PLL Based Time Synchronization in Wireless Sensor Networks

Time synchronization is a key component in numerous wireless sensor network applications. Most of the current software based time synchronization approaches suffer from communication overhead and lack of scalability. In this paper, we propose a hardware based approach based on voltage controlled crystal oscillator and phase locked loop techniques to achieve and maintain sub microsecond level time synchronization. Our approach does not require any exchange of synchronization messages with neighboring nodes. Performance evaluations in Matlab demonstrate sub microsecond accuracy and robustness to infrequent loss of WWVB signal. The principle advantages of our solution is scalability, accuracy, and low communication overhead.