高速移动条件下的多普勒频移估计与校正

Estimation and Correction of Doppler Frequency Offset in High-speed Communication System

在遥测遥控通信系统中,经常会遇到发射机或接收机具有很高的移动速度。这将导致接收机接收到的数据包含很大的多普勒(Doppler)频移。多普勒效应使得接收数据的相位发生旋转,这将造成接收信号无法正确解调。对高速移动条件下的数字通信系统中存在的多普勒频移问题进行研究,并对盲估计算法与训练序列估计算法的性能进行比较与分析,并对采用训练序列算法估计频偏和相偏的FPGA实现过程中存在的主要问题进行讨论并提出解决方案。最后,仿真结果表明,所提到的硬件实现算法能够很好地估计和校正频偏与相偏。

In aeronautical telemetry systems,transmitters or receivers has a very high speed which results in datum received by the receiver containing a very large Doppler frequency offset.Doppler effect makes the phases of the signals rotate,which prevents the correct demodulation of signals.Doppler frequency offset caused under the condition of high speed motion and existing in a digital communication system is studied.The blind estimation algorithm is compared with training sequence estimation method and the results is analyzed.In addition,the main difficulties and solutions in the process of implementation of training sequence algorithm estimating frequency and phase offset using FPGA（Field Programmable Gate Array） are discussed in the thesis.At last,the simulation results show the mentioned hardware algorithm has a good performance of estimating and correcting the Doppler frequency offset and phase shift.