Frequency MMSE Equalization Combined with Kalman Channel Estimation in OFDM System

To combat with the ICI caused by the Doppler and carrier frequency errors, an autoregressive (AR) process is used to model time evolution of the fading channel and a novel frequency MMSE equalizer combined with Kalman channel estimator is proposed. Combined techniques outperform traditional linear and DFT interpolation methods in both slow and fast fading conditions. The complexity of the equalizer is reduced significantly by using the fact that only a few adjacent subchannels are major interferers to a desired subchannel. Mean squared error (MSE) and bit error rate (BER) performance of the proposed algorithm are verified by computer simulation