Secure Estimation Of Sensor Network Under Network Attack

Wireless sensor networks(WSN),which consist of numerous interconnected wireless sensor nodes,have been extensively applied in many fields,such as environmental monitoring,smart home and intelligent transportation.The optimal estimation algorithms based on minimum mean square error,such as Kalman filtering and information filtering,are often used in WSN state estimation to obtain accurate estimation.However,due to the wireless communication characteristics of wireless sensor networks,attackers can easily monitor the channels in the task domain of the network,inject bitstreams into the channels,and implement DoS attacks.It is of great significance to conduct in-depth research on attacks in sensor networkss.In this paper,the security of sensor network estimation and corresponding attack problem under centralized and distributed filtering are studied.The main works of this paper are as follows:1.A security mechanism of information filtering against eavesdropping and random packet loss in sensor networks is studied.When data is transmitted on the communication channel between sensors and a remote estimator,it can be overheard and discarded by the eavesdropper with a certain probability.The security mechanism enables each sensor node to transmit data with a certain probability.Through establishing the probability model of the mathematical expectation of the estimator's estimation error covariance,the optimization problem of transmission probability is transformed into a LMI problem.Besides,an algorithm for searching suboptimal probability is proposed to simplify the calculation and reduce the complexity.2.From the standing of attackers,an attack management for denial of service(DOS)to destroy the cooperative estimation in sensor networks with minimum energy consumption is studied.Among the communication channels between sensors and a remote estimator,the attacker chooses some channels and implements random DoS attacks,resulting randomly discard of the communication packets.In order to solve the complex optimization problem,a random power allocation method with threesteps is proposed.Firstly,the minimum channel number and node set are given.Secondly,for the general system and the special system,the sufficient and necessary conditions of packet loss probability are given,respectively.Finally,the optimal attack parameters are obtained according to a simple nonlinear programming problem derived by the first two steps.3.Furthermore,DoS attack scheme design is continued to apply to distributed network estimation environment.With distributed estimation,each node takes measurement and communication for accurate estimation.Aimed at the distributed Kalman consistency network estimation process with limited measurement ability,the attacker chooses part of the channels to launch an attack,which brings out the random lost of data.Meanwhile,the attacker has a certain energy limit.By relaxing the objective function to a lower bound maximization problem and the analysis of the local network estimation,and ultilizing Markov chain model to construct the explicit equation of the objective problem,simplify optimization solving process,and finally determine the time allocation of DoS attackers.