Power allocation, relay selection and energy cooperation strategies in energy harvesting cooperative wireless networks

In this paper, optimal power allocation and relay selection strategies in energy harvesting cooperative wireless networks are studied. In particular, signal-to-noise ratio (SNR)-maximizing based power allocation and relay selection without and with energy cooperation—via wireless energy transfer—are considered. Moreover, total relay power minimization subject to target end-to-end SNR is investigated. The different optimal strategies are formulated as optimization problems, which are non-convex. Thus, intelligent transformations are applied to transform non-convex problems into convex ones, and polynomial-time solution procedures are proposed. Simulation results illustrate that power allocation strategies achieve higher end-to-end SNR than relay selection ones. Finally, energy cooperation is shown to be effective in improving endto-end SNR, while total relay power minimization balances end-to-end SNR, transmit power consumption, and harvested energy. Copyright © 2016 John Wiley & Sons, Ltd.