Phoenix: An epidemic approach to time reconstruction

Jayant Gupchup, Douglas Carlson, Rǎzvan Musǎloiu-E., Alex Szalay, Andreas Terzis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Harsh deployment environments and uncertain run-time conditions create numerous challenges for postmortem time reconstruction methods. For example, motes often reboot and thus lose their clock state, considering that the majority of mote platforms lack a real-time clock. While existing time reconstruction methods for long-term data gathering networks rely on a persistent basestation for assigning global timestamps to measurements, the basestation may be unavailable due to hardware and software faults. We present Phoenix, a novel offline algorithm for reconstructing global timestamps that is robust to frequent mote reboots and does not require a persistent global time source. This independence sets Phoenix apart from the majority of time reconstruction algorithms which assume that such a source is always available. Motes in Phoenix exchange their time-related state with their neighbors, establishing a chain of transitive temporal relationships to one or more motes with references to the global time. These relationships allow Phoenix to reconstruct the measurement timeline for each mote. Results from simulations and a deployment indicate that Phoenix can achieve timing accuracy up to 6 ppm for 99% of the collected measurements. Phoenix is able to maintain this performance for periods that last for months without a persistent global time source. To achieve this level of performance for the targeted environmental monitoring application, Phoenix requires an additional space overhead of 4% and an additional duty cycle of 0.2%.

Original languageEnglish (US)
Title of host publicationWireless Sensor Networks - 7th European Conference, EWSN 2010, Proceedings
Pages17-32
Number of pages16
DOIs
StatePublished - 2010
Event7th European Conference on Wireless Sensor Networks, EWSN 2010 - Coimbra, Portugal
Duration: Feb 17 2010Feb 19 2010

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume5970 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference7th European Conference on Wireless Sensor Networks, EWSN 2010
Country/TerritoryPortugal
CityCoimbra
Period2/17/102/19/10

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science

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