Abstract
A distributed arithmetic coding algorithm based on source symbol purging and using the context model is proposed to solve the asymmetric Slepian–Wolf problem. The proposed scheme is to make better use of both the correlation between adjacent symbols in the source sequence and the correlation between the corresponding symbols of the source and the side information sequences to improve the coding performance of the source. Since the encoder purges a part of symbols from the source sequence, a shorter codeword length can be obtained. Those purged symbols are still used as the context of the subsequent symbols to be encoded. An improved calculation method for the posterior probability is also proposed based on the purging feature, such that the decoder can utilize the correlation within the source sequence to improve the decoding performance. In addition, this scheme achieves better error performance at the decoder by adding a forbidden symbol in the encoding process. The simulation results show that the encoding complexity and the minimum code rate required for lossless decoding are lower than that of the traditional distributed arithmetic coding. When the internal correlation strength of the source is strong, compared with other DSC schemes, the proposed scheme exhibits a better decoding performance under the same code rate.
Highlights
IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Since the scheme proposed in this article needs to use the context model in the coding process, a randomly generated binary order-1 Markov source sequence of length N will be used as the source sequence
At the encoder of this scheme, some source symbols are purged from the source sequence to obtain additional compression gain, and a forbidden symbol is added to the source alphabet to ensure a better bit error rate performance at the decoder
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Another idea to implement the DSC scheme based on arithmetic coding is to puncture the output bitstream of the arithmetic encoder This is a very convenient solution to obtain the additional compression gain, which will not be affected by the skewed probability distribution of the source. Unlike the previous puncture-based schemes in which the punctured bits are discarded, the purged symbols in the proposed scheme are extracted from the source sequence to further reduce the bit rate, but are used as the context for the coding of the subsequent symbols The advantage of this method is that the original correlation between adjacent symbols in the source sequence is preserved, and the additional compression gain obtained will not be affected by the skewed probability distribution of the source.
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