Power-Based Diagnosis of Node Silence in Remote High-End Sensing Systems.

Troubleshooting unresponsive sensor nodes is a significant challenge in remote sensor network deployments. While prior work often targets low-end sensor networks, this article introduces a novel diagnostic tool, called the telediagnostic powertracer, geared for remote high-end sensing systems. Leveraging special properties of high-end systems, this in situ troubleshooting tool uses external power measurements to determine the internal health condition of an unresponsive node and the most likely cause of its failure. We develop our own low-cost power meter with low-bandwidth radio, propose both passive and active sampling schemes to measure the power consumption of the host node, and then report the measurements to a base station, hence allowing remote (i.e., tele-) diagnosis. The tool was deployed and tested in a remote solar-powered sensing system for acoustic and visual environmental monitoring. It was shown to successfully distinguish between several categories of failures that cause unresponsive behavior including energy depletion, antenna damage, radio disconnection, system crashes, and anomalous reboots. It was also able to determine the internal health conditions of an unresponsive node, such as the presence or absence of sensing and data storage activities (for each of multiple applications). The article explores the feasibility of building such a remote diagnostic tool from the standpoint of economy, scale, and diagnostic accuracy. The main novelty lies in its use of power consumption as a side channel, which has more availability than other I/O ports, to diagnose sensing system failures.