Abstract: Symbol Timing Offset（STO） estimation is one of the main synchronization operations in Orthogonal Frequency Division Multiplexing（OFDM） systems. To achieve the fine timing synchronization, this paper proposes a blind timing synchronization algorithm based on constellation characteristics for OFDM systems. A new timing metric function is defined via energy criterion in the constellation area, and then the STO estimation is obtained by maximizing the timing metric function. The proposed algorithm is bandwidth efficient, because it doesn’t need pilot tones or training symbols. The simulation results show that the performance of proposed algorithm is better than that of the other algorithms in both Additive White Gaussian Noise（AWGN） and multipath fading channels.

Key words: Orthogonal Frequency Division Multiplexing（OFDM）, timing, blind synchronization, constellation

摘要： 符号定时同步是OFDM最主要的同步之一。为了得到精确的定时同步，提出了一种基于星座点特征的盲定时同步算法。新算法以星座点区域的能量作为判决依据，定义了一种新的定时尺度函数，通过对定时尺度函数最大化得到定时偏移的估计值。算法不需要导频或训练符号，不会降低频谱效率。仿真表明：不论在加性白高斯噪声信道还是多径衰落信道，算法性能均优与其他几种算法。

关键词: 正交频分复用, 定时, 盲同步, 星座点