Research Article
An Energy Efficient and Accurate Slot Synchronization Scheme for Wireless Sensor Networks
@INPROCEEDINGS{10.1109/BROADNETS.2006.4374378, author={Lillian Dai and Prithwish Basu and Jason Redi}, title={An Energy Efficient and Accurate Slot Synchronization Scheme for Wireless Sensor Networks}, proceedings={3rd International ICST Conference on Broadband Communications, Networks, and Systems}, publisher={IEEE}, proceedings_a={BROADNETS}, year={2006}, month={10}, keywords={clock drift guard time slot synchronization spanning tree synchronization error wireless sensor network}, doi={10.1109/BROADNETS.2006.4374378} }- Lillian Dai
Prithwish Basu
Jason Redi
Year: 2006
An Energy Efficient and Accurate Slot Synchronization Scheme for Wireless Sensor Networks
BROADNETS
IEEE
DOI: 10.1109/BROADNETS.2006.4374378
Abstract
Existing slotted channel access schemes in wireless networks assume that slot boundaries at all nodes are synchronized. In practice, relative clock drifts among nodes cause slot misalignment over time and can result in catastrophic data loss in such systems. We propose a simple network-wide slot synchronization scheme (Slot-Sync and Slot-Resync) suitable for duty-cycling wireless sensor networks. The proposed scheme attains high accuracy by circumventing dominant sources of error inherent in traditional time synchronization protocols. At moderate duty-cycle frequencies, the proposed scheme also has the unique advantage of eliminating re-synchronization (re-sync) overhead completely, thereby achieving slot re-sync essentially for free. We provide an energy efficient slot guard time and re- sync interval design for the proposed scheme and analyze several spanning tree structures for slot-alignment message propagation. In addition, we derive upper bounds on the synchronization (sync) error for a family of trees. Through simulations, we compare the spanning trees we propose to those used for time sync in literature and show up to 80% reduction in sync error and up to 70% reduction in energy needed for slot-alignment message propagation by choosing appropriate tree structures.
