900-MHz Multipath Propagation Measurements for U.S. 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, rms delay spreads are less than 12 µs. Urban areas typically have rms delay spreads on the order of 2-3 µs. and continuous multipath power out to excess delays of 5 µs. In hilly residential areas and in open areas within a city, root mean square (rms) delay spreads are slightly larger, typically having values of 5-7 µs. In very rare instances, reflections from city skylines and mountains can cause rms delay spreads in excess of 20 µs. The worst case profiles show resolvable diffuse multipath components at excess delays of 100 µs. and amplitudes 18 dB below that of the first arriving signal.