Channel Modeling and Parameter Optimization for Hovering UAV-Based Free-Space Optical Links

Recently, the use of multi-rotor (MR) unmanned aerial vehicles (UAVs) has emerged as a promising solution for establishing flexible free-space optical communication links. We address, in this paper, the accurate channel modeling to assess the benefits of MR UAV-based deployment for such links. In particular, in the absence of active tracking subsystems, we derive statistical models for ground-to-UAV, UAV-to-UAV, and UAV-to-ground links over both Gamma-Gamma and log-normal atmospheric turbulence models. Unlike previous works on this topic, our proposed model considers the joint effect of atmospheric turbulence along with position and angle-of-arrival fluctuations. The high accuracy of the proposed analytical models is verified by comparing numerically solved and Monte Carlo simulation results in terms of link outage probability. We further discuss the impact of different transmitter/receiver parameters and their optimization in view of maximizing the link availability.