Master Synchronization in Physical-Layer Communications of Wireless Sensor Networks

Synchronization in physical layer of wireless sensor networks is critical in restricting complexity of tag node and power consumption. Considering the master-to-tag communication (i.e., receiving signal from a master or anchor node by tag nodes), we propose a scheme on the basis of the principles of feedback control, to transfer the signal acquisition functionality from the tag receivers to the master nodes in a cluster. Furthermore, the algorithm of timing acquisition and phase adjustment do work in the master transmitter, and the tag nodes just need feedback results of the phase detection. The tag nodes do not require complicated clock or phase adjustment circuit any more or estimation in synchronization either. Thus, this master synchronization method reduces the complexity of tag nodes and power consumption. Due to the large random time delay in the wireless feedback loop, there exists the problem of stability and convergence in the acquisition. We analyze it and present a feasible scheme for the proposed master synchronization. In order to reduce acquisition time and cost in feedback, a two-step master acquisition algorithm is proposed. The acquisition performance under nonideal channel is analyzed, and further verified by simulations.