The Theory And Performance Analysis Of Physical Layer Secure Transmission With Perfect And Imperfrct CSI

The physical layer security technology abandons the traditional security methods based on the infeasible complex computation,and innovatively utilizes the inherently randomness,uniqueness and non-replicability of the wireless noise channel,and takes the noise of the channel as the “secret key” to realize the security of the wireless data transmission.However,most of the existing physical layer secure transmission related researches are based on the assumption of the ideal channel state information.Actually,channel estimation errors always exist,so we mostly only have the imperfect channel state information.The researches of the physical layer secure transmission based on ideal channel information deviate from the real systems and can't achieve the security goal because they lack of the adaptability of the non-ideal factors.Based on the above considerations,this paper aims at improving the security of the wireless communications,and studies the performance of physical layer secure transmission system under non-ideal channel estimation.The main research work is as follows:1.The “unconditional security” transmission system based on the MIMO wiretap channel is studied.Firstly,the “dominant channel” is established by using the beamforming technique based on SVD precoding.The simulation results show that the technique can be effective to be beneficial to legitimate recipients with either the perfect or imperfect channel state information.Secondly,this paper proposes a secure coding scheme based on BCH code.The result of MATLAB simulation shows that the scheme significantly increases the bit error rate of eavesdropper.2.The security performance of the multi-antenna beamforming model and the “unconditional security” transmission model under the condition of ideal and non-ideal channel,which proves the influence of channel estimation error on the security performance of the system and the realizability of the physical layer security transmission In actual communication system.The multi-antenna physical layer security transmission system is tested based on the USRP-LabVIEW platform.The result shows that the proposed system has the security and reliability of communication,which proves that the system can fulfill the unconditional security transmission.3.The MISOSE model based on the combination of the artificial noise and the collaboration interference is established.We take the system security rate as the measurement indicator of the system security performance and optimize the power allocation scheme with the maximum of the system security rate.4.Under the MISOSE collaboration model and the non-ideal scenario,system models under three different scenarios are established.System security rates under optimal power allocation scheme are calculated respectively by MATLAB.The max value of the system security rate under ideal conditions are compared.The influences of estimation errors on the system security performance are shown.The possibility of the realization of the physical layer security is verified under the real communication environment with channel estimation errors.In addition,when the power allocation rate at the transmitter varies from 0 to 1,the variation curves of the system security rate under the three models with the estimation errors and the mode which under ideal conditions are shown by MATLAB.And the optimal allocation schemes are fund.