CRI: CRD: Open Research Testbed For Underwater Ad Hoc and Sensor Networks (ORTUN)
This collaborative project, developing the first open testbed infrastructure for the underwater networking community, enables open access with the capability to conduct experiments remotely. The infrastructure, based on open research platforms, consists of a testbed that enables wide and systematic experimental evaluation and comparison of underwater acoustic networks. The work, involving this rapidly deployable testbed that can be shared by the underwater networking community, aims to demonstrate the ability of the facility to facilitate field experiments. The project represents a higher-level collaborative that arose from two collaborative groups. One group developing the facility, the other working mainly on the experiments utilizing the facility. The testbed is expected to be a buoy-based system that can be easily taken to different environments. When operational, these systems will be deployed 5 or 6 times a year. The infrastructure will consist of two types of nodes with different capabilities. The first type of node of the rapidly deployable testbed will offer a fixed physical layer capability using acoustic modems such as the WHOI micromodem or the ISI S-modem to implement a physical layer with limited reconfigurability interfaced to a reconfigurable network processor. This network processor will support algorithm/protocol implementation and testing at higher network layers. The Network functions on the Fixed Physical Layer testbed will be hosted by a Gumstix processor which will then communicate with physical layer modems such as the WHOI Micromodem or USC/ISI S-modem via a serial port. Ten to fifteen fixed physical layer nodes will be built including up to 3 gateway nodes. Each gateway node of the testbed will be equipped with wireless RF communication enabling real-time monitoring and control of network performance. The fixed physical layer nodes will be smaller and more easily deployed than the second type of node which is the all-layer node. The all-layer node is a more capable node that will ultimately support algorithm/protocol implementation and acoustic data collection at all networking layers. In addition to the equipment included in the fixed physical layer nodes (i.e., a gumstix network processor and the ability to support relatively fixed physical layer modems such as the WHOI Micromodem and the ISI S-modem), the all-layer nodes will also include a general purpose data acquisition system (D/A and A/D) with substantial disk storage and in-situ processing capability. The MIT r-modem software will be implemented on this general purpose hardware and, along with MATLAB, will enable user implementation and testing of algorithms and the gathering of acoustics data at the physical layer in addition to the testing at higher network layers that it will share in common with the fixed physical layer nodes. Three to five all-layer nodes will be built. The rapidly deployable testbed, using two types of nodes with varying capabilities, should significantly enhance research at all network layers while setting the stage for future infrastructure improvements.
Many research groups investigating fundamental questions about how to design such networked systems that utilize acoustic communications in complex underwater environments have had their overall effort significantly slowed by the lack of common means to test and compare protocols under realistic environmental conditions. This infrastructure responds to the need for consensus on analytic or simulation models for underwater networks where researchers need the ability to gather experimental data under real world conditions in order to make progress.
The network stack will be modular by design with sockets used to enable cross layer control and communication. The physical, MAC, Network and Application layers will be populated with sample components to enable users test their own algorithms or protocols without having to populate the entire stack. Users will be able to write modules to test their own algorithms or protocols at different layers and selectively replace the sample modules with their own. While the development of the modular architecture and sample modules for the network stack will be done with close coordination between all participating institutions, the lead institution for the layers that will be provided are Physical Layer (MIT for the all-layer system, WHOI for the Fixed-PHY system), MAC Layer (USC/ISI), Network Layer (UConn, a geo-routing protocol), and Application Layer (UMass, a DTN routine service). The open characteristic of the testbeds and their usefulness for conducting research will be demonstrated by the members of the team (primarily UConn and UMass as described above) and a few selected outside participants. In addition, acoustic receptions suitable for physical layer research will be made available to the general research community via the Internet.
Broader Impacts: This work enables the essential capability of research groups to examine fundamental research questions and their potential solutions in the real world. The infrastructure will directly benefit many on-going research projects in this field A large number of potential users in the community may benefit from this testbed infrastructure. In addition to the significant research impact, the infrastructure is expected to make a very strong educational impact as well, supporting classes bringing remote access to field experiments to students for whom traditional experiments would have been too costly. The infrastructure can accelerate research and education in the underwater networking field.
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