Quantifying the Effect of the Optimization of an M-fold Transmitter Diversity Scheme with Atmospherically Induced Beam Wander and Scintillation

Transmitter diversity is an effective fading mitigation scheme in an optical geostationary satellite feeder uplink. We quantify the performance of the scheme over a slow fading channel where the atmospheric turbulence causes scintillation and wandering of the optical beam resulting in deep fades at the satellite receiver. For given atmospheric conditions and residual beam pointing jitter, we optimize the transmit power of each beam to obtain the minimum overall power scintillation index and achieve a bit error rate gain of 0.46dB considering intensity modulation and direct detection.