Multihop Optical Wireless Communication Over ${\cal{F}}$-Turbulence Channels and Generalized Pointing Errors with Fog-Induced Fading

TL;DR

This paper develops analytical models for multihop optical wireless communication systems affected by atmospheric turbulence, pointing errors, and fog, providing new bounds and performance metrics validated by simulations.

Contribution

It introduces novel statistical bounds and analytical expressions for multihop OWC performance under complex channel impairments, including Fisher-Snedecor ${\

Findings

Derived upper bounds on PDF and CDF of SNR for multihop OWC.

Presented analytical outage probability and ABER expressions involving Fox's H and Meijer's G functions.

Validated analytical results with Monte-Carlo simulations and analyzed the impact of relay nodes.

Abstract

Multihop relaying is a potential technique to mitigate channel impairments in optical wireless communications (OWC). In this paper, multiple fixed-gain amplify-and-forward (AF) relays are employed to enhance the OWC performance under the combined effect of atmospheric turbulence, pointing errors, and fog. We consider a long-range OWC link by modeling the atmospheric turbulence by the Fisher-Snedecor ${\cal{F}}$ distribution, pointing errors by the generalized non-zero boresight model, and random path loss due to fog. We also consider a short-range OWC system by ignoring the impact of atmospheric turbulence. We derive novel upper bounds on the probability density function (PDF) and cumulative distribution function (CDF) of the end-to-end signal-to-noise ratio (SNR) for both short and long-range multihop OWC systems by developing exact statistical results for a single-hop OWC system under the combined effect of ${\cal{F}}$-turbulence channels, non-zero boresight pointing errors, and fog-induced fading. Based on these expressions, we present analytical expressions of outage probability (OP) and average bit-error-rate (ABER) performance for the considered OWC systems involving single-variate Fox's H and Meijer's G functions. Moreover, asymptotic expressions of the outage probability in high SNR region are developed using simpler Gamma functions to provide insights on the effect of channel and system parameters. The derived analytical expressions are validated through Monte-Carlo simulations, and the scaling of the OWC performance with the number of relay nodes is demonstrated with a comparison to the single-hop transmission.