Research On Data Exchange In Wireless Sensor Networks

Wireless sensor network,which is integration of sensor techniques,embedded computation techniques,wireless communication techniques and distributed computation techniques,consists of large number of self organized sensor nodes with sensing,computing and communication capabilities,and it has been used for numerous applications including military surveillance,facility monitoring,emergency rescue and environmental monitoring.Data exchange is one of the most fundamental and important operations in wireless sensor networks.Sensor nodes sample the local environment information, and then transmit the data to the destination nodes through the multi-hop routing with the assistance of intermediary nodes.Meanwhile,each sensor nodes request for the new data collected by all the other nodes.The communication model is All to All,which is termed as data exchange.The dissertation pays special attention to three performances indexes in the course of data exchange studying.First,energy efficient is of great importance in energy-constrained sensor networks.It is directly related to the energy consumption for each nodes,further influence the system lifetime of the whole network. Second,network delay is another important index for data exchange applications. It is defined as the time involved in data transmission,routing,and data aggregation. In the end,it is very significant to supply data reliability in mobile sensor networks.The mobility of sensor nodes leads to weak transport link in the network, packets can not ensure to be received by target nodes in time.Therefore, data reliability is the precondition of putting to use of data exchange systems.Although many works on data exchange have been presented,it is necessary to refine existing results and design new protocols for new problems.Theoretical study on practical data exchange models should be strengthened further.For the design of protocols,existing protocols still have vast development space in improving system energy consumption and lifetime.Moreover,distributed protocols are desired.For solving practical applications,past protocols can not satisfied the requirement of practical systems.Not only the design of new protocols for new problems but also the improvement in existing protocol needs further work.With this concern,the main research content of this dissertation is as follows: An Efficient Data Exchange Protocol using Improved Star Trees in Wireless Sensor Networks-DEIST(Data Exchange using Improved Star Trees):The main goal of this data exchange protocol is to exchange data between any pair of two nodes in an energy and delay efficient manner so that network lifetime is prolonged and delay is reduced.In order to confirm the area partition mechanism,related theoretical analysis and experimental simulation are provided.We divide the sensor area into four equal grids and each sensor node associates itself with a virtual grid based on its location information. In each grid,a novel mechanism is proposed to choose root node with location information of sensor nodes.After the root node has been chosen, an efficient data exchange Star-Tree is constructed and used to achieve the exchange behavior inside each grid.The fused data of each grid will be sent to the global center node for data exchange between neighborhood grids. Simulations show that our protocol significantly prolongs the lifetime to the multiple-chain protocols,and the delay can be reduced 20%to 30%.●Energy Efficient Distributed Data Exchange Protocol in Wireless Sensor Networks-DDET(Distributed Data Exchange Tree):In practical applications, such as the Single Soldier System,only a few sensor nodes request for data information.Besides,because of the functional requirement characteristics of these nodes,the data request rates of sensor nodes may different from each other.Hence,we focus on sensor nodes data exchange problems of non-uniform data request rates,and provide a energy efficient distributed protocol DDET.First,the gathered information of all sensor nodes is sorted by their data requiring rate,then,each round the node with the maximum request rate will join the data exchange spanning tree for energy conservation, in the end,the virtual branch cut mechanism will be used to choose the root node of the spanning tree.Simulation results show that compared with DEIST our protocol significantly prolongs the lifetime and the total energy consumption reduces 3%. ●A Intelligent Guide System Based on Wireless Sensor Networks.The intelligent guide system,which is based on wireless sensor network technique and related hardware,is applicable to exhibition halls,museum and scenic spots. This dissertation introduces in detail the general design scheme and the functional modules.Data exchange module provides reliable mechanism of the transmission route,and support multiple data communication model,such as unicast,broadcast,all to all etc,which greatly extend system function. We have developed the prototype system which is under system debugging in the target area.The contributions and novelties of this dissertation are as following:1.It is the first time that this dissertation present non-uniform data request rates data exchange model which involved in two kinds of nodes,sensor nodes and relay nodes.The generality and adaptability of this model is very extensive.2.For uniform data request rates data exchange problem,the dissertation present a novel algorithm to construct improved star trees to improve the Chain based protocol performances.The simulation results show its efficiency in energy consumption and system lifetime.3.For non-uniform data request rates data exchange problem,we design a distributed and localized protocol.4.The dissertation describes a intelligent guide system based on wireless sensor networks.Taken the mobility of sensor nodes into consideration,we provide a reliable data exchange strategy.Now,we have finished the prototype system on MicaZ nodes platform.