Joint source/channel iterative arithmetic decoding with JPEG 2000 image transmission application

Abstract

Motivated by recent results in Joint Source/Channel coding and decoding, we consider the decoding problem of Arithmetic Codes (AC). In fact, in this article we provide different approaches which allow one to unify the arithmetic decoding and error correction tasks. A novel length-constrained arithmetic decoding algorithm based on Maximum A Posteriori sequence estimation is proposed. The latter is based on soft-input decoding using a priori knowledge of the source-symbol sequence and the compressed bit-stream lengths. Performance in the case of transmission over an Additive White Gaussian Noise channel is evaluated in terms of Packet Error Rate. Simulation results show that the proposed decoding algorithm leads to significant performance gain while exhibiting very low complexity. The proposed soft input arithmetic decoder can also generate additional information regarding the reliability of the compressed bit-stream components. We consider the serial concatenation of the AC with a Recursive Systematic Convolutional Code, and perform iterative decoding. We show that, compared to tandem and to trellis-based Soft-Input Soft-Output decoding schemes, the proposed decoder exhibits the best performance/ complexity tradeoff. Finally, the practical relevance of the presented iterative decoding system is validated under an image transmission scheme based on the JPEG 2000 standard and excellent results in terms of decoded image quality are obtained.

Accumulator Aided Decoding of Low Complexity SISO Arithmetic Codes with Image Transmission Application

“…In this section we briefly describe the encoding and decoding process of arithmetic codes as in [16], [12]. , which may be nonbinary, is mapped to a binary string based on the source probability model.…”

“…A low complexity soft-input soft-output arithmetic decoder based on Chase-like decoding [17] was proposed in [12]. The arithmetic encoder generates a binary vector C of variable length M, which is interleaved to produce U.…”

“…Most of these discussed schemes depend on specific trellis constructions and eventually pruning the trellis or reducing it. However, as stated in [12], as the number of source sequence length and source alphabet size increases, the decoding complexity becomes intractable. A practical low complexity alternative to trellis based SISO decoders uses Chase like decoding for VLC coded sources [12], [13], [14].…”

“…However, as stated in [12], as the number of source sequence length and source alphabet size increases, the decoding complexity becomes intractable. A practical low complexity alternative to trellis based SISO decoders uses Chase like decoding for VLC coded sources [12], [13], [14]. These decoders show considerable improvement over classical hard decision decoding of arithmetic codes.…”

“…Our main contribution in this paper is improving the performance of Chase-like arithmetic SISO decoder system of [12] (with intermediate convolutional code stage) by the use of rate 1 accumulator. Improvement is obtained with same number of decoding iterations and overall code rate.…”