ABSTRACT

P.I. Mtira, Urbashi (USC) Proposal #: 0520324
Collaborating Institution: Presig (WHOI) Proposal #: 0519903
Collaborating Institution: Fall (Intel) Proposal #: 0520040
Collaborating Institution: Stojanovic (MIT) Proposal #: 0520075

PROJECT TITLE: NeTS-NOSS: Networking the Digital Ocean

Project Summary

Observatory science efforts will rely heavily on the ability to communicate reliably between instruments, vehicles, operators, platforms, and sensors of all types. These activities will require integrated networks of instruments, sensors, robots, and vehicles to cooperate forming a "digital ocean." Underwater communication via propagating acoustic signals holds the best promise for reliable and general purpose wireless communications in the ocean. Significant advances have been made in recent years to establish physical layer point-to-point links in many types of ocean environments. Yet, the development of higher layer techniques suitable for the challenging characteristics of the ocean environment remains largely unexplored territory. Networking the "digital ocean" via underwater acoustic communications remains one of the formidable technical obstacles to the a fully networked ocean. Challenges to be overcome by underwater acoustic modem and network designers include: severely limited range-dependent bandwidth and attenuation, extensive time-varying multipath propagation, and low speed of sound propagation in water resulting in long propagation delays. For sensor network deployment, these features imply that asynchronous and adaptive networking must be considered, typical medium access control will not be feasible, deterministic algorithms may not be feasible due to the stochastic nature of underwater networks, and link quality prediction and estimation will be paramount to delivering the desired quality of service. Finally, distance-dependent bandwidth implies that everything from capacity analysis to medium access control must be redeveloped under these new constraints. Terrestrial sensor networks are typically distinguished by high node density, large amounts of potentially correlated sensed data, stringent limitations on system resources, and multiple sources of uncertainty. Underwater sensor networks have even stronger limitations. To achieve the goals of an undersea sensor network, the PIs propose to study the following: network topology optimization and estimation, channel & energy-aware routing, delay/disruption tolerant underwater networking, cross-layer designs which integrate underwater channel characteristics, impact of the underwater acoustic channel on scaling laws and fundamental limits, experimental validation of system concepts for underwater acoustic networking

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