A novel method of Narrow-Band Interference suppression using IIR lattice filter in DSSS and its performance analysis

A novel Narrow-Band Interference (NBI) suppression method of IIR lattice notch filter based on the combination of NBI suppression in both time and frequency domain in DSSS is proposed. This method is implemented in a parallel processing structure. The frequency of NBI signal is accurately obtained by employing optimal window functions in the time domain and spectrum correcting method in frequency domain. The optimal rejection bandwidth of IIR notch filter in the frequency domain is obtained adaptively according to the error of frequency estimation and interference to signal ratio. Then the IIR notch filter coefficients are adjusted timely and adaptively. Analysis and results of the experiment show that the proposed method has better stabilization and real-time property than traditional adaptive NBI suppression methods of IIR, and minimizes the distortion of the signal in the full suppression of narrow-band interference.