Blind beamforming for DS-CDMA systems

Abstract

Code Division Multiple Access (CDMA) has been proposed as an efficient access method for cellular and personal communication systems outperforming the classical FDMA and TDMA techniques. But, in contrast to them, CDMA systems are interference limited, being the interferences mainly the other users. A variety of methods have been proposed to combat this multi-access interference (MAI), such as the correlation detector, the maximum likelihood detector, linear detectors, subtractive interference cancellation detectors. However, spatial diversity can be combined with the existing methods to further increase the reduction of the interference. Many efforts have been spent in this direction during the last years. In this paper, a novel blind beamforming algorithm based on the introduction of an explicit redundancy structure within the spreading codes is described.