Spatial division multiple access technology and its application to wireless communication systems

Space is one of the "final frontiers" when it comes to next generation wireless communication systems. Large-scale penetration of such such systems into our daily lives will require significant reductions in cost and increases in capacity, benefits proper exploitation of the spatial dimension can offer. That this is certainly the case is attested to by the significant number of companies that have been recently formed to bring products based on such concepts to the wireless marketplace. The approaches range from "switched-beam" to "fully-adaptive" with the benefits provided by the various approaches differing accordingly. At the fully-adaptive end of the spectrum is spatial division multiple access (SDMA) technology. SDMA technology employs antenna arrays and multi-dimensional nonlinear signal processing techniques to provide significant increases in capacity and quality of many wireless communication systems. It is especially well-suited to the current and next generation cellular systems termed personal communications services (PCS). Antenna arrays coupled with adaptive signal processing techniques employed at base stations improve coverage, capacity and trunking efficiency allowing lower cost deployments with cells of moderate to large size. The basic principles and architecture of SDMA wireless communication systems are outlined. Experimental results obtained from systems built to these new architectural specifications are presented demonstrating the efficacy of SDMA technology.