Capacity-approaching turbo coding and iterative decoding for relay channels

Zheng Zhang, Tolga M. Duman

Research output: Contribution to journalArticlepeer-review

100 Scopus citations


In this paper, we design turbo-based coding schemes for relay systems together with iterative decoding algorithms. In the proposed schemes, the source node sends coded information bits to both the relay and the destination nodes, while the relay simultaneously forwards its estimate for the previous coded block to the destination after decoding and re-encoding. The destination observes a superposition of the codewords and uses an iterative decoding algorithm to estimate the transmitted messages. Different from the block-by-block decoding techniques used in the literature, this decoding scheme operates over all the transmitted blocks jointly. Various encoding and decoding approaches are proposed for both single-input single-output and multi-input multi-output systems over several different channel models. Capacity bounds and information-rate bounds with binary inputs are also provided, and it is shown that the performance of the proposed practical scheme is typically about 1.0-1.5 dB away from the theoretical limits, and a remarkable advantage can be achieved over the direct and multihop transmission alternatives.

Original languageEnglish (US)
Pages (from-to)1895-1905
Number of pages11
JournalIEEE Transactions on Communications
Issue number11
StatePublished - Nov 2005


  • Channel capacity
  • Cooperative diversity
  • Full duplex
  • Information rates
  • Iterative decoding
  • Multihop
  • Multiple-input multiple-output (MIMO)
  • Relay
  • Turbo coding

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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