一种基于短时傅里叶变换的OFDM时间同步方法

A Short-Time Fourier Transform Based Symbol Timing Approach for OFDM Systems

该文提出了一种基于短时傅里叶变换的OFDM符号同步方法。该方法通过短时傅里叶变换得到OFDM信号的二维幅度谱,并提取其中的周期平稳时频结构信息,估计出OFDM符号的无ISI时间区间,并选取该区间的最佳位置作为OFDM符号起始位置估计。仿真结果表明:该方法相对于常规的时间相关算法能有效地对抗低信噪比环境。

A blind short-time Fourier transform based approach for symbol timing in OFDM systems is proposed. The key of the described algorithm leans upon the periodic 2-D time-frequency spectrum structure. By searching the flat regions in the time direction of time-frequency spectrum of the received signal, ISI-free intervals are estimated, where optimum symbol start can be easily located. Simulation results show that the proposed algorithm is quite robust against low SNR environment, and outperforms time-domain correlation based algorithms.