Power splitting and relay optimization for two-way relay SWIPT systems

We study the simultaneous wireless information and power transfer (SWIPT) problem for the multiuser two-way relay network. We adopt power splitting (PS) receivers and one amplify-and-forward (AF) relay. Aiming at minimizing the total relay transmit power under constraints of received SINR and harvested power, we optimize the PS ratios and the relay processing matrix at the same time. We first reformulate the optimization problem as a quadratically constrained quadratic program (QCQP) and analyze the feasibility of this QCQP. We find several necessary conditions for the problem to be feasible. Since solving the problem or just finding a feasible point of this problem is NP-hard, we use the feasible point pursuit-successive convex approximation (FPP-SCA) to obtain an approximately optimal solution.