Skip to content


  • Research Article
  • Open Access

NAF, OAF, or Noncooperation: Which Protocol to Choose?

EURASIP Journal on Advances in Signal Processing20072008:546470

  • Received: 1 June 2007
  • Accepted: 1 November 2007
  • Published:


The two main Amplify and Forward cooperative protocols are the orthogonal (OAF) and the nonorthogonal one (NAF). In this paper, we consider a given source, relays, a destination, and a channel realization and we try to resolve the following problem: what is the best way to communicate: without cooperation or using one of the two cooperative protocols? This is equivalent to a power-sharing problem on the cooperation frame between source and relays aiming to the short-term channel capacity maximization. The obtained solution shows that cooperative protocol choice depends only on the available power at the relays. However the decision to cooperate depends on the channel conditions. We show that our power allocation scheme with relay selection improves the outage probability compared to the selective OAF and the NAF protocols and has a significant capacity gain.


  • Information Technology
  • Quantum Information
  • Full Article
  • Publisher Note

Publisher note

To access the full article, please see PDF.

Authors’ Affiliations

France Telecom Division of Research and Development, 38-40 Rue du Général Leclerc, Issy les Moulineaux Cedex 9, 92794, France


© A. Saadani and O. Traoré. 2008

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.