Performance Evaluation of the Vertical Layered UWOC System With Spatial Diversity

The performance of the vertical layered underwater wireless optical communication (UWOC) system with spatial diversity is investigated in this letter. Specifically, multiple receivers are configured to mitigate the underwater optical turbulence (UOT)-induced fading. Assuming that the UOT over the vertical UWOC link is characterized by the cascaded Gamma-Gamma (GG) distribution, the attenuation coefficient is calculated by chlorophyll-based model, and the approximated Beckmann distribution is adopted to quantify the misalignment between the transceivers, the exact analytical expressions of the average bit error rate (ABER) for this vertical layered UWOC system with optimal combining (OC), selection combining (SC), and equal gain combining (EGC) techniques are derived in terms of multivariate Fox-H function with the Stieltjes transform method, integration by parts, and characteristic function (CHF)-based approach, respectively. Monte Carlo simulations are provided to validate the correctness of the presented theoretical results.