Propagation characteristics on microcellular urban mobile radio channels at 910 MHz

Abstract

The results of measurements made to determine propagation characteristics on urban mobile radio channels with low base-station antennas and line of sight between the base and mobile units are reported. Results show that multipath propagation conditions would be significantly less severe if small-celled systems were implemented. Root-mean-square delay spread averages computed by considering all multipath signal components with powers greater than 25 dB below the peak were reduced by a factor of approximately four in comparison to those typical in conventional systems. In addition, microcellular-type channels have Rician, rather than Rayleigh, envelope fading characteristics and correspondingly different frequency correlation statistics. The area bounded by the correlation envelope is introduced as a measure of channel quality, and these areas are shown to be larger for Rician channels than for Rayleigh channels.< >