中文摘要：

针对水声信道多径、时变、多普勒等恶劣传输特点对水声语音通信的严重影响，本文采用多通道时间反转和时频差分OFDM进行水声语音通信技术方案设计，该方法首先通过多通道时间反转进行时间域和空间域多径聚焦，进而结合时频差分OFDM调制解调抑制残留多径的影响。由于无需采用信道估计和均衡算法，系统实现方便、复杂度低，同时对信道具有一定程度的稳健性。该方法语音压缩编码采用混合激励线性预测编码。仿真实验和海试实验表明了本文方案的有效性。

英文摘要：

The difficulties of underwater acoustic pose significant challenges to underwater acoustic channel, i.e., multipath, time varying and Doppler shifting speech communication. In this paper, multi-channel time reversal is incorporated with time-frequency differential orthogonal frequency division multiplexing （OFDM） technology to design an underwater acoustic speech communication system, which enables time-frequency domain focusing of multipath by multi-channel time reversal, as well as suppressing of the residual multipath with time-frequency differential OFDM. Thus the employment of complicated channel estimation and equalization are avoided to facilitate the low complexity system implementation. In addition, the mixed-excitation linear predictive （MELP） is employed for speech encoding. The simulation and sea trial demonstrate the effectiveness of the method at presence of time varying multipath underwater acoustic channel.