Design techniques for orthogonal Modulated filterbanks based on a compact representation
IEEE Transactions on Signal Processing
Analysis and design of OFDM/OQAM systems based on filterbank theory
IEEE Transactions on Signal Processing
Spreading codes for direct sequence CDMA and wideband CDMA cellular networks
IEEE Communications Magazine
The alamouti scheme with CDMA-OFDM/OQAM
EURASIP Journal on Advances in Signal Processing - Special issue on filter banks for next-generation multicarrier wireless communications
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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.