Data Fusion In Wireless Sensor Networks Based On D-S Theory

With the rapid development and extensive application of Wireless Sensor Networks(WSNs),the data generated in WSNs have increased greatly.How to implement data fusion to reduce the amount of communication,save the energy consumption of sensor nodes,prolong the lifetime of WSNs and improve data accuracy has become one of the most important research topics in WSNs.This paper first introduces the theoretical basis about the multi-source technology and the basic knowledge of Dempster-Shafer theory of evidence(D-S theory),and then focuses on some key issues applying D-S theory in the process of multi-source data fusion in Wireless Sensors Networks.The work of the dissertation is partly supported by the National Natural Science Foundation of China,Beijing Natural Science Foundation,and Research Fund for the Docoral Program of Higher Education of China.The main work of this thesis is stated as follows:(1)In order to solve the problem of faulty node detection in WSNs,the belief assignment strategy based on "measured distance" between sensor nodes is proposed.The traditional BBA construction methods are mostly based on "frequency" of communication and the sensor readings to establish BBA,they are insufficient use of unknown information shortcomings.The belief assignment strategy proposed in this paper uses the reading distance between the sensor and its neighbor nodes as the distance calculation method between the measured target and the sample date set,it makes good use of the advantage of the D-S theory can deal with the unknown information,and takes the surrounding environment of the sensor into account,which can effectively eliminate the fault type of sensor which caused by environmental impact and make the fusion result more accurate.The simulation results show that:when the network fault rate is less than 35%,the effect appears in the fault detection rate,the missed detection rate and the false detection rate of the proposed detection algorithm is better.(2)This paper proposes an algorithm to solve the problem of high conficting evidence in the process of the fusion of D-S theory.By adopting the idea of "single source of evidence having different credibility",the paper proposes a method of"conflict quantity" allocation of Conflict Information is reassigned,a portion of the conflict information is assigned to the focal element of the evidence,and the remainder is assigned to the recognition framework(?).In the wireless sensor networks environment,compared with the existing conflict processing algorithm,the proposed combination rule has the characteristics of fast convergence speed,low data transmission amount and low computational complexity.This paper uses formula derivation and example simulation method to validate the correctness and function of the new combination rule,the results show that it is in accordance with the definition and properties of D-S theory,and it has faster convergence speed,better fusion effect and lower computational complexity compared with the existing methods.At the end of the paper,the research results are summarized,and the future research directions are also discussed.