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Sum-Rate Maximization in Active RIS-Assisted Multi-Antenna WPCN

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china communications 2024年第6期21卷 23-39页

作者： Jiang Jie Lyu Bin Chen Pengcheng Yang Zhen School of communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials Sciences and Technology Nanjing UniversityNanjing 210003China

In this paper,we propose an active reconfigurable intelligent surface(RIS)enabled hybrid relaying scheme for a multi-antenna wireless powered communication network(WPCN),where the active RIS is employed to assist both wireless energy transfer(WET)from the power station(PS)to energyconstrained users and wireless information transmission(WIT)from users to the receiving station(RS).For further performance enhancement,we propose to employ both transmit beamforming at the PS and receive beamforming at the *** formulate a sumrate maximization problem by jointly optimizing the RIS phase shifts and amplitude reflection coefficients for both the WET and the WIT,transmit and receive beamforming vectors,and network resource *** solve this non-convex problem,we propose an efficient alternating optimization algorithm with the linear minimum mean squared error criterion,semidefinite relaxation(SDR)and successive convex approximation ***,the tightness of applying the SDR is *** results demonstrate that our proposed scheme with 10 reflecting elements(REs)and 4 antennas can achieve 17.78%and 415.48%performance gains compared to the single-antenna scheme with 10 REs and passive RIS scheme with 100 REs,respectively.

关键词： active reconfigurable intelligent surface beamforming sum-rate maximization wireless powered communication network

A survey on blockchain-enabled federated learning and its prospects with digital twin

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Digital communications and Networks 2024年第2期10卷 248-264页

作者： Kangde Liu Zheng Yan Xueqin Liang Raimo Kantola Chuangyue Hu State Key Lab on Integrated Services Network School of Cyber EngineeringXidian UniversityXi'anChina Department of communications and Networking Aalto UniversityEspooFinland Yangtze Delta Region Blockchain Technology Research Institute JiaxingChina

Digital Twin(DT)supports real time analysis and provides a reliable simulation platform in the Internet of Things(IoT).The creation and application of DT hinges on amounts of data,which poses pressure on the application of Artificial Intelligence(AI)for DT descriptions and intelligent *** Learning(FL)is a cutting-edge technology that enables geographically dispersed devices to collaboratively train a shared global model locally rather than relying on a data center to perform model ***,DT can benefit by combining with FL,successfully solving the"data island"problem in traditional ***,FL still faces serious challenges,such as enduring single-point failures,suffering from poison attacks,lacking effective incentive *** the successful deployment of DT,we should tackle the issues caused by *** from industry and academia have recognized the potential of introducing Blockchain Technology(BT)into FL to overcome the challenges faced by FL,where BT acting as a distributed and immutable ledger,can store data in a secure,traceable,and trusted ***,to the best of our knowledge,a comprehensive literature review on this topic is still *** this paper,we review existing works about blockchain-enabled FL and visualize their prospects with *** this end,we first propose evaluation requirements with respect to security,faulttolerance,fairness,efficiency,cost-saving,profitability,and support for ***,we classify existing literature according to the functionalities of BT in FL and analyze their advantages and disadvantages based on the proposed evaluation ***,we discuss open problems in the existing literature and the future of DT supported by blockchain-enabled FL,based on which we further propose some directions for future research.

关键词： Digital twin Artificial intelligence Federated learning Blockchain

Persymmetric adaptive polarimetric detection of subspace range-spread targets in compound Gaussian sea clutter

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Journal of Systems Engineering and Electronics 2024年第1期35卷 31-42页

作者： XU Shuwen HAO Yifan WANG Zhuo XUE Jian National Key Laboratory of Radar Signal Processing Xidian UniversityXi’an 710071China Xi’an Electronic Engineering Research Institute Xi’an 710100China Beijing Institute of Radio Measurement Beijing 100039China School of communications and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

This paper focuses on the adaptive detection of range and Doppler dual-spread targets in non-homogeneous and nonGaussian sea *** sea clutter from two polarimetric channels is modeled as a compound-Gaussian model with different parameters,and the target is modeled as a subspace rangespread target *** persymmetric structure is used to model the clutter covariance matrix,in order to reduce the reliance on secondary data of the designed *** adaptive polarimetric persymmetric detectors are designed based on the generalized likelihood ratio test(GLRT),Rao test,and Wald *** the proposed detectors have constant falsealarm rate property with respect to the clutter texture,the speckle covariance *** results on simulated and measured data show that three adaptive detectors outperform the competitors in different clutter environments,and the proposed GLRT detector has the best detection performance under different parameters.

关键词： sea clutter adaptive polarimetric detection compound Gaussian model subspace range-spread target persymmetric structure

Demonstration of controlled high-dimensional quantum teleportation

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Science china(Physics,Mechanics & Astronomy) 2024年第3期67卷 1-6页

作者： Min-Yu Lv Xiao-Min Hu Neng-Fei Gong Tie-Jun Wang Yu Guo Bi-Heng Liu Yun-Feng Huang Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Centerfor Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China State Key Laboratory of Information Photonics and Optical communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China

Controlled quantum teleportation(CQT), which is regarded as the prelude and backbone for a genuine quantum internet, reveals the cooperation, supervision, and control relationship among the sender, receiver, and controller in the quantum network within the simplest unit. Compared with low-dimensional counterparts, high-dimensional CQT can exhibit larger information transmission capacity and higher superiority of the controller's authority. In this article, we report a proof-of-principle experimental realization of three-dimensional(3D) CQT with a fidelity of 97.4% ± 0.2%. To reduce the complexity of the circuit, we simulate a standard 4-qutrit CQT protocol in a 9×9-dimensional two-photon system with high-quality operations. The corresponding control powers are 48.1% ± 0.2% for teleporting a qutrit and 52.8% ± 0.3% for teleporting a qubit in the experiment, which are both higher than the theoretical value of control power in 2-dimensional CQT protocol(33%). The results fully demonstrate the advantages of high-dimensional multi-partite entangled networks and provide new avenues for constructing complex quantum networks.

关键词： high dimension quantum information quantum teleportation quantum nonlocality

Topological phases and edge modes of an uneven ladder

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Chinese Physics B 2024年第8期33卷 154-168页

作者：商文创韩熠宁 Shimpei Endo 高超 Department of Physics Zhejiang Normal UniversityJinhua 321004China Key Laboratory of Optical Information Detection and Display Technology of Zhejiang Zhejiang Normal UniversityJinhua 321004China Department of Engineering Science The University of Electro-CommunicationsTokyo 182-8585Japan

We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of *** an uneven ladder presents rich band structures classified by the closure of either direct or indirect *** also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge *** also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band ***,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the *** this way,the topological phases can be efficiently extracted through winding *** propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.

关键词： ladder model symmetry-protected topological phase topological invariant bulk-boundary correspondence

Optical edge-to-screw singularity state conversions

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Photonics Research 2024年第8期12卷 1689-1695页

作者： HAOLIN LIN JUNHUI JIA GUOHUA LIU YANWEN HU ZHEN LI ZHENQIANG CHEN SHENHE FU Department of Optoelectronic Engineering Jinan UniversityGuangzhou 510632China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and communications Guangzhou 510632China Guangdong Provincial Engineering Research Center of Crystal and Laser Technology Guangzhou 510632China

Optical singularity states,which significantly affect propagation properties of light in free space or optical medium,can be geometrically classified into screw and edge *** different types of singularity states do not exhibit direct connection,being decoupled from each other in the absence of external *** we demonstrate a novel optical process in which a higher-order edge singularity state initially nested in the propagating Gaussian light field gradually involves into a screw singularity with a new-born topological charge determined by order of the edge *** considered edge state comprises an equal superposition of oppositely charged vortex and antivortex *** theoretically and experimentally realize this edge-to-screw conversion process by introducing intrinsic vortex–antivortex *** also present a geometrical representation for mapping this dynamical process,based on the higher-order orbital Poincaré*** this framework,the edge-to-screw conversion is explained by a mapping of state evolution from the equator to the north or south pole of the Poincaré*** demonstration provides a novel approach for manipulating singularity state by the intrinsic vortex–antivortex *** presented phenomenon can be also generalized to other wave systems such as matter wave,water wave,and acoustic wave.

关键词： interaction Poincaré wave

A Novel Multi-Stream Fusion Network for Underwater Image Enhancement

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china communications 2024年第2期21卷 166-182页

作者： Guijin Tang Lian Duan Haitao Zhao Feng Liu Jiangsu Key Laboratory of Image Processing and Image Communication Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Key Laboratory of Wireless communications Nanjing University of Posts and TelecommunicationsNanjing 210003China

Due to the selective absorption of light and the existence of a large number of floating media in sea water, underwater images often suffer from color casts and detail blurs. It is therefore necessary to perform color correction and detail restoration. However,the existing enhancement algorithms cannot achieve the desired results. In order to solve the above problems, this paper proposes a multi-stream feature fusion network. First, an underwater image is preprocessed to obtain potential information from the illumination stream, color stream and structure stream by histogram equalization with contrast limitation, gamma correction and white balance, respectively. Next, these three streams and the original raw stream are sent to the residual blocks to extract the features. The features will be subsequently fused. It can enhance feature representation in underwater images. In the meantime, a composite loss function including three terms is used to ensure the quality of the enhanced image from the three aspects of color balance, structure preservation and image smoothness. Therefore, the enhanced image is more in line with human visual ***, the effectiveness of the proposed method is verified by comparison experiments with many stateof-the-art underwater image enhancement algorithms. Experimental results show that the proposed method provides superior results over them in terms of MSE,PSNR, SSIM, UIQM and UCIQE, and the enhanced images are more similar to their ground truth images.

关键词： image enhancement multi-stream fusion underwater image

A Dual-Cluster-Head Based Medium Access Control for Large-Scale UAV Ad-Hoc Networks

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china communications 2024年第5期21卷 123-136页

作者： Zhao Xinru Wei Zhiqing Zou Yingying Ma Hao Cui Yanpeng Feng Zhiyong Key Laboratory of Universal Wireless communications Ministry of EducationSchool of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing100876China

Unmanned Aerial Vehicle(UAV)ad hoc network has achieved significant growth for its flexibility,extensibility,and high deployability in recent *** application of clustering scheme for UAV ad hoc network is imperative to enhance the performance of throughput and energy *** conventional clustering scheme,a single cluster head(CH)is always assigned in each ***,this method has some weaknesses such as overload and premature death of CH when the number of UAVs *** order to solve this problem,we propose a dual-cluster-head based medium access control(DCHMAC)scheme for large-scale UAV *** DCHMAC,two CHs are elected to manage resource allocation and data forwarding ***,two CHs work on different *** of CH is used for intra-cluster communication and the other one is for inter-cluster communication.A Markov chain model is developed to analyse the throughput of the *** result shows that compared with FM-MAC(flying ad hoc networks multi-channel MAC,FM-MAC),DCHMAC improves the throughput by approximately 20%~50%and prolongs the network lifetime by approximately 40%.

关键词： dual cluster head medium access control UAV swarm

Early warning of core network capacity in space-terrestrial integrated networks

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Journal of Systems Engineering and Electronics 2024年第4期35卷 855-864页

作者： HAN Sai LI Ao ZHANG Dongyue ZHU Bin WANG Zelin WANG Guangquan MIAO Jie MA Hongbing china Unicom Research Institute Beijing 100044China china United Network communications Group Company Limited Beijing 100033China

With the rapid development of low-orbit satellite com-munication networks both domestically and internationally,space-terrestrial integrated networks will become the future development *** space and terrestrial networks with limi-ted resources,the utilization efficiency of the entire space-terres-trial integrated networks resources can be affected by the core network *** order to improve the response efficiency of core networks expansion construction,early warning of the core network elements capacity is *** on the inte-grated architecture of space and terrestrial network,multidimen-sional factors are considered in this paper,including the number of terminals,login users,and the rules of users’migration during *** artifical intelligence(AI)technologies,the regis-tered users of the access and mobility management function(AMF),authorization users of the unified data management(UDM),protocol data unit(PDU)sessions of session manage-ment function(SMF)are predicted in combination with the num-ber of login users,the number of ***,the core network elements capacity can be predicted in *** proposed method is proven to be effective based on the data from real network.

关键词： space-terrestrial integrated networks core network element capacity artificial intelligent(AI)