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Étude des modulations à porteuses multiples et à spectre étalé : analyse et optimisation

Abstract : The digital communication systems know a significant expansion because of the more and more important demand for mobility, various services and for the integration of the most recent multimedia applications. The researches presented in this thesis aim to study new communication schemes for mobile radio communication systems as well as indoor communication systems. The new element is the combination of two techniques: spread spectrum which allows to make use of code division multiple access and multicarrier modulations. Thanks to this combination, it is possible to benefit from the OFDM robustness and spectral efficiency, and from multiple access capacity of CDMA techniques. Two schemes combining OFDM and CDMA are particularly detailed and analyzed.

The first technique, name MC-CDMA is studied on a multipath Rayleigh fading channel. Several equalization receiver techniques or diversity combining are undertaken and a more general approach to the detection is suggested. It consists in integrating the spreading function into the equalization process in order to improve the detection reliability. These equalization techniques are inserted and combined in different ways into the interference cancelation structures.

If the MC-CDMA is generally suggested for synchronous and quasi-synchronous links, MT-CDMA can be used within an asynchronous context. The theoretical performances of this system are developed and compared to DS-CDMA systems' performances.
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Contributor : Jean-Yves Baudais <>
Submitted on : Tuesday, May 10, 2005 - 12:10:54 PM
Last modification on : Thursday, January 7, 2021 - 4:20:18 PM
Long-term archiving on: : Friday, April 2, 2010 - 10:16:11 PM


  • HAL Id : tel-00009214, version 1


Jean-Yves Baudais. Étude des modulations à porteuses multiples et à spectre étalé : analyse et optimisation. Autre. INSA de Rennes, 2001. Français. ⟨tel-00009214⟩



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