Linear frequency modulation interference suppression in direct sequence spread spectrum systems

For suppressing the linear frequency modulation interference in a direct sequence (DS) spread spectrum system, a direct sequence spread spectrum receiver with an interference exciser using fractional Fourier transform is presented. Based on the fact that the localization performance of a given LFM interference varies in different fractional Fourier domains, the detection and parameter estimation of the interference are implemented using the fractional Fourier transform. The interference can be reconstructed and excised adaptively. Performance analyses and simulation results have showed that the proposed method works effectively in a large dynamic range. It is easy in computation and simple in implementation.