n-Channel Multiple Descriptions: Theory and Constructions

Rohit Puri1 and S. Sandeep Pradhan2
(Professor Kannan Ramchandran)
(DARPA) F30602-00-2-0538

Multiple description (MD) source coding has recently emerged as an attractive framework for robust multimedia transmission over unreliable channels, such as the Internet and the wireless medium. The basic idea in MD coding is to generate multiple descriptions of the source, such that each description independently describes the source with a certain fidelity, and when more than one description is available, they can be synergistically combined to enhance the quality.

In this work, we present new achievable rate regions and code constructions for the symmetric n-channel multiple descriptions (MD) coding problem for n>2. Our approach is inspired by unexplored connections between MD and the problem of distributed source coding.

We describe the underlying information-theoretic framework, and then formulate practical code constructions based on scalar/vector quantizers and linear channel codes to emulate the information theoretic performance.

S. S. Pradhan, R. Puri, and K. Ramchandran, "(n,k) Source Channel Erasure Codes: Can Parity Bits also Refine Quality?" Proc. Conf. Information Sciences and Systems, Baltimore, MD, March 2001.
R. Puri, S. S. Pradhan, and K. Ramchandran, "n-Channel Multiple Descriptions: Theory and Constructions," Data Compression Conf., Snowbird, UT, April 2002.
R. Puri, S. S. Pradhan, and K. Ramchandran, "n-Channel Symmetric Multiple Descriptions: New Rate Regions," Int. Symp. Information Theory, Lausanne, Switzerland, July 2002.
1Postdoctoral Researcher
2Professor, University of Michigan, Ann Arbor

Send mail to the author : (rpuri@eecs.berkeley.edu)

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