Estimation of Time-Variant Channels for OFDM Systems Using Kalman and Wiener Filters

In this paper, two channel estimation schemes for OFDM systems are investigated in a time-variant channel. The orthogonality of the subcarriers is destroyed in a time-variant channel, resulting in intercarrier interference (ICI). To mitigate the ICI, the 2D Kalman filtering (2D KF) scheme estimates the channel in time domain by using the Kalman filters in both time and frequency domains and the iterative Wiener filtering (IWF) scheme calculates the ICI through the iteration. To mitigate error propagation, comb-type pilots are adopted in the two proposed schemes. Simulation results show that the proposed schemes have better performance than the conventional schemes.