In order to mitigate fading and reduce time dispersion on urban mobile radio channels, it has been proposed that future sys tems should be configured with many small cells having low powered base stations with streetlamplevel antennas. This configura~ tion contrasts with that of systems designed in the pact in which one centrally-located, high-powered base station with an elevated antenna is employed to serve a large coverage area 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 in this par per. Cumulative distribution functions for envelope fading, as well as delay spread and frequency correlation Statistics are presented.In addition, comparisons are made with simlar statistics for conventional channels. There are no previously pubiished papers regarding these characteristics on microcellular-type 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 thaw typical in conventional systems. In addition, microcellular-type channels have Rician, rather than Rayleigh, envelope fading characteristics, and correspondingly diaerent frequency correlation statistics. The advantage of the Rician characteristics may be twc-fold. First, on Rician channels, with narrow transmission bandwidths, a desired error rate can be achieved in a digital system with a lower received bit energy to noise power spectral density ratio than that required for equivalent performance on a Rayleigh channel. Secondly, since correlation remains high over large bandwidths it is believed that, without equalization or diversity, the bandwidth available for communication with acceptable error performance on Rician channels is significantly greater than that available on Rayleigh channels with comparable time dispersion Characteristics.

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