Connectivity Analysis of Multi-UAV Communication Systems with Simplified Fresnel Propagation Model in Urban Scenarios

The rapidly changing propagation environment during flight is a huge challenge for multi-UAV systems. The wireless channel changing with the propagation environment has an important impact on the information sharing between UAVs, especially in urban scenario. However, the recent research on the statistical properties of Air to Air (A2A) channels cannot be directly used in the control link connectivity analysis due to the complexity. In this paper, a simplified A2A channel model based on Fresnel propagation theory is proposed and applied to investigate the connectivity of communication topologies for control information sharing in multi-UAV systems. Considering UAV flying in 3D space, the impact of 3D blockages is focused on in this paper. Theoretical results show that the average strength of edges decreases with the increase of the density of buildings, which implies that the connectivity between UAVs deteriorate during the UAV flight from the suburbs to the city. What's more, the connectivity of the multi-UAV systems is weakened with the increase of the building density and increased with the increase of the size of multi-UAV systems.