Capacity analysis of the Underwater Visible Light Communication Systems over Salinity-Induced Turbulence with Noises

Underwater visible light communication links are mainly impaired by absorption and scattering due to impurities and turbidity in the water, limiting channel capacity. For the first time, this article conducts the channel capacity analysis of underwater visible light communication systems in the saline water channel for both horizontal and vertical routes in the presence of different noises, including shot noise, thermal noise and background noise. This way, new lower bound expressions on channel capacity are derived when additional constraints are imposed on the channel input. Based on the analysis, it is seen that the capacity of the saline water channel is decreased at a fixed signal to noise ratio compared to the tap water channel. The attenuation of optical signal further increases as the noises surge, leading to degradation in the system’s capacity.