Improved estimation of time varying and frequency selective channels for OFDM systems

In this paper, we deal with channel estimation for OFDM systems operating in time and frequency selective channels. In order to exploit the frequency correlation of the channel transfer function, we use the Karhunen-Love expansion to separate the signal space from the noise space. Afterwords, we use decision-directed technique for tracking the time varying coefficients of the transfer function in the signal space. Our simulation results show the robustness of the proposed scheme with respect to least square channel estimator.