Research On Physical Layer Security Performance Of D2D Communication Systems In Cellular Networks

With the rapid development of social science and technology,people's requirements for communication efficiency and communication quality are getting higher and higher.Scarce spectrum resources become an important factor restricting the development of mobile communications.In order to provide higher transport rates,system capacity,and improve spectrum utilization,D2 D communication technology has produced.The introduction of D2 D technology in cellular networks can also reduce the burden and delays,improve fairness,and meet the needs of green communications.However,D2 D communication is a type of wireless communication.The open communication environment makes wireless signal transmission very easy to be monitored by illegal users.The traditional security mechanism guarantees the effectiveness of the algorithm through the extremely high computational complexity,with the advent of quantum computers,it has shown many limitations,and it is particularly important to explore the physical layer security issues in wireless mobile signal transmission.This paper combines D2 D communication with physical layer security to study the physical layer security performance of D2 D communication systems in cellular networks.First,under the cellular network,this paper regards D2 D interference as friendly interference,and studies the physical layer security performance of the relay D2 D communication system when D2 D users reuse cellular user spectrum resources.A reasonable mathematical model is used to describe the relay D2 D system in a cellular network.The relay is selected from idle cellular users and used as amplifying and forwarding to solve the problem of limited distance.With the goal of maximizing the maximum achievable security rate of cellular users,the mathematical expressions of the optimal base station transmit power,optimal D2 D power,and optimal channel allocation scheme are derived under the requirements of transmission rate for D2 D users.The problem is solved by constructing a mixed integer optimization model,which is multi-constraint and non-convex.We propose a power control algorithm in a single-user scenario and a channel allocation algorithm in a multi-user scenario.The numerical results show the algorithm of jointing the power and channel optimization can increase the security rate and improve physical layer security performance of cellular users,compared with the traditional random access algorithms.Main tasks are as follows:Secondly,the physical layer secure communication algorithm of D2 D systembased on artificial noise is discussed.This paper combines the multi-antenna technology,cooperative relay technology,and artificial interference technology to study the physical layer security performance of the system.We take the maximum achievable security rate as a measure and design artificial noise to achieve a situation that does not affect the normal communication of legitimate users.According to different target needs,three design schemes of precoding vectors for desired signals are discussed,and the distribution coefficients of artificial noise and useful signal power are optimized.Based on the above three steps,a physical layer secure communication algorithm for a D2 D system based on artificial noise is proposed.Simulation results show that through reasonable design and power allocation,adding artificial noise at the base station can effectively reduce the eavesdropping rate of eavesdroppers and the physical layer security performance of the system is greatly improved.