Performance Analysis of Space–Time Block-Coded MIMO Systems With Imperfect Channel Information Over Rician Fading Channels

The performance analysis of space-time block-coded multiple-input-multiple-output (STBC-MIMO) systems in Rician fading channels for perfect and imperfect channel state information (CSI) is presented in this paper. Accurate expressions of average bit error rate (BER) and symbol error rate (SER) of STBC-MIMO for multiple phase-shift keying (MPSK) and quadrature amplitude modulation (QAM) are derived. Based on asymptotic analysis and Nakagami approximation for Rician fading, closed-form expressions of approximate average BER and SER are obtained for low and high signal-to-noise ratios (SNRs). By combining the error rate expressions of low SNR and SNRs, approximate BER and SER expressions can be obtained for different SNRs. Computer simulation shows that the theoretical analysis is in good agreement with the simulation results, and the approximate expressions derived from the integration of high and low SNR asymptotic analyses are close to the accurate formulas for different SNRs. The asymptotic analysis at high SNR indicates that the coding gain is affected by the Rice factor, transmit and receive antenna numbers, code rate, and modulation, whereas the diversity gain is governed by the transmit and receive antenna numbers. However, the diversity gain will be zero at high SNR in the presence of estimation errors because of the error floor in the error probability curves.