V-BLAST receivers for downlink MC-CDMA systems

Multiple-input-multiple-output multicarrier-code division multiple access (MIMO MC-CDMA) systems are presented for future mobile Internet and multimedia packet transmission. A linear MMSE V-BLAST detector per subcarrier is proposed for MIMO MC-CDMA systems. This MMSE detector has much better performance than the zero-forcing (ZF) detector, and even better than that of iterative V-BLAST detectors with ZF/MMSE, which is not true for MIMO single carrier systems or MIMO OFDM systems. This is because iterative detection before despreading for MIMO MC-CDMA systems suffers significantly from multiple access interference and error propagation. At the same time, the despreading process after the iterative detection offsets the advantage of iterative detection over linear detection. The performance of various V-BLAST detectors for MIMO MC-CDMA systems is evaluated through simulations.