Joint Time Switching and Power Allocation for Multicarrier Decode-and-Forward Relay Networks with SWIPT

Employing energy harvesting (EH) at the relay with simultaneous wireless information and power transfer is promising to prolong lifetime of energy-constrained relay networks. In this letter, considering multicarrier decode-and-forward (DF) relay network with time-switching (TS) based relaying, we investigate the optimization problem which jointly designs TS ratios of EH and information-decoding at the relay, TS ratio of signal forwarding from relay to destination as well as power allocation (PA) over all subcarriers at source and relay. Our objective is to maximize end-to-end achievable rate of DF relay networks subject to transmit power constraint at source and EH constraint at relay. We propose to decouple the optimization problem into a convex problem and a quasi-convex problem. For the quasi-convex problem, we propose to solve it by bisection search. Simulation results demonstrate that our proposed joint TS and PA optimization scheme outperforms the scheme with fixed TS ratio of EH.