On the Performance of the UAV-based Multi-Source FSO Communications

Relay-based free-space optical (FSO) communication systems efficiently mitigate the effects of turbulence-induced atmospheric scintillation. Conventional ground-based relays are immobile, which makes their optimal use difficult. Unmanned aerial vehicles (UAVs), with their dynamic mobility and adaptability, offer unique options for FSO relay systems. This study investigates a UAV-based FSO system utilizing a dual-hop decode-and-forward mechanism with multiple sources on the transmission side. The performance analysis of this system is improved by incorporating the Gamma-Gamma (GG) distribution, which represents atmospheric turbulence, and by considering atmospheric losses, pointing errors, and arrival angle variations. We derive the probability density function (PDF) for these components and create a realistic formula for the PDF of the total channel gain.