Ergodic capacity analysis of underwater FSO systems over scattering-induced fading channels in the presence of Weibull oceanic turbulence

Scattering is considered as the main degrading factor in underwater optical wireless communication (UOWC) systems, especially in turbid environments over moderate and long link spans. For that reason, the optics community is making an extra effort to accurately model its impact on the system performance, by means, for example, of the channel capacity. This paper addresses the performance analysis of UOWC systems over a novel scattering-induced fading channel along with the effect of oceanic salinity-induced turbulence, and provides novel closed-form expressions to compute such a performance in terms of ergodic capacity. Asymptotic results are also derived in order to shed some light on how such a scattering-induced fading deteriorates the capacity performance in a variety of water conditions such as clear ocean and coastal waters. In particular, the presented results show quite a similar impact when strong and moderate oceanic turbulence conditions are considered, which demonstrates that scattering-induced fading is a critical degrading effect in UOWC systems, especially in turbid environments. Analytical and asymptotic results are further verified by Monte Carlo simulations.