Soft-bit decoding of regular low-density parity-check codes

Sheryl L Howard, Vincent C. Gaudet, Christian Schlegel

Research output: Contribution to journalArticle

15 Scopus citations


A novel representation, using soft-bit messages, of the belief propagation (BP) decoding algorithm for low-density parity-check codes is derived as an alternative to the log-likelihood-ratio (LLR)-based BP and min-sum decoding algorithms. A simple approximation is also presented. Simulation results demonstrate the functionality of the soft-bit decoding algorithm. Floating-point soft-bit and LLR BP decoding show equivalent performance; the approximation incurs 0.5-dB loss, comparable to min-sum performance loss over BP. Fixed-point results show similar performance to LLR BP decoding; the approximation converges to floating-point results with one less bit of precision.

Original languageEnglish (US)
Pages (from-to)646-650
Number of pages5
JournalIEEE Transactions on Circuits and Systems II: Express Briefs
Issue number10
StatePublished - Oct 2005
Externally publishedYes



  • Belief propagation (BP)
  • Iterative decoding algorithms
  • Low-density parity-check (LDPC) codes
  • Soft output decoding

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering

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