基于叠加训练序列的FSO-OFDM系统时间同步算法

Timing synchronization method for FSO-OFDM system based on superimposed training sequence

提出了一种可适用于自由空间光通信的非对称限幅正交频分复用系统的时间同步方法,通过在时域上叠加伪随机序列,将训练序列与用户数据同时发送,在接收端使用本地产生的序列与接收信号进行互相关运算获得同步信号。叠加训练序列仅将训练序列叠加在部分用户数据之上,改善了传统插入训练序列算法会降低频谱利用率和信息传输效率的特性。仿真结果表明,相较于传统的插入训练序列同步方法,提出的基于叠加训练序列的时间同步方法在大气湍流环境中同步正确率更高,同步性能更好,而且提高了频谱利用率及信息传输效率。

A new timing synchronization method for FSO-OFDM system with the superimposed m-sequences is proposed.Superposition of pseudo-random sequence in the time domain sends the training sequence and the user data at the same time.The receiver uses a locally generated sequence and the received signal cross-correlation operation to obtain the synchronization signal.The training sequence is just superimposed on top of the part of the user data.It improves the features of a traditional insert training sequence algorithm and reduces the efficiency of spectrum utilization and transmission of information superimposed training.Simulation results show that compared with traditional insert training sequence synchronization method,the proposed time synchronization method based on superimposed training sequence synchronization in the atmospheric turbulence environment has higher accuracy rate,and better synchronization performance,and improves the spectrum efficiency and information transmission efficiency.