Channel Measurements and Modeling of Wooded Hilly Terrain At Sub-1 GHz Band

The study of sub-1 GHz wireless channels in wooded hilly terrain (WHT) holds significant importance for the deployment and optimization of emergency communication systems. In this letter, we conduct a comprehensive measurement of broadband channels at 380 and 640 MHz in WHT. From the measured data, we extract and model the root-mean-square (rms) delay spread and shadow fading (SF) for both line-of-sight (LoS) and non-line-of-sight (NLoS) links. The fitting results reveal that the rms delay spreads in both LoS and NLoS conditons can be modeled as a Lognormal distribution with mean values of approximately 1.1 and 2.9 $\mu$s, respectively. The SF across all conditions follows a zero-mean normal distribution with a standard deviation ranging from 2.18 to 3.23 dB. In addition, two distinct path loss models are proposed for different link conditions. Comparison with measured results demonstrates the high accuracy of both models in predicting path loss.