Iterative demodulation and decoding of differential space-time block codes

A differential space-time block code (DSTBC) is shown to be a recursive code that can be realized by a trellis. It can therefore be used as an inner code in a serial concatenated structure with an outer convolutional code and a random interleaver. We propose iterative demodulation and decoding of this concatenated system without channel state information (CSI). Because of the additional coding gain from the serial concatenation, the proposed system outperforms the same convolutional coded system using a space-time block code (STBC) with perfect CSI in a static Rayleigh fading channel. Additional performance enhancement can be achieved when linear prediction and per-survivor processing are applied to the proposed system for channel estimation. The resulting differential system has a performance close to the equivalent coherent receiver diversity system in a time-varying flat fading channel.