Research On Energy Balance And Unequal Clustering Routing Protocol In Wireless Sensor Networks

Wireless sensor networks(WSNs)is an ad-hoc network,which is composed of massive small sensor nodes with limited sensibility,processing and communicating capability.Sensors nodes are able to quickly deploy in various complex environments and implement reliable information collection which provides a wide range of applications for WSNs such as military reconnaissance,environmental monitoring,health care,agriculture,space exploration,and disaster rescue,and so on.However,because of the complicated deployment of WSNs,power supply of sensor nodes is usually provided by micro batteries.Therefore,how to efficiently use nodes' energy is the key to practical applications of WSNs.Routing protocol has a significant impact on the energy efficiency of WSNs.Clustering routing can improve network scalability and energy efficiency;however,it has imperfection in energy balance.On one hand,energy of cluster heads deplete too fast;On the other hand,the cluster heads which are closer to the base station has hot-spot problem.To mitigate these problems,this thesis mainly discusses several questions about clustering routing protocol of WSNs:unequal clustering mechanism,muti-hop routing in clusters and cluster head rotation mechanism.The main contents of this thesis include:(1)A new energy balance and unequal clustering(EBUC)algorithm is proposed for WSNs.Considering the fact that sensor nodes are usually randomly deployed,besides of the distance between a candidate cluster head and base station,its node degree is also introduced to a better control of its competition radius,so as to form a more reasonable unequal cluster structure.Cluster Adaptive Value(CAV)is introduced when choosing cluster head.CAV considers candidate sensor nodes'residual energy and the distance between the nodes and its neighbors.A candidate cluster head which has high residual energy and a short average distance to its neighbors possess a great CAV which means it has a great probability to become a cluster head.In inter-cluster communication phase,every cluster head selects a neighbor cluster head that has the minimum routing cost value as its relay node.And the routing cost value is based on residual energy,amount of cluster members and location information.Simulation results demonstrate that EBUC can efficiently decrease and balance energy consumption,so as to extend network lifetime.(2)The time driving based cluster heads rotation will result in some problems,such as an unnecessary consumption of energy and difficulties of optimizing the rotation period.To mitigate these problems,we introduce an auction mechanism based local-area cluster head rotation(ALCR)algorithm in which bidders' cost formulation consider residual energy and distance to auctioneer.In order to decrease the message exchange overhead,a time-based winner determination for the auction is also proposed.Simulation results demonstrate that EBUC with the local-area cluster head rotation algorithm can efficiently balance energy consumption even in the condition that the whole cluster heads rotation period is extended to certain value.