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Sensibilité des systèmes OFDM-CDMA aux erreurs de synchronisation en réception radio-mobile.

Abstract : In the research area of wireless communications, the combination of Orthogonal Frequency Division Multiplexing (OFDM) and Code Division Multiple Access (CDMA) has been investigated for the fourth generation telephony systems.
In this thesis, a detailed description of the two dimensional (2D) spreading system, called « OFDM-CDMA », is developed for the downlink communication scheme. The goal of this the thesis is multifold.
First, a comparison between the performance of different spreading schemes is identified to show the benefit supported by the 2D solution with respect to the 1D spreading solutions.
Second, it is known that these different solutions implement a large number of sub-carriers and as a consequence, will be high sensitive to Radio Frequency (RF) impairments and synchronization errors.
Thus, we established the sensitivities of these multi carrier spreading systems to these impairments as well as their sensitivities to channel estimation errors and Doppler spread while the orthogonality between codes is accounted for.
These sensitivities are given in terms of the Signal to Interference and Noise Ratio (SINR) at the output of the detector.
In order to show how these sensitivities may change with the channel coding, we established a relation between the link level measure expressed in terms of the SINR and the system level measure expressed in terms of the Bit Error Rate (BER) at the output of the channel decoder.
Eventually, we gave granted limits on the values of the impairments as well as a comparison between degradations of different spreading schemes due to these impairments.
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Contributor : Jean-Michel Vanpé <>
Submitted on : Wednesday, January 23, 2008 - 2:49:27 PM
Last modification on : Friday, March 19, 2021 - 5:00:28 PM
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  • HAL Id : tel-00214147, version 1



Youssef Nasser. Sensibilité des systèmes OFDM-CDMA aux erreurs de synchronisation en réception radio-mobile.. Traitement du signal et de l'image [eess.SP]. Institut National Polytechnique de Grenoble - INPG, 2006. Français. ⟨tel-00214147⟩



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