Optimization of generalized beam model in free space optical communication and scrutinization of bit error probability for strong atmospheric turbulence channel

Beam models and parameters are directly related to transmission which can appear from transmission errors in free space optical communications. The value of scintillation index for these beam models increases or decreases the error of data transmission. In this study, optimum beam model is found based on the general beam formulation. The analysis is according to the size of different sources and displacement parameters of beam models from the general beam formulation (such as Gaussian beam, cos-Gaussian beam, cosh-Gaussian beam, annular beam) and it is found that the scintillation index of the optimum beam is at smaller than the other beam models.Other influences effecting the transmission in free space optical communication is the turbulent atmosphere. Weak or strong turbulence affects bit error rate of data transmission. In this study, analytic and numeric analysis for strong turbulence have been made based on the general beam models that has been studied for weak turbulence based on general beam formulation (such as Gaussian beam, cos-Gaussian beam, cosh-Gaussian beam, annular beam), comparisons being made at different source sizes, displacement parameters and structure constants.Beam models are introduced in strong turbulence and bit error rates for each model are obtained and calculated for Gamma-Gamma distribution and figures of bit error rates against SNR ( Signal to Noise Ratio) are plotted. Scintillations for beam models obtained from the general beam formulation are compared with the optimum beam models at different source sizes, displacement parameters and structure parameters in the figures of BER-SNR and the optimum beam is obtained.