一种改进的基于DS／CDMA信号共轭周期平稳特性的载波频偏盲估计方法

A modified frequency offset estimator by using the signal' s Conjugate cyclostationarity in DS/CDMA system

在DS／CDMA系统中,我们可以利用接收信号的共轭周期平稳特性估计载波频偏,但是用于估计频偏的样本个数的有限性降低了这类方法估计结果的准确性和稳定性。为此本文在这类方法的基础上提出了一种改进的载波频偏盲估计方法,该方法通过对接收信号预置一个已知的载波频偏,有效的消除了有限的样本个数对估计性能造成的影响。同时它是一种盲估计算法,不需要专门的训练序列,不会降低无线带宽利用率。仿真结果表明该方法能够很好的利用有限长度的样本数据快速准确的估计出系统载波频偏,它的估计性能较改进前的方法有明显的提高。

In DS/CDMA systems, we can develop a blind frequency offset estimator by using the signal＇s conjugate cyclostationary. But the finitude of the sampling data will degrade the performance of these kinds of estimator. So we propose a modified frequency offset estimator by analyzing the effect of the finite sample data. The estimator adds a known frequency offset to the received signals for canceling the negative effect of the finite of the sampling data. Also, it＇s a blind estimator and do not slow the data rate of transmission. The simulation results provided in this paper show the estimator can estimate the frequency offset fast and exactly by using the finite sample data and has better performance than the un-modified method.