Research On Cluster-based Routing Protocol For Wireless Sensor Networks

With the development of sensor technology,embedded computing technology, wireless communication technology and distributed information processing technology,Wireless Sensor Networks (WSN) attract more and more attention. They are self-organizing wireless networks which are composed of large numbers of sensor nodes.They can be used for real-time monitoring of the target network area.By deploying large numbers of wireless sensor nodes which have the capabilities of sensing, collecting and disposing the information of the objects,they can obtain the information of the target area object and then send this information to user to analyze and dispose through wireless communication. They have broad application prospects,such as military reconnaissance,agriculture production, industrial production, intelligent transportation and so on.In the academic field,the research of all aspects of WSN is a hot issue.one of these is the routing protocol for WSN.The routing protocols mainly solve the problem that how to build the routing path and how to transmit data in the network.The performance of the protocol is related to the performace of the whole network closely. Since WSN has the characterisitic of limited enenrgy,the routing protocol developed for WSN must reduce the energy dissipiation as much as possible.Though the existing hierachy protocols for WSN can meet the requirments of WSN to some extent,they have some aspects to be improved.So it is indispensable to make improvements on the existing protocols to enhance the performance of the protocols.The thesis studies and analyzes the routing protocols of WSN,especially gives a detailed analysis to LEACH,then proposes a protocol based on LEACH.Firstly the study makes improvement on the cluster-head node numbers,which is not a desired number in LEACH. In the first round,the sink concludes the optimical number of cluster-head node using the fomulas.On recieving the geographical information of each node,the sink divides the whole monitored area into several sectors according to the optimal number of the cluster-head nodes,then selects a node to act as cluster-head in each sector.Secondly, LEACH uses the equivalent probability for cluster-head election,which may lead to bad results that the node which has little energy or is in an reasonable location becomes cluster-head.In order to solve this problem,the improved protocol adopts the follwing method:the cluster-head of prior round decides the cluster-head of the current round according to the information of the location and energy of all the cluster nodes.At last,to solve the problem that the node which is far from the sink consumes much more energy than the node which nears to the sink,the improved protocol adopts the new multi-hop communication mechanism in the inter-cluster communication. the improved protocol can extend the lifetime of the whole network.Finally,the improved protocl was implemented in NS, the improved protocol was compared with LEACH protocol.Simulation results show that the improved protocol can achieve a better performance in terms of the network lifetime,the total energy consumption,the data recieved by the sink.It can reduce the avergy energy dissipation and prolong the lifetime of the network.