A Linear Time Synchronization Algorithm for Underwater Wireless Sensor Networks

Large propagation delay and node movement are considered to be two significant attributes that differentiate an underwater wireless sensor network (UWSN) from a ground wireless sensor network (WSN). Considering the effects of both propagation delay and movement, we propose a time synchronization algorithm suitable for a UWSN. An underwater node can move out of and into another node´s range frequently. With the proposed algorithm, no time synchronization is necessary if the time stamps of the received data packets are within the tolerance. In this fashion, the network underwater does not need to perform global time synchronizations periodically, which reduces the time used to synchronize clocks among sensor nodes. The simulation results show the time cost for synchronization is linear to the data packets exchanged.