Maximum a Posteriori Decoding of Arithmetic Codes in Joint Source-Channel Coding
Arithmetic codes are being increasingly used in the entropy coding stage in many multimedia transmission applications. Combining channel coding with arithmetic coding can give implementation and performance advantages compared to separate source and channel coding. In this work, novel improvements are introduced into a technique by Grangetto et al. that uses maximum a posteriori (MAP) estimation for decoding joint source-channel coding using arithmetic codes. The arithmetic decoder is modified for quicker symbol decoding and error detection by the introduction of a look-ahead technique, and the calculation of the MAP metric is modified for faster error detection. These modifications also result in improved performance compared to the original scheme. Experimental results show an improvement of up to 0.4 dB when using soft-decision decoding and 0.6 dB when using hard-decision decoding.
KeywordsArithmetic coding Joint source-channel coding Maximum a posteriori decoding
Unable to display preview. Download preview PDF.
- 6.MacKay, D.J.C.: Information Theory, Inference, and Learning Algorithms, ch. 25, pp. 324–333. Cambridge University Press (2003)Google Scholar
- 8.Bi, D., Hoffman, M.W., Sayood, K.: Joint Source Channel Coding Using Arithmetic Codes. Synthesis Lectures on Communications. Morgan & Claypool Publishers (2010)Google Scholar
- 10.Lelewer, D.A., Hirschberg, D.S.: Data compression. ACM Computing Surveys (3), 261–296 (September 1987)Google Scholar
- 11.Sayir, J.: Arithmetic coding for noisy channels. In: Proceedings of the 1999 IEEE Information Theory and Communications Workshop, pp. 69–71 (June 1999)Google Scholar