A lower bound on the mean squared correlations for band-limited asynchronous DS/CDMA systems

Yutaka Jitsumatsu, Tohru Kohda

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Multiple-access interference (MAI) depends on chip pulse shapes in chip-asynchronous direct sequence/code division multiple access (DS/CDMA) systems. The mean squared MAI averaged over relative time delays is expressed in a quadratic form, where a coefficient matrix is derived from the pulse shapes, while a variable vector consists of aperiodic autocorrelation functions of the signature sequences. This quadratic form gives a lower bound of the mean squared MAI, which is equivalent to the Welch bound if the pulse shape is a delta function. For any continuous pulse shapes, however, the mean squared MAI is shown to be reduced beyond the Welch bound. In case of rectangular pulse, the mean squared MAI is reduced by 13.4%, whereas the reduction ratio is 5.2% for band-limited pulses with excess bandwidth 0.5.

Original languageEnglish
Title of host publicationProceedings - 2006 IEEE International Symposium on Information Theory, ISIT 2006
Pages1524-1528
Number of pages5
DOIs
Publication statusPublished - Dec 1 2006
Event2006 IEEE International Symposium on Information Theory, ISIT 2006 - Seattle, WA, United States
Duration: Jul 9 2006Jul 14 2006

Publication series

NameIEEE International Symposium on Information Theory - Proceedings
ISSN (Print)2157-8101

Other

Other2006 IEEE International Symposium on Information Theory, ISIT 2006
CountryUnited States
CitySeattle, WA
Period7/9/067/14/06

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Information Systems
  • Modelling and Simulation
  • Applied Mathematics

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    Jitsumatsu, Y., & Kohda, T. (2006). A lower bound on the mean squared correlations for band-limited asynchronous DS/CDMA systems. In Proceedings - 2006 IEEE International Symposium on Information Theory, ISIT 2006 (pp. 1524-1528). [4036222] (IEEE International Symposium on Information Theory - Proceedings). https://doi.org/10.1109/ISIT.2006.262123