Time delay spread measurements at two frequencies in a small city

Abstract

Time delay spread and signal level measurements were made in the streets of a small city at 850 MHz and 1.9 GHz. The results are compared to earlier measurements made in the same city at 850 MHz. The root mean square (rms) time delay spread was statistically the same at the two frequencies. The maximum rms time delay spread observed was 920 nanoseconds (ns). However, this dropped to under 476 ns for coverage radii under 300 meters. When the transmitter and receiver were on the same street, received power levels could be modelled by an averaged two-ray model with linear attenuation. The non-same-street distance exponent of path loss was 5.0 at 1.9 GHz. The rms time delay spread doubled, statistically, for every 18 dB increase in path loss at 1.9 GHz.