Research On Secure Transmission Technology Of H-Ybrid Multicast In Wireless Relay Network

The broadcast characteristics of the wireless relay network make the legitimate signal easy to eavesdrop,which poses a great challenge to the safe transmission of the signal.At present,the security communication based on physical layer has aroused wide concern of scholars,as a kind of security mechanism that take advantage of the randomness of channel,such as interference and fading,it occupies more and more important position in the field of information security.The purpose of exploring the secure transmission of the hybrid multicast technology is to ensure that the effective signal which is not acquired by the eavesdropping users in the broadcast process,but only transmit to the legitimate receiving users.This paper mainly studies the security problem of using hybrid multicast technology to transmit signal in massive multi-input and multi-output(massive MIMO)relay network,the detailed summary is as follows:Firstly,based on the existing antenna arrays,this paper presents a new type of array:cylindrical antenna array.Compared with the existing antenna arrays,the results show that the cylindrical array can achieve better safety rate.Secondly,this paper considers the security performance of the system on the physical layer,and assumes that all the channel state information(CSI)can be obtained.This paper presents a hybrid unicast/multicast transmission system in a massive MIMO channel,all the receiving end users are divided into multicast users,unicast users and eavesdropping users.After sending signals,multicast users and unicast users to receive legitimate signals,while suppressing the interception of eavesdropping users receive signals.And the goal is to achieve the maximum security rate for the system.The main anti-eavesdropping scheme is:using linear precoding and multicast beamforming to eliminate the signal interference in each group,and then using the null space method to eliminate the signal interference between each group of users,while making the wiretap channel orthogonal,to suppress the role of signal.At the same time,the proposed anti?eavesdropping scheme for this antenna array can also achieve a better security rate.Finally,the mutual coupling effect is considered in the simulation results,and the effectiveness of the anti-eavesdropping scheme can be verified in the real channel environment.The results show that,with the increase of signal-to-noise ratio,the number of transmitter antennas and the number of eavesdropping terminals,the system security rate can be significantly improved under the condition of massive MIMO wireless relay network,which is applied to different channel models.