A Triple-Parameter Based Multi-Relay Selection Strategy for Wireless-Powered Cooperative Network

This paper studies a wireless-powered cooperative network consisting of a single source, multiple wireless-powered relays, and a single destination. The relays harvest radio frequency energy from the source, decode the information, and use beamforming to forward the information to the destination. We develop a triple-parameter-based multi-relay selection (TPMRS) strategy to determine how to assign the energy harvesting and information decoding tasks to different relays. By modeling the TPMRS strategy as a finite state Markov chain, we derive the stationary distribution of each state and obtain an analytical expression of the system throughput. The optimal parameters that maximize the system throughput are obtained via exhaustive search. The numerical and simulation results validate the correctness of the model and derivations. In addition, our proposed TPMRS strategy outperforms the existing multi-relay selection scheme.