Multi-Hop UAV-Based FSO System Over Doubly Inverted Gamma-Gamma Turbulence Channel

In this letter, we consider a recently introduced doubly inverted Gamma-Gamma (IGGG) turbulence channel model and analyze the performance of a multi-hop unmanned-aerial-vehicle (UAV)-based free space optics (FSO) communication system assuming a decode-and-forward (DF) relaying strategy. UAV-based FSO communication improves wireless connectivity, allowing flexible deployment to establish a line-of-sight (LoS) communication with ground-based nodes. The channel modeling incorporates atmospheric turbulence, non-zero boresight pointing errors, path loss, and angle of arrival (AoA) fluctuations. The closed-form expressions for the outage probability (OP), average bit error rate (ABER), and ergodic capacity (EC) are derived over the IGGG turbulence channel with non-zero boresight pointing errors. In addition, the diversity gain and outage/BER floor are calculated from the asymptotic analyses. To validate all the analytical expressions, Monte-Carlo simulations are conducted utilizing the IGGG turbulence channel model.