Research And FPGA Realization Of Narrow-band Interference Suppression Algorithm In DSSS

Narrow-band interference (NBI) is a very important problem in direct sequence spread-spectrum communication system, which affects the performance of the whole system. The system will not function property sometimes even malfunction when the power of narrow-band interference surpasses the jamming margin. The paper studies the NBI suppression algorithm in DSSS, designs and implements the DSSS NBI suppression algorithm based on the FPGA platform which can be applied in practice. The DSSS NBI suppression algorithm is a time-domain adaptive filtering algorithm. The de-spreaded and filtered signal will be as anticipant signal of adaptive filtering algorithm after being re-spreaded in the DSSS NBI suppression algorithm, from this method, we can get a quite pure anticipant signal which can be used to improve the performance of DSSS NBI suppression.The theory analysis, MATLAB simulation and FPGA realization show that the DSSS NBI suppression algorithm can be used in practical engineering. The algorithm is not sensitive to the central frequency and numbers of the NBI and can suppress the stationary and slowly changed NBI effectively. When the central frequency, bandwidth and amplitude of the NBI changed, the algorithm can continuously analyze the NBI, makes the adaptive filter's notch position, notch width and notch depth change adaptively. Finally, the NBI can be suppressed completely. Therefore, the DSSS NBI suppression algorithm can suppress the NBI effectively. The ameliorative performance of the DSSS communication system has attained expectant purpose because of applying the DSSS NBI suppression algorithm.