Clock synchronization over bluetooth

Abstract

Clock synchronization is key to many applications of wearable device networks. High synchronization accuracy requires platform-dependent hardware-level timestamping, which is not possible for wearable devices from different platforms. Clock synchronization done on application layer ensures universality for heterogenous platforms but has lower accuracy. This research aims to evaluate the universal principle of Network Time Protocol, an application level approach, and propose a new approach using external signals to assist clock synchronization. Different types of external input from sensors are studied to determine the most suitable for clock synchronization. These different approaches are implemented using Adafruit Flora and Android smartphones, which support Bluetooth and have sensors to detect external signals. Evaluation of results shows that clock synchronization assisted by audio input has the best performance, with error of less than 1 millisecond.