Spatial Division Multiple Access (SDMA) is a technology with promising prospects for increasing the capacity of Wireless Communications Networks (WCN's). By employing low-cost arrays of antennas and sophisticated signal processing techniques, SDMA provides directional radio transmission and reception capabilities which dramatically increase the number of simultaneous links that can be supported on a single frequency channel. The basic SDMA components - emitter location estimation, spatially selective transmission and spatially selective reception - were validated during the Phase I research effort by a series of half- duplex receive-only and transmit-only experiments. The proposed Phase II effort is to build a fully functional,full-duplex, SDMA prototype for analog cellular telephones (AMPS protocol). This prototype will be used for SDMA algorithm refinement and development, and will serve as a data collection platform for SDMA radio-frequency environment studies. The Phase III effort will be to conduct operational tests with the assistance of a cellular service provider. The market potential for a system that provides increased capacity in wireless information/communication networks is immense. Over 200 million domestic and foreign subscribers are predicted by the year 2000 in a $100 billion annual market. Current systems are at or near capacity in a market which is one-fifth as large, so techniques for increasing capacity are vital to the industry.
