On the Performance of a HAPS Assisted AF Based Dual-hop FSO Communication System

In this study, we examine the performance of a dual-hop assisted amplify-and-forward (AF) based high altitude platform station (HAPS) free space optical (FSO) communication system. The HAPS used in the considered system act as an AF relay to provide connectivity between the two terrestrial stations. FSO links characterized by Gamma-Gamma atmospheric turbulence, pointing errors, and angle-of-arrival (AoA), provide connectivity between ground stations and HAPS. Closed-form expression for the outage probability (OP) and bit-error-rate (BER) of the considered AF relayed dual hop HAPS-FSO system are derived in this work. The numerical results reveal that the system's OP and BER are influenced by atmospheric turbulence, beam width, angle of deviation of the HAPS along with the different modulation techniques.