On Carrier Spacing in Multicarrier CDMA Systems

Ha H. NGUYEN  Ed SHWEDYK  

Publication
IEICE TRANSACTIONS on Communications   Vol.E87-B   No.3   pp.768-771
Publication Date: 2004/03/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technology
Keyword: 
CDMA,  multicarrier-CDMA,  carrier spacing,  

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Summary: 
This letter considers multicarrier CDMA systems using rectangular chip waveform, where each user's data stream is serial to parallel converted to a number of lower rate streams. Each lower rate stream is then spread by a random spreading code and a suitable chip rate before modulating orthogonal carriers. It is shown that, for a fixed system bandwidth and a given number of carriers, there exists an optimal carrier spacing that minimizes the multiple access interference. Numerical examples also show that the multicarrier DS-CDMA system previously proposed in performs very close to the muticarrier CDMA system using the optimal carrier spacing.