A time synchronization circuit with sub-microsecond skew for multi-hop wired wearable networks

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• 作者：Fardin Derogarian ; ^{mpt09020@fe.up.pt" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Joã ; o Canas FerreiraAuthor Vitae ; VÍ ; tor M. Grade TavaresAuthor Vitae
• 关键词：Body area networks ; Wearable sensor network ; Time synchronization protocol ; CMOS ASIC
• 刊名：Microprocessors and Microsystems
• 出版年：2015
• 出版时间：November 2015
• 年：2015
• 卷：39
• 期：8
• 页码：1029-1038
• 全文大小：1878 K

文摘

This paper describes and evaluates a fully digital circuit for one-way master-to-slave, highly precise time synchronization in a low-power wearable system equipped with a set of sensor nodes. These sensors are connected to each other in a mesh topology, with conductive yarns used as one-wire bidirectional communication links. The circuit is designed to perform synchronization in the MAC layer, so that the deterministic part of the clock skew between nodes is kept constant and compensated with a single message exchange. In each sensor node, the synchronization circuit provides a programmable clock signal and a real-time counter for time stamping. Experimental results from a fabricated ASIC (in a CMOS 0.35 μ$\mathrm{\mu }$m technology) show that the circuit keeps the one-hop average clock skew below 4.6 ns and that the skew grows linearly as the hop distance to the reference node increases. The sub-microsecond average clock skew achieved by the proposed solution satisfies the requirements of many wearable sensor network applications.