Pseudo-codeword landscape

Michael Chertkov, Mikhail Siepanov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

34 Scopus citations


We discuss The performance of Low-Density-Parity-Check (LDPC) codes decoded by means of Linear Programming (LP) at moderate and large Signal-to-Noise- Ratios (SNR). Utilizing a combination of the previously introduced pseudocode word-search method and a new "dendro" trick, which allows us to reduce the complexity of the LP decoding, we analyze the dependence of the Frame-Error-Rate (FER) on the SNR. Under Maximum-A-Posteriori (MAP) decoding the dendro-code, having only checks with connectivity degree three, performs identically to its original code with high-connectivity checks. For a number of popular LDPC codes performing over the Additive-White-Gaussian-Noise (AWGN) channel we found that either an error-floor sets at a relatively low SNR, or otherwise a transient asymptote, characterized by a faster decay of FER with the SNR increase, precedes the error-floor asymptote. We explain these regimes in terms of the pseudo-codeword spectra of the codes.

Original languageEnglish (US)
Title of host publicationProceedings - 2007 IEEE International Symposium on Information Theory, ISIT 2007
Number of pages5
StatePublished - 2007
Externally publishedYes
Event2007 IEEE International Symposium on Information Theory, ISIT 2007 - Nice, France
Duration: Jun 24 2007Jun 29 2007

Publication series

NameIEEE International Symposium on Information Theory - Proceedings
ISSN (Print)2157-8101


Other2007 IEEE International Symposium on Information Theory, ISIT 2007

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Information Systems
  • Modeling and Simulation
  • Applied Mathematics


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