Performance of the FSO System Modeled with Gamma-Chi-square Distribution and DPSK and BPSK Modulation Scheme.

The paper discusses the FSO (Free-Space Optics) system modeled with Gamma-Chi-square distribution, which is based on the analytically Gamma-Chi-square (or Gamma-Rician) model. This model is obtained as a product of the two models - the Gamma model and the Chi-square (or Rician) model. Analytical expressions for the Average Bit Error Rate (ABER) of the FSO system were calculated for the given model when signals modulated with DPSK and BPSK formats are transmitted through the channel. Based on analytical expressions, numerical results were obtained and presented in graphic form. The ABER behavior for different category of atmospheric turbulence and Rician K factor as a function of average signal power is presented.