Robust Beamforming for SWIPT in Massive MIMO

Abstract

In this paper, joint robust information- and energy-beamformers are designed for simultaneous wireless information and power transfer (SWIPT) in a multiuser beamspace massive multiple-input multiple-output (MIMO) system with imperfect channel state information (CSI). Instead of directly resorting to semi-definite relaxation (SDR), we reduce the computational complexity by converting the initial non-convex optimization to a power allocation problem, where the optimal beamforming vectors are derived in closed-form. Theoretical results and simulations demonstrate that the proposed method achieves the globally optimal point for the initial design when the channel estimation errors are small, and leads to good suboptimal performance when the channel estimation errors are large.