Exploiting Smartphone Peripherals for Precise Time Synchronization

Achieving precise time synchronization across a collection of smartphones poses unique challenges due to their limited hardware support, exclusively wireless networking interface, and restricted timing stack control. Given the ubiquity and popularity of smartphones in modern distributed applications, clock discrepancies often lead to degraded application performance. In this paper, we present and evaluate alternative approaches to attain precise time synchronization by leveraging the various peripherals available on modern smartphone devices. Our evaluation across Android smartphones typically attains synchronization accuracy within (i) 200μs using audio, (ii) 3000μs using Bluetooth Low Energy, and (iii) 1000μs using Wi-Fi. Under certain conditions, we show that smartphones synchronized using one peripheral can accurately timestamp and generate synchronous events over other peripherals. The provided guide and accompanying open-source implementations offer developers a means to select the appropriate time synchronization technique when building distributed applications.