Blind detection of space-time block codes and application for iterative receiver

Blind detection of a space-time block coding (STBC) scheme without channel state information (CSI) was proposed by V. Tarokh et al. (see Proc. ICUPC´98, vol. 2, p.917-20, 1998); the method suffered a performance penalty of 3 dB compared to coherent detection. Compared to differential STBC, this scheme requires no differential encoder at the transmitter. We present a new blind detection method for STBC. We show that by defining an intermediate variable, the STBC encoder can be modeled as a Markov process and described by a trellis. Coding gain is revealed in the STBC with QPSK and 8PSK modulation. A Viterbi decoder can be applied for STBC at the receiver without knowledge of CSI. The new scheme can perform better than the conventional blind detection of STBC. Furthermore, the new blind STBC decoder is used in the iterative blind detection of STBC.