Mixed Dual-Hop IRS-Assisted FSO-RF Communication System with H-ARQ Protocols

TL;DR

This paper analyzes a hybrid FSO-RF communication system enhanced with IRS and H-ARQ protocols, deriving analytical performance metrics and validating them through simulations to improve reliability in 5G networks.

Contribution

It introduces a novel mixed dual-hop FSO-RF system with IRS and H-ARQ, providing closed-form expressions for key performance metrics and insights into system diversity gain.

Findings

Derived closed-form PDFs and CDFs of end-to-end SNR.

Analyzed outage probability and packet error rate.

Validated analytical results with Monte Carlo simulations.

Abstract

Intelligent reflecting surface (IRS) is an emerging key technology for the fifth-generation (5G) and beyond wireless communication systems to provide more robust and reliable communication links. In this paper, we propose a mixed dual-hop free-space optical (FSO)-radio frequency (RF) communication system that serves the end user via a decode-and-forward (DF) relay employing hybrid automatic repeat request (HARQ) protocols on both hops. Novel closed-form expressions of the probability density function (PDF) and cumulative density function (CDF) of the equivalent end-to-end signal-to-noise ratio (SNR) are computed for the considered system. Utilizing the obtained statistics functions, we derive the outage probability (OP) and packet error rate (PER) of the proposed system by considering generalized detection techniques on the source-to-relay (S-R) link with H-ARQ protocol and IRS having phase error. We obtain useful insights into the system performance through the asymptotic analysis which aids to compute the diversity gain. The derived analytical results are validated using Monte Carlo simulation.