Virtual Full-Duplex Buffer-Aided Relaying in the Presence of Inter-Relay Interference

TL;DR

This paper introduces a joint relay selection and beamforming approach for virtual full-duplex buffer-aided relaying in relay networks, effectively mitigating inter-relay interference and approaching ideal full-duplex performance.

Contribution

It proposes a novel joint relay selection and beamforming scheme that considers inter-relay interference, enhancing the capacity of buffer-aided relay networks.

Findings

Proposed schemes approach ideal full-duplex performance asymptotically.

Joint relay selection and beamforming effectively mitigate inter-relay interference.

Adaptive rate transmission maximizes end-to-end data rate.

Abstract

In this paper, we study virtual full-duplex (FD) buffer-aided relaying to recover the loss of multiplexing gain caused by half-duplex (HD) relaying in a multiple relay network, where each relay is equipped with a buffer and multiple antennas, through joint opportunistic relay selection (RS) and beamforming (BF) design. The main idea of virtual FD buffer-aided relaying is that the source and one of the relays simultaneously transmit their own information to another relay and the destination, respectively. In such networks, inter-relay interference (IRI) is a crucial problem which has to be resolved like self-interference in the FD relaying. In contrast to previous work that neglected IRI, we propose joint RS and BF schemes taking IRI into consideration by using multiple antennas at the relays. In order to maximize average end-to-end rate, we propose a weighted sum-rate maximization strategy assuming that adaptive rate transmission is employed in both the source to relay and relay to destination links. Then, we propose several BF schemes cancelling or suppressing IRI in order to maximize the weighted sum-rate. Numerical results show that our proposed optimal, zero forcing, and minimum mean square error BF-based RS schemes asymptotically approach the ideal FD relaying upper bound when increasing the number of antennas and/or the number of relays.