Performance of Intelligent Reflecting Surface-Based Wireless Communications Using QAM Signaling

Abstract

In this paper, we analyze the performance of bandwidth-efficient quadrature amplitude modulation (QAM) techniques for intelligent reflecting surface (IRS)-assisted wireless communications over Rayleigh fading channels. New closed-form expressions of the generic average symbol error rate (ASER) for rectangular QAM, and square QAM are derived. Moreover, simplified expressions of the ASER for low signal-to-noise-ratio (SNR) and high SNR regions are also presented, which are useful to provide insights analytically. The impact of modulation parameters and the number of IRS elements employed is thoroughly analyzed. We also verify our theoretical results through simulations. Our results demonstrate that employing IRS significantly enhances the ASER performance over Rayleigh fading channels, particularly in low SNR regimes. The result highlights the potential of IRS-assisted wireless communications for applications like the Internet-of-Things (IoT) that require low-powered communication solutions. © 2023 IEEE.