Multiuser Full-Duplex Two-Way Communications via Intelligent Reflecting Surface

TL;DR

This paper introduces a novel IRS-assisted full-duplex multiuser communication system that enhances coverage and spectral efficiency by jointly optimizing precoding and reflection coefficients, effectively reducing interference.

Contribution

It proposes a new IRS deployment strategy for full-duplex multiuser systems, with a joint optimization framework and efficient algorithms to improve coverage and fairness.

Findings

The proposed algorithms converge reliably.

IRS deployment significantly improves coverage.

Enhanced spectral efficiency demonstrated in simulations.

Abstract

Low-cost passive intelligent reflecting surfaces (IRSs) have recently been envisioned as a revolutionary technology capable of reconfiguring the wireless propagation environment through carefully tuning reflection elements. This paper proposes deploying an IRS to cover the dead zone of cellular multiuser full-duplex (FD) two-way communication links while suppressing user-side self-interference (SI) and co-channel interference (CI). Based on information exchanged by the base station (BS) and all users, this approach can potentially double the spectral efficiency. To ensure network fairness, we jointly optimize the precoding matrix of the BS and the reflection coefficients of the IRS to maximize the weighted minimum rate (WMR) of all users, subject to maximum transmit power and unit-modulus constraints. We reformulate this non-convex problem and decouple it into two subproblems. Then the optimization variables in the equivalent problem are alternately optimized by adopting the block coordinate descent (BCD) algorithm. In order to further reduce the computational complexity, we propose the minorization-maximization (MM) algorithm for optimizing the precoding matrix and the reflection coefficient vector by defining minorizing functions in the surrogate problems. Finally, simulation results confirm the convergence and efficiency of our proposed algorithm, and validate the advantages of introducing IRS to improve coverage in blind areas.