Time Synchronization in Bluetooth-based Sensor Networks

Wireless sensor networks have attracted a lot of attention lately due to their wide range of applications from inventory management to battlefield surveillance. In most cases, an accurate time synchronization is essential to provide a common time reference and facilitate coordinated actions. However, a particular challenge arises when it is considered that network nodes are clocked by low-cost, low-stability oscillators, besides suffering of strong power consumption and computational capacity constraints. Based on that, this paper presents a synchronization technique for Bluetooth-based sensor networks populated by highly resource constrained sensing nodes that require a synchronization accuracy in the order of a few milliseconds. In addition, the main factors influencing time synchronization are characterized and experimentally validated in a real system. Finally, the proposed synchronization technique was successfully implemented and evaluated on an Arduino-based wireless sensor network, whose motivational application is the localization of acoustic events.