基于虚拟多用户模型的长码直扩信号伪码估计

PN Sequence Estimation of Long-code DSSS Signals Based on Virtual Multiuser Model

针对长码直接序列扩频(DSSS)信号的伪随机码(PN)盲估计问题,提出了一种新的周期长码直接序列扩频信号(PLC DSSS)模型。该模型等同于虚拟多用户短码扩频DS-CDMA系统,采用DS-CDMA的谱范数来估计同步偏移,该算法不需要更多假定限制,利用相关函数二阶矩、特征值分解和模糊酉矩阵方法就可以完成伪码序列的估计。实验结果表明,在较低信噪比下就可以完成对PN码序列的精确估计,表现出良好的性能。

For the blind estimation of long- code direct sequence spread spectrum（DSSS）signals, a new period- ic long code（PLC） DSSS signals model as equivalent to a virtual multiuser short - code DSSS system is present- ed. The spectral norm in the DS- CDMA system is exploited to estimate the synchronous offset, then second- order correlation function, eigenvalue decomposition and ambiguity matrix methods are employed to estimate long - code spreading codes, without further restricting assumptions. Experimental results show that the algorithm can complete precisely the estimation of PN code in low SNR. The proposed algorithm has good performance.