Collaborative NETS-NECO: Wireless Underwater Multi-tiered Acoustic Networks (WUMAN)

在过去十年中，在为许多海洋环境建立高性能声学通信链路方面取得了重大进展。然而，水声网络的发展一直很有限，这与陆地无线网络形成了鲜明的对比。在水下环境中，网络节点既不小也不便宜，恶劣的环境使网络部署变得困难。网络设计受到水声传播基本特性的挑战：信道衰减依赖于距离和信号频率，导致带宽依赖于距离；广泛的时变多径导致延迟传播数十或数百毫秒，而低速(1500 m/S)会导致严重的运动引起的多普勒失真和极端的信道延迟。这些事实需要在所有网络层上专门设计通信算法和协议，它们的交叉耦合，以及对整个系统拓扑和体系结构的仔细考虑。在水下无线网络的设计中，挑战是利用而不是避免声传播的特殊影响。为了实现这一目标，重点放在三个方面：体系结构设计(确定层次和多跳的程度，以及相关的算法和协议)、系统优化和资源分配(功率和带宽)。目前还没有关于优化网络部署的分析结果；此外，系统容量也是未知的。基于声传播物理规律的分析结果，而不是基于类似无线电的模型，有望为面临高延迟和有限资源挑战的未来网络设计提供有用的工具。

Significant advances have been made over the past decade to establish high performance acoustic communication links for many ocean environments. However, there has been limited development on underwater acoustic networks, the fact that is in stark contrast with the terrestrial wireless networks. In an underwater environment, network nodesare neither small nor inexpensive, and the harsh environment renders network deployment difficult. Network design is challenged by the fundamental nature of underwater sound propagation: channel attenuation depends on the distance and signal frequency, resulting in a distance-dependent bandwidth; extensive time-varying multipath causes delay spreads of tens or hundreds of milliseconds, and low speed of sound (1500 m/s) results in severe motion-induced Doppler distortion and extreme channel latency. These facts necessitate dedicated design of communication algorithms and protocols on all network layers, their cross-coupling, as well as careful consideration of the overall system topology and architecture. In the design of underwater wireless networks, the challenge is to exploit, rather than avoid the peculiar effects of acoustic propagation. Towards this goal, emphasis is placed on three areas: architecture design (determining the degree of hierarchy and multi-hopping, and associated algorithms and protocols), system optimization, and resource allocation (power and bandwidth). Currently, no analytical results exist on optimized network deployment; furthermore, system capacity is unknown. Anaytical Results that are based on physical laws of acoustic propagation, and not on radio-like models, are expected to provide useful tools in the design of future networks challenged by high latency and limited resources.