Chriss A. Hammerschmidt and Robert T. Johnk

Abstract: This paper discusses a mobile propagation measurement in Los Angeles, CA and compares these measurements to the output from the Irregular Terrain Model (ITM). Propagation measurements are currently being used at the Institute for Telecommunication Sciences (ITS) to improve and validate the ITM propagation model. In this paper, these measurements are compared to the predicted terrain attenuation losses from ITM as a function of four different terrain databases. We began using ITM to calculate clutter losses (i.e. attenuation due to vegetation and man-made structures) by subtracting the ITM prediction from the measured data. As with any model, the estimation of clutter losses changes as the prediction from ITM changes based on the terrain database; therefore, it is important to understand why these changes occur. This paper briefly discusses the measurement system, the results from this campaign, and the output from ITM as a function of four different terrain databases of various horizontal resolutions.

Keywords: attenuation; Fresnel zones; Irregular Terrain Model (ITM); mobile propagation; terrain database

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