Unified Performance Assessment of Optical Wireless Communication over Multi-Layer Underwater Channels

TL;DR

This paper provides a unified analytical framework for assessing the performance of multi-layer underwater optical wireless communication systems under various turbulence models, validated by simulations and measurement data.

Contribution

It introduces unified expressions for key performance metrics of UWOC systems over multiple turbulence models, including the integration with terrestrial OWC links and validation with real data.

Findings

Unified performance analysis for multiple turbulence models.

Analytical expressions validated by Monte-Carlo simulations.

Insights into system behavior at high SNR with diversity order analysis.

Abstract

In this paper, we model the multi-layer vertical underwater link as a cascaded channel and unify the performance analysis for the underwater optical communication (UWOC) system using generalized Gamma (GG), exponential GG (EGG), exponentiated Weibull (EW), and Gamma-Gamma ({\Gamma}{\Gamma}) oceanic turbulence models. We derive unified analytical expressions for probability density function (PDF) and cumulative distribution function (CDF) for the signal-to-noise ratios (SNR) considering independent and non-identical (i.ni.d.) turbulent models and zero bore-sight model for pointing errors. We develop performance metrics of the considered UWOC system using outage probability, average bit error rate (BER), and ergodic capacity with asymptotic expressions for outage probability and average BER. We develop the diversity order of the proposed system to provide a better insight into the system performance at a high SNR. We also integrate a terrestrial OWC (TOWC) subjected to the combined effect of generalized Malaga atmospheric turbulence, fog-induced random path gain, and pointing errors to communicate with the UWOC link using the fixed-gain amplify-and-forward (AF) relaying. We analyze the performance of the mixed TWOC and multi-layer UWOC system by deriving PDF, CDF, outage probability, and average BER using the bivariate Fox H-function. We use Monte-Carlo simulation results to validate our exact and asymptotic expressions and demonstrate the performance of the considered underwater UWOC system using measurement-based parametric data available for turbulent oceanic channels.