FSO Communication capacity in turbulent and dispersive channel with AWGN noise

In this paper, we have investigated the FSO communication capacity in the presence of the temporal pulse broadening effect which caused by the group velocity dispersion and atmospheric turbulence. We have modeled the pulse propagation in atmospheric turbulence and chromatic dispersion by using the two-frequency mutual coherence function (MCF). By using the Shannon-Hartly theorem, we have derived an analytical expression for signal to noise ratio of the propagating Gaussian pulse in dispersive and turbulent atmospheric channel. The results shows that the capacity communication degrades drastically under the temporal pulse broadening effect. The degradation is very important for a longer distance. By increasing the power of the transmitted signal, and choosing the appropriate transceiver altitude, we can minimize the pulse-broadening effect on FSO capacity.