900-MHz multipath propagation measurements for US digital cellular radiotelephone

The results of multipath power delay profile measurements of 900-MHz mobile radio channels in Washington, DC, Greenbelt, MD, Oakland, CA, and San Francisco, CA, are presented. The measurements have focused on acquiring worst-case profiles for typical operating locations. The data reveal that at over 98% of the measured locations, root mean square (RMS) delay spreads are less than 12 mu s. Urban areas typically have RMS delay spreads on the order of 2-3 mu s and continuous multipath power out to excess delays of 5 mu s. In hilly residential areas and in open areas within a city, RMS delay spreads are slightly larger, typically having values of 5-7 mu s. In very rare instances, reflections from city skylines and mountains can cause RMS delay spreads in excess of 20 mu s. The worst-case profiles show resolvable diffuse multipath components at excess delays of 100 mu s and amplitudes 18 dB below that of the first arriving signal. >