Adaptive Detectors for MIMO DS/CDMA Communication Systems

In multiple-input-multiple-output (MIMO) communication systems, multiple antennas are employed at the transmitter and the receiver. Compared with conventional systems, it has been recognized that MIMO is an important technology in obtaining higher data rate and increasing the system capacity. This paper proposes two new linear multiuser detectors and their adaptive implementations for the synchronous multiuser direct- sequence code division multiple-access systems in a MIMO multipath fading environment. First, we employ the total least squares (TLS) method and the estimation of signal parameters via rotational invariance techniques (ESPRIT) to construct the multiuser detector structures. Second, we use the least mean square algorithm in the TLS-based and ESPRIT-based multiuser detectors to develop four adaptive receivers. We also analyze the probability of bit error of the proposed receivers. Simulation results show the performance comparisons of the proposed receivers.