A beamspace-time blind RAKE receiver for sectored CDMA systems

Abstract

A beamspace-time (BT) RAKE receiver is proposed for multiple access interference (MAT) suppression and multipath diversity reception in sectored wireless CDMA communications. The scheme involves three stages. First, a set of adaptive beamformers encompassing a prescribed angular sector is constructed on an antenna array, each providing effective suppression of out-of-sector MAI and reception of in-sector signal. Second, a set of adaptive correlators is attached to each beam to combat in-sector MAI. Finally, the beamspace correlator output data are combined to capture the signal multipaths coherently. The above three-stage operation is performed in a blind mode in that no training signal is needed. The only information required is the signature, timing and a rough estimate of the angle of arrival (AOA) of the desired signal.