Pipelined Turbo Multiuser Detection and Kalman Channel Estimation for MU-MIMO SC-FDMA Systems

Single carrier-frequency division multiple access (SC-FDMA) has been adopted as the uplink transmission standard in fourth generation cellular network to enable the power efficiency transmission in mobile station. Since multiuser multiple-input multiple-output (MU-MIMO) is a promising technology to fully exploit the channel capacity in mobile radio network, this paper investigates the uplink transmission of SC-FDMA systems with orthogonal space frequency block codes (SFBC). It is necessary to joint consider the channel estimation, multiuser detection and turbo equalization for MU-MIMO SC-FDMA system. The pipelined turbo equalizer architecture has the feature that multiple soft-decisions become available at various processing stage. These multiple decisions from different pipeline stage have varying levels of reliability and can be used to track the variation of the channels. A critical issue in turbo receiver design is long processing latency due to inherent iterative processing of information. Pipeline architecture reduces the latency and improves processing throughput in turbo receivers and thus is the prevailing choice of the implementation architecture. The optimum channel estimator is a Kalman-based channel estimator for MU-MIMO SC-FDMA systems. In this paper, we use the pipelined structure to design the iterative channel tracking, multiuser detection and turbo equalization which with low latency, reasonable computation complexity and good channel tracking capability. Some simulation examples for uplink scenario are given to demonstrate the effectiveness of the proposed schemes.