Energy efficiency analysis of energy harvesting relay-aided cooperative networks

Cooperative relaying is a promising technology which can improve the energy efficiency of cellular networks. However, the relays´ static power consumption may cancel out the energy saved by the deployed relays. Energy harvesting (EH) technique is introduced for relay nodes in cellular networks in order to deploy flexibility and reduce the energy charge. Due to the EH property, relay nodes cannot maintain a stable energy flow and keep active with a certain probability, which would degrade the benefit from relay-aided cooperative transmission. In this paper, an analytical model is proposed to investigate the energy efficiency of cellular networks aided by EH relay nodes. Meanwhile, the closed-form expressions of coverage probabilities and mean achievable rates for different links are derived. Numerical results show that EH relays bring more improvement on energy efficiency compared with non-EH relayed transmission. The influence of the density and transmit power of stations is also given through numerical simulation.