LDPC codes for non-uniform memoryless sources and unequal energy allocation

Idoia Ochoa, Pedro M. Crespo, Mikel Hernaez

Research output: Contribution to journalArticlepeer-review


In this paper, we design a new energy allocation strategy for non-uniform binary memoryless sources encoded by Low-Density Parity-Check (LDPC) codes and sent over Additive White Gaussian Noise (AWGN) channels. The new approach estimates the a priori probabilities of the encoded symbols, and uses this information to allocate more energy to the transmitted symbols that occur less likely. It can be applied to systematic and non-systematic LDPC codes, improving in both cases the performance of previous LDPC based schemes using binary signaling. The decoder introduces the source non-uniformity and estimates the source symbols by applying the SPA (Sum Product Algorithm) over the factor graph describing the code.

Original languageEnglish (US)
Article number5572892
Pages (from-to)794-796
Number of pages3
JournalIEEE Communications Letters
Issue number9
StatePublished - Sep 2010
Externally publishedYes


  • Systematic and non-systematic LDPC codes
  • non-uniform memoryless sources
  • unequal energy allocation

ASJC Scopus subject areas

  • Modeling and Simulation
  • Computer Science Applications
  • Electrical and Electronic Engineering


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