OFDM系统中利用PN序列相关的一种快速扫频算法

New frequency scan algorithm based on PN sequence correlation for OFDM system

提出一种新的基于PN帧头OFDM系统的扫频算法,利用PN的相关峰值,实时调整扫频步长、扫频方向,在频率锁定完成频偏初步估计后,扫频模块停止工作。与无扫频的PN相关同步算法相比,本算法提高了300kHz左右的频率同步范围,与固定步长和随机步长扫频算法相比,本算法扫频锁定所需时间缩短了50%以上,在高斯和多径信道下此算法均能快速纠正大范围频偏。本文给出了框架图与仿真结果,并在FPGA中完成了测试。

This paper proposes a new frequency scan algorithm for OFDM system with the PN pilot. This scan algorithm adjusts the step and direction of the scanning frequency using the peak value of PN sequence correlation. When the frequency is locked and the estimation of frequency offset is finished, the scan module stops working. Compared with the PN correlation frequency synchronization algorithm without frequency scanning, the algorithm proposed in this paper increases about 300kHz frequency offset. Compared with fixed step and random step scan algorithms, this algorithm shortens the scanning time by 50 percent. The algorithm can quickly correct a wide range frequency offset in a Gaussian and multi-path interference channel. The framework diagram and simulation result are shown in this paper, and the algorithm is realized and tested in an FPGA.