低信噪比直扩信号的盲解扩

Blind despreading of direct spread spectrum sequence signal in lower SNR

针对接收机对直接扩频序列信号进行自动侦收的需要,提出了低信噪比下直扩信号参数的盲估计方法:利用循环谱检测可以准确估计出载频和码片速率;应用功率谱二次处理估计出扩频码周期;利用特征向量法估计扩频伪码序列;分析、讨论了全盲接收信号的采样率估计方法。仿真结果表明,在没有任何先验知识的情况下,该方法能普遍适用于低信噪下的BPSK,QPSK,16QAM,64QAM等直扩信号的参数估计,从而完成信号的盲解扩。

Based on the necessity for the automatic detection of the direct spread spectrum sequences （DSSS） , an efficient algorithm for estimating the parameters of the DSSS signals was presented without any prior knowledge. The carrier frequency and the chip rate was obtained by the cyclic spectrum detection. The period of pseudo-noise （PN） sequence was estimated by the twice process of the power spectrum. Decomposing the eigenvector, the PN sequence was acquired. The methods for the estimation of the blind signal had been studied. It was shown by the computer simulation that the algorithm can be used for estimating of BPSK, QPSK, 16QAM,64QAM DSSS signals and realizing the de-spreading at low SNR.