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  • Research Article
  • Open Access

CDMA Transmission with Complex OFDM/OQAM

  • 1,
  • 1Email author,
  • 1 and
  • 1
EURASIP Journal on Wireless Communications and Networking20072008:748063

  • Received: 15 May 2007
  • Accepted: 10 August 2007
  • Published:


We propose an alternative to the well-known multicarrier code-division multiple access (MC-CDMA) technique for downlink transmission by replacing the conventional cyclic-prefix orthogonal frequency division multiplexing (OFDM) modulation by an advanced filterbank-based multicarrier system (OFDM/OQAM). Indeed, on one hand, MC-CDMA has already proved its ability to fight against frequency-selective channels thanks to the use of the OFDM modulation and its high flexibility in multiple access thanks to the CDMA component. On the other hand, OFDM/OQAM modulation confers a theoretically optimal spectral efficiency as it operates without guard interval. However, its orthogonality is limited to the real field. In this paper, we propose an orthogonally multiplex quadrature amplitude modulation (OQAM-) CDMA combination that permits a perfect reconstruction of the complex symbols transmitted over a distortion-free channel. The validity and efficiency of our theoretical scheme are illustrated by means of a comparison, using realistic channel models, with conventional MC-CDMA and also with an OQAM-CDMA combination conveying real symbols.


  • Orthogonal Frequency Division Multiplex
  • Multiple Access
  • Spectral Efficiency
  • Quadrature Amplitude Modulation
  • Perfect Reconstruction

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Authors’ Affiliations

France Telecom, Research & Development Division, RESA/BWA, 4 rue du Clos Courtel, Cesson-Sévigné, Cedex, 35512, France


© Chrislin Lélé et al. 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.