Ray-tracing and UTD analyses for microcellular communications in urban scene: a software methodology that uses 3-D GIS data of buildings

Prediction methods of electromagnetic propagation in urban areas are now more accurate because calculators are more powerful and especially environmental data have better quality and a greater trade. Several methods, both empirical and more deterministic algorithms, have been proposed in scientific literature. Deterministic computation uses detailed geometrical data of buildings or of generic obstacles and assures better predictions within microcell areas. Many deterministic methods have been proposed, e.g: vertical-plane-launch (VPL), vertical-plane/slant-plane (SP/VP), etc. We introduce our method, based on vertical-plane-launch, that includes a different approximation for multiple diffraction at horizontal edges. Our algorithm uses terrain altitude data to take into account reflections from terrain. We have dedicated special care to final conversion of the data structures. In order to decrease the calculation time of the simulations we have added a three-dimensional (3-D) extension of circular representation (CR) proposed by Lee. We show simulation results of multipath propagation in urban areas. In particular we examine the special case of a transmitting antenna located on the rooftop of a building inside the centre of Rome. Regarding these tests we use 3-D building data, elaborated by using a data-base of Rome municipality ownership. Finally, the software architecture of our GIS platform TERRAPACK^Lt; is described