Wideband 3-D Characterization of Mobile Radio Channels in Urban Environment

This paper describes 3-D radio channel measurements at the base which combines an RF switched receiver array and a synthetic aperture technique and allows full 3-D characterization of the channel. Additionally, dual-polarized patch antennas as array elements enable full determination of the polarization properties of the impinging signals. We describe measurements at over 70 di erent transmitter positions and three receiver array sites with di erent sectors and antenna heights. Our results show that the received energy is concentrated within identi able clusters in the azimuth-elevation-delay domain. We demonstrate that the observed propagation mechanisms are mainly determined by the environment close to the base station. Street canyon propagation dominates also when the receiver array is at or even above rooftop level with the studied measurement distances. Thus the azimuth spectrum at the BS site is fairly independent of the location of the mobile. Signal components propagating over the rooftop are often related to re ections from high-rise buildings in the surroundings.