多径软扩频信号伪码周期盲估计  

Blind period estimation of PN sequence for multipath tamed spread spectrum signal

作　　者：杨强[1] 张天骐[1] 赵亮[1] 

机构地区：[1]重庆邮电大学信号与信息处理重庆市重点实验室,重庆400065

出　　处：《计算机应用》2017年第7期1837-1842,共6页journal of Computer Applications

基　　金：国家自然科学基金资助项目(61671095;61371164);信号与信息处理重庆市市级重点实验室建设项目(CSTC2009CA2003);重庆市教育委员会科研项目(KJ130524;KJ1600427;KJ1600429)~~

摘　　要：针对多径信道下因多径衰落造成软扩频信号伪码周期难以估计的问题,提出了一种基于二次功率谱的多径软扩频信号伪码周期盲估计方法。首先,将一般的单径软扩频信号扩展到多径模型;然后,在多径软扩频信号模型的基础上计算信号的一次功率谱;其次,将求出的一次功率谱作为输入信号计算信号的二次功率谱,理论分析表明信号的二次功率谱在伪码周期整数倍处将会出现峰值谱线;最后,通过检测峰值谱线间的间距就可以实现多径软扩频信号的伪码周期估计。通过仿真实验表明,在伪码周期估计正确率为100%、伪码序列长度为127位和255位时,所提方法比时域相关法提高信噪比约1 d B和2 d B;在同一对比条件下,所需要的平均累加次数均少于时域相关法。实验结果表明,所提方法对伪码周期进行估计,在减少计算量的同时,还提高了估计的正确率。To estimate pseudo code period of multipath tamed spread spectrum signal, a blind method based on power spectrum reprocessing was proposed to estimate the pseudo code period of the tamed spread spectrum signal in muhipath channel. Firstly, the general single path tamed spectrum signal was extended to muhipath model. Then, the primary power spectrum of the signal was calculated on the basis of the tamed spread spectrum signal model in multipath environment. Next, the obtained primary power spectrum was used as the input signal to calculate the secondary power spectrum of the signal, and the theoretical analyses showed that the peak line of the secondary power spectrum of the signal would appear in the integral multiple of the pseudo code period. Finally, the pseudo code period of the tamed spread spectrum signal could be estimated by detecting the spacing between the peak spectrum lines. In the comparison experiments with time domain correlation method, the Signal-to-Noise Ratio （SNR） of the proposed method was improved by about 1 dB and 2 dB when the correct rate of pseudo code period was 100% and the length of pseudo code sequence was 127 bits and 255 bits, and the average accumulation times of the proposed method was less under the same condition. The experimental results show that the proposed method not only has less computational complexity, but also improves the estimation correct rate.

关 键 词：软扩频信号 多径信道 二次功率谱 伪码周期 盲估计 

分 类 号：TN911.7[电子电信—通信与信息系统]