Aijun Song, Ph.D. - US grants

Abstract
_____________________________________________________________________________________
Collaborative Research: Data Communication via Particle Velocity Channels - A Paradigm Shift in Underwater Acoustic Communication

Over 75% of the earth?s surface is covered with water, with many resources upon which human life depends. High speed wireless data communication with acoustic waves among underwater sensors, deepwater moored instruments, autonomous underwater vehicles, and surface vessels is of crucial importance in many applications of national interest. Examples include offshore oil industry, environmental and ocean monitoring to predict natural disasters such as hurricanes, and so on. However, the underwater acoustic channel is a complex and highly bandlimited environment, and the achievable data rates by current systems are much smaller than the needs.

The core novel idea of the research is to transform the foundation of underwater acoustic communication, by communicating over the unexplored degrees of freedom of the acoustic field, i.e., the acoustic particle velocity channels. Over the past few decades, only the pressure channel of the acoustic field has been used for underwater communication. The key concept in this research is to take advantage of the vector components of the acoustic field, such as the three components of acoustic particle velocity. Particle velocity channels are promising for high speed communication, due to their possibly smaller delay spreads. The small size of particle velocity transceivers is another advantage over large pressure-only arrays traditionally used for underwater communication. In this research the investigators develop a cohesive framework for high rate underwater communication via acoustic particle velocity channels. The research objectives fall into two closely-related categories: channel modeling and transceiver design. Channel modeling objectives aim at understanding and characterization of particle velocity channels, whereas transceiver design objectives address new issues encountered at the channel modeling stage.

This INSPIRE award is partially funded by the Arctic Natural Sciences Program in the Division of Polar Programs in the Directorate for Geosciences, the Communications, Circuits and Sensing Systems Program in the Division of Electrical, Communications and Cyber Systems in the Directorate for Engineering,and the Division of Computer and network Systems in the Directorate for Computer and Information Science and Engineering.

The PIs propose to design and develop an integrated underwater acoustic sensor network for ice-covered
seas. It will transmit data wirelessly through acoustic waves from sub-surface ocean sensors to a receiving array with a surface connection to satellites and the Internet. The PIs will expand the limits and capabilities of underwater communication networks in the transition zone where sea ice changes from 1) smooth land-fast ice to 2) ridged mobile ice to 3) open water. This transition zone evolves in both time and space within the 30-50 km foot-print of the proposed networked sensor and communication network array. This goal requires integration of both existing knowledge from a set of diverse disciplines and intellectual innovations within each discipline. It will modify underwater communication network theory, coastal acoustic propagation and scattering, and experimental design of oceanography. Providing long-term, long-range acoustic connectivity, the PI team will address three major new research challenges: 1) Mid-frequency (1-5 kHz), mid-range (10 km) acoustic wave propagation in the transition zone; 2) Data telemetry in the new communication environment; and 3) Resilient sensor networks that cope with and harness complex dynamics of the transition zone. The multi-disciplinary team will implement reliable modem hardware, integrate it with resilient network protocol, and optimize the system design for Arctic deployment to support an ocean experiment off Thule, Greenland.

The sensor and communication network will support 1) long-term, intelligent distributed Arctic observing systems, 2) assimilation of remote-sensing and in-situ under-ice measurements, and 3) regional and global climate modeling with real-time measurements. Such a network holds the promise to revolutionize under-ice ocean sampling in polar regions. Data will be broadly disseminated via the web and archived for public access. Planned outreach includes participation in the field program of Greenlandic residents from the Inupiat village of Qaanaaq and meaningful classroom involvement from the elementary to community college levels. The PIs are also committed to outreach through their global print, radio, TV, and electronic media contacts.

The capability to explore and monitor our aquatic environments, such as the ocean, lakes, and seaports, is vital to science advancements and societal needs. Examples of applications include environmental monitoring, geophysical surveys, ocean resource management, and more. The next technological breakthrough is to use a fleet of aquatic robots as a mobile underwater acoustic network that autonomously collect and transmit information while navigating in the aquatic environment. Although recent years have seen many new advancements in related fields, the much-needed underwater network technologies still have not materialized. There is a need within the research community for an at-scale community testing infrastructure for underwater networks that can support a wide array of research to enable this future. This project seeks to identify the fundamental research challenges that the community would like to explore in such a testbed, and also have the community define and specify the type of infrastructure that will be most conducive for such wide-ranging experimentation. To this end, the project aims to organize two workshops to engage personnel from the scientific, federal, and commercial sectors in order to develop an infrastructure blueprint to advance the field of underwater mobile communications and networking. The project advances the progress of science by bringing together resources and facilitating development of a research vision for multiple technical fields, including underwater communications and networking, marine robotics, and ocean monitoring. It incubates innovation to address multiple societal challenges, for example, disaster response in the ocean or water quality monitoring in waterways. The workshops aim to broaden the impact by engaging K-12 educators, for example science teachers and aquarium curators.

The main contributions of the project are a research workshop and an infrastructure workshop. The research workshop engages scientists and practitioners from multiple sectors, domestic and international, including: 1) scholars from diverse technical fields in academia with interest or stake in the ocean/underwater ecosystems; 2) scientific staff from various federal funding agencies; 3) scientists from naval research centers; 4) scientists and practitioners from sub-sea industries. The goal of the research workshop is to identify emerging trends, urgent needs, potential users and innovative technologies that will require the services of a large-scale test infrastructure. The goals of the infrastructure workshop are to generate an infrastructure blueprint and to form an able research team to develop, deploy and maintain the community infrastructure. Through these two workshops, the project fosters collaboration among workshop participants from diverse sectors. The envisioned infrastructure is an open-source mobile underwater acoustic network testbed that provides easy access and shared use by the communities of acoustic communications, underwater networking and systems, marine robotics, and data sciences. It seeks to lower the threshold for the research community to utilize underwater mobile communications and, thus, fosters interdisciplinary research.

Wireless communication technologies in the ocean are critical to scientific, commercial, and national defense operations, and yet are still primitive, especially with respect to their data rates and reliability. This project develops new underwater acoustic communications and networking strategies to improve network efficiency in the harsh ocean environment, through underwater in-band full-duplex (IBFD) acoustic networks. The project creates a vertically integrated research experience for both undergraduate and graduate students by exposing them to interdisciplinary research. Through partnerships with local communities, the project investigators develop outreach programs to attract future students, especially those from minority and under-represented communities, to STEM disciplines.

The objectives of the project is to develop innovative acoustic IBFD networks that contain: 1) spectrally efficient physical layer receivers capable of acoustic-specific self-interference cancellation, and 2) cross-layer protocols allowing enhanced network efficiency via IBFD. Guided by a cross-layer, interdisciplinary methodology, the project includes four research tasks: 1) Interference cancellation through acoustic-specific methods; 2) Prototyping of acoustic IBFD modems and networks, 3) Field experiments to evaluate acoustic IBFD communications and networking, and 4) Development of cross-layer simulation and optimization toolboxes. To maximize outcomes, this project leverages a range of existing instruments, resources, tools, and design experiences from the research team.

This project, developing one of the first Software Defined Network (SDN)-based underwater mobile testbeds to support the operation of marine robot fleets, aims to address a technological bottleneck, that of achieving integrated communications and navigation underwater. A fleet of Autonomous Surface Vehicles (ASV)s are directed to follow sampling Autonomous Underwater Vehicles (AUVs) to provide acoustic and Magnetic Induction (MI) communication over relatively short ranges. Launching the following effort thrusts: Acoustic & MI Communication; Control of ASVs & UAVs; SDN architecture; and Integration and evaluation.

The testbed will be designed to achieve cost-effectiveness, transferability, flexibility, and scalability and is expected to become a stable instrument that is accessible by multiple research communities that include ocean acoustics, communication and networking, robotics, oceanography and environmental sciences. The hybrid acoustic/MI communication will be used to achieve reliability and high data rates across the mobile network for ASVs and AUVs, while smooth autonomy of the fleet would be ensured by cooperative localization and real-time data transfer among the ASV-AUV pairs. The testbed is expected to enable various research directions, including underwater swarming, deep-learning-based underwater joint networking and navigation, and integrated oil spill responses.

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.

Thousands of miles of pipelines crisscrossing the Gulf of Mexico seafloor are the veins for the offshore oil and gas industry in the U.S. and the world. Leaks and ruptures in those pipelines lead to not only enormous economic loss but also environmental disasters. The goal of this project is to effectively monitor the subsea infrastructure such as offshore pipelines, and efficiently deliver the sensed information for subsequent control and action. To provide a viable solution, this project will integrate piezoelectric transducer designs, acoustic communications, stress wave communications (SWC), and hybrid networking, and conduct experiments and field tests to validate the proposed designs. Such a vision needs efforts from both engineering and scientific perspectives, and the success of the proposed transformative research will significantly improve the design, analysis and implementation of subsea infrastructure monitoring and data transmission systems. The research outcomes will potentially contribute to a future subsea Internet of Things and ocean big data systems, and have impact on offshore oil and gas industry, pollution control, ocean agriculture, disaster rescue, etc. The project will also provide special interdisciplinary training opportunities for both graduate and undergraduate students, particularly women and minority students, across multiple institutions through both research work and related courses.

This project aims to develop an effective subsea infrastructure health monitoring, and efficient information delivery network design via five synergistic thrusts: (1) structural health monitoring, which will employ Lead Zirconate Titanate (PZT) transducers to perform integrated structural health monitoring of pipelines, including impact, leakage, and damage detection, and explore how to send the detected damage information via SWC; (2) SWC channel modeling, which will conduct model analysis and simulation of SWC traveling along a fluid-filled pipeline in the subsea environment, and characterize SWC channels in a complicated pipeline network; (3) adaptive time reversal acoustic communications, which will characterize the acoustic communication channel in high frequency bands of 80-200 kilohertz for short range transmissions in the ocean and develop new adaptive communication receivers and strategies based on time reversal processing; (4) hybrid subsea network development, which will develop a hybrid subsea wireless network to integrate traditional acoustic communications and SWC depending on the subsea infrastructure, and study the hybrid network performance from multiple perspectives; (5) integrated experimental validation, which will conduct a series of lab and at-sea field tests on campus and at industrial/academic collaborators' sites to verify the proposed designs.

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.

Our oceans are integral to climate regulation, nutrient production, oil and gas retrieval, and transportation. As such, there is significant interest to develop underwater sensor network technologies for scientific, environmental, commercial, safety, and military missions in the oceans. The WUWNet conference has established itself as one of the premier technical venues in the field of underwater sensor networks. The fourteenth ACM WUWNet, which will be held in Atlanta, Oct 23-25, 2019, promises to build on its previous success and further expand the scope. The organizing committee is in charge of putting together a very strong program, including technical sessions, panels, keynote speeches, and special sessions, as well as poster/demo sessions and vendors exhibit.
This main goal of the project is to promote student participation in WUWNet19. Participation in high-quality scientific meetings, such as WUWNet, is an extremely important part of the research training experiences. It allows the students to interact with their peers, gives opportunities the young investigators to learn from senior researchers and scholars, exposes the students to cutting-edge research, and allows the students to take part in discussions that are likely to shape the future of the field. The requested funding will be used to provide travel support for both undergraduate and graduate students who might otherwise be unable to attend the conference.

A total amount of $16,000 will be used to support approximately sixteen students to attend WUWNet19. Special attention will be paid to recruit the first-time attendees from undergraduate and beginning graduate groups. The project will give high preference to support the under-represented groups to participate in WUWNet'19, including women, minorities, and students with disabilities.

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.

The aquatic environments, including the oceans, lakes, and rivers, are the basis for life. An exciting direction is to use a group of robots to support science and discovery in aquatic environments. Currently, there are no shared infrastructures available to the nation?s institutions to investigate how a group of robots can coordinate with each other in the underwater environment. This project develops a low-cost and flexible infrastructure, referred to as mu-Net, to support both laboratory tests and field experiments for users from institutions around the nation. The mu-Net infrastructure, a collaborative project between the University of Alabama and Georgia Institute of Technology, advances underwater technologies by lowering the research participation threshold. It also supports the training of the next generation workforce to manage and preserve marine resources.

The mu-Net infrastructure uses a service-oriented, non-hierarchical software architecture to facilitate integrated sensing, communications, and navigation. It consists of 1) re-configurable, open-source software suites for simulations and emulations, 2) miniaturized aquatic robots for laboratory tests, 3) commercial-off-the-shelf autonomous surface vehicles and autonomous underwater vehicles for lake tests, and 4) user services to support shared usage. The mu-Net framework merges the functionality of network-centric and autonomy-centric structures to enhance flexible networking capability for collaborative robots. The intellectual merit resides in that the infrastructure enables research in multiple directions. Examples of the enabled research include cooperative and coordinated marine robotics, underwater mobile communication networks, joint networking and navigation of marine robots, and underwater Internet of Things.

The mu-Net infrastructure aims to break down the underwater networking-robotics disciplinary barrier and promote close interactions between the two fields. It significantly lowers the participation barrier for researchers in a wide range of areas like marine biology, food sources, and economic development. It has the potential to inspire more exploration of the earth?s vast water bodies for scientific and commercial activities. The project uses a spectrum of community engagement activities, such as annual workshops, conference special sessions, summer training school, and deployment camps, to expand user communities. In addition, enabled by the cost-effective assets and fueled by the participation of users via social media, mu-Net attracts widespread adoption for different education and research purposes, ranging from ocean-literacy education, workforce training, academic research, to industrial technology development.

The project website is gtsr.gatech.edu/munet.html, where users can access experimental management portal, open-source simulators, design repositories, test data, and so on. The project website is regularly updated during the project period and is planned to be maintained through at least three years after the expiration of the project.

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.