Performance Improvement of Drone MIMO Relay Station Using Selection of Drone Placement

This paper evaluates multiple-input multiple-output (MIMO) transmission when a small autonomous unmanned aerial vehicle (drone) is used as a relay station. Although the propagation loss is reduced by using the drone relay station, it has the issue of increased spatial correlation due to the direct wave. Therefore, we clarify that the channel capacity characteristics of MIMO system using drone relay stations are improved by introducing a propagation environment control method (PECM) that selects drones in optimal arrangement from multiple drones.