Channel estimator for OFDM systems with 2-dimensional filtering in the transform domain

A discrete Fourier Transform (DFT)-based pilot-assisted channel estimator is presented for OFDM systems operating in frequency-selective time-variant channels. Filtering is done in the transform domain with two separable 1-dimensional filters. A rectangular window is used to filter low energy channel impulse response samples. The window width is chosen to achieve low channel information loss. A Wiener filter is then applied in the time direction for better noise suppression. Frequency responses of all subcarriers are estimated from filtered samples by means of DFT. The parameters of the filters are fixed at the design stage. The estimator has low hardware complexity and low computation load due to simple and non-adaptive structures.