Joint Relay-User Beamforming Design in Full-Duplex Two-Way Relay Channel

TL;DR

This paper proposes a novel beamforming design for full-duplex two-way relay channels that balances self-interference suppression and signal quality, outperforming traditional zero-forcing methods.

Contribution

A new joint relay-user beamforming approach that reserves some self-interference and uses an alternating optimization algorithm for improved performance.

Findings

Outperforms zero-forcing beamforming in simulations.

Achieves near-ideal transmit power levels.

Provides a convergence-guaranteed optimization method.

Abstract

A full-duplex two-way relay channel with multiple antennas is considered. For this three-node network, the beamforming design needs to suppress self-interference. While a traditional way is to apply zero-forcing for self-interference mitigation, it may harm the desired signals. In this paper, a design which reserves a fraction of self-interference is proposed by solving a quality-of-service constrained beamforming design problem. Since the problem is challenging due to the loop self-interference, a convergence-guaranteed alternating optimization algorithm is proposed to jointly design the relay-user beamformers. Numerical results show that the proposed scheme outperforms zero-forcing method, and achieves a transmit power close to the ideal case.