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Advances in Multimedia
Volume 2010, Article ID 416797, 14 pages
http://dx.doi.org/10.1155/2010/416797
Review Article

UEP Concepts in Modulation and Coding

1School of Engineering and Science, Jacobs University Bremen, 28759 Bremen, Germany
2Silver Atena Electronic Systems Engineering GmbH, Hamburg, Germany
3Department of Computer Science and Electrical Engineering, Luleå University of Technology, 97187 Luleå, Sweden
4University of Nice, Sophia-Antipolis, BP 2135, 06103 Nice, France
5ETIS ENSEA/UCP/CNRS, 95014 Cergy-Pontoise, France

Received 28 February 2010; Accepted 27 June 2010

Academic Editor: C.-C. Kuo

Copyright © 2010 Werner Henkel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

First unequal error protection (UEP) proposals date back to the 1960's (Masnick and Wolf; 1967), but now with the introduction of scalable video, UEP develops to a key concept for the transport of multimedia data. The paper presents an overview of some new approaches realizing UEP properties in physical transport, especially multicarrier modulation, or with LDPC and Turbo codes. For multicarrier modulation, UEP bit-loading together with hierarchical modulation is described allowing for an arbitrary number of classes, arbitrary SNR margins between the classes, and arbitrary number of bits per class. In Turbo coding, pruning, as a counterpart of puncturing is presented for flexible bit-rate adaptations, including tables with optimized pruning patterns. Bit- and/or check-irregular LDPC codes may be designed to provide UEP to its code bits. However, irregular degree distributions alone do not ensure UEP, and other necessary properties of the parity-check matrix for providing UEP are also pointed out. Pruning is also the means for constructing variable-rate LDPC codes for UEP, especially controlling the check-node profile.