Optical Wireless Underwater Channel Modelling in the Presence of Turbulence

Abstract

A method of modelling turbulence as a scattering phenomenon in the simulation of underwater photon propagation is presented in this paper. The model treats oceanic turbulence as an optical scattering phenomenon rather than as a fading parameter. The channel impulse responses both with and without turbulence are generated and it is shown that the delay spread increases with turbulence. The double gamma function is then applied to these responses as an appropriate channel model. From this model the frequency response is calculated for three different turbulence values in turbid harbour water, showing that the channel bandwidth decreases as turbulence strength increases. Finally, the distribution of the total number of received photons within a symbol duration in different conditions of weak turbulence are shown to follow a normal distribution.