Time Synchronization and Clock Parameter Estimation for Wireless Sensor Networks with Unequal Propagation Delays

Time synchronization is a prerequisite and also a critical support technique for wireless sensor networks (WSNs). Traditional synchronization protocols have some drawbacks, such as limited synchronization accuracy, high energy consumption, and strict node deployment requirement, which limits their application in underwater WSNs. In view of the shortcomings of the traditional schemes, we propose an energy-efficient synchronization protocol which explores the nature of broadcasting to save energy. Based on the proposed protocol, the minimum variance unbiased estimation (MVUE) of the clock offsets is further derived to obtain higher synchronization accuracy. Remarkably, the proposed protocol can be applied to randomly deployed WSNs with unequal propagation delays, especially underwater WSNs. Simulation results confirm the superiority of the proposed protocol in both terrestrial and underwater WSNs.