Scalable synchronization of clocks in wireless sensor networks

✍ Scribed by Jun Liu

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 364 KB
• Volume: 6
• Category: Article
• ISSN: 1570-8705
• DOI: 10.1016/j.adhoc.2007.07.001

✦ Synopsis

In many sensor-based applications, identifying the sequence of event occurrence is useful. When local clocks lack synchronizations, it is difficult or time-consuming to determine the order of event occurrence. In this paper, we first describe a centralized method for pseudo-synchronizing non-base clocks to a base clock. The pseudo-shift between a pair of nonbase/base clocks is estimated by the difference of the occurrence times of pairs of events included in direct ''happenedbefore'' relations that only involve this pair of sensors. Evaluation results suggest that this method can closely make non-base clocks synchronized with a base clock without violating the direct ''happened-before'' relations. The centralized pseudo-synchronization method demands a OðN 3 Þ computational overhead on the base sensor in a network of N sensors. Then, in order to distribute the computational overhead across all sensors, a localized pseudo-synchronization method is proposed by taking advantage of the topologies of wireless sensor networks.