带残余频偏的QPSK-DSSS信号伪码序列盲估计  

Blind Estimation of Pseudo-Code Sequence of QPSK-DSSS Signal with Residual Carrier

作　　者：陈显露 张天骐[1] 孟莹 王晓烨 CHEN Xianlu;ZHANG Tianqi;MENG Ying;WANG Xiaoye(School of Communication and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065

出　　处：《北京邮电大学学报》2022年第3期90-95,共6页Journal of Beijing University of Posts and Telecommunications

基　　金：国家自然科学基金项目(61771085)。

摘　　要：针对正交相移键控(QPSK)调制的带残余频偏直接序列扩频(DSSS)信号伪码序列难以估计的问题,提出信号相关矩阵特征分解结合全数字锁相环(DPLL)进行伪码序列估计的方法。首先对接收信号进行采样和分段得到数据矩阵;根据最大化信号相关矩阵的谱范数估计出伪码序列的同步点;在同步基础上再计算信号相关矩阵的特征子空间;针对其主分量特征向量带有残余频偏且相位存在π/2跳变的问题,采用全数字锁相环跟踪和消除其残余频偏进而恢复伪码序列。研究结果表明,针对QPSK-DSSS信号,所提方法能够实现负信噪比下伪码序列的盲估计。To solve the estimation difficulties of pseudo-code sequence of direct sequence spread spectrum(DSSS) signals with quadrature phase shift keying(QPSK) modulation with residual carrier, a method of pseudo-code sequence estimation is proposed based on signal correlation matrix eigendecomposition combined with all digital phase locked loop(DPLL). First, the received signal is sampled and segmented to obtain the data matrix. Then, the synchronization point of pseudo-code sequence is estimated by maximizing the spectral norm of signal correlation matrix. Based on synchronization, the characteristic subspace of signal correlation matrix is calculated. To eliminate the residual carrier of the eigenvector of the principal component and the phase change of π/2, a DPLL tracking and a residual carrie elimination are used to recover the pseudo-code sequence. The research results show that, for QPSK-DSSS signals, the proposed method can achieve blind pseudo-code sequence estimation under negative signal to noise ratio.

关 键 词：扩频通信 伪码序列盲估计 正交相移键控 特征值分解 锁相环 

分 类 号：TN911.7[电子电信—通信与信息系统]