A low-complexity near-ML detector for a 3 × nR hybrid space-time code

In a MIMO wireless communications system, a space-time block code specifies how the data symbols are transmitted over different antennas at different time instants. A hybrid space-time code attempts to obtain some of the available diversity and multiplexing gains, achieving low error probability and high data rate. The LD StBc-VBLAST hybrid code layers one spatial-multiplexing antenna (to increase the data rate) and one Alamouti encoder (to provide diversity). A low-complexity, nearly optimum decoder algorithm for LD STBC-VBLAST is presented. Its error probability is comparable to that of a maximum-likelihood detector, with much lower computational complexity. The performance of the detector is evaluated over both uncorrelated and correlated channels. It is shown that the proposed decoder remains nearly optimum despite channel correlation.