Clustering Hierarchy Protocol Based On Sink Centralized Management In Wireless Sensor Network

Wireless Sensor Networks (WSN) is a monitoring network composed of hundreds or thousands of sensor nodes, the nodes networking each other by self-organizing. WSN's main function is to collect information of the target object in sensing field, and process data according to the need and the results are sent to sink and finally transmit to management node. The prominent characteristic of WSN is limited energy, therefore low power high efficiency network protocol is the focus of WSN research.There is one kind protocol in WSN is clustering protocol which will divide the network into multiple levels, high-level cluster head nodes are responsible for collecting data from the lower-level nodes and processing these data, and then cluster heads send the result to the sink node.Hierarchical clustering protocol realizes the network to divide the level management, and improves the network's expandability and stability, and prolongs the lifetime of the network.LEACH protocol is a classical clustering protocol which its thoughts are adopted by multiple protocols. LEACH can be run independently without human intervention, but the completely distributed algorithm sacrifices the energy efficiency. For example, each node elects itself to be a cluster head by probability, and cluster head position is random, and switch round of cluster head is fixed etc. It's hard to avoid the situation that there are too many or too few cluster head when the number of cluster heads is controlled by probability. The location of the cluster head cannot be predicted, the unreasonable distribution of cluster head will intensify the energy consumption of the node. Moreover, even if node is elected cluster head for equal times, nodes which is far to sink obviously consumes more energy than ones close, which is against the balance of energy consumption.In order to improve these deficiencies, this paper proposes a clustering hierarchy protocol based on sink centralized management (SCMCHP), which makes full use of the advantage of sink. Sink collects network status information and completes all kinds of algorithm, and ordinary nodes complete their tasks according to the guidance information of sink. In this protocol, sink calculates the optimal number of clusters based on the network characteristics. Using a new center node sorting coefficient, SCMCHP improves the center node clustering algorithm which enhances the rationality of the clustering. On the basis of the residual energy of node and the energy consumption of node when it is elected cluster head, protocol chooses its cluster head next stage. Cluster head switch based on average energy within clusters, reasonable switch threshold value is obtained by simulation, which ensures the rationality of cluster head selection, and balances the network energy consumption, and reduces the switching frequency of cluster head. Based on energy optimization, cluster head rules further balance the network energy consumption and increase energy efficiency.The simulation results show that SCMCHP protocol can reduce the cost of network operation, and prolong the network lifetime, and increase the number of the network packets sent, and balance the energy consumption of each node in the network. It is proved that this protocol has a certain degree of applicability for the network whose nodes have different initial energy.