A Space-Time Non-Stationary and Consistent Model for 6G Multi-UAV Cooperative Channels

In this paper, a novel space-time non-stationary and consistent channel model is proposed for sixth-generation (6G) multiple-unmanned aerial vehicle (multi-UAV) cooperative communication systems. In the proposed model, clusters are divided into single-clusters and twin-clusters to mimic the complex multi-UAV cooperative propagation environment. Furthermore, three-dimensional (3D) continuously arbitrary trajectories of multi-UAVs are imitated by time-variant accelerations and integration of time. A new method, which integrates the visibility region (VR) and birth-death (BD) process, is developed to capture cooperative space-time non-stationarity and consistency. In the developed method, the typical multi-UAV features, such as 3D continuously arbitrary trajectories and flight height, are also considered. Key channel statistical properties of multi-UAV cooperative channels, such as cooperative space-time-frequency correlation function (STF-CF) and singular value spread (SVS), are derived. Simulation results demonstrate that cooperative space-time non-stationarity and consistency are adequately captured.