Joint Estimation of Carrier Frequency Offset and Channel Complex Gains for OFDM Systems in Fast Time-varying Vehicular Environments

Eric Pierre Simon (1, 2) , Hussein Hijazi (1, 3) , Laurent Ros (3) , Marion Berbineau (4) , Pierre Degauque (1, 2)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 TELICE - IEMN - Télécommunication, Interférences et Compatibilité Electromagnétique - IEMN
3 GIPSA-CICS - GIPSA - Communication Information and Complex Systems
4 INRETS/LEOST - Laboratoire Electronique, Ondes et Signaux pour les Transports

In this paper, the physical nature of the radiochannel is considered by using an L-path channel model to developing an algorithm for OFDM systems operating in fast time-varying vehicular environment. Assuming the Time of Arrival (TOA) is known, a novel iterative pilot-aided algorithm for joint estimation of multi-path Rayleigh channel complex gains and Carrier Frequency Offset (CFO) is introduced. Each complex gain time-variation, within one OFDM symbol, is approximated by a Basis Expansion Model (BEM) representation. An autoregressive (AR) model is built for the parameters to be estimated (the AR model for the BEM coefficients is based on the Jakes process). The algorithm performs recursive estimation using Extended Kalman Filtering. Hence, the channel matrix is easily computed, and the data symbol is estimated with free intersub- carrier-interference (ICI) when the channel matrix is QR-decomposed. It is shown that only one iteration is sufficient to achieve the performance of the ideal case where knowledge of channel response and CFO is available.

Mots clés: Carrier frequency estimation; Delay estimation; Fast fading; Filtering algorithms; IIterative algorithms; Kalman filters; OFDM; Parameter estimation; Rayleigh channel; Recursive estimation; Time-varying channel

Domaines: Traitement du signal et de l'image [eess.SP]; Traitement du signal et de l'image [eess.SP]

Eric Pierre Simon, Hussein Hijazi, Laurent Ros, Marion Berbineau, Pierre Degauque. Joint Estimation of Carrier Frequency Offset and Channel Complex Gains for OFDM Systems in Fast Time-varying Vehicular Environments. ICC 2010 - IEEE International Conference on Communications, May 2010, Cape Town, South Africa. 5 p., ⟨10.1109/ICCW.2010.5503938⟩. ⟨hal-00539132⟩