Channel estimation for OFDM with fast fading channels by modified Kalman filter

In OFDM systems, time-varying channels destroy the orthogonality between subchannels and cause interchannel interference (ICI) in conventional frequency-domain channel estimation approaches. To compensate for this ICI, we propose a new channel estimator for OFDM systems in a fast and frequency-selective Rayleigh fading channel. The proposed method is based on a new modified Kalman filter (MKF). The time-varying channel is modeled as an autoregressive (AR) process and the proposed MKF is used to estimate this AR parameter. In addition, to track the time-varying channel, a channel predictor using regression analysis and the minimum mean-squared error (MMSE) time-domain equalizer are also proposed. The simulation results show that the proposed channel estimator can effectively compensate for ICI.