Performance evaluation of IRS-assisted one-bit control-based mixed FSO-RF communication system

In this paper, we investigate the performance of the novel one-bit control intelligent reflecting surface (IRS)-assisted mixed free-space optical (FSO)-radio frequency (RF) communication system, where an IRS is utilized over the RF hop to empower the end-to-end system performance. The FSO link is assumed to be affected by path loss, nonzero boresight pointing error, and atmospheric turbulence, which is modeled by generalized Malaga (M\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {M}$$\end{document})-distribution, whereas the multipath fading in RF link is modeled by Nakagami-m distribution. In particular, unified closed-form expressions for the outage probability (OP), bit-error-rate (BER), and ergodic capacity (EC) are derived for optical heterodyne detection (OHD) and intensity modulation with direct detection (IMDD) techniques. We also derive the achievable diversity order of the considered IRS-assisted system by obtaining the asymptotic OP and asymptotic BER expressions. In addition, we derive the asymptotic EC of the considered system. The numerical results show that the proposed IRS-assisted system significantly outperforms the conventional mixed FSO-RF system without IRS. Moreover, the impact of the number of reflecting elements, practical reflection amplitude, and controlling mechanism at the IRS is studied on the system performances.