隨著近幾年無線通訊的成長，使得穿戴式裝置的種類越來越多樣，不同品牌所選用的無線通訊與平台也不盡相同。在高度仰賴溝通的物聯網(Internet of Things, IoT)時代，若要設計兼具低功耗與廉價的裝置，時間同步方法就變得至關重要。而現今無線網路的時間同步方法與早期設計相比，面臨了要在時間同步精度與通用性之間做取捨。高精準的同步精度方法，通常會依賴該平台的硬體層級來實現，由於特殊的硬體元件需求，限制了開發人員的發展。加上物聯網會使用不同的無線電頻率與作業系統，而通常它們也都不會提供MAC層的時間戳記溝通介面，大大增加了時間同步的侷限性。

在本論文中我們基於NTP的概念，延伸設計了一種同步機制，該機制是利用市電透過電力線在環境中所產生電磁干擾(EMI) 的特性輔佐，經由解析並且融入解算式來處理時間同步在無線網路的不對稱性問題。不同於其他的時間同步方法，本論文不僅實現了毫秒級的精度外，在面對眾多相異平台的穿戴式裝置，還能增加時間同步機制的通用、移植以及可擴展性，並期望在不久的將來能普及於日常生活中。

With the growth of wireless communication in recent years, the types of wearable devices have become more and more diverse, and the wireless communication and platforms chosen by different brands are also different. In the era of the Internet of Things (IoT), which is highly dependent on communication, time synchronization methods are critical to designing devices that are both low-power and inexpensive. Compared with earlier designs, the time synchronization method of today's wireless network faces a trade-off between time synchronization accuracy and universality. High-precision synchronization accuracy methods are usually implemented by relying on the hardware level of the platform. Due to the special hardware component requirements, the development of developers is limited. In addition, the Internet of Things will use different radio frequencies and operating systems, and usually they do not provide a time stamp communication interface at the MAC layer, which greatly increases the limitations of time synchronization.

In this paper, we implement a synchronization method based on the concept of NTP, which analyzes and integrates the electromagnetic interference (EMI) characteristics generated by the mains in the environment to deal with the asymmetry of time synchronization in wireless networks. . Different from other time synchronization methods, this paper not only achieves millisecond-level accuracy, but also increases the universality, portability and scalability of the time synchronization method in the face of many different wearable device platforms, and is popularized in daily life.

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