  In this paper, we investigate the problem of two-way relay beamforming
optimization to maximize the achievable sum-rate of a simultaneous wireless
information and power transfer (SWIPT) system with a full-duplex (FD)
multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay. In
particular, we address the optimal joint design of the receiver power splitting
(PS) ratio and the beamforming matrix at the relay node given the channel state
information (CSI). Our contribution is an iterative algorithm based on
difference of convex (DC) programming and one-dimensional searching to achieve
the joint optimal solution. Simulation results are provided to demonstrate the
effectiveness of the proposed algorithm.
