Verifying path loss and delay spread predictions of a 3D ray tracing propagation model in urban environment

In this paper path loss and delay spread predictions of a 3D ray tracing software are compared to wideband radio channel measurements made in Helsinki city center. Measurements were carried out in the 2 GHz band by using a wideband radio channel sounder, which gives out complex channel impulse responses. Reference delay spreads were obtained from power delay profiles, and path losses were available after appropriate cable calibration measurements. Comparisons between measurement and propagation predictions were made in cases where a realistic directional BS antenna was placed (a) slightly below the rooftop level and (b) slightly above the rooftop level. For propagation modeling a fully 3D ray optical model was used.