一种新的基于短训练符号的OFDM联合时间频率同步算法  

A New Joint Timing and Frequency Synchronization Method for OFDM Based on Short Training Sequence

作　　者：田野 谈振辉[1] 

机构地区：[1]北京交通大学现代通信研究所,北京100044

出　　处：《铁道学报》2007年第1期61-65,共5页Journal of the China Railway Society

基　　金：国家自然科学基金资助项目(90104016)

摘　　要：提出了一种新的基于短训练符号的OFDM联合时间频率同步算法,通过使用一个长度为1.5倍OFDM符号长度的训练符号,可以很好地实现突发或连续的OFDM通信系统的同步,因此,本算法具有较低的系统冗余度。首先,接收端通过搜索两个在时域相同的短符号来完成粗定时同步,并且估计出小数频偏,然后对训练符号的样点数据进行小数频偏补偿,再使用本地序列与样点数据进行相关运算,得到整数频偏以及精确的定时同步位置。所有同步过程均在时域完成,因此具有较强的抗白噪声能力。仿真结果表明,该算法具有较小的定时估计误差和频偏估计误差,并且能估计大整数频偏。This paper presents a new OFDM synchronization method based on the short training sequence. By using a special training sequence whose length is one time and a half of that of the OFDM symbol , the presented method can perfectly realize the synchronization task either in a burst or continuous transmission mode. Thus, the system redundancy is lower. Firstly, by searching two short symbols which are identical in the time domain, the receiver can find out the coarse timing position and evaluate the decimal frequency offset. Then after compensating the sample data for the decimal frequency offset, the receiver correlates the sample data with the local sequence, thus the integral frequency offset and the final timing position are found. All the synchronization processes are finished in the time domain, so the algorithm is robust to white noises. The simulation results show that the proposed method can give out smaller estimation error, and large integral frequency offset can be corrected.

关 键 词：OFDM(正交频分复用技术) 定时同步 训练符号 频偏 

分 类 号：TN914.51[电子电信—通信与信息系统]