Performance evaluation of correlated-fading space-diversity FSO links

In order to analyze the performance of space-diversity free-space optical (FSO) systems over arbitrarily correlated Gamma-Gamma (ΓΓ) fading channels, we approximate the sum of correlated ΓΓ random variables (RVs) by an α-μ RV. We evaluate the bit error rate (BER) performance of a triple-aperture system based on the proposed method and show that there is a good match between the performances obtained by Monte-Carlo simulations using the ΓΓ channel model and via the proposed analytical method based on the approximate α-μ distribution.