37. RF-Based Energy Harvesting Cognitive Cellular Networks

Recently, fundamental research has demonstrated great potentials of integrating radio frequency (RF) energy harvesting techniques into cognitive cellular networks (CCNs). Such an integration can improve spectrum utilization and energy efficiency of wireless communication services. In CCNs with RF energy harvesting capability, when cellular base stations, i.e., primary transmitters, transmit signals to their mobile devices, secondary users (SUs) can harvest energy from the cellular channel, i.e., the primary channel, and store the energy in their batteries. Then, when the cellular channel becomes idle, the SUs can use the harvested energy to transmit data to their receivers. As such, we can utilize not only the available spectrum when the channel is idle but also energy scavenging when the channel is busy. This chapter first presents an overview of RF-based energy harvesting CCNs. Then, limitations are discussed, and some new solutions using ambient backscattering communication techniques are introduced to overcome the limitations. Finally, the chapter concludes with a discussion on the development of such networks and possible research directions.