快速哈达马变换在扩频序列并行捕捉中的应用

Application of Fast Hadamard Transform in Parallel Signature Code Acquisition

首先给出了 BLDS- SS QPSK信号模型 ,在此模型基础上介绍了最大似然估计 ( MLE)准则下基于数据调制和非数据调制两种并行捕捉方案。特别在非数据调制下 ,采用 m序列或 GOLD码作为扩频序列时 ,运用快速哈达马变换 ( FHT)可降低并行捕捉算法运算量 ,文中讨论了 FHT的应用。此外 ,对两种并行捕捉方案性能进行了计算机仿真 ,结果表明 :非数据调制方案优于数据调制方案。

The model for a QPSK bandlimited DS SS system is presented firstly. With maximum likelihood estimation (MLE) criterion, two kinds of parallel acquisition algorithms, which are based on data modulation and non data modulation, are introduced respectively. Specifically, when signature code is m sequence or Gold code, the computation of non data aided algorithm can be reduced by Fast Hadamard Transform (FHT). The application of FHT is discussed and simulations are carried out, which show that the acquisition performance of non data aided algorithm outperforms data aided algorithm.