Research On Secure Communication And Power Optimization Method Based On Non-orthogonal Artificial Noise

With the development of wireless communication security technology,especially the emergence of multi antenna technology,physical layer security technology has been widely used in wireless communication,such as artificial noise,beamforming,cooperative interference and so on.Artificial noise,as a physical layer security technology that can significantly increase the security of wireless communication system,has become a research hotspot in recent years.However,artificial noise is easily affected by communication channel freedom,transmission power and other conditions.The number of design schemes is small,and even can not be designed under some channel conditions.To solve the above problems,a non orthogonal artificial noise is proposed in this paper.The design of non orthogonal artificial noise is not limited by the degree of freedom of communication channel,and can be applied under the condition of any degree of freedom of communication channel.In order to realize the effective application of non orthogonal artificial noise,this paper studies the design scheme and power allocation of non orthogonal artificial noise,so as to improve the resource utilization efficiency of wireless communication system and the security performance of wireless communication.Firstly,this paper analyzes the application characteristics of artificial noise in low channel DOF communication,and expounds the design mechanism of artificial noise and the relationship between the number of design schemes and the channel DOF.On this basis,a non-orthogonal artificial noise design method is proposed for low-DOF channels.The product of non-zero artificial noise and channel matrix is constructed to obtain more artificial noise design schemes,which solves the problem that traditional artificial noise cannot be designed when channel null space does not exist.At the same time,according to the characteristics of non-orthogonal artificial noise,this paper proposes a GLQ-Learning optimization method which is suitable for non-orthogonal artificial noise,and uses this method to find the sub-optimal design scheme of non-orthogonal artificial noise.Secondly,the power distribution method of SISO and MIMO communication based on non-orthogonal artificial noise is studied in this paper.In order to improve the security capacity of wireless communication system,a power distribution model of wireless communication system with ideal channel state information,non-ideal channel state information,unknown listening channel state information and multi-user communication interference is constructed.The power expression of the channel estimation error is derived for the communication system with non-ideal channel state information.For the communication system whose eavesdropping channel state information is unknown,a method of security capacity representation of wireless communication system based on the probability statistical distribution of the number of eavesdropping antennas is studied.On this basis,the continuous convex approximation algorithm is used to optimize the above model.Finally,a power allocation method for large-scale MIMO secure communication based on non-orthogonal artificial noise is proposed.A new power distribution model based on statistical characteristics of the channel is constructed under the conditions of ideal channel,non-ideal channel and multi-user interference.For an ideal large-scale MIMO channel,a safe capacity expression based on diagamma function is derived for the first time.The derivative function of diagamma function is easy to solve and reduces the computational complexity.For non-ideal large-scale MIMO channel,we derive the expression of safe capacity based on gamma function for the first time.For large-scale MIMO channel with multi-user interference,we derive the expression of safe capacity of wireless communication system with multi-user interference and its ideal power distribution coefficient.