Terrain-Augmented Path Loss Modeling and Frequency Dependence Analysis in Mountainous Environments: Measurements from VHF to Microwave Bands

Accurate modeling of radio wave propagation in mountainous environments is essential for wireless communication systems in applications such as emergency rescue and public safety. Based on propagation measurements from VHF to microwave bands, this paper proposes a terrain-augmented close-in (TA-CI) model. The model incorporates two terrain features extracted from high-resolution digital elevation models (DEMs): the maximum terrain clearance height (hc) and the maximum diffraction angle (θmax). By comparing the model predictions at 83 MHz, 235 MHz, 632 MHz, 1.2 GHz, and 5.8 GHz, the proposed TA-CI model achieves higher prediction accuracy than both the close-in (CI) model and the floating-intercept (FI) model in the coastal mountainous area of northern China and the plateau mountainous area of southern China. The root-mean-square prediction error is up to 33.9% lower than that of the CI model. The results of this work provide a propagation model for path loss prediction from VHF to microwave bands in mountainous environments.