This book focuses on the emerging research topic "e;green (energy efficient) wireless networks"e; which has drawn huge attention recently from both academia and industry. This topic is highly motivated due to important environmental, financial, and quality-of-experience (QoE) considerations. Specifically, the high energy consumption of the wireless networks manifests in approximately 2% of all CO2 emissions worldwide. This book presents the authors visions and solutions for deployment of energy efficient (green) heterogeneous wireless communication networks. The book consists of three major parts. The first part provides an introduction to the "e;green networks"e; concept, the second part targets the green multi-homing resource allocation problem, and the third chapter presents a novel deployment of device-to-device (D2D) communications and its successful integration in Heterogeneous Networks (HetNets). The book is novel in that it specifically targets green networking in a heterogeneous wireless medium, which represents the current and future wireless communication medium faced by the existing and next generation communication networks. The book focuses on multi-homing resource allocation, exploiting network cooperation, and integrating different and new network technologies (radio frequency and VLC), expanding the network coverage and integrating new device centric communication paradigms such as D2D Communications. Whilst the book discusses a significant research topic supported with advanced mathematical analysis, the resulting algorithms and solutions are explained and summarized in a way that is easy to follow and grasp. This book is suitable for networking and telecommunications engineers, researchers in industry and academia, as well as students and instructors.

Muhammad Ismail: Postdoctoral Research Associate, Electrical and Computer Engineering Department, Texas A&M University at Qatar, Doha, Qatar. Dr. Ismail's area of expertise is related to radio resource allocation in a heterogeneous wireless medium. He is a co-recipient of the best paper award at IEEE ICC '14 for a paper related to green resource allocation in a heterogeneous wireless medium: M. Ismail, A. T. Gamage, W. Zhuang, and X. Shen, "Energy efficient uplink resource allocation in a heterogeneous wireless medium," IEEE ICC'14, (to be listed in IEEExplore).

Muhammad Zeeshan Shakir: Assistant Research Scientist, Electrical and Computer Engineering Department, Texas A&M University at Qatar, Doha, Qatar. Dr. Shakir's research interests include design and deployment of diverse green wireless communication systems including hyper-dense heterogeneous small-cell networks with particular focus on traffic offloading techniques and backhauling technologies. He has published more than 50 technical journal and conference papers and has contributed to 6 books.

Khalid Qaraqe: Professor, Electrical and Computer Engineering Department, Texas A&M University at Qatar, Doha, Qatar. Dr. Qaraqe has over 15 years of experience in the telecommunications industry. He has worked for Qualcomm, Enad Design Systems, Cadence Design Systems/Tality Corporation, STC, SBC and Ericsson. His research interests include communication theory and its application to design and performance analysis of cellular systems and indoor communication systems. Particular interests are in the development of 4G LTE, cognitive radio systems, broadband wireless communications and diversity techniques.

Erchin Serpedin: Professor, Electrical and Computer Engineering Department, Texas A&M University, College Station, Texas, USA. Dr. Serpedin is the author of two research monographs, one edited textbook, 100 journal papers and 180 conference papers, and has served as associate editor for approximately 12 journals including IEEE Transactions on Information Theory, IEEE Signal Processing Magazine, IEEE Transactions on Communications, and IEEE Communications Letters. His research interests include signal processing, wireless communications, computational statistics, and bioinformatics and systems biology. He is currently serving as editor in chief of the Eurasip Journal on Bioinformatics and Systems Biology, an online journal edited by Springer. He is also an IEEE Fellow.

This book focuses on the emerging research topic "green (energy efficient) wireless networks" which has drawn huge attention recently from both academia and industry. This topic is highly motivated due to important environmental, financial, and quality-of-experience (QoE) considerations. Specifically, the high energy consumption of the wireless networks manifests in approximately 2% of all CO2 emissions worldwide. This book presents the authors' visions and solutions for deployment of energy efficient (green) heterogeneous wireless communication networks. The book consists of three major parts. The first part provides an introduction to the "green networks" concept, the second part targets the green multi-homing resource allocation problem, and the third chapter presents a novel deployment of device-to-device (D2D) communications and its successful integration in Heterogeneous Networks (HetNets).

The book is novel in that it specifically targets green networking in a heterogeneous wireless medium, which represents the current and future wireless communication medium faced by the existing and next generation communication networks. The book focuses on multi-homing resource allocation, exploiting network cooperation, and integrating different and new network technologies (radio frequency and VLC), expanding the network coverage and integrating new device centric communication paradigms such as D2D Communications. Whilst the book discusses a significant research topic supported with advanced mathematical analysis, the resulting algorithms and solutions are explained and summarized in a way that is easy to follow and grasp. This book is suitable for networking and telecommunications engineers, researchers in industry and academia, as well as students and instructors.

Preface xi

Acknowledgements xiii

Dedication xv

Part I INTRODUCTION TO GREEN NETWORKS

1 Green Network Fundamentals 3

1.1 Introduction: Need for Green Networks 3

1.2 Traffic Models 5

1.2.1 Traffic Spatial Fluctuation Modelling 6

1.2.2 Traffic Temporal Fluctuation Modelling 8

1.3 Energy Efficiency and Consumption Models in Wireless Networks 9

1.3.1 Throughput Models 9

1.3.2 Power Consumption Models 10

1.3.3 Energy Efficiency and Consumption Models 19

1.4 Performance Trade-Offs 23

1.4.1 Network-side Trade-Offs 24

1.4.2 Mobile User Trade-Offs 26

1.5 Summary 28

2 Green Network Solutions 29

2.1 Green Solutions and Analytical Models at Low and/or Bursty Call Traffic Loads 29

2.1.1 Dynamic Planning 29

2.1.2 MT Radio Interface Sleep Scheduling 34

2.1.3 Discussion 37

2.2 Green Solutions and Analytical Models at High and/or Continuous Call Traffic Loads 38

2.2.1 Scheduling for Single-Network Access 38

2.2.2 Scheduling for Multi-Homing Access 41

2.2.3 Scheduling with Small-Cells 41

2.2.4 Relaying and Device-to-Device Communications 42

2.2.5 Scheduling with Multiple Energy Sources 45

2.2.6 Discussion 47

2.3 Green Projects and Standards 48

2.4 Road Ahead 49

2.5 Summary 52

Part II MULTI-HOMING RESOURCE ALLOCATION

3 Green Multi-homing Approach 55

3.1 Heterogeneous Wireless Medium 55

3.1.1 Wireless Networks 56

3.1.2 Mobile Terminals 57

3.1.3 Radio Resources and Propagation Attenuation 57

3.2 Green Multi-homing Resource Allocation 58

3.3 Challenging Issue…