多径衰落信道下OFDM系统帧同步方法

Fast and simple frame synchronization scheme for OFDM systems over multipath fading channels

针对OFDM系统对同步错误十分敏感的特点,提出了一种OFDM系统中多径衰落信道高速移动环境的帧同步方法。该算法融合了时域中加入的叠加的低能量的m序列的自相关性和保护间隔的冗余信息,提高了同步信号的能量;通过使用融合门限检测法,改善了基于相关的帧同步方法的准确性。仿真证明,该算法在多径瑞利衰落信道下的帧同步正确概率比常规相关算法高70%,达到了最佳性能,而且叠加的低能量的m序列的加入对系统传输性能性能影响可以忽略。

OFDM systems are very sensitive and vulnerable to synchronization error. A frame synchronization scheme over Rayleigh fading channels in high-speed mobile environment for OFDM systems is proposed. The autocorrelation of the superimposed m-sequence with very low power in time domain and the information of the guard intervl are used to produce the synchronization signal so that the peak sharpness of the synchronization signal is improved, and the co-threshold detector method is employed so that the accuracy of the proposed frame synchronization methods is raised greatly. It is shown by computer simulation that the correctness probability can be increased by 70% compared to the common correlation methods in multipath fading channels. In addition, the power of the superimposed m-sequence is so low that the effect of superimposed m-sequence on performance of the systmes can be ignored.