Research On Cluster-based Routing Protocol And Its Application For Wireless Sensor Networks

Wireless sensor networks (WSNs) consist of large numbers of sensor nodesdistributed in a certain area, organizing themselves into a wireless Ad Hoc network. Thetask of WSNs is to collect physical information and transmit it to one or several users.Because a microsensor node must operate on a tiny battery with limited energy thatrecharge or replacement is not an option due to the complex environment it deployed, aparamount design consideration for WSNs is how to extend the system life time withoutsacrificing system reliability.In this dissertation, the following topics related with WSNs are investigated andsome methods are proposed to improve performance of the existing methods.(a) As a representative of hierarchy-based protocol in WSNs, LEACH is an elegantsolution for energy efficiency. However, LEACH still has some deficiencies such as thegreat cluster and small cluster coexist, unreasonable cluster head selection while thenodes have different energy, the node still consumes energy after the death of the clusterhead. A new energy-efficient LEACH-based protocol is proposed that employed clustermember threshold and merged the tiny cluster to avoid the great cluster and smallcluster existing at the same time, estimated cluster head’s energy to reduce unnecessaryenergy consumption. Analysis and simulation results show that our proposed algorithmprovides more uniform energy consumption among nodes and can prolong networklifetime compared to LEACH.(b) Based on cooperation model of game theory, an energy balancing cooperationmodel in wireless sensor networks is proposed in this dissertation, taking all thefollowing factors into consideration: the costs function and benefits function of node toforward data, the relationship between the number of forwarding data packets andenergy through the establishment of node’s payment function. Its objective is to balancethe energy consumption and maximize the network lifetime. An energy factor and thenumbers of data packets transmitted are presented to make the energy consumption ofthe network tend to equilibrium. Based on cooperation model, a distributed clusteringalgorithm with cooperation model (DCACM) is proposed. It reduces the energyconsumption of cluster head effectively by adding the cooperative node to forward data.(c) A distributed clustering algorithm with optimal search model for wireless sensor networks (DCOS) and a search model is proposed in which a node, according toits operation mode, initial probability and carrier sense multiple access. The searchmodel is to find a viable resource allocation method, so that the maximum probability ofsuccessful communication node with the resource restricted circumstances. The aim ofclustering algorithm is to balance the energy consumption of the network, and tomaximize the network lifetime. In the design of DCOS, taking all the following factorsinto consideration: the selection of cluster head rules related to the overlay networkneeds the least number of nodes, the residual energy of node and adjacent node number,set limit of cluster head waiting time to avoid the cluster head energy consumption, setthe node threshold to avoid unbalanced energy consumption in the clustering process.(d) A design greenhouse based on wireless sensor networks is proposed in thisdissertation through the study of the basic principles and structure of environmentalmonitoring and control system in greenhouse. The research content includes the designof wireless nodes based on CC2430, the design of power amplifier module based onCC2591, realization of tree network. At last, performance testing of the modulesdesigned is completed and the result of overall experimentation is given.