OFDM系统一种新的多普勒频偏估计方法

A Novel Method of Estimating Maximum Doppler Frequency for OFDM Systems

多普勒频偏估计是移动通信系统中的一个重要研究内容。提出了一种OFDM移动通信系统中新的多普勒频偏估计方法。该方法利用接收信号的功率会随着信道的变化而变化并且变化的速率与最大多普勒频偏有一定的关系这一特点,在接收端测量出每一帧接收信号的平均功率,并把一定数目的平均功率值存储起来,先进行粗估计,再进行细估计,这样就求出了接收信号的功率变化速率,从而查表得到最大多普勒频偏。文中对这一方法进行了仿真验证,仿真结果表明,此方法可以有效的估计多普勒频偏,并且具有实现简单和受噪声影响小的优点。

Doppler shift estimation is an important subject in wireless communication systems. This paper proposes a novel method of estimating maximum Doppler shift for OFDM system. The method makes use of the fact that the power of the received signal will change as the channel changes and its velocity of changing relates closely to the maximum Doppler frequency, so the maximum Doppler frequency can be acquired by measuring the velocity of power changing of the received signal. First, we get the average power of each frame, then store them into an array. Secondly, we proceed rough estimation and precise estimation by using the points of the array. Finally, the velocity of power changing is obtained, so the Doppler shift is obtained by inquiring the form. We use computer simulation to demonstrate this point and the result shows that this method can estimate the max Doppler shift effectively and has the vitues that it can easily be implemented and the noise has little influence on it.