Practical Modeling and Beamforming for Intelligent Reflecting Surface Aided Wideband Systems

TL;DR

This paper develops a practical reflection model for IRS in wideband systems, optimizing beamforming and power allocation to improve realistic wireless communication performance.

Contribution

It introduces a realistic phase-amplitude-frequency reflection model for IRS and jointly optimizes transmit power and beamforming in wideband OFDM systems.

Findings

Practical reflection model significantly impacts IRS design.

Joint optimization improves system performance.

Simulation validates the effectiveness of the proposed model.

Abstract

Intelligent reflecting surface (IRS) has emerged as a revolutionizing solution to enhance wireless communications by intelligently changing the propagation environment. Prior studies on IRS are based on an ideal reflection model with a constant amplitude and a variable phase shift. However, it is difficult and unrealistic to implement an IRS satisfying such ideal reflection model in practical applications. In this letter, we aim to investigate the phase-amplitude-frequency relationship of the reflected signals and propose a practical model of reflection coefficient for an IRS-aided wideband system. Then, based on this practical model, joint transmit power allocation of each subcarrier and IRS beamforming optimization are investigated for an IRS-aided wideband orthogonal frequency-division multiplexing (OFDM) system. Simulation results illustrate the importance of the practical model on the IRS designs and validate the effectiveness of our proposed model.