Spatial Diversity For FSO Communication Systems Over Correlated Atmospheric Turbulence Channels
Résumé
This paper investigates the bit error rate (BER)performance of spatial diversity free-space optical (FSO) com-munication systems using on-off keying modulation. The studyconsiders correlated log-normal FSO channels as well as pathlosses due to weather effects using intensity modulation anddirect detection schemes. An approximated moment generatingfunctions (MGF) for the joint probability density function ofcorrelated log-normal channels are considered. Using MGFapproximation, BER expressions for repetition codes (RCs) andorthogonal space time block codes (OSTBCs) in correlated log-normal channels are derived. Results show that RCs outperformOSTBCs in correlated channel conditions. In addition, the effectof different weather conditions (e.g., haze, rain and fog) onthe BER performance of the FSO links are studied. MonteCarlo simulation results are further provided to demonstratethe validity of the proposed mathematical analysis