Wireless Information and Power Transfer in Relay Systems with Multiple Antennas and Interference

TL;DR

This paper analyzes a dual-hop relay system with multiple antennas that harvests energy and transmits information, examining the effects of interference and different processing schemes on system performance.

Contribution

It introduces a comprehensive analysis of energy harvesting relay systems with multiple antennas under interference, comparing three linear processing schemes and optimizing power splitting.

Findings

Multiple antennas enhance energy harvesting and system performance.

Interference can be exploited to improve system performance.

The choice of processing scheme significantly affects the gains from interference.

Abstract

In this paper, an energy harvesting dual-hop relaying system without/with the presence of co-channel interference (CCI) is investigated. Specifically, the energy constrained multi-antenna relay node is powered by either the information signal of the source or via the signal receiving from both the source and interferer. In particular, we first study the outage probability and ergodic capacity of an interference free system, and then extend the analysis to an interfering environment. To exploit the benefit of multiple antennas, three different linear processing schemes are investigated, namely, 1) Maximum ratio combining/maximal ratio transmission (MRC/MRT), 2) Zero-forcing/MRT (ZF/MRT) and 3) Minimum mean-square error/MRT (MMSE/MRT). For all schemes, both the systems outage probability and ergodic capacity are studied, and the achievable diversity order is also presented. In addition, the optimal power splitting ratio minimizing the outage probability is characterized. Our results show that the implementation of multiple antennas increases the energy harvesting capability, hence, significantly improves the systems performance. Moreover, it is demonstrated that the CCI could be potentially exploited to substantially boost the performance, while the choice of a linear processing scheme plays a critical role in determining how much gain could be extracted from the CCI.