Intelligent reflecting surfaces for full duplex systems: performance over nakagami-m fading with a direct link

Full-duplex (FD) communication and intelligent reflecting surfaces (IRS) have emerged as transformative technologies for enhancing spectral efficiency (SE) in wireless networks. While FD can potentially double the link capacity, its performance is constrained by self-interference (SI). Leveraging IRS can mitigate SI effectively and improve overall system performance. This work investigates the performance of IRS-aided FD communication over Nakagami-m fading channels with a non-negligible direct link. A comprehensive mathematical framework is developed, and closed-form analytical expressions for outage probability (OP) are derived under the effects of residual SI. Numerical results reveal that increasing the number of IRS elements N from 2 to 5 significantly reduces OP. For example, at an SNR of 5 dB, the OP decreases from 0.3 to 10-2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ 10<^>{-2}$$\end{document} with IRS-only communication. Including the direct path further enhances performance, reducing OP from 0.3 to 0.1 at N=2. These results underscore the critical role of IRS elements and the direct path in mitigating SI and optimizing SE in FD systems.