Measurement and Ray-tracing for UAV Air-to-air Channel Modeling

Unmanned aerial vehicles (UAVs) have been widely used for both civil and mission-critical applications with ever-increasing values in the next decade. The UAV channel shows some unique characteristics due to high mobility and variable attitudes of the UAVs. In this paper, an air-to-air (A2A) channel at 1420 MHz in the urban scenario is measured. The delay and power of the multipath components (MPCs) are analyzed based on the measurement data. Besides, a ray-tracing (RT) simulator is calibrated to be applicable for more UAV scenarios, through which extensive simulations are conducted. The attitude of the moving UAV is set to change during the RT simulations, including pitch-up, cruise, and pitch-down flight. Correspondingly, tapped-delay line (TDL) models of A2A channels are developed. Moreover, Doppler spectrum of each tap is modeled by Jakes spectrum. The proposed channel models can be helpful for designing UAV communication systems.