Abstract: An improved timing synchronization algorithm based on ZC( Zadoff-Chu) sequence is proposed in order to improve timing synchronization accuracy of OFDM ( Orthogonal Frequency Division Multiplexing ) system． This algorithm combined the sequence inversion of Minn algorithm with the sequence conjugate of Park algorithm． The new sequences replaced PN sequences with ZC sequences that good autocorrelation and low crosscorrelation．Even in the timing position error，the system can still be precisely timing synchronized． Under the channel of AWGN ( Additive Gaussian White Noise) ，the number of subcarriers is 256，16QAM modulation and demodulation，Matlab simulation shows that the improved algorithm eliminates the influence of minor peak on timing synchronization in Minn algorithm and Park algorithm． Timing deviation and MSE ( Mean Square Error) are lower than Minn algorithm and Park algorithm within － 15 ～ 15 dB，which improves timing accuracy． When the SNR is 15 dB，the timing MSE of the improved algorithm is 4． 2 × 10 － 6，which is the optimal state for estimating performance．

Key words: orthogonal frequency division multiplexing ( OFDM) , timing synchronization, zadoff-chu ( ZC) sequence, timing deviation, timing mean square error