关键词: 正交频分复用, 符号定时, 训练符号, 共轭对称

Abstract: An improved symbol timing synchronization algorithm for OFDM systems is proposed to solve timing ambiguity and high interference peak. The reasons for these problems are analyzed, and two new training symbols are designed. These symbols can estimate symbol timing offset and carrier frequency offset. A new timing metric function is presented and analyzed. The proposed algorithm has an impulse-shaped timing metric with different cyclic prefix length and almost has no interference peaks. Computer simulation results show that the performance of the proposed algorithm is better than that of the previous algorithms, and the mean and variance are equal to zero when Signal Noise Ratio（SNR） is greater than 5 dB in Additive White Gaussian Noise（AWGN） channel, so the rigorous timing synchronization may be accomplished.

Key words: orthogonal frequency division multiplexing, symbol timing, training symbol, conjugate symmetric