Open Access

CDMA Transmission with Complex OFDM/OQAM

  • Chrislin Lélé1,
  • Pierre Siohan1Email author,
  • Rodolphe Legouable1 and
  • Maurice Bellanger1
EURASIP Journal on Wireless Communications and Networking20072008:748063

DOI: 10.1155/2008/748063

Received: 15 May 2007

Accepted: 10 August 2007

Published: 16 August 2007

Abstract

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.

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Authors’ Affiliations

(1)
France Telecom, Research & Development Division, RESA/BWA

Copyright

© 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.