一种针对短码、周期长码直扩信号扩频序列盲估计方法

提出一种新的针对短码和周期长码直接序列扩频(DSSS，Direct Sequence Spread-Spectrum) 信号的扩频序列盲估计方法。将周期长码DSSS信号建模为多用户短码DSSS信号系统,根据接收信号相关矩阵最大特征值个数，判断一个PN周期内调制信息符号个数，依此盲估计信息速率，同时形成分段相关矩阵矢量。利用改进二阶统计盲辨识（SOBI，Second Order Blind Identification）算法盲估计多用户分段DSSS的PN序列，根据特定约束条件(如m序列、Gold序列)去分段相位模糊，最终形成周期长码PN序列。仿真结果表明该算法的有效性，且适应较低信噪比。

A Method for Blind Estimation of PN Sequence of Short-Code and Periodic Long-Code DSSS Signal

A new method to blindly estimate the PN sequence of short-code(SC) and periodic long-code(PLC) direct sequence spread spectrum signals(DS-SS) is presented in this paper. The PLC DSSS signal is modeled as an multi-user short-code DSSS system. The information rate is blindly estimated according to the number of information symbols modulated during a period of spreading sequence according to the number of eigen-values of the received signal correlation matrices. This enables us to exploit an improved second order blind identification(SOBI) to estimate users’ spreading sequence, and make use of special constraint condition (such as m- or Gold-sequence) to eliminate the phase ambiguity, and form the blind estimation of long-code PN sequence lastly. Simulations show that the proposed method can provide a good estimation for all kinds DSSS signals in non-cooperative context, even in low
signal-to-noise (SNR).