Research On Secure Transmission Technology Of D2D Communication Based On The Theory Of Physical Layer Secrecy Communication

Device-to-Device(D2D)communication technology has been introduced into cellular networks as a terminal direct communication technology.With its advantages of high speed,low latency and low consumption,D2D communication technology has a broad application prospect in wireless communication networks.Because of the openness of the wireless channel,D2D communication based on the terminal direct communication mechanism,is easier to be wiretapped by other cellular users of the same networks.It is of great significance to study the D2D security transmission problem of cellular networks.The main contents of this paper are as follows.A beamforming strategy of D2D security transmission for basic cellular network based on convex optimization technology is proposed.In the case of perfect CSI,this paper establishes an optimization model in single cell cellular networks aimed at minimizing the power of system by taking the information rate of the legal users and the secure transmission rate of system as constraints.By utilizing convex optimization technology,the optimal transmission scheme of the base station is given.Furthermore,an optimization model on premise of knowing uncertainties of CSI is established.Combined with Charnes-Cooper transform and S-Procedure theorem,a robust beamforming strategy of D2D secure transmission for single cell cellular networks under finite feedback information is proposed.D2D communication security issues occur mostly in the edge region of multiple adjacent cellular cells,which is covered by all base station transmission ranges.In view of the above complicated model,a joint beamforming strategy based on multi-cell cooperation of D2D security transmission is proposed.Considering the case of perfect CSI,combined with multi-cell cooperation and beamforming precoding techniques,an optimization model aimed at minimizing the total system power is established by taking the information rate of the legal receiving terminals of each cell in the system and the secure transmission rate of the local cell as constraints.Utilizing semi-definite relaxation algorithm and Gaussian randomization method,the optimal transmit power and transmission scheme of each base station are obtained.Aiming at the D2D security transmission problem of single cell scenarios with limited information feedback,the proposed D2D security transmission beamforming strategy in this paper,which aims at minimizing the total system power,can guarantee the secure transmission of the system.Aiming at the D2D security transmission problem in the edge area of multiple adjacent cellular cells,the proposed joint multi-cell beamforming safe transmission strategy based on multi-cell cooperation can effectively reduce the total power of the system.Simulation results verify the feasibility and effectiveness of the above strategies.