A QUASI THREE-DIMENSIONAL RAY TRACING METHOD BASED ON THE VIRTUAL SOURCE TREE IN URBAN MICROCELLULAR ENVIRONMENTS

The increase in mobile communications traffic has led to heightened interest in the use of ray tracing (RT) methods together with digital building databases for obtaining more accurate and efficient propagation prediction in urban microcellular environments. In this paper, a novel quasi three-dimensional (3-D) RT algorithm is presented by taking into account the advantages of both the image theory (IT) and the shooting-and- bouncing ray (SBR) method. It is based on creating a new virtual source tree in which the relationship between neighbor nodes is a left-son-and-right-brother one. Our theoretical results of the signal path loss along the streets are compared with measurements which have been reported for city streets in Tokyo and Ottawa City for various values of the propagation parameters. The good agreement with these measurements indicates that our prediction model works well for such microcellular communication applications. The proposed method can provide the reliable theory basis for radio-wave propagation prediction and network planning in urban microcellular environments.