Combining Time Switching Energy Harvesting and Relay Selection for Energy-Efficient Cooperative Communication Networks

Cooperative communication system is a promising candidate to support 5G communication technology because it has the ability to overcome multipath fading and increase channel capacity. Relay is an important part of forwarding information to the destination in a cooperative network. When a relay works continuously, its energy will be depleted quickly, shortening the network's lifetime. The increasing demand for multimedia data services also increases the power consumption of relays and networks. In this paper, a combined time switching energy harvesting (EH) and relay selection (RS) system, referred to as a multi-relay EHRS network, is proposed to improve the energy efficiency of cooperative communication networks. The proposed network model is introduced by considering the fading of the mixed Rician and Rayleigh channels. It also presents the detailed EH and RS processes in the network. The throughput and energy efficiency of the proposed and conventional networks, i.e., multirelay with and without RS, are analyzed and simulated. The simulation results show that the throughput of the proposed network is higher than that of the conventional networks. The energy efficiency of the proposed network is also more efficient than those of the two conventional networks. When a distance from source to destination is 150 m, the proposed multi-relay EH-RS could save energy by 84.8% compared to conventional multi-relay RS and 95.6% compared to conventional multirelay networks. Therefore, the proposed multi-relay EH-RS network could become an appropriate cooperative method to support future 5G technologies.