BER analysis of coherent FSO systems with SC receive diversity over correlated turbulence channels

In this letter, we study the average bit-error-rate (BER) performance of coherent free space optical communication systems with selection combining (SC) receive diversity over correlated Gamma-Gamma channels under non-Kolmogorov turbulence. Novel and computationally efficient analytical expressions over correlated and independent Gamma-Gamma channels of the average BER are derived. Then using these analytical expressions, we analyze the effects of the spectral power law and the channel correlation coefficient on the average BER performance. The correctness of the analytical results is verified by Monte Carlo simulation. This work will help with the further investigation of the fading correlation in the spatial diversity systems.