Simultaneous Radio and Physical Mapping for Cellular-Connected UAV by Fusing Radio and Sensing Data

Radio map is a promising technology to enable environment-aware wireless communications, which may strengthen the flight safety and enhance communication performance for cellular-connected unmanned aerial vehicles (UAVs). However, conventional interpolation-based radio map construction method relies on the large amount of measurement data and it usually gives poor performance if only limited data along a single UAV flight is available. In this paper, we propose an effective map construction method called Simultaneous Radio and Physical Mapping (SRaPM), which concurrently constructs three closely related radio and physical maps by fusing both radio and sensing data collected by the UAV, namely the link state map (LSM), channel gain map (CGM), and building height map (BHM). Specifically, the received signal strength (RSS) is measured while the UAV receives communication signal from the ground base station (GBS), based on which a hypothesis test problem is solved to determine whether the line of sight (LoS) link is blocked. At the same time, the sensors equipped on the UAV sense the locations of the reflection points, based on which some knowledge about the location and height of the buildings in different directions are deduced. Then, the obtained radio and sensing results are used to update the LSM, CGM and BHM. Numerical results are provided to show the effectiveness of the proposed map construction method as compared with the benchmarking spatial interpolation method.