Intelligent Reflecting Surface-assisted Free-space Optical Communications

TL;DR

This paper explores how intelligent reflecting surfaces can enhance free-space optical communications by relaxing line-of-sight requirements, comparing different technologies, and outlining future research challenges.

Contribution

It provides an overview of optical IRS technologies, compares them with RF IRSs and relays, and identifies open problems for future IRS-assisted FSO research.

Findings

Optical IRSs can potentially improve FSO link reliability.

Comparison shows optical IRSs have unique advantages over RF IRSs.

Open research problems include optimization and practical deployment challenges.

Abstract

Free-space optical (FSO) systems are able to offer the high data-rate, secure, and cost-efficient communication links required for applications such as wireless front- and backhauling for 5G and 6G communication networks. Despite the substantial advancement of FSO systems over the past decades, the requirement of a line-of-sight connection between transmitter and receiver remains a key limiting factor for their deployment. In this paper, we discuss the potential role of intelligent reflecting surfaces (IRSs) as a solution to relax this requirement. We present an overview of existing optical IRS technologies; compare optical IRSs with radio-frequency IRSs and optical relays; and identify various open problems for future research on IRS-assisted FSO communications.