OOK Modulated Optical Satellite Communications System for CCSDS Standardization

Abstract

An optical satellite communications link is affected by a severe fading due to an atmospheric turbulence. The transmitter and receiver should be designed to overcome signal distortion caused by fading. The received signals are also degraded by optical and electrical distortion factors. NICT started experimental verification of optical satellite communications using Small Optical TrAnsponder (SOTA) last September. The SOTA measurement campaign provides optical satellite downlink data. Thus, a practical fading generator with respect to the collected experimental data has been developed for a better understanding of the optical satellite channel. The developed fading generator consists of two components: fade level and noise variance generators based on model fitting the measured distribution into a probability density function of theoretical atmospheric turbulence. In this paper, characteristics of the collected data, the model fitting technique for the fading generator, and the system simulation using the generator are presented.