Usage of smart antenna for cancelling neighboring base-station interferences in wireless CDMA communications

Abstract

The capacity of wireless CDMA systems in the forward link is limited by both intra-cell and inter-cell cochannel interferences. In particular, when the mobile is close to a cell boundary, the desired signal from home base station (BS) is disturbed by relatively strong interference from neighboring BSs. In this paper, a receiver architecture is suggested at the mobile to utilize a small two-antenna array for interference cancellation. Such a canceller works well only when the channel vector of desired signal is known. We use the identifying spreading codes (as in IS-95 for example) to provide an adaptive channel vector estimate, and control the beam steering weight, hence improving the system capacity.