Hovering UAV-Based FSO Communications with DF Relaying: A Performance Analysis

Abstract

Due to the low cost installation, unlicensed spectrum, line-of-sight (LoS) nature, and high bandwidth, free space optics (FSO) communication can be used as a high-capacity and cost-efficient solution for future wireless networks. However, due to the LoS nature of FSO links, the connectivity between the transmitter and receiver FSO links gets easily blocked by tall buildings. To overcome this limitation, unmanned-aerial-vehicles (UAVs) can be used as mobile relays by installing FSO transceivers on them to provide connectivity to ground base stations in non-LoS scenarios. This paper analyzes the performance of a hovering UAV-based dual-hop (DH) FSO communications with decode-and-forward (DF) relaying. The channel is modeled by taking atmospheric path loss, atmospheric turbulence, non-zero boresight pointing errors, and angle-of-arrival (AoA) fluctuations into account. The unified closed-form expressions are obtained for outage probability, average symbol error rate (SER), and ergodic capacity considering both heterodyne (HD) and direct detection (DD) techniques for ground-to-UAV (GU) and UAV-to-ground (UG) links over the generalized Málaga distribution. In addition, asymptotic analysis for the above performance metrics has been carried out to obtain the diversity gain of the system. © 2023 IEEE.