Joint Doppler Scale Estimation and Timing Synchronization in Underwater Acoustic Communications

In underwater acoustic communication systems, Doppler effect caused by the relative motion of transmitter and receiver will seriously deteriorate the performance. In this paper, we propose a joint Doppler scale estimation and timing synchronization method in underwater acoustic communications, where the superimposed hyperbolic frequency modulation (HFM) signal is used as the preamble. The timing position and the Doppler factor are simultaneously obtained by two parallel correlators of the received signals. Simulation results show that the proposed method can estimate the Doppler factor correctly, as well as correcting the deviation of timing synchronization. Compared with the traditional method, the proposed joint Doppler scale estimation and timing synchronization method achieves a better performance. In addition, the results of a sea experiment demonstrate the feasibility of the proposed method.