Optimizing a Binary Intelligent Reflecting Surface for OFDM Communications under Mutual Coupling

TL;DR

This paper investigates optimizing a binary intelligent reflecting surface (IRS) for OFDM systems considering practical issues like mutual coupling and frequency selectivity, proposing a low-complexity configuration method evaluated on a realistic setup.

Contribution

It introduces a low-complexity solution for IRS configuration in wideband OFDM systems accounting for mutual coupling and unbalanced states, with evaluation on a realistic simulation setup.

Findings

Effective IRS configuration method for wideband OFDM.

Performance improvements demonstrated in simulation.

Addresses practical limitations like mutual coupling.

Abstract

An intelligent reflecting surface (IRS) can greatly improve the channel quality over a frequency-flat channel, if it is configured to reflect the incident signal as a beam towards the receiver. However, the fundamental limitations of the IRS technology become apparent over practical frequency-selective channels, where the same configuration must be used over the entire bandwidth. In this paper, we consider a wideband orthogonal frequency-division multiplexing (OFDM) system that is supported by a fairly realistic IRS setup with two unbalanced states per element and also mutual coupling. We describe the simulation setup considered in the IEEE Signal Processing Cup 2021, propose a low-complexity solution for channel estimation and IRS configuration, and evaluate it on that setup.