Oswald Jumira, MIH Media Lab, Department of Electrical and Electronic Engineering, University of Stellenbosch, Stellenbosch, South Africa. Sherali Zeadally, Associate Professor University of the District of Columbia, Washington DC, USA.

• PREFACE ixCHAPTER 1. ENERGY EFFICIENCY IN CELLULAR NETWORKS  11.1. Overview of cellular communication networks 11.2. Metrics for measuring energy efficiency in cellular wireless communication systems 41.3. Energy efficiency in base stations 41.4. Energy-efficient cellular network design 101.5. Interference management and mitigation 111.6. Enabling technologies 121.6.1. Energy-efficient communication via cognitive radio 121.6.2. Using cooperative relays to support energy-efficient communication 131.6.2.1. Enabling energy-efficient communication via fixed relays 141.6.2.2. Communications in cellular networks via user cooperation 15CHAPTER 2. ENERGY EFFICIENCY IN WIRELESS AD HOC NETWORKS 172.1. Overview of wireless ad hoc networks 172.2. Metrics for measuring energy efficiency in wireless ad hoc networks 182.3. Energy losses in wireless ad hoc networks 192.4. Energy efficiency in wireless sensor networks 202.4.1. Energy efficiency in wireless sensor networks 212.5. Mobile ad hoc networks (MANETs) 322.5.1. Energy efficiency in mobile ad hoc networks 33CHAPTER 3. ENERGY EFFICIENCY IN WIRELESS LOCAL AREA NETWORKS 373.1. Overview of wireless local area networks 373.2. Energy consumption metrics for WLANs 393.3. Energy efficiency in WLANs 403.3.1. Physical layer-based energy-efficient schemes 403.3.2. Medium access control (MAC) layer-based energy-efficient schemes 403.3.3. Cross-layer-based energy-efficient schemes 433.4. Energy efficiency strategies in IEEE 802.11n 46CHAPTER 4. ENERGY HARVESTING IN WIRELESS SENSOR NETWORKS 494.1. Energy harvesting 494.1.1. The harvesting concept 534.1.1.1. Universal energy-harvesting model 544.2. Harvesting techniques 554.2.1. Mechanical energy sources 554.2.2. Thermal energy sources 574.2.3. Radiation energy sources 584.2.4. Comparison of harvesting sources 604.3. Energy harvesting storage devices 614.4. Power management for EH-WSN 624.4.1. Discussion on power management for energy harvesting systems 634.5. Conclusion 64CHAPTER 5. FUTURE CHALLENGES AND OPPORTUNITIES 655.1. Energy efficiency in cellular networks 655.1.1. Low-energy spectrum sensing 665.1.2. Energy-aware medium access control and energy-efficient routing 665.1.3. Energy-efficient resource management in heterogeneous cellular networks 675.1.4. Cross-layer design and optimization 675.1.5. Energy considerations in practical deployments of cooperative and cognitive radio systems 685.2. Energy efficiency in ad hoc networks 695.2.1. Sampling techniques 695.2.2. MAC protocols 705.2.3. Routing 705.2.4. Mobility challenges 715.2.5. Cognitive radio technology applied in wireless ad hoc networks 715.3. Energy efficiency in WLAN 715.3.1. IEEE 802.11ac (gigabit Wi-Fi) 715.3.2. MIMO-based WLAN 725.3.3. Super Wi-Fi (IEEE 802.22) 725.4. Energy harvesting in wireless sensor networks 735.4.1. Challenges for energy harvesting in harsh conditions 735.4.2. Radiation-based energy harvesters 745.4.3. Mechanical sources 745.4.4. Thermal sources 755.4.5. Medical energy harvesting for wireless sensor devices 755.5. Energy efficiency for wireless technologies for developing countries 76BIBLIOGRAPHY 79LIST OF ACRONYMS 97INDEX 101