Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of t...Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink channels.We exploit the benefits of satellite-terrestrial integrated network(STIN)and a novel absorptive reconfigurable intelligent surface(RIS)for improving the security of satellite downlink communications(SDC)in the presence of eavesdroppers(Eves).This paper aims to maximize the achievable secrecy rate of the earth station(ES)while satisfying the signal reception constraints,harvested power threshold at the RIS,and total transmit power budget.To solve this nonconvex problem,we propose a penalty-function based dual decomposition scheme,which firstly transforms the original problem into a two-layer optimization problem.Then,the outer layer and inner problems are solved by utilizing the successive convex approximation,Lagrange-dual and Rayleigh quotient methods to obtain the beamforming weight vectors and the reflective coefficient matrix.Finally,simulation results verify the effectiveness of the proposed scheme for enhancing the SDC security.展开更多
现代战术网中的业务越来越复杂,现有的网络控制方案难以有效支持。软件定义网络(Software Defined Network,SDN)架构可以提高战术网灵活性,但由于战术网脆弱的无线环境特征及SDN的集中式控制特点,该架构存在很高的单点故障风险,控制信...现代战术网中的业务越来越复杂,现有的网络控制方案难以有效支持。软件定义网络(Software Defined Network,SDN)架构可以提高战术网灵活性,但由于战术网脆弱的无线环境特征及SDN的集中式控制特点,该架构存在很高的单点故障风险,控制信道的失效会导致整个网络崩溃。针对这一问题,提出了一种基于协议无感知转发(Protocol Oblivious Forwarding,POF)的动态可伸缩控制方案。采用带内带外混合控制的方法,可以在环境高度动态的战术网中实现韧性控制。当带外控制信道失效后,网络可以基于带内控制与数据平面自定义协议相结合的方式,继续维持一定的网络功能。实验结果表明,本方案对于不稳定的战术网有较强的适应能力,在带外控制失效信道时仍能保障网络可用并使时延保持在0.1 s左右的范围。展开更多
基金supported by the National Natural Science Foundation of China(No.62201592)the Research Plan Project of NUDT(ZK21-33)the Young Elite Scientist Sponsorship Program of CAST,China(2021-JCJQ-QT-048)。
文摘Satellite communications have attracted significant interests due to its advantages of large footprint and massive access.However,the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink channels.We exploit the benefits of satellite-terrestrial integrated network(STIN)and a novel absorptive reconfigurable intelligent surface(RIS)for improving the security of satellite downlink communications(SDC)in the presence of eavesdroppers(Eves).This paper aims to maximize the achievable secrecy rate of the earth station(ES)while satisfying the signal reception constraints,harvested power threshold at the RIS,and total transmit power budget.To solve this nonconvex problem,we propose a penalty-function based dual decomposition scheme,which firstly transforms the original problem into a two-layer optimization problem.Then,the outer layer and inner problems are solved by utilizing the successive convex approximation,Lagrange-dual and Rayleigh quotient methods to obtain the beamforming weight vectors and the reflective coefficient matrix.Finally,simulation results verify the effectiveness of the proposed scheme for enhancing the SDC security.
