窄带干扰环境下直扩信号伪码的盲估计方法研究

为了解决窄带干扰条件下低信噪比直扩信号扩频码的盲估计问题，该文提出了一种直扩信号的相关矩阵累加平均结合矩阵特征分解的方法。该方法首先按照已获知的直扩信号扩频码周期、码速率等二次统计特性参数对接收信号进行取样处理以获得一个观察向量集，接着用所提出的方法对该集合进行处理，其结果可以估计出信号所夹杂的窄带干扰(以多音干扰为例)特征波形，同时还可以进一步估计出信号的扩频码序列。利用前者，可以进一步消除信号所夹杂的窄带干扰，而利用后者则可以对接收信号实行盲解扩处理。理论分析和数值结果都表明了该方法非常有效，并能工作在较低的输入信噪比和很低的信号干扰比环境下。

Study on the DS-SS Signals Despreading without the PN Sequence under Narrow Band Interference

In this paper, an approach of eigen-analysis for DS-SS signals under narrow band (multiple tone) interference is proposed, which can estimate the PN (Pseudo Noise) sequence blindly in the low SNR(Signal Noise Ratio) and SlR(Signal Interference Ratio) DS-SS signals. Of course, the parameters of the DS-SS signals (such as period and chip interval of the PN sequence) need to be known. Firstly, the received signal is divided into a lot of non-overlapping temporal vectors according to the period of PN sequence, and then the correlation matrix of the vectors is calculated and accumulated. The eigenvalue decomposition of the matrixes can be computed and the narrow band interference waveforms and the PN sequences of the received signals from the main component eigenvectors can be blindly estimated in the end. Based on the estimated narrow band interference waveforms and PN sequences, the narrow band interference can be rejected, and the DS-SS signals despreading without the PN code can be realized too. Theoretic analysis and experimental results show that the approach is very effective. It can work well on the lower SNR and SIR ambient.