Practical design considerations for digital mobile radio systems operating in the mountainous terrain

Two methods for reducing the relative strength of long-delayed echoes received in mobile radio environments in the presence of distant reflectors are explored. These methods are: (i) the application of directional base antennas with the main lobe facing the service area in order to avoid direct illumination of the mountain, and (ii) installing base antennas inside built-up areas rather than at the city boundaries where a clear view of mountains may exist. Using a simulation study based on a recently developed path loss model, the effectiveness of the measures in reducing the strength of long-delayed echoes and the delay spread is quantified. The method and the results are described.