This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable int...This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable intelligent surfaces(DARISs)as-sisted physical layer security(PLS)scheme denoted by DARISs-PLS to protect the secrecy message trans-mission.We formulate a secrecy rate maximization problem for the proposed DARISs-PLS scheme by considering a power budget constraint for the two ac-tive reconfigurable intelligent surfaces(ARISs)and AP.To address the formulated optimization problem,we jointly optimize the reflecting coefficients for the two ARISs and the beamforming at the AP in an it-erative manner by applying Dinkelbach based alter-nating optimization(AO)algorithm and a customized iterative algorithm together with the semidefinite re-laxation(SDR).Numerical results reveal that the pro-posed DARISs-PLS scheme outperforms the dou-ble passive reconfigurable intelligent surfaces-assisted PLS method(DPRISs-PLS)and single ARIS-assisted PLS method(SARIS-PLS)in terms of the secrecy rate.展开更多
Reconfigurable intelligent surface(RIS)is a novel meta-material which can form a smart radio environment by dynamically altering reflection directions of the impinging electromagnetic waves.In the prior literature,the...Reconfigurable intelligent surface(RIS)is a novel meta-material which can form a smart radio environment by dynamically altering reflection directions of the impinging electromagnetic waves.In the prior literature,the inter-RIS links which also contribute to the performance of the whole system are usually neglected when multiple RISs are deployed.In this paper we investigate a general double-RIS assisted multiple-input multiple-output(MIMO)wireless communication system under spatially correlated non line-of-sight propagation channels,where the cooperation of the double RISs is also considered.The design objective is to maximize the achievable ergodic rate based on full statistical channel state information(CSI).Specifically,we firstly present a closedform asymptotic expression for the achievable ergodic rate by utilizing replica method from statistical physics.Then a full statistical CSI-enabled optimal design is proposed which avoids high pilot training overhead compared to instantaneous CSI-enabled design.To further reduce the signal processing overhead and lower the complexity for practical realization,a common-phase scheme is proposed to design the double RISs.Simulation results show that the derived asymptotic ergodic rate is quite accurate even for small-sized antenna arrays.And the proposed optimization algorithm can achieve substantial gain at the expense of a low overhead and complexity.Furthermore,the cooperative double-RIS assisted MIMO framework is proven to achieve superior ergodic rate performance and high communication reliability under harsh propagation environment.展开更多
设计：该研究是一在牙科学校进行的RCT。干预措施：共224例患者随机进入2个治疗组．123例患者进行计算机辅助制作的KaVo Everest HPC冠（KaVo Dental GmbH，Biberach an der Riss，德国）修复，101例患者进行金冠修复。所有冠均用传统...设计：该研究是一在牙科学校进行的RCT。干预措施：共224例患者随机进入2个治疗组．123例患者进行计算机辅助制作的KaVo Everest HPC冠（KaVo Dental GmbH，Biberach an der Riss，德国）修复，101例患者进行金冠修复。所有冠均用传统的玻璃一离子黏结剂黏结。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62071253,Grant 62371252 and Grant 62271268in part by the Jiangsu Provincial Key Research and Development Program under Grant BE2022800in part by the Jiangsu Provincial 333 Talent Project.
文摘This paper considers a multi-antenna ac-cess point(AP)transmitting secrecy message to a single-antenna user in the presence of a single-antenna illegal eavesdropper(Eve)and proposes a double ac-tive reconfigurable intelligent surfaces(DARISs)as-sisted physical layer security(PLS)scheme denoted by DARISs-PLS to protect the secrecy message trans-mission.We formulate a secrecy rate maximization problem for the proposed DARISs-PLS scheme by considering a power budget constraint for the two ac-tive reconfigurable intelligent surfaces(ARISs)and AP.To address the formulated optimization problem,we jointly optimize the reflecting coefficients for the two ARISs and the beamforming at the AP in an it-erative manner by applying Dinkelbach based alter-nating optimization(AO)algorithm and a customized iterative algorithm together with the semidefinite re-laxation(SDR).Numerical results reveal that the pro-posed DARISs-PLS scheme outperforms the dou-ble passive reconfigurable intelligent surfaces-assisted PLS method(DPRISs-PLS)and single ARIS-assisted PLS method(SARIS-PLS)in terms of the secrecy rate.
基金supported in part by the Xi’an Jiaotong-Liverpool University(XJTLU)Research Development Fund(2024–2027)under Grant RDF-23-02-010supported in part by the Guangdong Basic and Applied Basic Research Foundation under Grant 2023A1515110732+5 种基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant 62071247supported in part by the Science and Technology Development Fund,Macao,China SAR under Grants 0087/2022/AFJ and 001/2024/SKLin part by the National Natural Science Foundation of China under Grant 62261160650in part by the Research Committee of University of Macao,Macao SAR,China under Grants MYRG-GRG2023-00116-FST-UMDF and MYRG2020-00095-FSTsupported in part by the NSFC under Grant 62261160576 and 62301148in part by the Fundamental Research Funds for the Central Universities under Grant 2242023K5003.
文摘Reconfigurable intelligent surface(RIS)is a novel meta-material which can form a smart radio environment by dynamically altering reflection directions of the impinging electromagnetic waves.In the prior literature,the inter-RIS links which also contribute to the performance of the whole system are usually neglected when multiple RISs are deployed.In this paper we investigate a general double-RIS assisted multiple-input multiple-output(MIMO)wireless communication system under spatially correlated non line-of-sight propagation channels,where the cooperation of the double RISs is also considered.The design objective is to maximize the achievable ergodic rate based on full statistical channel state information(CSI).Specifically,we firstly present a closedform asymptotic expression for the achievable ergodic rate by utilizing replica method from statistical physics.Then a full statistical CSI-enabled optimal design is proposed which avoids high pilot training overhead compared to instantaneous CSI-enabled design.To further reduce the signal processing overhead and lower the complexity for practical realization,a common-phase scheme is proposed to design the double RISs.Simulation results show that the derived asymptotic ergodic rate is quite accurate even for small-sized antenna arrays.And the proposed optimization algorithm can achieve substantial gain at the expense of a low overhead and complexity.Furthermore,the cooperative double-RIS assisted MIMO framework is proven to achieve superior ergodic rate performance and high communication reliability under harsh propagation environment.
文摘设计：该研究是一在牙科学校进行的RCT。干预措施：共224例患者随机进入2个治疗组．123例患者进行计算机辅助制作的KaVo Everest HPC冠（KaVo Dental GmbH，Biberach an der Riss，德国）修复，101例患者进行金冠修复。所有冠均用传统的玻璃一离子黏结剂黏结。
