Performance of Alamouti space-time code in time-varying channels with noisy channel estimates

In this paper, we derive the theoretical performance of the Alamouti space-time code in time-varying Rayleigh fading channels with noisy channel estimates. The receiver algorithms presented in this paper are the maximum-likelihood (ML) symbol detector with the linear combining scheme, which was suggested by Alamouti (1998), and the ML space-time decoder. The bit error probability for the linear combining scheme and the sequence error probability for the ML space-time decoder are presented as functions of the pilot filter coefficients, the multipath power profile, the normalized Doppler frequency, the pilot SNR and the data SNR. We also compare the bit error performance of the linear combining scheme with the bit error performance of the system without transmit diversity. The results indicate that the Alamouti space-time code with the linear combining scheme is outperformed by the no transmit diversity system at high Doppler frequency or low pilot SNR.