一种快速正交频分复用频率跟踪算法

提出了一种快速的正交频分复用(OFDM)系统载波频率跟踪算法，该方法采用基于变步长的自适应滤波算法。经过频率粗同步后，以变步长的最小均方算法(VLMS)进行频率补偿。在算法的初始使用大的步长值加快算法的收敛速度，然后使用小的步长使残留的频率偏移最小。由于不需要训练序列，故该算法是盲的，没有频带效率损失。仿真结果表明，所提出方案能显著提高误码率性能，高精度的频率偏移估计几乎可以使频率偏移得到完全补偿，且算法的收敛速度比固定步长的算法快得多。

A Fast Frequency Tracking Algorithm for OFDM

This paper proposed a fast frequency tracking scheme for orthogonal frequency-division multiplexing(OFDM) system based on variable step size adaptive filtering algorithm. After coarse frequency synchronization, frequency offset compensation is carried out using variable step size least mean square algorithm(VLMS). High value of step size is used initially to cause fast convergence of the algorithm and in the later iteration smaller value of step size is used to minimize the frequency offset. A training data sequence is not required, the method is blind and there is no reduction in bandwidth efficiency. The simulation results show that significant bit error rate performance improvement is achieved. The precision of frequency offset estimation is so high that the frequency offset can be almost entirely compensated. Also, convergence of the algorithm is much faster than the fixed step size algorithm.