Wireless Propagation Modeling by Using Ray-Tracing

Abstract

The asymptotic high frequency techniques, based on the Geometrical Optics (GO), the Geometrical Theory of Diffraction (GTD), and its extension such as the Uniform Theory of Diffraction (UTD), can be used to study the propagation of wireless electromagnetic signals in complex environments. Indeed, at high frequencies, it is possible to use the ray concept to trace the paths followed by electromagnetic waves from the transmitting to the receiving antenna, and to calculate the attenuation suffered by virtue of its interaction with the obstacles present in its environment. After a brief overview of the evaluation of electromagnetic fields by using the GO and/or the GTD/UTD, the fundamental geometric concepts of the ray-tracing algorithms are presented. Next, some acceleration techniques, necessary to efficiently model wireless propagation in outdoor and indoor environments, are discussed. Furthermore, leveraging the fact that the ray-tracing algorithm provides all the data necessary for a complete characterization of wireless propagation, it is used to derive some important parameters such as Path Loss, Delay Spread, channel frequency and impulse response, Power Delay Profile and Spreading Function.