Low-density graph codes for coded cooperation on slow fading relay channels

Dieter Duyck, Joseph Jean Boutros, Marc Moeneclaey

Research output: Contribution to journalArticle

20 Citations (Scopus)


We study Low-Density Parity-Check (LDPC) codes with iterative decoding on block-fading (BF) Relay Channels. We consider two users that employ coded cooperation, a variant of decode-and-forward with a smaller outage probability than the latter. An outage probability analysis for discrete constellations shows that full diversity can be achieved only when the coding rate does not exceed a maximum value that depends on the level of cooperation. We derive a new code structure by extending the previously published full-diversity root-LDPC code, designed for the BF point-to-point channel, to exhibit a rate-compatibility property which is necessary for coded cooperation. We estimate the asymptotic performance through a new density evolution analysis and the word error rate performance is determined for finite length codes. We show that our code construction exhibits near-outage limit performance for all block lengths and for a range of coding rates up to 0.5, which is the highest possible coding rate for two cooperating users.

Original languageEnglish
Article number5895062
Pages (from-to)4202-4218
Number of pages17
JournalIEEE Transactions on Information Theory
Issue number7
Publication statusPublished - 1 Jul 2011



  • Block fading channels
  • density evolution
  • low-density parity-check code
  • mutual information
  • relay channels

ASJC Scopus subject areas

  • Information Systems
  • Computer Science Applications
  • Library and Information Sciences

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