A New Channel Estimation Method for OFDM Systems Based on Adaptive-Asymmetric Filter in the Transform Domain

A new channel estimation method is proposed for orthogonal frequency division multiplexing (OFDM) mobile systems based on comb-type pilot. The proposed method utilizes adaptive-asymmetric filter in the transform domain. Asymmetric filter is proposed to reduce more noise for channel estimation based on the characteristic of transform-domain signal, and adaptive adjustment of the cutoff frequency is utilized to eliminate the error floor of channel estimation at high signal-to-noise ratios. Signal-to-noise ratio estimation is implemented in the transform domain. We investigate the performance of the proposed method by measuring symbol error rate with 16QAM as the modulation. Simulation results show that the proposed method outperforms the conventional transform-domain interpolation and the frequency-domain low-pass interpolation.