A preliminary comparison of two propagation prediction methods for 2-D microcells: ray tracing and TLM

This paper presents a preliminary comparison of two coverage prediction methods developed for urban microcellular environments. In this study a particular building layout is chosen as an example. The two considered methods are (1) a ray tracing method taking into account multiple specular reflections and single diffraction phenomena and (2) a time domain approach based on a transmission line matrix (TLM) method. Both methods consider infinitely high buildings and no ground reflection. The results of both methods are compared to measurements provided by KPN Research, (Netherlands). The prediction results of the ray tracing clearly show the contributions of the reflected ray which can be traced individually. The TLM method also produces results where reflections can be identified although not as clearly. Comparisons of prediction results provide an insight on measurements that can be performed to assess the existence of specular reflection in microcellular environments. Good agreement is achieved between either predictions and the measurements, even though the relevant buildings are not always above the base station antenna but only cross the radials from the base station antenna to the mobile.