Multistage receiver for differential space-time block codes

Tarokh´s differential space-time block codes (DSTBC) can provide a full spatial diversity and be decoded without channel state information. The bit error rate performance of a conventional differential detection has 3-dB degradation compared to a coherent detection in a quasi-static fading channel. Differential detection experiences more degradation in a fast fading channel and error floor appears at high SNR. In [E. Chiavaccini and G.M. Vitetta, May 2002], an approximate maximum likelihood receiver was derived and it reduced the error floor significantly. In this paper, we modify the receiver in [E. Chiavaccini and G.M. Vitetta, May 2002] and apply the concept of multistage decision-directed estimator with intrablock-interference cancellation to obtain further improvement. The proposed receiver works efficiently at moderate to high SNR and at the fading rate between f_dT = 0.02 and f_dT = 0.07.