关键词: UW, 单载波频域均衡, 多径效应, 帧同步, 多普勒频移

Abstract: A single carrier system with frequency domain equalization （SC-FDE） based on UW （Unique Word） is designed for underwater acoustic communication.The basic configuration and principle of the system are discussed.A correlation synchronization algorithm based on UW is proposed for correlation peak split caused by multi-path，which can improve frame synchronization precision significantly.Doppler frequency-shift estimation and emendation algorithm based on UW，and channel estimation and equalization algorithm based on UW are discussed .The performance of this system is analyzed.The results show that the single carrier system with frequency domain equalization（SC-FDE） using correlation synchronization algorithm based on UW can improve frame synchronization precision，exactly estimate the serious Doppler frequency-shift and multi-path，track channel time-variability.The system can produce low BER at high signal-noise ratio.The SC-FDE based on UW is promising in underwater acoustic communications.

Key words: UW, single carrier systems with frequency domain equalization, multi-path propagation, frame synchronization, Doppler frequency shift