基于迭代信息传递技术的直扩信号捕获  

Direct-sequence Spread-spectrum Signal Acquisition Using Iterative Message-passing Techniques

作　　者：徐定杰[1] 姜利 沈锋[1] 

机构地区：[1]哈尔滨工程大学自动化学院,黑龙江哈尔滨150001

出　　处：《计算机仿真》2008年第3期318-322,共5页Computer Simulation

摘　　要：随着对直扩系统抗干扰性和隐蔽性要求的不断提高,作为扩频码的PN码序列的周期长度也在不断的增长,因此,如何实现长PN码直扩信号的快速捕获成为系统实现的关键问题之一。针对此问题,提出将基于图模型的迭代信息传递算法(IMPA)应用于直扩信号捕获。直扩信号捕获根据接收信号的信道信息直接生成与接收信号序列粗同步的本地伪码序列,改变了传统捕获方法中本地伪码序列的生成方式,大大缩短了信号的捕获时间。详细说明了基于该技术的直扩信号捕获的实现原理和实现方法,并对基于该技术的直扩信号捕获进行了仿真。仿真结果表明该方法能够在低信噪比下实现信号的快速捕获,而且实现的复杂度较低。With the increased requirement on anti - jamming and concealment in direct - sequence spread - spectrum system, a longer period PN code is required. Therefore, how to achieve direct - sequence spread - spectrum sig- nal is very important. So, a new method of direct - sequence spread - spectrum signal acquisition using iterative message-passing algorithm based on graphs is proposed. This method can realize rude synchronism between received signal and local PN code directly, change the creation mode of local PN code in traditional acquisition model, shorten the average acquisition time greatly. In this paper, the principle and realization of this method are given. The results of simulation show that this method can make the acquisition time greatly decreased and the performance of acquisition improved, when the SNR is low. At the same time, the complication is reduced.

关 键 词：信号捕获 自适应门限 迭代信息传递算法 因子图 

分 类 号：TN966.2[电子电信—信号与信息处理]