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Optimization-based mode selection scheme for OAM millimeter wave system in the off-axis misalignment case

Digital communications and networks 2024年第1期10卷 101-108页

作者： Haie Dou Lei Wang Bin Kang Baoyu Zheng Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing210003China School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China

Millimeter-wave transmission combined with Orbital Angular Momentum(OAM)has the advantage of reducing the loss of beam power and increasing the system ***,to fulfill this advantage,the antennas at the transmitter and receiver must be parallel and coaxial;otherwise,the accuracy of mode detection at the receiver can be seriously *** this paper,we design an OAM millimeter-wave communication system for overcoming the above ***,the first contribution is that the power distribution between different OAM modes and the capacity of the system with different mode sets are analytically derived for performance *** second contribution lies in that a novel mode selection scheme is proposed to reduce the total interference between different *** results show that system performance is less affected by the offset when the mode set with smaller modes or larger intervals is selected.

关键词： Orbital angular momentum Millimeter wave Off-axis misalignment Mode selection Capacity

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QoE oriented intelligent online learning evaluation technology in B5G scenario

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Digital communications and networks 2024年第1期10卷 7-15页

作者： Mingzi Chen Xin Wei Peizhong Xie Zhe Zhang School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing210003China Institute of Higher Education Nanjing University of Posts and TelecommunicationsNanjing210003China

Students'demand for online learning has exploded during the post-COvID-19 pandemic ***,due to their poor learning experience,students'dropout rate and learning performance of online learning are not always *** technical advantages of Beyond Fifth Generation(B5G)can guarantee a good multimedia Quality of Experience(QoE).As a special case of multimedia services,online learning takes into account both the usability of the service and the cognitive development of the *** that affect the Quality of Online Learning Experience(OL-QoE)become more *** get over this dilemma,we propose a systematic scheme by integrating big data,Machine Learning(ML)technologies,and educational psychology ***,we first formulate a general definition of OL-QoE by data analysis and experimental *** formula considers both the subjective and objective factors(i.e.,video watching ratio and test scores)that most affect ***,we induce an extended layer to the classic Broad Learning System(BLS)to construct an Extended Broad Learning System(EBLS)for the students'OL-QoE *** the extended layer can increase the width of the BLS model and reduce the redundant nodes of BLS,the proposed EBLS can achieve a trade-off between the prediction accuracy and computation ***,we provide a series of early intervention suggestions for different types of students according to their predicted OL-QoE *** timely interventions,their OL-QoE and learning performance can be *** results verify the effectiveness oftheproposed scheme.

关键词： B5G Online learning Quality of experience

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Equivalent Bandwidth Concept and Its Usage in the network Selection

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China communications 2025年第2期22卷 213-225页

作者： Ma Anhua Pan Su Zhou Weiwei Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education Nanjing University of Posts and TelecommunicationsNanjing 210003China

Maximize the resource utilization efficiency and guarantee the quality of service(QoS)of users by selecting the network are the key issues for heterogeneous network operators,but the resources occupied by users in different networks cannot be compared *** paper proposes a network selection algorithm for heterogeneous ***,the concept of equivalent bandwidth is proposed,through which the actual resources occupied by users with certain QoS requirements in different networks can be compared *** the concept of network applicability is defined to express the abilities of networks to support different *** proposed network selection algorithm first evaluates whether the network has enough equivalent bandwidth required by the user and then prioritizes network with poor applicability to avoid the situation that there are still residual resources in entire network,but advanced services can not be *** simulation results show that the proposed algorithm obtained better performance than the baselines in terms of reducing call blocking probability and improving network resource utilization efficiency.

关键词： call blocking probability equivalent bandwidth heterogeneous network network applicability

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Joint Optimization of Resource Allocation and Trajectory Based on User Trajectory for UAV-Assisted Backscatter Communication System

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China communications 2024年第2期21卷 197-209页

作者： Peizhong Xie Junjie Jiang Ting Li Yin Lu School of Communication and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications) Ministry of EducationNanjing 210003China

The Backscatter communication has gained widespread attention from academia and industry in recent years. In this paper, A method of resource allocation and trajectory optimization is proposed for UAV-assisted backscatter communication based on user trajectory. This paper will establish an optimization problem of jointly optimizing the UAV trajectories, UAV transmission power and BD scheduling based on the large-scale channel state signals estimated in advance of the known user trajectories, taking into account the constraints of BD data and working energy consumption, to maximize the energy efficiency of the system. The problem is a non-convex optimization problem in fractional form, and there is nonlinear coupling between optimization *** iterative algorithm is proposed based on Dinkelbach algorithm, block coordinate descent method and continuous convex optimization technology. First, the objective function is converted into a non-fractional programming problem based on Dinkelbach method,and then the block coordinate descent method is used to decompose the original complex problem into three independent sub-problems. Finally, the successive convex approximation method is used to solve the trajectory optimization sub-problem. The simulation results show that the proposed scheme and algorithm have obvious energy efficiency gains compared with the comparison scheme.

关键词： energy efficiency joint optimization UAV-assisted backscatter communication user trajectory

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A teacher-student based attention network for fine-grainedimage recognition

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Digital communications and networks 2025年第1期11卷 52-59页

作者： Ang Li Xueyi Zhang Peilin Li Bin Kang Key Laboratory of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing210003China School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing210003China School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing210003China

Fine-grained Image Recognition(FGIR)task is dedicated to distinguishing similar sub-categories that belong to the same super-category,such as bird species and car *** order to highlight visual differences,existing FGIR works often follow two steps:discriminative sub-region localization and local feature ***,these works pay less attention on global context *** neglect a fact that the subtle visual difference in challenging scenarios can be highlighted through exploiting the spatial relationship among different subregions from a global view ***,in this paper,we consider both global and local information for FGIR,and propose a collab.rative teacher-student strategy to reinforce and unity the two types of *** framework is implemented mainly by convolutional neural network,referred to Teacher-Student Based Attention Convolutional Neural network(T-S-ACNN).For fine-grained local information,we choose the classic Multi-Attention network(MA-Net)as our baseline,and propose a type of boundary constraint to further reduce background noises in the local attention *** this way,the discriminative sub-regions tend to appear in the area occupied by fine-grained objects,leading to more accurate sub-region *** fine-grained global information,we design a graph convolution based Global Attention network(GA-Net),which can combine extracted local attention maps from MA-Net with non-local techniques to explore spatial relationship among *** last,we develop a collab.rative teacher-student strategy to adaptively determine the attended roles and optimization modes,so as to enhance the cooperative reinforcement of MA-Net and *** experiments on CUB-200-2011,Stanford Cars and FGVC Aircraft datasets illustrate the promising performance of our framework.

关键词： Fine-grained image recognition Collab.rative teacher-student strategy Multi-attention Global attention

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Quality-Aware Massive Content Delivery in Digital Twin-Enabled Edge networks

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China communications 2023年第2期20卷 1-13页

作者： Yun Gao Junqi Liao Xin Wei Liang Zhou School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

Massive content delivery will become one of the most prominent tasks of future B5G/6G ***,various multimedia applications possess huge differences in terms of object oriented(i.e.,machine or user)and corresponding quality evaluation metric,which will significantly impact the design of encoding or decoding within content delivery *** get over this dilemma,we firstly integrate the digital twin into the edge networks to accurately and timely capture Quality-of-Decision(QoD)or Quality-of-Experience(QoE)for the guidance of content ***,in terms of machinecentric communication,a QoD-driven compression mechanism is designed for video analytics via temporally lightweight frame classification and spatially uneven quality assignment,which can achieve a balance among decision-making,delivered content,and encoding ***,in terms of user-centric communication,by fully leveraging haptic physical properties and semantic correlations of heterogeneous streams,we develop a QoE-driven video enhancement scheme to supply high data *** results demonstrate the remarkable performance improvement of massive content delivery.

关键词： content delivery digital twin edge networks QoD QoE

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Efficient security analysis for quantum key distribution against side-channel leakage

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Optics Express 2025年第10期33卷 20588-20597页

作者： Ma, Luo-Jia Wang, Yue-Ying Sun, Ming-Shuo Zhang, Chun-Hui Ding, Hua-Jian Zhou, Xing-Yu Wang, Qin Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 China Broadband Wireless Communication and Sensor Network Technology Key Lab of Ministry of Education NUPT Nanjing210003 China

Quantum key distribution (QKD) allows the transmission of keys with unconditional security. Nevertheless, a discrepancy remains between the theoretical framework and the practical implementation, as device imperfections are frequently neglected in most QKD protocols. Some previous works proposed to use Hong-Ou-Mandel interference to quantify information leakage from side-channels. However, the security bound was relatively loose, resulting in poor performance. In this paper, we present an improved method for the security analysis of practical QKD protocols and provide a more precise parameter estimation. Furthermore, we apply it to several important QKD protocols, including BB84, measurement-device-independent, and twin-field, and carry out corresponding numerical simulations. Our work demonstrates significant improvements in both the key rate and the transmission distance compared to previous methods, representing a crucial step towards the practical implementation of QKD. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Quantum cryptography

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Highly efficient twin-field quantum key distribution with neural networks

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Science China(Information Sciences) 2023年第8期66卷 281-282页

作者： Jingyang LIU Qingqing JIANG Huajian DING Xiao MA Mingshuo SUN Jiaxin XU Chun-Hui ZHANG Shipeng XIE Jian LI Guigen ZENG Xingyu ZHOU Qin WANG Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Telecommunication and Networks National Engineering Research Center Nanjing University of Posts and Telecommunications

Quantum key distribution(QKD) allows two legitimate parties, Alice and Bob, to share a series of random bits that are secured by the laws of quantum mechanics. As a remarkable theoretical progress towards longer distances, the proposal of twin-field QKD(TF-QKD) [1] shows the capability to break a repeaterless bound and provides a key rate in the square-root scale of channel transmittance(i.e.,

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Offloading Model of 5G Intelligent Terminal Based on UC-MEC and Node Consensus Mechanism 15

Offloading Model of 5G Intelligent Terminal Based on UC-MEC ...

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15th IEEE International Conference on wireless communications and Signal Processing, WCSP 2023

作者： Wang, Lei Su, Yufei Dou, Haie Cui, Jingwu Zheng, Baoyu Nanjing University of Posts and Telecommunications School of Communications and Information Engineering Nanjing China Nanjing University of Posts and Telecommunications Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing China

ISBN: (纸本)9798350324662

Offloading for 5G intelligent terminals is an important requirement of mobile edge computing (MEC), which can reduce the load of terminal devices and provide more powerful computing power and services. However, due to the interference between different users and the waste of a lot of resources, the role of MEC is greatly limited. In the article, energy-saving blockchain technology is introduced into the user-centric MEC (UC-MEC) system. However, in UC-MEC, it is necessary to comprehensively consider task offloading and energy consumption optimization in the consensus process to improve overall energy efficiency. To solve these problems, a new offloading model of 5G intelligent terminal is proposed, which realizes safe and efficient resource utilization by jointly optimizing the bandwidth and computing resource allocation of access point (AP). The research also proposed a resource consensus mechanism based on Zookeeper atomic broadcast (RC-ZAB), and the parallel optimization framework of relaxed hybrid alternative direction method of multipliers (RH-ADMM) to solve the problems of resource transaction and energy consumption optimization. The experimental results show that compared with the comparison method, the total energy consumption of the proposed method is reduced by 41.39% at most, and the total delay is reduced by 29.80% at most. © 2023 IEEE.

关键词： blockchain Mobile edge computing resource consensus task offloading user-centric

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Properties of focused Laguerre–Gaussian beam propagating in anisotropic ocean turbulence

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Chinese Physics B 2024年第2期33卷 386-393页

作者：王新光马洋斌袁邱杰陈伟王乐赵生妹 College of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel *** the Rytov approximation theory,we derive the analytical formula of the channel capacity of the focused LG beam in the anisotropic ocean turbulence,and analyze the relationship between the capacity and the light source parameters as well as the turbulent ocean *** is found that the focusing mirror can greatly enhance the channel capacity of the system at the geometric focal plane in oceanic *** results also demonstrate that the communication link can obtain high channel capacity by adopting longer beam wavelength,greater initial beam waist radius,and larger number of transmission ***,the capacity of the system increases with the decrease of the mean squared temperature dissipation rate,temperature-salinity contribution ratio and turbulence outer scale factor,and with the increase of the kinetic energy dissipation rate per unit mass of fluid,turbulence inner scale factor and anisotropy *** to a Hankel–Bessel beam with diffraction-free characteristics and unfocused LG beam,the focused LG beam shows superior anti-turbulence interference properties,which provide a theoretical reference for research and development of underwater optical communication links using focused LG beams.

关键词： vortex beam orbital angular momentum focusing mirror anisotropic turbulence

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