Iterative Source-Channel Decoding using Short Block Codes

Iterative source-channel decoding (ISCD) exploits the residual re-dundancy of the source, e.g., codec parameters, for quality improve-ments. In contrast to the well-known convolutional coded ISCD sys-tems, we propose in this paper an ISCD scheme which features a su-perior performance but is based solely on two short block codes. The block codes serve as highly redundant index assignment and rate-1 inner channel code respectively. The improved capabilities are con-firmed by EXIT charts. Finally, the effects of imperfect knowledge of the receiver on the residual redundancy are analyzed. With the proposed flexible index assignment no feedback from the receiver to the transmitter is required and competitive results are obtained even for slightly erroneously estimated residual redundancy. 1