Time synchronization in wireless senor and actuator networks.

Abstract

The purpose of time synchronization is to allow the different nodes' clocks in a network to get relatively close values at any moment. Currently, time synchronization is a fundamental problem in wireless sensor and actuator networks (WSANs). Indeed, many WSANs applications, including node localization, sleep schedule, and data aggregation, require accurate time synchronization to function properly. In this thesis, we propose two cluster-based time synchronization protocols for WSANs, namely Sensor and Actuator Networks Synchronization Protocol (SANSync), and Optimized Sensor and Actuator Networks Synchronization Protocol (OSANSync). These protocols, contrary to existing protocols, fully exploit the available resources of the actuators, particularly their large transmission range, to improve time synchronization accuracy. We also propose a heuristic-based method to select the ROOT node through which all the other nodes in the network are synchronized. The proposed method is fully distributed and can be easily integrated into time synchronization protocols to improve their performance.