关键词：通信；HFM信号；多普勒估计；水声通信
摘 要：This paper presents the application of the hyperbolic frequency modulated (HFM) signal to acoustic propagation in order to improve the performance of underwater acoustic (UWA) communications.Due to the large delay spread caused by multipath propagation and the severe Doppler Effect of the channel,we propose the using of double HFM signals as preambles for Doppler estimation,flame synchronization in UWA communications.A theoretical analysis about Doppler-invariability of HFM signals was provided firstly,then some numerical simulations about Doppler estimation were implemented,and experiments on testing performance of double-HFM preambles for frame synchronization in the pool were carried out as well.The simulation and experimental results show that using double-HFM signals as preambles has the capability to take an explicit Doppler estimation and retiming for frame synchronization,demonstrating that it has a good prospect in underwater acoustic communication system,especially for moving platforms.