Propagation in Urban Microcells with High Rise Buildings

In this paper 2D and 3D ray-tracing-predictions based on UTD are compared to measurements in urban microcellular environments characterized by an irregular mixture of building heights due to the presence of relatively high rise buildings. It is shown that the 2D ray-tracing underestimates the measurement in area far from the transmitter. The theoretical study and the preliminary comparisons with measurements in Rotterdam (NL) showed that the 3D backward diffraction by high rise buildings might account for the propagation in area far from the transmitter and overcome the limitation of the 2D model in these areas. Trees were found to influence heavily the 2D prediction. Taking into account the same 3D contributions becomes even more important when there are obstructions such as trees in the 2D plane. A reasonable agreement with measurement can be obtained with a combined 3D and 2D (considering the absorption effects of trees) predictions.