Joint Optimal Power Allocation and Relay Selection in Full-Duplex Energy Harvesting Relay Networks

In this paper, the optimal power allocation and relay selection problems in full-duplex (FD) relay networks are investigated, where the amplify-and-forward (AF) relays are wireless powered by energy harvesting technology. The entire transmission process is divided into wireless energy harvesting phase and full-duplex information transfer phase, which is termed as the time switching scheme. For wireless full-duplex relay networks, the transmit power of the source node is always same in the two phase. Therefore, the proposed joint optimal power allocation and relay selection strategy can obtain the different transmit power of the source node in two phase and then select the optimal cooperative relay from the relay set, which aims to maximize the information rate under the condition of total power limitation. Using Lagrangian multiplier method, the closed-form expressions of optimal transmit power can be obtained. In addition, two cases depending on the number of antennas used for energy harvesting are considered, which can fully exploit the hardware resources. Simulation results show that the proposed FD scheme has better performances than the existing schemes.