EAGER: Prototype Validation of Surface-Reflected Acoustic Communication Links in Underwater Environments

本项目开发并验证了一种用于在水下装置中节点之间建立声学通信链路的新技术。基本上，声学链路的带宽有限，并且受到缓慢和多径信号传播的影响。这些问题使水下通信成为一项挑战，并促使使用定向天线在通信节点之间建立视线（LOS）路径。但是，在服务于应用程序时或由于水流而引起的节点移动将破坏LOS链路，从而阻碍节点之间的有效通信。为了克服这一挑战，该团队开发了一种新的基于表面的反射（SBR）方案，该方案允许节点利用来自水面或底部的反射声链路作为非视距（NLOS）通信链路。将开发一个原型调制解调器，以利用多模态方向换能器来验证使用SBR方案时建立NLOS通信的可行性。原型设计可以用于网络协议，如节点发现、本地化、媒体访问控制和路由。最终的结果是一个有效的定向声通信平台，减轻了多径传播的影响，同时充分利用了可用的空间频谱。这个项目将提高许多民用和科学应用的有效性。这些应用的例子包括搜索和救援、海岸巡逻、海洋数据收集、环境监测、辅助导航和安全监视。该项目还将帮助丰富传感器网络、机器人、嵌入式和分布式系统的本科和研究生课程，同时提供向当地初中和高中展示原型的机会，以激发下一代科学家和工程师对这项技术的兴趣。

This project develops and validates a novel technique for establishing acoustic communication links among nodes in an underwater setup. Basically, acoustic links have limited bandwidth and suffers from slow and multi-path signal propagation. These issues make underwater communication a challenge and motivate the use of directional antennas to establish line-of-sight (LOS) paths between communicating nodes. However, the node mobility while serving an application or due to water current will break LOS links and thus hinders effective communication among nodes. To overcome this challenge, the team develops a novel surface-based reflection (SBR) scheme that allows nodes to utilize reflected acoustic links from the water surface or bottom as non-line-of-sight (NLOS) communication links. A prototype modem is to be developed to utilize a multimodal directional transducer for validating the feasibility of establishing NLOS communication when using the SBR scheme. The prototype design could be leveraged for networking protocols such as node discovery, localization, medium access control and routing. The end result is an efficient directional acoustic communication platform that mitigates the effects of multipath propagation while fully utilizing the available spatial spectrum.This project will boost the effectiveness of many civil and scientific applications. Examples of these applications include search-and-rescue, coastal patrol, oceanographic data collection, environmental monitoring, assisted navigation, and security surveillance. The project will also help enrich the undergraduate and graduate curricula in sensor networks, robotics, and embedded and distributed systems while providing outreach opportunities to demonstrate the prototype to local middle and high schools in order to stimulate interest in this technology among the next generations of scientists and engineers.