The Research On Localization Algorithm And The Security Of Localization In Wireless Sensor Network

Wireless sensor networks (WSNs) are constructed by minute self-organizing nodes which make up of randomly distributed sensors, data processing units and communication modules. WSNs recurs to all kinds of sensors embedd in the nodes to monitor cooperately, sense and gather the information of various circumstance and monitored object, then, processes the information and transmits it to the terminal user by wireless and self-organizing methods. Finally, it can validly connect the physical world, the computer world and the human society. In the process of collecting and processing information in WSNs, the information must bind with the node's position so that it is meaningful. Therefor, the technique of locating is one support technique of wireless sensor networks. New application circumstance gives the technique of locating in WSNs some new challenges. And security becomes a key factor to the technique of locating due to the open wirless environment and lacking of physical protection in WSNs.The special environment of Underwater Sensor Network gives the localization great challenges. In this page, the depth information is used for localization. Considering the difficulty of time synchronization under water, a distance measurement approach of TDoA (time difference of arrival) named TBLT is proposed, which do not rely on time synchronization. According TBLT, a new localization scheme named NLSBT is designed. To combine the depth information with projection technique and use two buoys with mobility simultaneously, NLSBT transforms 3D positioning problem to positioning in a plane, and get the node's position by the relationship of two circles in the same plane. NLSBT is energy conservation because it does not rely on the degree of nodes and the number of beacons, in which the node does not need communicate each other and only listen the beacon packets. After intensive experiment and theoretical analysis, NLSBT show better performance with other schemes, such as low storage, computation and communication, and also show good robustness in the environment of underwater.As the same with other support techniques in WSNs, locating also exists of security problem, also faces the inner and outside attack, and more seriously exists of the attack to hardware. In this paper, the attacks in techniques of locating is analysed, and the existing secure techniques of locating is surveyed. Based on these work, the part security problem of DV-Hop algorithm in APS (AD Hoc Position System) is studied. The algorithmn of DV-Hop depend on the exchange of data packets to estimate the distance to the node that has a known position, which is very cheap and convenience to the network with limited resource. But its security is not taken into account in the original design. Wormhole attack is simple and easy to implement in known types of attacks, which makes two far nodes directly communicate and in which the attacker does not need modify the packets. Lunching wormhole attack in DV-hop can cause the algorithm invalid. In this paper, wormhole attack in DV-hop is discussed, and a new scheme, which is named DWDV, that is proposed to defend wormhole attack. DWDV is simulated on positif2.0 based on OMNET++ and the experimental results show that DWDV can effectively defend wormhole attack and make more nodes get a valid position.