Propagation characteristics on microcellular urban mobile radio channels at 910 MHz

To mitigate fading and reduce time dispersion on urban mobile radio channels, it has been proposed that future systems be configured with many small cells having low-powered base stations with street-lamp-level antennas. 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. Cumulative distribution functions for envelope fading as well as delay spread and frequency correlation statistics are presented. Comparisons are made with similar statistics for conventional channels. Results show that multipath propagation conditions would be significantly less severe if small-celled systems were implemented. Root mean square delay spread averages are reduced by a factor of approximately four in comparison with those typical in conventional systems. In addition, microcellular-type channels have Rician, rather than Rayleigh, envelope fading characteristics, and correspondingly different frequency correlation statistics, which offers further advantages