Statistical modeling of received signal strength for an FSO link over maritime environment

Free space optical communications (FSO) have the potential to substantially improve communications technology in terms of channel capacity and offer an alternative to their RF counterpart. Additional characteristics related to security, immunity, flexibility and low cost issues render FSO a reasonable candidate for military applications. FSO technology does not come without challenges. Its major issue is the local meteorological parameters that give rise to various atmospheric phenomena. The purpose of this work is to facilitate the performance prediction of an FSO communication link over a maritime environment by utilizing macroscopic meteorological parameters, i.e. air temperature, wind speed, relative humidity, air pressure, dew point, solar radiation and sea temperature, obtained from point measurements. The received signal strength indicator (RSSI) of the FSO receiver has been utilized as the performance metric of the channel and a closed form expression has been deduced. The model has then been validated against real meteorological data and the predicted RSSI values exhibited a reasonably strong correlation with the observed ones. Atmospheric turbulence has been taken into account using the Navy Surface Layer Model (NAVSLaM) to estimate the structure index parameter from the same meteorological data and thus allowed for a statistical correlation between the refractive index structure parameter and RSSI.