Effects of Non-Fixed Scatterers' Random Movements on Ultra-Wideband Miso Channels

Abstract

Abstract-Most wireless channel models assume fixed scatterers with specific geometrical distributions in the propagation environment. In reality most scatterers move with random movements on the azimuth plane. In this paper, the effects of such scatterers' random movements on the cross-correlation function (CCF) of wideband (WB) and ultra-wideband (UWB) non-isotropic multiple-input multiple-output (MIMO) channels are characterized. The CCF of WB/UWB MIMO channels is calculated not by assuming a specific geometry for scatterers in space but based on specific mathematical relationships between physical parameters of the wireless channel along with appropriate assumptions on their probability density functions (pdfs). The CCF is used to determine the influence of moving scatterers, in a stationary scenario, on the power spectral density (PSD) and the coherence time of WB and UWB multiple-input single-output (MISO) channels, as a particular case of MIMO channels. Unlike the fixed scatterers case, the PSD is not a band-limited process, it decays with frequency.