基于皮肤电位的可穿戴设备应用层时钟同步
Application-Layer Clock Synchronization for Wearables Using Skin Electric Potentials Induced by Powerline Radiation
摘要：
网络节点的时钟同步设计面临着异构平台的同步精度和通用性之间的基本权衡，因为高同步精度通常需要依赖于平台的硬件级网络数据包时间戳。本文介绍了TouchSync，一种新的可穿戴设备的室内时钟同步方法，它在保持通用性的同时实现了毫秒级的精度，因为它只使用标准的系统调用，例如读取系统时钟，采样传感器和发送/接收网络消息。TouchSync的设计是由我们广泛测量的一个关键发现驱动的，即电力线辐射引起的皮肤电位（SEP）在同一佩戴者甚至不同佩戴者身上都是显著的、周期性的和同步的。TouchSync将SEP信号集成到网络时间协议的通用原理中，并通过融合多个同步轮中的模糊结果来解决整数模糊度问题，从而得出两个同步可穿戴设备之间的准确时钟偏移。通过我们的共享代码，TouchSync可以轻松集成到任何可穿戴应用程序中。基于我们的Arduino和TinyOS实现的广泛评估表明，TouchSync的同步误差在同一佩戴者和相距10公里的两个佩戴者之间分别低于3和7毫秒。
英文摘要：
Design of clock synchronization for networked nodes faces a fundamental trade-off between synchronization accuracy and universality for heterogeneous platforms, because a high synchronization accuracy generally requires platform-dependent hardware-level network packet timestamping. This paper presents TouchSync, a new indoor clock synchronization approach for wearables that achieves millisecond accuracy while preserving universality in that it uses standard system calls only, such as reading system clock, sampling sensors, and sending/receiving network messages. The design of TouchSync is driven by a key finding from our extensive measurements that the skin electric potentials (SEPs) induced by powerline radiation are salient, periodic, and synchronous on a same wearer and even across different wearers. TouchSync integrates the SEP signal into the universal principle of Network Time Protocol and solves an integer ambiguity problem by fusing the ambiguous results in multiple synchronization rounds to conclude an accurate clock offset between two synchronizing wearables. With our shared code, TouchSync can be readily integrated into any wearable applications. Extensive evaluation based on our Arduino and TinyOS implementations shows that TouchSync's synchronization errors are below 3 and 7 milliseconds on the same wearer and between two wearers 10 kilometers apart, respectively.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
