Enhancement of unequal error protection properties of LDPC codes
EURASIP Journal on Wireless Communications and Networking
Path Pruning for Unequal Error Protection Turbo Codes
IZS '06 Proceedings of the 2006 International Zurich Seminar on Communications
Modern Coding Theory
Design of bandwidth-efficient unequal error protection LDPC codes
IEEE Transactions on Communications
On the UEP capabilities of several LDPC construction algorithms
IEEE Transactions on Communications
Factor graphs and the sum-product algorithm
IEEE Transactions on Information Theory
Design of capacity-approaching irregular low-density parity-check codes
IEEE Transactions on Information Theory
Analysis of sum-product decoding of low-density parity-check codes using a Gaussian approximation
IEEE Transactions on Information Theory
A recursive algorithm for the exact BER computation of generalized hierarchical QAM constellations
IEEE Transactions on Information Theory
Extrinsic information transfer functions: model and erasure channel properties
IEEE Transactions on Information Theory
Regular and irregular progressive edge-growth tanner graphs
IEEE Transactions on Information Theory
Nonuniform error correction using low-density parity-check codes
IEEE Transactions on Information Theory
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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. Bitand/ 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.