Abstract:

Direct sequence spread spectrum (DSSS) can suppress interference to a certain extend in satellite communication. However, because the spreading gain is limited, when strong interference is more than the system interference tolerance margin, the system transmission performance would be reduced sharply. The technology of transform domain signal processing could detect and suppress interference in the DSSS, so it could improve the anti-interference ability of the system. Wavelet packet transform which has the excellent time-frequency local analysis ability, is very suitable for interference detection and suppression in the DSSS system. The regular wavelet packet decomposition and the best wavelet packet decomposition are studied, and a new method for interference suppression based on the best wavelet packet decomposition is proposed, which combines subband power ratio and the minimum power threshold to location and suppress interference. The simulation results show that the proposed algorithm enhances the performance and anti-interference ability of the system greatly, increases the computational complexity slightly, compared to that based on regular wavelet packet decomposition and the traditional fast Fourier transformation (FFT) algorithm. It is a more effective method to suppress interference in the satellite DSSS communication system.