AG channel measurements and characteristics analysis in hilly scenarios for 6G UAV communications

As an important part of sixth generation (6G) integrated space-air-ground-sea networks, unmanned aerial vehicle (UAV) communications have aroused great attention and one of its typical application scenarios is the hilly environments. The related UAV air-ground (AG) channel characteristics analysis is crucial for system design and network evaluation of future UAV communications in hilly scenarios. In this paper, a recently conducted channel measurements campaign in a hilly scenario is presented, which is conducted at the center frequencies of 2.585 GHz and 3.5 GHz for different flight trajectories. Based on the measurement data, some key channel characteristics are analyzed, including path loss (PL), shadow fading (SF), Rician K-factor, root mean square (RMS) delay spread (DS), and temporal auto-correlation function (ACF). Finally, the comparison of typical channel characteristics under circular and straight trajectories is given. The related results can provide a theoretical reference for constructing future UAV communication system in hilly scenarios.