Prediction of multipath delay profiles in mountainous terrain

Abstract

Measurements of the complex impulse response of 900 MHz radio channels in mountainous terrain in British Columbia, Canada, are used to quantify values for the normalized scattering cross section /spl sigma//sup 0/ for mountains covered with evergreen trees. The bistatic radar equation is then used in a propagation model to predict characteristics of the impulse response in similar terrain from topographical data. Three-dimensional (3-D) propagation models for mountainous areas are important, because such areas stress to the limit the multipath handling capabilities of most air interfaces. /spl sigma//sup 0/ is related to a more fundamental characteristic /spl gamma/ of the surface via Lambert's law. The measured value of /spl gamma/ is -21.1 /spl plusmn/2.9 dB, which is similar to some of the very few other values found in the literature. Using this value of /spl gamma/, the predicted multipath delay profiles correspond well with measurements. The results can be used to predict complex impulse responses in mountainous terrain which may be convolved with a simulated data stream to predict error rate, outage or other aspects of wireless system performance.