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Estimation de canal à évanouissements plats dans les transmissions sans fils à relais multibonds

Abstract : This thesis deals with the estimation of the multihop Amplify-and-Forward relay communications. The various objects (transmitter, relays, receivers) can be fixed or mobile. Each link is modeled by a flat fading Rayleigh channel, with a Doppler spectrum resulting from twodimensional (2D, leading to the U-shape Dopller spectrum) or three-dimensional (3D, leading to a flat Doppler spectrum) scattering environments. The cascade of channel hops is approximated by a first-order autoregressive (AR(1)) model and is tracked by a standard estimation algorithm, the Kalman Filter (KF). The common method used in the literature to tune the parameter of the AR(1) model is based on a Correlation Matching (CM) criterion. However, for slow fading variations, another criterion based on the off-line Minimization of the Asymptotic Variance (MAV) of the KF is shown to be more appropriate. For both the CM and MAV criteria, this thesis gives analytic justification by providing approximated closed-form expressions of the estimation variance in output of the Kalman filter, and of the optimal AR(1) parameter. The analytical results are calculated for given Doppler frequencies and Signal-to-Noise Ratio for both scattering environments, whatever the number and type of transmission hops (Fixed-to-Mobile or Mobile-to-Mobile). The simulation results show a considerable gain in terms of the Mean Square Error (MSE) of the well tuned Kalman-based channel estimator, especially for the most common scenario of slow-fading channel.
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Contributor : Soukayna GHANDOUR-HAIDAR Connect in order to contact the contributor
Submitted on : Friday, March 20, 2015 - 11:47:53 AM
Last modification on : Friday, March 25, 2022 - 9:41:19 AM
Long-term archiving on: : Monday, June 22, 2015 - 7:17:10 AM


  • HAL Id : tel-01133741, version 1



Soukayna Ghandour - Haidar. Estimation de canal à évanouissements plats dans les transmissions sans fils à relais multibonds. Traitement du signal et de l'image [eess.SP]. UNIVERSITÉ DE GRENOBLE, 2014. Français. ⟨tel-01133741⟩



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