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Item Performance Analysis of Dual-Hop AF/DF Relay Utilizing BCH Code in an Underwater Vertical Wireless Optical Link(Institute of Electrical and Electronics Engineers Inc., 2024) Savidhan Shetty, C.S.; Achala, G.; Prasad Naik, R.; Shripathi Acharya, U.S.; Chung, W.-Y.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. © 2013 IEEE.Item Multiuser Data Transmission Aided by Simultaneous Transmit and Reflect Reconfigurable Intelligent Surface in Underwater Wireless Optical Communications(Institute of Electrical and Electronics Engineers Inc., 2024) Naik, R.P.; Salman, M.; Bolboli, J.; Savidhan Shetty, C.S.; Chung, W.-Y.Recent research in the wireless communications field has focused on the reconfigurable intelligent surface (RIS), which can enhance energy and spectrum efficiency by reconfiguring radio waves to propagate in a specific direction. In this study, we applied the simultaneous transmit and reflect (STAR)-RIS to an underwater wireless optical communication (UWOC) system. In contrast to a conventional RIS, a STAR-RIS allows multiple users to transfer data simultaneously in all directions by obtaining a UWOC channel despite underwater turbulence, beam attenuation, blockage, and pointing errors. Underwater turbulence-induced fading was obtained by using exponential and generalized Gamma distributions, and numerical analysis were performed to evaluate the outage probability, bit error rate (BER), and channel capacity of a direct UWOC channel, conventional RIS assisted UWOC channel, and STAR-RIS assisted UWOC channel. The BER performance was also evaluated according to the number of reflective elements, type of modulation scheme, impact of pointing errors, blockage levels, and varying the transmit-reflection coefficient. Monte-Carlo simulations were performed to validate the analytical results for the BER and outage probability with respect to the average signal-to-noise ratio. Experiments were performed to demonstrate the received luminous intensity performance with respect to the incident beam luminous intensity of the proposed STAR-RIS assisted UWOC channel. © 1967-2012 IEEE.