Research On Routing And Time Synchronization Protocol For Ultra - Low Power Wireless Sensor Networks

The routing and time synchronization are two key technologies of Wireless Sensor networks (WSN). The performance of routing technology affects the extent of the balanced energy consumption of WSN and the performance of time synchronization is the foundation of the WSN’s coordination. Therefore, the research of this paper includes the routing and time synchronization of WSN.At First, the concepts and research status of routing and time synchronization are introduced in this paper. We found the problem of the key nodes around Sink nodes early death which because of the heavy energy consumption, and the problem of the clock drift(CD) of time synchronization for ultra-low duty-cycle WSN.Second, to solve the problem of energy consumption of key nodes in WSN, a new ant colony routing algorithm on the dynamic adjustment of forward angle based on residual energy(DAFARE) was proposed. Time-synchronization protocol with collaboration from root-node class(TPCRC) was proposed to solve the problem of CD.DAFARE adjust the forward angle dynamically according to residual energy and distance in the range of initial forward angle. The problem of the key nodes around Sink nodes early death can be solved smoothly, and the key nodes’energy can be protected well. The simulation suggests that the effective life can be improved of approximately 50% by DAFARE, compared with FMEPNF. The results on MATLAB shows that, by DAFARE, the network energy consumption can be balanced effectively and the lifetime and coverage of WSN can be prolonged. DAFARE also has a good success rate of information transmission and network coverage.TPCRC solves the CD of ultra-low duty-cycle WSN by the collaboration from root-node class. Nodes finish the synchronization with root-node class of synchronization sublayer firstly, then finish the synchronization with root-node. By this way, the CD can be solved, and the time synchronization of WSN be realized. The results on MATLAB show that, TPCRC can solve the CD of ultra-low duty-cycle WSN, and the synchronization rate can be achieved approximate 100% quickly. Even with the packet loss rate 20%, TPCRC can also show a strong adaptability.