Adaptive CMMSE receivers for space-time block coded MIMO CDMA systems

A technique that can suppress multiple access interference (MAI) in space-time block coded (STBC) multiple-input multiple-output (MIMO) CDMA systems is developed. The proposed scheme, called the constrained minimum mean square error (CMMSE) receiver, is an extension of our method (see Hong, S.C. et al., Proc. VTC´02 Spring, 2002) to MIMO systems. The proposed CMMSE receiver for STBC systems has the identical complexity and rate of convergence as those of the CMMSE receiver for a SISO system, irrespective of the number of transmission antennas. Closed-form expressions for signal-to-interference-and-noise ratio (SINR) of the proposed and conventional maximum likelihood (ML) receivers are derived. As a result, it is shown that the proposed CMMSE receiver can provide significant performance improvement over the existing ML receiver.