ABSTRACT
Energy efficiency and spectrum efficiency are two critical issues in wireless communications. Previously, much effort has been on efficient use of the spectrum via various technologies such as compressive sensing and spectrum sensing [42]. On the other hand, a battery-operated wireless network must operate in an energy conservation manner so as to extend the lifetime of the network. Particularly in the development of the Internet of Things (IoT), energy efficiency is becoming equally or even more important in contrast to spectrum efficiency and prompting new waves of research activities. To achieve high energy efficiency, approaches have been proposed to deal with the problem from different angles across the layers from hardware up to application. These include efficient energy management techniques for peripheral devices on hand-held and embedded hardware platforms [43], energyefficient medium access control design [44], energy-aware routing algorithm
and topology generation [45, 46, 47], and energy-efficient algorithms for broadcast and multicast applications [48]. While each of these areas has received a lot of attention separately in recent years, a joint design of energy efficiency across the layers remains very limited due to the complexity of this problem. Our aim is to tackle the energy efficiency problem from cooperative transmission, relay selection, and scheduling perspectives in a batterypowered wireless network.
