Research On Secure Communication Algorithm Of Multiple Input Multiple Output Wireless Communication System

It is well known that the media of wireless transmission has the characteristics of openness.The information sent by the sender may be eavesdropped by the illegal recipient,resulting in information leakage and information security problems.In this paper,the security of MIMO channel is studied in the presence of eavesdroppers.Firstly,the multi-input and multi-output security problem with cooperative interference is studied.The cooperative interference is used to transmit artificial interference noise to the eavesdropper,which does not receive information.Assuming that all channel states are known,under the power constraints of transmitter and cooperative jammer,the security rate of the system is maximized by joint optimization of transmit covariance matrix and interference covariance matrix.The objective function is transformed by substitution function,and then the optimal solution is obtained by alternate iteration.At the same time,the feasibility of this method is proved by simulation.Then a multi-input and multi-output model of wireless information and energy co-transmission communication system is studied.The working mode of the receiver is full duplex.While receiving information,the receiver can send artificially interfering noise,which interferes with the eavesdropper,and also interferes with itself.The receiver is equipped with an energy collection device,and the signal flow at the receiver is divided into two parts.All channel states are known,and the security rate of the system is maximized by optimizing the transmission covariance matrix,interference covariance matrix and energy allocation factor.Since the objective function is non-convex,two methods are used to solve it.The first is to transform the objective function by using the substitution function,and then solve it by using alternating iteration to converge to the local optimal solution.The second is based on Taylor expansion,which is transformed,and then solved by alternating iteration to converge to the local optimal solution.After that,we use simulation to prove that these two methodscan solve the security problems of the system very well,and the method is feasible.