Dynamic Adaptive Wireless Networks with Autonomous Robot Nodes

University Of Southern California, Los Angeles CA

Investigators

Abstract

Multihop wireless capabilities are enabling communication and coordination among autonomous nodes in unplanned environments and configurations. At the same time wireless channels present challenges of dynamic operating conditions, power constraints for autonomously-powered nodes, and complicated interactions between high level behavior and lower level channel characteristics (e.g. increased synchronized communication significantly degrades channel characteristics). The major goal of the research proposed here is the development, testing, and characterization of algorithms for scalable, application-driven, wireless network services using a heterogeneous collection of communicating mobile nodes. Some of these nodes will be autonomous (robots) in that their movements will not be human-controlled. The others will be portable, thus making them dependent on humans for transportation. While the focus of the work is on the mobile nodes, the project includs immobile computers on the network as well. The project emphasizes that most (though not all) of the mobile nodes will have modest sensing, computational, and communication resources. The chief scientific motivation behind the work is the design of robust, efficient, and scalable algorithms. The project hypothesizes that distributed algorithms that rely on local interactions have many compelling characteristics, resulting in these properties. There is significant overlap between the problems of coordinating the autonomous mobile nodes that carry some of the sensors and the algorithms that direct the flow of information from sources(s)to sink(s) in the network. Both sets of algorithms need to be carefully designed to improve robustness, efficiency, and scalability. As motivation the project proposes that the experimental part of the research be conducted on a testbed which simulates some characteristics of an urban post-earthquake scenario in a building. The sensors in the experiments will be distributed geographically (within the building) and linked by a wireless network. Many of the mobile nodes will be largely autonomous, serving as easily-accessible knowledge collectors and repositories, and exercising a wide range of independent options in the dispatch and control of information flow and resources. Other mobile nodes will be carried about the environment by people. The project will study issues of scale (how many sensor nodes does the application software accommodate), fault tolerance (how robust is the system to loss of sensors and/or communication) and efficiency (e.g. time vs. quality of service). As part of a one-year pilot study funded by NSF, the project has been conducting initial research in the issues underlying a system such as the one above. The project also recently received a substantial equipment grant from the Office of Naval Research to support the experimental portion of this work. The project has identified two key unsolved sub-problems that are relevant to the overall goals: localization and communication coverage. In this proposal the project discusses the broad research challenges in the area of communication and coordination of autonomous mobile nodes. The project then focuses on the two key problems as concrete questions that will be addressed in the research and describes a method involving simulation and experimentation to study them systematically.