一种基于Hilbert-Huang变换的直扩信号盲检测方法

Detection of DSSS Based on Hilbert-Huang Transform

针对直扩信号在低信噪比情况下难以检测的问题,提出一种基于Hilbert-Huang变换的盲检测算法。通过对信号进行经验模态分解,根据能量最大原则对得到的内蕴模态函数进行筛选和提取,实现信号的重构;计算其时间、瞬时频率及幅值的分布图和边际谱,从而检测出直扩信号并估计出载频。理论分析和仿真实验表明该算法在信噪比为-16dB的情况下能有效地检测出直扩信号。

In order to solve a difficult problem with detecting low signal-to-noise DSSS signals, a method based on Hilbert-Huang transform is presented. Signals are decomposed into intrinsic mode functions （IMF） by empirical mode decomposition（ EMD）, then these IMFs are shifted and abstracted for being reconstructed according to the energy maximum criteria, and its amplitude and magrginal spectrum are calculated, thereby carrier frequency is estimated. Theoretical analysis and simulation experiments show the algorithm can detect DSSS effectively when the signal to noise ratio is 16dB.