基于均值移位的载频盲估计算法  

Blind Estimation of Carrier Frequency with Mean Shift Algorithm

作　　者：李小捷[1] 许录平[1] 陈佳[1] 

机构地区：[1]西安电子科技大学电子工程学院,西安710071

出　　处：《系统仿真学报》2009年第5期1451-1454,1458,共5页Journal of System Simulation

基　　金：国防科工委预研课题(B1120060329)

摘　　要：针对非协作通信领域的MPSK和MQAM信号载频估计与调制方式识别互相依赖问题,提出了一种无需调制方式先验知识的高精度载频盲估计算法。通过相位差分布特性的分析建立了相位差密度极值点与频偏的联系,引入模式识别中广泛应用的核密度估计方法对相位差进行密度估计,并以均值移位算法完成密度极值点的求解,达到载波估计的目的。仿真结果表明算法大大降低了信噪比门限,并且载频的粗估计算法也具有较高的精度,可以作为独立的频偏估计算法用于频偏精度要求不是非常高的场合。A blind carrier frequency estimation algorithm for MPSK and QAM signal with unknown modulation type was proposed. The relationship between the local mode and frequency offset was established based on the characteristic of the phase difference. Then the probability density was estimated with a kernel-based estimator, and mean shift technique was used tofind the local mode, thus the frequency offset was estimated with high accuracy. The experimental results show that the method can lower the SNR threshold dramatically, and the rough estimated value can be used as an independent algorithm for the estimation of carrier frequency in many occasions.

关 键 词：载频估计 核密度估计 均值移位 非协作通信 

分 类 号：TN911.6[电子电信—通信与信息系统]