NeTS: Small: Enabling Long-Range Underwater Backscatter via Van-Atta Acoustic Networks

执行低功率远程水下传感的能力可以对气候学，海洋学，海洋生物学，粮食安全，国防，甚至是地外探索产生变革性影响。由于超过95%的海洋尚未被观察或探索，该项目旨在突破可扩展和低功率海洋传感的极限，以便可扩展地测量海洋的生命体征（温度，压力，盐度），用于气候模型，天气预报，灾害响应和海洋生物发现。可扩展和低功耗水下传感在粮食安全方面也有重要应用，它可以支持世界上增长最快的粮食部门——水产养殖（海产品养殖）。为此，该项目将开发基础技术，提高可扩展海洋传感的能力，并通过出版物、技术转让和面向公众的视频向学术界、工业界和更广泛的公众传播这些技术，以增加公众对科学、技术和气候的教育和参与。本提案的目标是设计，构建和评估一个低功耗，远程水下反向散射网络。水下后向散射是一种新型通信技术，其功耗比现有的低功耗水声通信技术低5-6个数量级。然而，现有的水下后向散射设计的通信范围限制在几到几十米，这限制了它们的可扩展性和应用领域。为了克服这种范围限制，该项目探索了水下反向散射的反向反射设计。现有的结构由于向各个方向反向散射水声而效率低下，与之相反，所提出的设计将通过向发送者反向散射声音来实现更高的效率。这种反向方向性可以提高反向散射数据包的信噪比，从而提高通信范围、吞吐量和可扩展性。为了实现反向反射水下后向散射，该提案将设计Van-Atta架构，该架构在过去50年里已经在无线RF（射频）领域得到了证明，但从未在水下环境或声学网络中应用过。该提案将探索通过Van-Atta阵列实现2D和3D反向定向的设计，将这些设计实现到实际系统中，并将其开发成用于水下通信和定位的端到端可扩展网络。如果成功，该系统将成为首个实现低功耗远程水下反向散射的系统，为水下环境的可扩展网络传感铺平道路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The ability to perform low-power long-range underwater sensing can have transformative impact on climatology, oceanography, marine biology, food security, defense, and even extra-terrestrial exploration. Motivated by the fact that over 95% of the ocean has not been observed or explored, this project aims to push the limits of scalable and low-power ocean sensing in order to scalably measure the ocean’s vital signs (temperature, pressure, salinity) for climate models, weather prediction, disaster response, and marine life discovery. Scalable and low-power underwater sensing also has important applications in food security, where it can support the world's fastest-growing food sector, aquaculture (seafood farming). To this end, the project will develop fundamental technologies that advance the ability for scalable ocean sensing and disseminate these technologies to the academic community, industry, and the broader public through publications, technology transfer, and public-facing videos about the developed technologies to increase public education and engagement with science, technology, and climate.The goal of this proposal is to design, build, and evaluate a low-power, long-range underwater backscatter network. Underwater backscatter is a new communication technology that consumes 5-6 orders of magnitude lower power than prior low-power underwater acoustic communication technologies. However, existing designs for underwater backscatter are limited in their communication range to within few to tens of meters, which restricts their scalability and application domains. To overcome this range limitation, this project explores retroreflective designs for underwater backscatter. In contrast to existing architectures which are inefficient because they backscatter underwater sound in all directions, the proposed designs will achieve much higher efficiency by backscattering sound retroreflectively to the sender. This retrodirectivity enables boosting the signal-to-noise ratio of the backscatter packets, which in turn boosts communication range, throughput, and scalability. To realize retroreflective underwater backscatter, the proposal will design Van-Atta architectures, which have been demonstrated over the past 50 years in the wireless RF (Radio Frequency) domain, but have never been applied before in underwater environments or acoustic networks. The proposal will explore designs that enable 2D and 3D retrodirectivity through Van-Atta arrays, implement these designs into practical systems, and develop them into end-to-end scalable networks for both underwater communication and localization. If successful, the resulting system will be the first to enable low-power long-range underwater backscatter, paving the way for scalable networked sensing of underwater environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.