Satellite-UAV Communications

This section considers a dual-hop cooperative satellite-UAV communication system including a satellite (S) and a group of cluster headers (CHs), respectively, with a group of uniformly distributed UAVs. Specifically, the CHs serve as aerial decode-and-forward (DF) relays to forward the information transmitted by the S to the UAVs. Moreover, free-space optical (FSO) and RF technologies are adopted over S-CH and CH-UAV links to exploit the high directivity of FSO over long-distance transmission and the omnidirectional coverage ability of RF. The positions of the CHs in the three-dimensional space follow the Matern hard-core point processes (MHCPP) type II, in which each CH cannot be closer to another by less than a predefined distance. Three cases of CH-UAV links are considered during the performance modeling: Interference-free, interference-dominated, and interference-and-noise. Then, the coverage performance of the S-CH link and CH-UAV links in the three cases is studied, and the closed-form analytical expressions of the coverage probability (CP) over both links are derived. The asymptotic expressions for the CP over the S-CH link and CH-UAV link in the interference-free case are derived. Finally, numerical results are provided to validate our proposed analytical models, and thus, some meaningful conclusions are achieved.