EM vector channel estimation and V-BLAST/PIC detection for multiuser long-code MIMO CDMA in multipath Rayleigh fading channels

Recently, a training-based vector channel estimation scheme has been proposed for single-user CDMA systems with aperiodic spreading codes. In this paper, we extend it to the reverse link of multiuser MIMO CDMA system. We also use the generalized MMSE multiuser detector to suppress multiuser interference so then we can get good initial vector channel estimates for each user. In the data transmission period, we combine the generalized MMSE multiuser detector, the maximum likelihood (ML) MIMO detector, and vector channel prediction of next channel vectors. The simulation results show that the vector channel estimation outperforms scalar channel estimation in multiuser MIMO CDMA systems.