Performance Analysis of UAV-Based FSO Communication over Doubly Inverted Gamma-Gamma Turbulence Channel

In this paper, we have utilized a recently proposed doubly inverted Gamma-Gamma (IGGG) turbulence channel to model an unmanned-aerial-vehicle (UAV)-based free space optics (FSO) communication system. UAVs enhance wireless connectivity, facilitate dynamic deployment to enable line-of-sight (LoS) communication with ground-based nodes, and offers higher data rates above 10 GBPS. However, the performance of UAV-based FSO communication is affected due to the presence of atmospheric turbulence, path loss, nonzero boresight pointing errors, and angle-of-arrival (AoA) fluctuations. By deriving the closed-form expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the instantaneous signal-to-noise ratio (SNR) of the FSO link, the performance of UAV-based FSO communication is evaluated. Furthermore, outage probability, average symbol error rate (SER), and ergodic capacity expressions are obtained using the PDF and CDF by taking into account both heterodyne (HD) and direct detection (DD) techniques for ground-to-UAV (G2U), UAV-to-UAV (U2U) and UAV-to-ground (U2G) scenarios. Monte-Carlo simulations, which are performed using the recently proposed IGGG channel model, are carried out to validate all the analytical expressions.