Intelligent Reflecting Surfaces-Aided Mixed FSO/RF Communication System

Free space optics (FSO) communication offers various advantages like higher bandwidth, higher data rates, etc., when compared with its counterpart, i.e. radio frequency (RF) communication. Despite that the FSO link is adversely affected due to atmospheric turbulence, obstructions between transmitter and receiver, and pointing errors. In this work, we propose a mixed FSO/RF system based on decode-and-forward (DF) relaying technique consisting of a FSO-based transmitter node (i.e. source), a relay node, which is capable of receiving FSO signal and transmitting RF signal, and an RF-based receiver node (i.e. destination). Furthermore, both FSO and RF links are aided with intelligent reflecting surfaces (IRS). The main goal of the proposed system model is to increase the coverage and overall system reliability of the existing mixed FSO/RF system. Specifically, we investigate the performance of the proposed system by deriving the closed-form expressions for outage probability and average bit error rate (BER) in terms of multivariate Fox’s H-function without using central limit theorem. Moreover, the numerical results are shown along with some insightful discussions. From numerical results, it is deduced that IRS-assisted mixed FSO/RF system performs better than the existing mixed FSO/RF systems without IRS. Finally, analytical results are verified by performing Monte-Carlo simulations.