进行帧同步的目的是为了得到帧头的位置，以分辨以符号周期为单位的延时。本质上，目的是寻找一个接收端已知的已发送信号的参考信号（即训练序列）以进行后续的如信道估计和信道均衡的操作。有关帧同步的理论有很多，这里只实现一种基于训练序列的相关性质的方法。(The purpose of fr a me synchronization is to get the position of the fr a me header to resolve the delay in symbol periods. In essence, the purpose is to find a reference signal (ie a training sequence) of the transmitted signal known to the receiving end for subsequent operations such as channel estimation and channel equalization. There are many theories about fr a me synchronization, here only one method based on the nature of training sequences is implemented.)