说明：  受制于严重的衰减，电磁波在水中的传播距离非常有限，因此以声波为载 体的水声通信是在水下实现无线信息传输的主要方式。水声通信无论是在军事方面还是在民 用方面都有重要的作用，随着人类加快开发海洋的步伐，对水声通信技术的需求也变得越来 越迫切。文章对水声通信技术进行了综合介绍。首先介绍了水声通信的概念和意义，着重分 析了水声信道的特点以及水声通信面临的困难，然后对目前应用较多的几种典型水声通信技 术进行了介绍，最后对水声通信技术的发展方向进行了展望。
(Due to severe attenuation, the transmission distance of electromagnetic waves is significantly limited in water. Hence, underwater acoustic communication has become the domi- nant approach for achieving wireless communication in the ocean. Underwater acoustic communi- cation is very important for both military and civilian usage, and with the speeding up of marine de- velopment, has seen an ever increasing demand. An overview of the challenges in underwater acoustic communications is presented in this paper. We introduce some basic concepts, emphasiz- ing the properties of underwater acoustic channels and current challenges. Then, several typical techniques are presented. To conclude, some future developments are described.)