Design and multiple trellis decoding for concatenated constant envelope non-orthogonal space-time block codes

The concatenation of FEC-code with full-rate, constant envelope, non-orthogonal space-time block codes (STBC) is analyzed. A suitable design criterion, average rank criterion is derived for such concatenated codes, wherein eigenvalue distribution rather than the minimum rank of STBC is taken into account. Based on this criterion, an efficient approach to searching proper code matrices is proposed. In addition, a multiple trellis decoding method is applied to the concatenated non-orthogonal STBCs with very low decoding delay. The simulation results of several concatenated codes applying different 3 × 3 STBCs with constant envelope confirm the new design criterion. As the average rank of STBC increases, the BER performance of such a concatenated code improves correspondingly. Moreover, the proper concatenated 3 × 3 constant envelope STBC proposed outperforms the concatenated code with existing 3 × 3 full-rank but changeable envelope STBC designed with respect to the minimum rank criterion.