A study on noise canceling system based on adaptive filter for OFDM system

The orthogonal frequency division multiplexing (OFDM) system is widely studied for realizing high-speed wireless communications in recent years. In OFDM system, the frequency domain equalizer is used in order to compensate the signal degradation by a multipath. However, the estimation accuracy of channel response is deteriorated by the additive white Gaussian noise (AWGN). In order to solve the problem, we propose the noise canceling system based on an adaptive filter. An OFDM signal is periodic with a period of fast Fourier transform (FFT). Therefore, the current OFDM signal has high correlation with the signal shifted by the period of FFT. On the other hand, the current AWGN is not correlated with the AWGN shifted by the period of FFT. In the proposed system, the AWGN is canceled by taking advantage of the difference between the autocorrelation of the OFDM signal and the autocorrelation of the AWGN.