Energy Harvesting Based Relay Selection in Cooperative Wireless Networks

In this paper, we address the relay selection problem in the cooperative energy harvesting (EH) network where the optimal mobile terminal will be selected as the relay if it can obtain expected profits. We model the utility as the power difference between the collected energy by using the time switching (TS) EH technique and the consumed energy by relaying signals. This relay selection problem is formulated as a convex optimization problem with nonlinear constraints. An interior point penalty function based method is proposed to approach the global optimal result. The iteration algorithm is described and the simulations are presented. Simulations unveil there is a tradeoff between the optimal TS coefficient and the transmission power of the relay node and conclude that our proposed single relay selection scheme outperform the common random relay selection policies in terms of the energy revenue and system throughput.