Saurabh Ganeriwal
ABSTRACT
Radio duty cycling has received significant attention in sensor networking literature, particularly in the form of protocols for medium access control and topology management. While many protocols have claimed to achieve significant duty-cycling benefits in theory and simulation, these benefits have often not translated to practice. The dominant factor that prevents the optimal usage of the radio in real deployment settings is time uncertainty between sensor nodes. This paper proposes an uncertainty-driven approach to duty-cycling where a model of long-term clock drift is used to minimize the duty-cycling overhead. First, we use long-term empirical measurements to evaluate and analyze in-depth the interplay between three key parameters that influence long-term synchronization - synchronization rate, history of past synchronization beacons and the estimation scheme. Second, we use this measurement-based study to design a rate-adaptive, energy-efficient long-term time synchronization algorithm that can adapt to changing clock drift and environmental conditions while achieving application-specific precision with very high probability. Finally, we integrate our uncertainty-driven time synchronization scheme with a MAC layer protocol, BMAC, and empirically demonstrate one to two orders of magnitude reduction in the transmit energy consumption at a node with negligible impact on the packet loss rate.
- Dutta, P., Grimmer, M., Arora A., Bibyk S., Culler D. Design of a wireless sensor network platform for detecting rare, random, and ephemereal events. Special Track on Platform Tools and Design Methods for Network Embedded Sensors (SPOTS), 2005.Google Scholar
- Polastre, J., Hill, J., Culler, D. Versatile low power medium access for wireless sensor networks. In Proceedings of the ACM Conference on Embedded Networked Sensor Systems (SenSys), 2004. Google ScholarDigital Library
- Ye, W., Heidemann, J., Estrin, D. An energy-efficient MAC protocol for wireless sensor networks. In Proceedings of the 21st International Conference of the IEEE Computer and Communications Societies (Infocom), 2002.Google Scholar
- Dam, T. V., Langendoen, K. An adaptive energy-efficient MAC protocol for wireless sensor network. In Proceedings of the ACM Conference on Embedded Network Sensor Systems (SenSys), 2003. Google ScholarDigital Library
- Maroti, M., Kusy, B., Simon, G., Ledeczi, A. The flooding time synchronization protocol. In Proceedings of the Second ACM Conference on Embedded Networked Sensor Systems (SenSys), November 2004. Google ScholarDigital Library
- Elson, J., Girod, L., Estrin D. Fine-grained network time synchronization using reference broadcasts. In Proceedings of the Fifth Symposium on Operating Systems Design and Implementation (OSDI), Boston, MA, December 2002. Google ScholarDigital Library
- Ganeriwal, S., Kumar, R., Srivastava, M. B. Timing-sync protocol for sensor networks. In Proceedings of the First ACM Conference on Embedded Networked Sensor Systems (SenSys), Los Angeles, CA, November 2003. Google ScholarDigital Library
- CENS habitat sensing group at James Reserve. http://www.jamesreserve.edu/Google Scholar
- Simon G., Maroti, M., Ledeczi, A., Balogh, G., Kusy, B., Nadas, A., Pap, G., Sallai, J., Frampton, K. Sensor network- based counter sniper system. In Proceedings of the Second ACM Conference on Embedded Networked Sensor Systems (SenSys), November 2004. Google ScholarDigital Library
- Mills, D. L. Internet time synchronization: The network time protocol. Global States and Time in Distributed Systems, IEEE Computer Society Press, 1994.Google Scholar
- Sundararaman, B., Buy, U., Kshemkalyani, D. Clock synchronization for wireless sensor networks: A Survey. Ad-hoc Networks, 3(3): 281--323, May 2005.Google ScholarCross Ref
- Mills, D. L. Adaptive hybrid clock discipline algorithm for the Network Time Protocol. IEEE/ACM Transactions on Networking 6, 5 (October 1998), 505--514. Google ScholarDigital Library
- Rao, C. R. Linear statistical inference and its applications. John Wiley & Sons, New York, 1973.Google ScholarCross Ref
- Allan Variance. http://www.allanstime.com/AllanVariance.Google Scholar
- Tsiatsis, V., Sim, H., Ganeriwal, S., Ganesan, D., Srivastava, M. B. Implementation of rate adaptive time synchronization protocol in TinyOS. Technical Report, NESL 2005.Google Scholar
- Softfloat. http://www.jhauser.us/arithmetic/SoftFloat.htmlGoogle Scholar
- Chip-scale vapor-cell atomic clocks at NIST. http://www.bouldernist.gov/timefreq/ofm/smallclock/Google Scholar
Index Terms
Estimating clock uncertainty for efficient duty-cycling in sensor networks
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