33 Power-Based Diagnosis of Node Silence in Remote High-End Sensing Systems YONG YANG, Philips Research North America LU SU, State University of New York at Buffalo MOHAMMAD KHAN, University of Connecticut MICHAEL LEMAY, TAREK ABDELZAHER, and JIAWEI HAN, University of Illinois, Urbana-Champaign 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 inter- nal 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 condi- tions 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. Categories and Subject Descriptors: C.2.3 [Computer Systems Organization]: Network Operations— Network monitoring; D.2.5 [Software]: Testing and Debugging—Diagnostics; G.3 [Mathematics of Computing]: Probability and Statistics—Time series analysis General Terms: Algorithms, Design, Experimentation, Measurement, Reliability A preliminary version of this article appeared in ACM/IEEE International Conference on Information Pro- cessing in Sensor Networks (IPSN) 2010 [Khan et al. 2010]. This work was done when Yong Yang was at the University of Illinois at Urbana-Champaign. Now he is with Philips Research North America. This work was supported in part by NSF CNS 06-26342, NSF CNS 09-05014, NSF CNS 09-17218, NSF CNS 07-16626, NSF CNS 07-16421, ONR N00014-08-1-0248, NSF CNS 05-24695, and grants from the MacArthur Foundation, Boeing Corporation, and Lockheed Martin. M. LeMay was with the University of Illinois at Urbana-Champaign while performing the work described herein, but he was employed by Intel Corporation at the time of submission. The views expressed are those of the authors only. Authors’ addresses: Y. Yang, Philips Research North America, 345 Scarborough Road, Briarcliff Manor, NY 10510; email: yong.yang_2@ philips.com; L. Su, State University of New York at Buffalo, 321 Davis Hall, Buffalo, New York 14260; email: lusu@buffalo.edu; M. Khan, University of Connecticut, 363 ITE Building, University of Connecticut, Storrs, CT 06269; email: maifi.khan@engr.uconn.edu; M. LeMay, Intel Corpo- ration, 2111 NE 25th Ave. JF2-75, Hillsboro, OR 97124; email: m@lemays.org; T. Abdelzaher and J. Han, Siebel Center for Computer Science, 201 N Goodwin Avenue, Urbana, IL 61801; emails: zaher@illinois.edu, hanj@cs.uiuc.edu. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies show this notice on the first page or initial screen of a display along with the full citation. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works requires prior specific permission and/or a fee. Permissions may be requested from Publications Dept., ACM, Inc., 2 Penn Plaza, Suite 701, New York, NY 10121-0701 USA, fax +1 (212) 869-0481, or permissions@acm.org. c  2014 ACM 1550-4859/2014/12-ART33 $15.00 DOI: http://dx.doi.org/10.1145/2661639 ACM Transactions on Sensor Networks, Vol. 11, No. 2, Article 33, Publication date: December 2014.