Research On Secure Feedback Coding Scheme Of Millimeter Wave Communication System Assisted By Intelligent Reflecting Surface

With 5G wireless networks into the commercialization phase,the millimeter wave(mm Wave)communication technology which can greatly improve data transmission rate play an important rule in the 5G.However,it is still characterized by poor diffraction capability in the transmission process which brings high cost and interference problems to 5G base station deployment.And in the next generation wireless networks under research,intelligent reflecting surface that be used to control the wireless propagation environment is considered as a promising solution,attracting the attention of academia and industry.Security performance is an important indicator of wireless communication system,and the combination of mm Wave and IRS brings corresponding security problems.The thesis studies the Physical Layer Security of IRS assisted mm Wave communication system when the channel condition of eavesdropper is similar to that of legitimate receiver,and proposes a security coding scheme based on channel feedback.The scheme has some advantages: low coding and decoding complexity and extremely low decoding error probability.And the simulation result shows that the scheme has good performance.In the thesis,the mm Wave single-input single-output communication system assisted by IRS is modeled.And we propose the channel feedback coding scheme with endogenous security mechanism.The scheme extends the classical Schalkwijk-Kailath type feedback coding scheme based on Gaussian white noise channel to the system.Then,we deduce the channel capacity of the communication system with feedback,and prove that the scheme can achieve channel capacity and increase secrecy capacity to the capacity,which indicates that no transmission rate is needed to be sacrified for secrecy.Then,we extend the SK-type feedback coding scheme to the mm Wave multi-input single-output communication systems assisted by IRS,and analyze the decoding error probability and achievable rate of the scheme,and prove that the rate is close to channel capacity of the system when the length of codeword approaches infinity.It is proved that the scheme naturally satisfies security constraint,and the secrecy capacity of the scheme is equal to capacity of the same model without secrecy constraint.Aiming at the different mm Wave single-input communication systems assisted by IRS,we propose two kinds of security feedback coding scheme.The simulation results show that the scheme can achieve very low error rate under very short code length after afinite number of iterations,and the eavesdropper’s error rate is close to 1.That is,the scheme can implement wireless security transmission of the system.