A Survey on Clock Synchronization Protocols in Wireless Sensor Networks

The Wireless Sensor Networks(WSNs) are important in the maintenance and monitoring of smart cities. The various activities in a smart city must be monitored periodically. Data aggregation, surveillance and tracking are done by the WSNs with the help of sensor nodes. The sensor nodes are the basic units of the WSNs. Each sensor node operation is timed by an inbuilt hardware clock. All the sensor node clocks must have the same notion of time for collision free transmissions. Therefore their internal clocks must be perfectly synchronized. In this paper, we present clock synchronization protocol that aim at synchronizing the clocks of sensor nodes. We have classified the protocols based on the propagation of the clock parameters and compared them on the basis of different performance parameters.