Performance Analysis of Relay-Assisted OWC Over Foggy Channel with Pointing Error

TL;DR

This paper analyzes the performance of relay-assisted optical wireless communication over foggy channels with pointing errors, deriving analytical expressions and demonstrating significant improvements over direct transmission in terms of outage probability, SNR, and power efficiency.

Contribution

It provides the first analytical performance analysis of relay-assisted OWC under fog and pointing errors, including new expressions for outage probability, SNR, and ergodic rate.

Findings

Relay-assisted OWC significantly reduces outage probability.

The system requires 30 times less power than direct transmission.

Performance metrics are validated through analytical and simulation methods.

Abstract

Signal fading due to atmospheric channel impairments and pointing error is a major bottleneck for the performance of optical wireless communication (OWC). In this paper, we consider an amplify-and-forward (AF) optical relaying to enhance the performance of the OWC system with a negligible line-of-sight (LOS) link under the combined effect of fog and pointing error. We analyze the end-to-end performance of the relay-assisted system, which consists of complicated probability distribution functions. We derive analytical expressions of the outage probability, average signal-to-noise ratio (SNR), and ergodic rate in terms of OWC system parameters. We also develop an exact integral-form expression of these performance metrics using the half-harmonic mean of individual SNRs to validate the tightness of the derived analytical expressions. The numerical and simulation analysis shows that the proposed dual-hop relaying has significant performance improvement when comparing to the direct transmission over considered channel impairments. Compared to the direct transmission, the relay-assisted system requires almost $30$ times less transmission power to achieve the same outage probability. The considered system also provides a significant gain in the average SNR and ergodic rate for practical scenarios of OWC deployment.