Study of bit-interleaved coded space-time modulation with different labeling

A bit-interleaved concatenated coding scheme consisting of an outer convolutional code and an inner space-time modulation together with an iterative decoding-demapping method is analyzed. As a result, two parameters based on bitwise pairwise error probabilities (b-PEP) for the cases with and without a-priori knowledge are proposed as new measures for a labeling of signal points suited to iterative decoding-demapping. In particular, we demonstrate that the two parameters are closely related to the transfer characteristic (TC) of the demapper and accordingly lead to the same design guideline as a TC analysis. By optimizing these two analytical parameters for an orthogonal space-time block code (oSTBC) employing 16QAM constituent symbols w.r.t. an outer simple 4-states rate 1/2 convolutional code, a highly power efficient concatenated scheme with rate of 2 bits per channel use is proposed, which offers an excellent trade off between power efficiency and complexity.