Abstract
Joint source-channel decoding is considered for a transmission system, in which the quantizer indices of several autocorrelated source signals are bit-interleaved, commonly channel encoded, and transmitted in parallel. Since the optimal decoding algorithm is not feasible in most practical situations, iterative source-channel decoding has been introduced. The latter is generalized in the present paper. Furthermore, it is shown in detail, that iterative source-channel decoding can be derived by insertion of appropriate approximations into the optimal joint decoding algorithm. The approximations allow the decomposition of the optimal decoder into two parts, which can be identified as the constituent decoders for the channel-code and the source-code redundancies. Similar as in other concatenated coding systems, the constituent decoders are applied in an iterative decoding scheme. Its performance is analyzed by simulation results.
Résumé
Dans cet article, nous considérons le décodage conjoint source-canal pour un système de transmission, dans lequel les indices des quantificateurs de plusieurs sources auto-corrélées sont entrelacés bit par bit, codés ensemble par un codage de canal, et transmis en parallèle. Comme l’algorithme de décodage optimal est trop complexe, le décodage iteratif source-canal est introduit et généralisé dans cet article. De plus, nous démontrons en détail que le décodage source-canal itératif peut se déduire après quelques approximations de l’algorithme de décodage conjoint optimal. Ces approximations per mettent la décomposition du décodeur optimal en deux parties que l’on peut identifier comme les décodeurs constituants prenant en compte respectivement la redondance du codage de canal et la redondance résiduelle du codage de source. Comme dans d’autres systèmes concaténés de codage, les décodeurs constituants sont utilisés dans un processus de décodage itératif. Les performances sont analysées grâce aux résultats de simulation.
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GöRTZ, N. A generalized framework for iterative source-channel decoding. Ann. Télécommun. 56, 435–446 (2001). https://doi.org/10.1007/BF02995454
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DOI: https://doi.org/10.1007/BF02995454