Ray tracing predictions for propagation characteristics in entrance radio link

In systems beyond IMT-2000, the microcell structure will be adopted to achieve adequate system capacity and link budget. Thus base stations (BS) would be mounted closer to the road than heretofore, and the shadowing effects due to buildings will be more serious in the entrance radio link between BS. This paper uses the ray-tracing calculation method to predict the propagation characteristics of microwave entrance radio links. The increases in excess path loss and delay spread due to shadowing are characterized as a function of the clearance factor for the first Fresnel zone along direct paths. When the clearance is more than 5 m, the path loss can be taken as free space loss; smaller clearance values yield average excess loss values of several dB, and the path loss increases strongly at negative clearance values. These results agree very well with the experimental results.