Connectivity analysis and user access design of ground-to-air ultraviolet communication networks

Considering the scattering feature in the ultraviolet (UV) spectrum that can support communication for mobile unmanned aerial vehicles (UAVs), we deploy UAVs equipped with UV communication. Specifically, we focus on ground-to-air UV networks where the UAV collects data from the ground nodes. Assuming that the ground nodes are distributed in two dimensions, we analyze the air-ground connectivity probability. The influence of the transmitter divergence angle on the connectivity probability is investigated. Then, we analyze the probability that there exists interference from multiple nodes. To guarantee reliable communication under such interference, we further propose a handshaking-based UAV access protocol. By solving the coloring problem, we determine the time slot allocation for handshaking and propose a greedy channel allocation method to maximize the average system throughput. Numerical results show the performance gain of the proposed protocol over existing works.