Fault-Tolerant Flooding Time Synchronization Protocol for Wireless Sensor Networks

Time synchronization is one of the basic middleware services in Wireless Sensor Networks. It is required in various applications such as target tracking, sensor event ordering, sound delay measurements and time-division multiplexing. Fault-tolerance in needed in order to perform correctly in the presence of faulty nodes. We extended Flooding Time Synchronization Protocol to support fault-tolerance in the case of malicious nodes that lie about their global time. The proposed algorithm will detect inconsistent global time and start asking the neighbors about their received global time. After it gathers sufficient information from its neighbors so that it can compute a new time value, it decides if the initially received global time was correct or not. If it was incorrect, the new computed value is stored. Otherwise, it permits the initial global time to be stored on the sensor device.