This paper proposes the optimal timing by maximizing signal-to-interference-plus-noise ratio (SINR) for hexagonal multicarrier modulation (HMM) over doubly dispersive channels.An iterative optimal timing algorithm is derived and it comes out that there is an allowable error between the mean delay of doubly dispersive channels and the optimal timing.In addition

an approximate optimal timing synchronization method is proposed.The theoretical analysis and computer simulation results show that the proposed optimal timing is outperform the traditional timing method about 2~3dB in SINR while signal-to-noise ratio (SNR) is 30dB and the approximate optimal timing algorithm achieves a smaller mean square error (MSE) than 10

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over doubly dispersive channels.