Shadowing due to multiple-edge diffraction

This paper presents a shadowing model due to diffraction from multiple knife-edge obstacles. By using the ray-tracing method, the statistical character of the shadowing phenomenon is determined and the results are compared with the statistical model based on log-normal shadowing. The effects of the number of obstacles, the distances between them, variations in their heights, and the range are investigated for various path geometries on the mean, the standard deviation and the correlation distance of diffraction loss. Probability density functions and histograms of diffraction losses obtained by the ray tracing approach and the log-normal model are compared to each other. Lognormal pdf was observed to be more accurate in modeling the shadowing losses due to multiple-edge diffraction in micro-cellular environments.