Outage Performance for Optical Feeder Link in Satellite Communications With Diversity Combining

This letter investigates the outage performance of an optical feeder link in satellite communications, where the gateway is equipped with multiple apertures and employs diversity combining schemes to mitigate the effect of atmosphere turbulence. In particular, by assuming that the optical link undergoes the Malaga fading, we first derive a closed-form expression for the outage probability (OP) of the considered system with selection combining (SC). Subsequently, when equal gain combining (EGC) is utilized, we present an approximate yet accurate probability density function expression for the sum of independent and identically distributed Malaga random variables. Next, we derive an OP expression for the considered system with EGC. To gain more insights, we further obtain diversity order for both SC and EGC schemes. It is found that the diversity order for both schemes is related to the number of receive apertures and the effective number of large-scale cells of the scattering process.