Optimal Signaling of MISO Full-Duplex Two-Way Wireless Channel

TL;DR

This paper models self-interference in MISO full-duplex two-way channels, formulates the rate region boundary, and derives optimal beamforming strategies with closed-form solutions, demonstrating significant rate gains over zero-forcing methods.

Contribution

It reformulates a non-convex optimization problem into convex semidefinite programs and proves beamforming as an optimal strategy with a closed-form solution.

Findings

Beamforming achieves any point on the Pareto boundary.

Closed-form expression for optimal beamforming weights.

Proposed beamforming outperforms zero-forcing in achievable rates.

Abstract

We model the self-interference in a multiple input single output (MISO) full-duplex two-way channel and evaluate the achievable rate region. We formulate the boundary of the achievable rate region termed as the Pareto boundary by a family of coupled, non-convex optimization problems. Our main contribution is decoupling and reformulating the original non-convex optimization problems to a family of convex semidefinite programming problems. For a MISO full-duplex two-way channel, we prove that beamforming is an optimal transmission strategy which can achieve any point on the Pareto boundary. Furthermore, we present a closed-form expression for the optimal beamforming weights. In our numerical examples we quantify gains in the achievable rates of the proposed beamforming over the zero-forcing beamforming.