Xianglong Kong

A New Cluster Routing Strategy Based on ZigBee

Zigbee is a wireless technology as an open global standard used in many applications such as interconnecting sensors, monitoring and automating home, medical, industrial, and agricultural systems where low power consumption are needed. Based on the ZigBee network, a good routing protocol has to be scalable and adaptive to the changes in the network topology. Thus protocols must perform well as the network grows larger or as the workload increases. In this paper we improved a new cluster routing protocol(called AODV Cluster). Fistly, AODV Cluster divides the ZigBee network topology into one or more logical clusters, A cluster label uses the ZigBee address allocation, the one cluster can share a new routing, which saved on energy of the network and reduced communication quantity. Simulation results shows that this protocol not only keep the AODV merit, but also advanced the scalability. Especially in dense network, performance is superior than AODV.

An Event -Triggered Time Synchronization Scheme for Sensor Networks

Distributed time synchronization is an important part of sensor networks. Due to the limited battery capacity of the sensor nodes, applicable schemes should concern the energy consumption of the networks. To achieve better efficiency, an event-triggered time synchronization scheme (ETTS) is presented, which aims at providing on-demand time synchronization in sensor networks. The scheme is composed of two phases: skew correction phase and estimation of offset phase. When timestamps from different clocks need to be compared, they can be reconciled after the event. ETTS removes the need to predict application requirements in advance, which means that the synchronization energy is only expended after an event has occurred. Compared to traditional schemes, for example, TPSN, simulation results show that ETTS achieves desired energy efficiency when the frequency of event is low.