Bit-interleaved pragmatic space-time codes: design and code construction

This paper addresses the design of bit-interleaved pragmatic space-time codes (BI-PSTC) over block fading channels (BFC). BI-PSTC are obtained with the serial concatenation of a convolutional encoder, a bit-interleaver and a space-time mapper, whereas the decoder is based on a Viterbi algorithm which uses suitably defined branch metrics. Here, a method for good BI-PSTC construction, which exploits the concept of generalized transfer function for space-time codes over BFC, is proposed. Codes for QPSK constellations achieving a considerable coding gain over known space-time codes are then derived. Different spectral efficiencies and fading rates (taken into account by the BFC model) are investigated.