Linear receiver interfaces for multiuser MIMO communications

We consider the uplink of a DS-CDMA wireless communication system with multiple users equipped with several transmit antennas. We assume that a multiple-antenna subsystem is added to an existing multiuser detector and we compare the performance of this receiver and that of an optimum receiver accounting for both spatial and multiple-access interference simultaneously. In the former case we say that the receiver is separate whereas in the latter we say that the receiver is joint. Several classes of separate and joint linear receivers are considered and their performance is evaluated asymptotically and by simulation.