Lightweight Precision-Adaptive Time Synchronization in Wireless Sensor Networks

Li LI  Yongpan LIU  Huazhong YANG  Hui WANG  

IEICE TRANSACTIONS on Communications   Vol.E93-B   No.9   pp.2299-2308
Publication Date: 2010/09/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.2299
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
sensor networks,  time synchronization,  precision adaptability,  energy efficiency,  

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Time synchronization is an essential service for wireless sensor networks (WSNs). However, fixed-period time synchronization can not serve multiple users efficiently in terms of energy consumption. This paper proposes a lightweight precision-adaptive protocol for cluster-based multi-user networks. It consists of a basic average time synchronization algorithm and an adaptive control loop. The basic average time synchronization algorithm achieves 1 µs instantaneous synchronization error performance. It also prolongs re-synchronization period by taking the average of two specified nodes' local time to be cluster global time. The adaptive control loop realizes diverse levels of synchronization precision based on the proportional relationship between sync error and re-synchronization period. Experimental results show that the proposed precision-adaptive protocol can respond to the sync error bound change within 2 steps. It is faster than the exponential convergence of the adaptive protocols based on multiplicative iterations.