Research On Physical Layer Security For The Future Wireless Communications

The future wireless networks(5G)will support massive users and terminal nodes access,various types of services,and provide ultra-high bandwidth,ultra-dense sites,ultra-high capacity.Security has become a key issue for the future wireless networks and it is the prior condition for various applications.However,compared with traditional wired networks with relatively stable transmission media,the radio characteristics of wireless channels and the mobile characteristics make the wireless communicated in the network are easily eavesdropped and injected by illegal users.In traditional wireless communication networks,cryptography is usually adopted at the network layer and upper layer to ensure system security.Classical cryptography technology is based on computation complexity,that is,assuming the attacker does not know the secret key so that he can not decrypt.However,with the development of computer technology,especially quantum computing,it will pose a huge challenge to the classic computing-based cryptography security scheme.At the same time,the cryptography-based security technologies can not meet the diverse security needs of the future wireless mobile networks.Compared with the traditional upper-layer security technology,the basic principle of the physical layer security is to utilize the physical randomness and uniqueness of wireless communications(eg,wireless fading channel,received signal strength,hardware fingerprinting,etc.)to provide users with light weight,high flexibility and high security communication.In the future wireless communication,combined the features of wireless channel with the physical layer signal design,modulation and coding together with the classical security encryption technology of the upper layer,provide a multilayer and intelligent security system.The physical layer security has been recognized as one of the key technologies of the future wireless network security and has a very broad prospect.Based on the background above,the main contrributions and innovations of this article are summarized as follows:1.Investigated the impact of random mobility on the wireless communication physical layer security,and proposed a random mobile physical layer security modelMost of the existing works only consider static scenarios and the impact of mobility on wireless physical layer security is not well understood.To fill this gap,we investigate physical layer security in the scenario with a random mobile receiver under Rayleigh fading channel and proposed a physical layer security model for mobile user physical layer in wireless networks.The secrecy performance under three typical random mobility model are invrestigated.We investigate the mobility secrecy characteristics under steady state running and provide a general analytical framework for computing the ergodic secrecy capacity(ESC).We derive tractable closed-form expressions of positive secrecy capacity probability(PSCP)and secrecy outage probability(SOP)for RWP and RD mobility users,respectively.By comparing secrecy performance of mobility with static case,we find that RWP mobile user can achieve much better secrecy performance than the others about 10%-20%.We then investigate the secrecy performance of RWP mobile user with pause time.Furthermore,two types of secrecy improvement strategies for random mobile users are proposed.Extensive simulation results validate our theoretical analysis.Finally,we extend our framework to other realistic scenarios.2.Proposed an MIMO beamforming combined with secure code unconditional secure communication modelAn unconditional secure communication model of MIMO beamforming combined with secure code is proposed for the high security demanded of the future wireless networks.Under this model,the legitimate communication parties can realizes almost zero information obtained by the eavesdroppers while still keeping rather lower error transmissions for the main channel,only by using the characteristics of the physical channel and do not need to share any secret key.A profound theoretical analysis for the MIMO advantage channel and the exact closed-form expressions of secrecy outage probability SOP for MIMO beamforming at the target security rate is given.We launch extensive experiments to verify the proposed security systems and demonstrate its feasibility and implement ability.Then the model is extended to MIMO beamforming and artificial noise AN combined with secure coding(MIMO-BAN).A lightweight artificial noise power allocation combined with security code strategy is proposed.The simulation results show that the proposed model can achieve better security and reliable communication performance with a shorter security code(code length is less than 100).3.Proposed a cross-layer secure transmission scheme of MIMO systemConsider the limitation of physical layer security completely depends on the randomness of physical channel,a MIMO cross-layer secure transmission scheme is proposed.By using an upper layer sequence control physics layer beamforming weight factor of the signal,the proposed schemes has realized the enhanced security transmission with smaller extra expenses and complexity.Compared with the MIMO physical layer security methods,the scheme enhanced security under two typical security disadvantages situation,one is that the eavesdropper can obtain accurate CSI information,The other is that the eavesdropper can acquire the control sequence.We perform a deal of theoretical analysis and simulation experiments,and a test in the real environment are also conducted to demonstrate its feasibility and implement ability.The proposed model can be employed in the applications with high security demanded.4.Proposed a mobile network identity-based attack detection schemeIBA(Identity-based attacks)are one of the most serious threats to wireless communication networks.Based on the mobility characteristics of wireless network,we proposed a Reciprocal Channel Variation-based Identification(RCVI)scheme to detect IBA attacks in wireless mobile networks.RCVI comprehensively utilize the decorrelation,randomness and reciprocity property of wireless channel to detect IBA well under various types of attack frames injection.The proposed scheme is theoretically analyzed and verified by numerical simulation.An advantage of RCVI is that it can be implemented with less overhead on 802.11 wireless network devices.Finally,experiments with real-world indoor and outdoor mobile environments by using off-the-shelf 802.11 devices are conducted,which demonstrate its feasibility and implement ability.