基于自相关函数的前向载波频偏估计算法

Feedforward carrier frequency offset estimator based on autocorrelation function

为解决前向载波频偏估计中捕获范围和估计精度矛盾的问题,在最大似然准则的基础上,同时利用短时延自相关函数捕获范围广和长时延自相关函数估计精度高的优点,给出了一种捕获范围宽、估计精度高、计算复杂度低的频偏估计方法。该算法将不同时延情况下得到的粗略估计值进行加权求和以得出精确频偏估计值,兼顾了不同时延的优点,同时在不同的信噪比情况下可以设置不同的加权系数,使得算法更能适应不同的信噪比。计算机仿真结果表明了该算法估计精度高、捕获范围广和计算复杂度低的性能。

In order to solve the problem of the contradiction between capturing range and estimation accuracy of feedforward carrier frequency offset estimator,a feedforward carrier frequency offset estimator with wide range,high accuracy and low complexity is proposed,which is based on maximum likelihood（ML） principle.The algorithm uses short delay autocorrelation function to get wide estimation range and long delay autocorrelation function to get high estimation accuracy.Accurate frequency offset estimation is obtained by calculating the weighted sum of the rough estimation which is obtained from different delay autocorrelation function.The algorithm can get better performance by changing the weighting coefficients in different SNR environment.Finally simulation results illustrate the algorithm performance of high estimation accuracy,wide capturing range and low complexity.