Design Techniques for Streamlined Integration and Fault Tolerance in a Distributed Sensor System for Line-crossing Recognition

Distributed sensor system applications (e.g., wireless sensor networks) have been studied extensively in recent years. Such applications involve resource-limited embedded sensor nodes that communicate with each other through self-organizing protocols. Depending on application requirements, distributed sensor system design may include protocol and prototype implementation. Prototype implementation is especially useful in establishing and maintaining system functionality as the design is customized to satisfy size, energy, and cost constraints. In this paper, we present a streamlined, application-specific approach to incorporating fault tolerance into a TDMA-based distributed sensor system for line-crossing recognition. The objective of this approach is to prevent node failures from translating into failures in the overall system. Our approach is specialized and light-weight so that fault tolerance is achieved without significant degradation in energy efficiency. We also present an asynchronous handshaking approach for providing synchronization between the transceiver and digital processing subsystem in sensor node. This provides a general method for achieving such synchronization with reduced hardware requirements and reduced energy consumption compared to conventional approaches, which rely on generic interface protocols. We demonstrate the capabilities of our approaches to fault tolerance and transceiver-processor integration through experiments involving a complete prototype wireless sensor network test-bed, and a distributed line-crossing recognition application that runs on this test-bed.