An Experimental Study of 2.4 GHz LoRa Path Loss for Air-to-Ground Communication in Rural Areas

Channel modeling in radio communication is crucial, especially for emerging technologies like LoRa. While LoRa shows promise for Unmanned Aerial Vehicle (UAV) telemetry and C2 channels, its progress in sub-GHz bands is hindered by duty cycle limitations. LoRa operating at 2.4 GHz has no such restrictions and can achieve higher data rates. However, the propagation characteristics and goodput performance of 2.4 GHz LoRa have not been well studied. In this work, we present path loss, round-trip time, and goodput measurements for air-to-ground communications (A2G) with 2.4 GHz LoRa. We compare our results with well-known path loss models, where we observe a relative fit by the Walfisch-Bertoni and Two-Ray models in rural-like areas. Our results demonstrate that for spreading factors SF=7 and SF=10, a link latency of less than 50 ms could be achieved, but it fails to meet the minimum required data rate required for a Command and Control (C2) link.