An Improved Clock Synchronization Algorithm for Wireless Sensor Network of Underground Water Supply Pipline

The improved clock synchronization algorithm SCRT (Synchronization through Carrying Reference Time-stamps) is proposed in this paper for the sensor network of water supply pipeline. This algorithm overcomes the limitation of the synchronous range of sensor nodes in PBS (Pairwise Broadcast Synchronization) algorithm. The algorithm combines the two synchronization: sender-receiver (SR) and receiver-only (RO). The head node in the cluster networks exchanges synchronous time information with the reference node, and a linear regression model is established. The estimations of phase offset and frequency offset are obtained by least squares method. Other members in the cluster synchronize the local clock according to the reference time-stamp carried by the sending and receiving clock messages of the head node, without additional synchronous messages. The quality of estimators is measured by the Cramer-Rao Lower Bound, and the optimal estimation is found by MATLAB simulation.