Performance analysis of satellite cluster-to-ship FSO system over doubly inverted gamma-gamma turbulence channel with LEO satellite experimental validation

In this work, a satellite cluster-to-ship free space optical (FSO) system model over the composite doubly inverted gamma-gamma (IGGG) atmospheric turbulence channel has been proposed, considering the effects of path loss and ship mobility for what we believe is the first time. To quantify the impacts of satellite cluster orbital configurations, minimum separation distance (MSD), and ship velocity in different atmospheric turbulence regimes, the closed-form expressions of outage probability (OP), average bit error rate (ABER), and ergodic capacity (EC) have been derived and verified by Monte Carlo simulations. Results show that although the OP, ABER, and EC performances of both linear and circular orbital configurations will deteriorate as the atmospheric turbulence worsens, the circular orbital configuration consistently outperforms the linear orbital configuration. Besides, reducing the MSD of the satellite cluster will further enhance the system performances while it would be degraded as the ship velocity increases. Specifically, one communication experiment between a low Earth orbit (LEO) satellite and a ground station is carried out under pointing correction and fine-tracking closed-loop control, in which the received signal-to-noise (SNR) logs are recorded to obtain the practical downlink OP, therefore verifying the proposed theoretical OP model.