Throughput Analysis and Optimization of Wireless-Powered Multiple Antenna Full-Duplex Relay Systems

TL;DR

This paper analyzes and optimizes the throughput of wireless-powered full-duplex relay systems with multiple antennas, focusing on beamforming and time-split strategies to enhance energy harvesting and interference suppression.

Contribution

It introduces new optimization schemes for beamformers and time-split parameters, providing closed-form solutions and guaranteeing rank-one optimality in certain scenarios.

Findings

Beamforming improves energy harvesting and interference suppression.

Optimal and suboptimal schemes significantly impact throughput performance.

Simulation confirms the importance of processing schemes and time-split choices.

Abstract

We consider a full-duplex (FD) decode-and-forward system in which the time-switching protocol is employed by the multi-antenna relay to receive energy from the source and transmit information to the destination. The instantaneous throughput is maximized by optimizing receive and transmit beamformers at the relay and the time-split parameter. We study both optimum and suboptimum schemes. The reformulated problem in the optimum scheme achieves closed-form solutions in terms of transmit beamformer for some scenarios. In other scenarios, the optimization problem is formulated as a semi-definite relaxation problem and a rank-one optimum solution is always guaranteed. In the suboptimum schemes, the beamformers are obtained using maximum ratio combining, zero-forcing, and maximum ratio transmission. When beamformers have closed-form solutions, the achievable instantaneous and delay-constrained throughput are analytically characterized. Our results reveal that, beamforming increases both the energy harvesting and loop interference suppression capabilities at the FD relay. Moreover, simulation results demonstrate that the choice of the linear processing scheme as well as the time-split plays a critical role in determining the FD gains.