Chase-Like Decoding of Arithmetic Codes with Image Transmission Applications

Several recent contributions have demonstrated that Joint Source/ Channel (JSC) decoding could be a powerful technique to make error correction in the case of transmission of entropy encoded streams. This paper addresses a new scheme for JSC decoding of Arithmetic Codes (AC) based on Maximum A Posteriori (MAP) sequence estimation. The proposed algorithm performs Chase-like decoding using a priori knowledge of the source symbol sequence and the compressed bit stream lengths. Simulation results show that the proposed decoding algorithm leads to significant performance gain in comparison with classical arithmetic decoding, while exhibiting very low complexity. The practical relevance of the proposed technique is validated in the case of image transmission across the AWGN channel. Lossless and lossy image compression schemes were considered, and the Chase-like arithmetic decoder shows excellent results.