Amplify-and-Forward Relaying 224 8.2.2 Decode-and-Forward Relaying 225 8.2.3 Performance Metrics 226 8.2.3.1 Amplify-and-Forward 226 8.2.3.2 Decode-and-Forward 227 8.2.4 Relay Selection 229 8.2.4.1 Full Selection 231 8.2.4.2 Partial Selection 231 8.2.5 Two-Way Relaying 233 8.3 Types of Energy Harvesting Relaying 235 8.4 From the Ambient Environment 237 8.5 From the Power Transmitter 241 8.5.1 One User and Single Antenna 241 8.5.2 Multiple Users and Single Antenna 242 8.5.3 One User and Multiple Antennas 244 8.6 From the Source 246 8.6.1 Amplify-and-Forward Relaying 247 8.6.2 Decode-and-Forward Relaying 250 8.6.2.1 Instantaneous Transmission 251 8.6.2.2 Delay- or Error-Constrained Transmission 253 8.6.2.3 Delay- or Error-Tolerant Transmission 254 8.6.2.4 Numerical Examples 255 8.6.3 Energy Harvesting Source 260 8.7 Other Important Issues 270 8.7.1 Interference 270 8.7.1.1 Time Switching 271 8.7.1.2 Power Splitting 273 8.7.2 Multi-Hop 275 8.7.2.1 Time Switching 276 8.7.2.2 Power Splitting 280 8.7.2.3 Numerical Examples 282 8.7.3 Others 291 8.8 Summary 292 References 293 Index 307

PROVIDES A SYSTEMATIC OVERVIEW OF A HOT RESEARCH AREA, EXAMINING THE PRINCIPLES AND THEORIES OF ENERGY HARVESTING COMMUNICATIONS This book provides a detailed and advanced level introduction to the fundamentals of energy harvesting techniques and their use in state-of-the-art communications systems. It fills the gap in the market by covering both basic techniques in energy harvesting and advanced topics in wireless communications. More importantly, it discusses the application of energy harvesting in communications systems to give readers at different levels a full understanding of these most recent advances in communication technologies. The first half of Energy Harvesting Communications: Principles and Theories focuses on the challenges brought by energy harvesting in communications. The second part of the book looks at different communication applications enhanced by energy harvesting. It offers in-depth chapters that: discuss different energy sources harvested for communications; examine the energy harvesters used for widely used sources; study the physical layer and upper layer of the energy harvesting communications device; and investigate wireless powered communications, energy harvesting cognitive radios, and energy harvesting relaying as applications. Systematically examines state-of-the-art energy harvesting techniquesProvides comprehensive coverage from basic energy harvesting sources and devices to the end usersLooks at the fundamental principles of energy harvesting communications, biomedical applications and intra-body communicationsWritten in a linear order so that beginners can learn the subject and experienced users can attain a broader view Written by a renowned expert in the field, Energy Harvesting Communications: Principles and Theories is an excellent resource for students, researchers, and others interested in the subject.