Performance Analysis of Dual-Hop AF/DF Relay Utilizing BCH Code in an Underwater Vertical Wireless Optical Link

Many attempts have been made to realize effective communication from the sea surface to ocean depths. One promising emerging technology is the deployment of underwater vertical wireless optical links to establish reliable and high-speed communication. In this study, we have attempted to evaluate the performance of an underwater vertical wireless optical communication (UVWOC) link operating beneath the ocean surface, utilizing amplify and forward (AF) as well as decode and forward (DF) relay systems. The investigation focuses on a vertical link traversing multiple layers of turbulence. The channel modeling of multiple layers under weak turbulence and strong turbulence conditions employs hyperbolic tangent log-normal and gamma-gamma distributions. Novel closed-form expressions are developed to quantify the average bit error rate and outage probability for dual-hop AF/DF relay UVWOC links in both weak and strong underwater turbulence conditions. The analysis accounts for attenuation losses and pointing errors. Monte-Carlo simulations validate the accuracy of the derived expressions. Furthermore, Bose-Chaudhuri-Hocquenghem (BCH) codes with parameters (n=31,k=11) and (n=63,k=18) are applied to enhance the integrity of information transfer over the AF/DF relay UVWOC link. This research contributes to understanding UVWOC links under diverse conditions and proposes coding techniques for improved reliability in challenging underwater environments.