Minimising downlink interference in cellular systems with adaptive antennas-results from Tsunami (II)

The Tsunami (II) project has investigated the performance of adaptive antenna technology in a cellular mobile network. The project consortium built an adaptive antenna DCS1800 base station and conducted field trials during January to May 1998 at a location in Bristol, UK. This paper presents results that show the benefit, in terms of reduced downlink interference, that was achieved through the use of beamforming techniques in the base station transmitter. Results from rural macrocell and urban microcell environments are presented. For the macrocell case, consistent reductions in downlink interference were achieved, approaching 12 dB. In the microcell experiments, the realisable benefits were not consistent over the full coverage area, but significant reductions in downlink interference were still obtained for specific beam directions.