MSE-Based Transceiver Designs for RIS-Aided Communications With Hardware Impairments

TL;DR

This paper develops an MSE-based transceiver design for RIS-assisted MIMO systems that accounts for hardware impairments, proposing an iterative optimization algorithm that significantly improves performance over traditional methods.

Contribution

It introduces a joint optimization framework for transceiver and RIS phase shifts considering hardware impairments, with a novel iterative algorithm and closed-form solutions.

Findings

Proposed scheme outperforms conventional algorithms without hardware impairment considerations.

Derived closed-form solutions for precoder and equalizer matrices.

Demonstrated significant MSE reduction through simulations.

Abstract

It is challenging to precisely configure the phase shifts of the reflecting elements at the reconfigurable intelligent surface (RIS) due to inherent hardware impairments (HIs). In this paper, the mean square error (MSE) performance is investigated in an RIS-aided single-user multiple-input multipleoutput (MIMO) communication system with transceiver HIs and RIS phase noise. We aim to jointly optimize the transmit precoder, linear received equalizer, and RIS reflecting matrices to minimize the MSE. To tackle this problem, an iterative algorithm is proposed, wherein the beamforming matrices are alternately optimized. Specifically, for the beamforming optimization subproblem, we derive the closed-form expression of the optimal precoder and equalizer matrices. Then, for the phase shift optimization subproblem, an efficient algorithm based on the majorization-minimization (MM) method is proposed. Simulation results show that the proposed MSE-based RIS-aided transceiver scheme dramatically outperforms the conventional system algorithms that do not consider HIs at both the transceiver and the RIS.