Lokesh K. Bansal, Aditya Trivedi, and Rekha Gupta
MIMO, MMSE, multipath fading channel, space–time trellis code, space–time turbo code
This paper deals with pilot symbol assisted (PSA) channel
estimation (CE) error of space–time turbo code (STTuC) in down-link multi-carrier code-division multiple-access (MC-CDMA) systems. The coding scheme is considered by employing minimum mean-square error (MMSE) detection technique with multiple-input multiple-output (MIMO) antenna diversity in multipath fading channel. The corresponding symbol error rate (SER) is obtained for MMSE receivers employing maximum a posteriori (MAP) algorithm to decode STTuC. The performance of STTuC-MC-CDMA systems is compared with the performance of space-time trellis coded (STTC) MC-CDMA system and it is observed that the STTuC-MC-CDMA system performs better compared to STTC-MC-CDMA system. This performance improvement comes at the cost of increased computational complexity. The analytical performance of cellular communication systems are usually calculated by considering perfect channel state information (CSI) at the receiver. But in practical systems, the channel gains at the receiver are obtained using CE techniques. Due to presence of inherent white Gaussian noise and multipath fading, the CE is imperfect and results in performance mismatch between the practical systems and results obtained considering perfect CSI. The SER results through simulation are also compared with the analytical results.