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  • Research Article
  • Open Access

Practical Quantize-and-Forward Schemes for the Frequency Division Relay Channel

EURASIP Journal on Wireless Communications and Networking20082007:020258

  • Received: 6 April 2007
  • Accepted: 13 November 2007
  • Published:


We consider relay channels in which the source-destination and relay-destination signals are assumed to be orthogonal and thus have to be recombined at the destination. Assuming memoryless signals at the destination and relay, we propose a low-complexity quantize-and-forward (QF) relaying scheme, which exploits the knowledge of the SNRs of the source-relay and relay-destination channels. Both in static and quasistatic channels, the quantization noise introduced by the relay is shown to be significant in certain scenarios. We therefore propose a maximum likelihood (ML) combiner at the destination, which is shown to compensate for these degradations and to provide significant performance gains. The proposed association, which comprises the QF protocol and ML detector, can be seen, in particular, as a solution for implementing a simple relaying protocol in a digital relay in contrast with the amplify-and-forward protocol which is an analog solution.


  • Information System
  • System Application
  • Performance Gain
  • Frequency Division
  • Significant Performance


Authors’ Affiliations

CNRS, Supéléc, Paris 11, 3 rue Joliot-Curie, Gif-sur-Yvette, 91190, France
Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609-2280, USA


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© B. Djeumou et al. 2007

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.