An improved model based on UTD for multiple diffractions by buildings

A new model for radio wave propagation prediction in urban mobile environments is proposed and the most rigorous expressions based on UTD for multiple diffractions by buildings and excess path losses are derived and analyzed. In the proposed model, building rows are supposed to have rectangular flat-roofed shapes with the same heights and spacings, which form a well-known structure of parallel building rows. Furthermore, electrical properties and surface roughness due to the actual building walls in a typical city are taken into account. The approach used in the new model, is based on UTD. Besides, a new heuristic UTD diffraction coefficient in addition to higher-order diffracted fields are suited to analyze the new model.