Energy efficiency optimization based joint relay selection and resource allocation for SWIPT relay networks

In this paper, a joint relay selection and resource allocation scheme is proposed for simultaneous wireless information and power transfer (SWIPT) relay networks with multiple Source nodes (SNs) and Destination nodes (DNs) pairs and energy harvesting Relay nodes (RNs). The transmit power, subchannel, power splitting ratio allocation for SNs/RNs and the relay selection scheme strategy are jointly optimized to maximize the total energy efficiency of all the SNs and RNs. The optimization problem is transformed equivalently into two subproblems, i.e., transmit power and power splitting ratio optimization subproblem of one SN-RN-DN path and the optimal relay and subchannel allocation subproblem. By applying iterative algorithm and Lagrange dual method, the optimal relay selection and resource allocation strategy are obtained. Simulation results demonstrate the efficiency of the proposed scheme.