Power Optimization And Antenna Selection Algorithm For Physical Layer Security In Full-duplex System

With the fast development of wireless communication system,the demand for communication rate and traffic,spectrum resources needed for the wireless communication system increase rapidly.However,the resources of the wireless communication system is limited,the expansion of wireless communication frequency is faced with great challenge.In recent years,the Co-time Co-frequency Full Duplex(CCFD)technology paid much attention by people.It can transmit and receive information at the same frequency by the same time,so it can solve the problem of wireless spectrum resources nervous.The self-interference is one of the most important factors in Full-duplex communication systems that.At present many researchers do some deep researches on self-interference elimination technology and good results have been achieved.The physical layer security in full duplex system is different from the physical layer security in traditional wireless communication system also because of the self-interference.It brings new interference environment and resource allocation requirements and it makes the full duplex physical layer security face more challenges and possibilities.First of all,this paper takes full advantage of the characteristics of Co-time Co-frequency Full Duplex system and proposed a method different from the traditional physical layer security.The model makes use of system self-interference to realize the secure transmission without any artificial noise and external interference nodes.This article also put forward the power optimization model,which minimizing the base station transmitted power or system transmission power while the system information transmission rate achieves the required secrecy rate.This article mainly use related theorem of convex optimization theory to solve the optimization model.In the case of the self-interference elimination incomplete,a two-stage solving method was put forward.In the case of power optimization of uplink and downlink,a method of using the cyclic coordinate descent was put forward.Simulation found that our proposed method can save more transmit power compared with traditional artificial noise method.This article also researches antenna selection algorithm for full-duplex system.In the case of The antenna matching number are fixed and known,we put forward random antenna selection method,the antenna selection method of legal channel capacity maximization and the antenna selection method of eavesdrop channel capacity minimization.The simulation found the antenna selection method of eavesdrop channel capacity minimize has a better performance when eavesdrop channel quality is better.In the case of antenna matching number unknown,we proposed a method based on antenna priority and the antenna priority depends on three principles:SINR of legal channel,SINR of eavesdrop channel and the safety coefficient criterion based on the antenna.Through the simulation we found the safety coefficient criterion method has better performance.The future work,the optimization model can be considered,such as the optimization model aimed to maximize security rate with the constraint conditions of transmission power as.We need to seek further new method to solve the new optimization model.At the same time,the future work can also be the different antenna power allocation problem,further optimize the power system and improve safety performance.In addition,the future work can also study the combination of antenna selection algorithm and the interference elimination,thus improve the overall performance of the system.