UWB Multipath Channel Model Based on Time-Domain UTD Technique

In this paper, we develop a deterministic UWB multipath channel model based on time-domain uniform geometrical theory of diffraction (TD-UTD) technique. The solution includes the three basic ray mechanisms of geometrical optics (GO) and UTD, i.e., directed ray, multi-reflected rays from lossy surfaces, and diffracted ray from lossy edge. Since the analysis is conducted in time-domain electromagnetic field, unlike statistical model, the approach for UWB channel model can determine not only signal attenuation, but also waveform distortion in terms of pulse shape and pulse duration when the UWB signal propagates in multipath environments. Here, a generic impulse response model by taking into account channel impulse response as well as transmitter and receiver antenna impulse responses is given. Then, the analytical description of time-domain single reflected ray and reflection coefficients of horizontal polarization and vertical polarization is provided. The time-domain multiple reflected rays are expressed by the convolution of individual reflection coefficient from lossy surfaces with different electromagnetic properties. The time-domain diffraction ray is described as time-domain diffraction coefficients and reflection coefficient. Finally, the simulation results in a typical office room are presented.