A low-complexity multiuser detector for asynchronous CDMA QPSK systems with adaptive antenna arrays

This paper deals with a multiuser detector for DS-CDMA wireless communication systems. The proposed detector's main feature lies in the joint utilization of the space and time processing techniques since adaptive antenna arrays and decorrelating multiuser receiver are supposed to be used together. Complexity growth is lowered by implementing a multiuser detection technique based on the sliding window algorithm. The DS-CDMA communication system considered resorts to QPSK modulated wideband signals so that a sliding window algorithm generalization is necessary. The simulation results shown here confirm that the proposed structure is near-far resistant even in the worst fading cases. As the sensor number increases a remarkable performance improvement takes place. Besides we show that the proposed receiver allows systems to exploit completely the array introduction while maintaining an acceptable computational complexity.