摘要
直扩系统中,为了硬件实现上的简便,PN码的捕获一般都采用串行搜索的方法。但当PN码很长时,由于要搜索的相位点很多,串行搜索法将使捕获时间过长。并且当信噪比较低时,会有较高的虚警概率。这些都会使系统的捕获性能下降。文献[6]针对长码提出了分布采样的快速捕获方案(DSA)。本文就此提出了改进,利用积累使之能够适应低达-50dB的低信噪比环境。仿真结果表明,改进后的算法改善了原算法在极低信噪比下的性能,降低了平均捕获时间。
In DS-CDMA systems,in order to simplify the hardware implementation,people usually adopt serial search（SSA） to synchronize PN code. But when PN code is very long,SSA will spend more time because there are many phase position to be cmopared. Specially, when the signal-to-noise is very low, the false alarm probability will be very high. All these factor will strongly debase acquisitive performance. Literature[ 6 ] proposed a new acquisition scheme called distributed sample acquisition（DSA） which＇is applicable to a long period PN code. We improve the scheme by accumulator,and make it available in -50dB＇ s Low SNR environment. The result of simulation proves that our improvement meliorates the old scheme＇ s performance with low SNR, and reduces the average acquisitive time.
出处
《信号处理》
CSCD
北大核心
2006年第3期299-302,共4页
Journal of Signal Processing
关键词
直扩系统
分布式采样捕获
积累
平均捕获时间
direct-sequence spread-Spectrum systems
distributed sample acquisition
accumulate
average acquisitive time
