A spectrum efficient cellular base-station antenna architecture

A concept is considered according to which using the spatial distribution of the users acquired by an array on reception, an antenna system can dynamically assign single narrow beams to illuminate lone mobiles, and broad beams to the numerous groupings along major highways. In this way, the level of cochannel interference is reduced, increasing the spectrum efficiency and, ultimately, the capacity of the network. The realization of such an adaptive base-station antenna requires an architecture capable of locating and tracking the mobiles, and thus a beamforming network capable of producing the multiple independent beams. These two tasks are illustrated as a source estimation or direction finding processor and a beamformer. A preliminary study was carried out to establish a figure of merit for the proposed antenna system in terms of the increase in spectrum efficiency that could be achieved relative to conventional antenna systems. The program of research described has demonstrated the feasibility of a multiple beam base-station antenna system for future high-capacity cellular networks, although there is much to be accomplished before it could be incorporated into an existing network.<>