A deterministic approach to predicting microwave diffraction by buildings for microcellular systems

A propagation prediction method that exploits a building database and considers the three-dimensional profile of the radio path is presented. Models and algorithms are provided that allow the application of Fresnel-Kirchhoff diffraction theory to arbitrarily oriented buildings of simple shapes. Building location information used by the diffraction models is in a form compatible with a geographic information system (GIS) database. Diffraction screens are constructed at all building edges, for both horizontal and vertical orientations, in order to consider all possible diffractions, and to compute field contributions that are often ignored. Multiple buildings and edges of the same building that introduce multiple successive diffractions are considered with a rigorous, recursive application of the diffraction theory that requires sampling the field distribution in each aperture. Robust and computationally efficient numerical methods are applied to solve the diffraction integrals