Error probability analysis of OOK and variable weight MPPM coding schemes for underwater optical communication systems affected by salinity turbulence

Underwater wireless optical communication (UWOC) systems are presented as a reliable alternative to typical underwater wireless systems (radio-frequency (RF) and acoustic waves) since they can provide much higher data rates with a higher level of communication security. Thus, a variety of potential applications have been recently proposed for UWOC systems, including offshore exploration, environmental monitoring, natural disaster precautions, or military operations. All of these must overcome the unpredictable nature of underwater channels due to scattering and turbulence processes associated with different factors, such as salinity, temperature, bubbles, or turbidity. Lately, a Weibull distribution has been demonstrated to have excellent agreement characterizing the fading of salinity-induced oceanic turbulence. Furthermore, an approximate closed-form expression is derived in this paper for the average bit error rate of any generic coding scheme by means of a Gauss-Laguerre quadrature. Numerical results obtained via Monte-Carlo simulation are provided to corroborate the validity of the derived analytical expressions.