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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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Side-channel free quantum digital signature with source monitoring

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Chinese Physics B 2025年第1期34卷 53-58页

作者： Luo-Jia Ma Ming-Shuo Sun Chun-Hui Zhang Hua-Jian Ding Xing-Yu Zhou Jian Li Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Broadband Wireless Communication and Sensor Network Technology Key Laboratory of Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

Quantum digital signature(QDS)can guarantee the information-theoretical security of a signature with the fundamental laws of quantum ***,most current QDS protocols do not take source security into account,leading to an overestimation of the signature *** this paper,we propose to utilize Hong–Ou–Mandel interference to characterize the upper bound of the source imperfections,and further to quantify information leakage from potential ***,we combine decoy-state methods and finite-size analysis in analyzing the signature *** results demonstrate the performance and feasibility of our *** current work can improve the practical security of QDS systems,thereby promoting their further networked applications.

关键词： Hong-Ou-Mandel interference side-channel free quantum digital signature

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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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Improved reference-frame-independent quantum key distribution with intensity fluctuations

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Chinese Physics B 2025年第2期34卷 48-52页

作者： Zi-Qi Chen Hao-Bing Sun Ming-Shuo Sun Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Broadband Wireless Communication and Sensor Network Technology Key Laboratory of Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

Reference-frame-independent quantum key distribution(RFI-QKD) can avoid real-time calibration operation of reference frames and improve the efficiency of the communication process. However, due to imperfections of optical devices,there will inevitably exist intensity fluctuations in the source side of the QKD system, which will affect the final secure key rate. To reduce the influence of intensity fluctuations, an improved 3-intensity RFI-QKD scheme is proposed in this *** considering statistical fluctuations and implementing global parameter optimization, we conduct corresponding simulation analysis. The results show that our present work can present both higher key rate and a farther transmission distance than the standard method.

关键词： quantum key distribution intensity fluctuations decoy-state method

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Securing STAR-FC-RIS empowered integrated sensing and multiuser communications against target eavesdropping

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Science China(Information Sciences) 2024年第11期67卷 335-346页

作者： Shuying LIN Yulong ZOU Fu XIAO Bin LI School of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications School of Computer Science Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications

This paper investigates a simultaneous-transmitting-and-reflecting fully-connected reconfigurable intelligent surface(STAR-FC-RIS) empowered integrated sensing and multiuser communications(ISAMC) network, where a dual-functional radar-communication base station detects a malicious radar target nearby and communicates with multiple legitimate users on the other side of the STAR-RIS. We utilize an integrated architecture that combines the fully-connected(FC)-RIS, an emerging type of beyond-diagonal(BD)-RIS, with the time-switching(TS)-STAR-RIS to enhance both the sensing and communications at the cost of possible target intercepting and propose the simultaneous-transmitting-and-reflecting fully-connected RIS(STAR-FCR) schemes to strike a balance between sensing and communications performance. Thereafter, observing the security-reliability performance tradeoff of the downlink ISAMC, we conduct closed-form analyses to compare COPs of round-robin scheduling(RS) and multiuser scheduling(MS) with the aid of a TS-based STAR-FC-RIS. Furthermore, we derive closed-form expressions of the sensing outage probability, communications outage probability(COP), and communications intercept probability, where an average of the three probabilities is exploited to obtain an optimized time allocation(OTA) of the *** results verify that the STAR-FCR-MS scheme outperforms the STAR-FCR-RS scheme in terms of sensing reliability and communications security. Moreover, an OTA remarkably enhances the overall performance of the STAR-FCR schemes of ISAMC systems.

关键词： simultaneous-transmitting-and-reflecting reconfigurable intelligent surface (RIS) fully-connected beyond-diagonal RIS integrated sensing and communications multiuser scheduling security

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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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Gray code based gradient-free optimization algorithm for parameterized quantum circuit

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Chinese Physics B 2024年第2期33卷 189-194页

作者：张安琪武春辉赵生妹 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China

A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this *** parameter of PQCs is encoded as a binary string,named as a gene,and a genetic-based method is adopted to select the *** individuals in the offspring are decoded in Gray code way to keep Hamming distance,and then are evaluated to obtain the best one with the lowest cost value in each *** algorithm is performed iteratively for all parameters one by one until the cost value satisfies the stop condition or the number of iterations is *** GCO algorithm is demonstrated for classification tasks in Iris and MNIST datasets,and their performance are compared by those with the Bayesian optimization algorithm and binary code based optimization *** simulation results show that the GCO algorithm can reach high accuracies steadily for quantum classification ***,the GCO algorithm has a robust performance in the noise environment.

关键词： gradient-free optimization Gray code genetic-based method

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Single-qubit quantum classifier based on gradient-free optimization algorithm

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Chinese Physics B 2023年第10期32卷 241-247页

作者：张安琪王可伦吴逸华赵生妹 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing 210003China

A single-qubit quantum classifier(SQC)based on a gradient-free optimization(GFO)algorithm,named the GFO-based SQC,is proposed to overcome the effects of barren plateaus caused by quantum ***,a rotation gate R_(X)(φ)is applied on the single-qubit binary quantum classifier,and the training data and parameters are loaded intoφin the form of vector *** cost function is decreased by finding the value of each parameter that yields the minimum expectation value of measuring the quantum *** algorithm is performed iteratively for all parameters one by one until the cost function satisfies the stop *** proposed GFO-based SQC is demonstrated for classification tasks in Iris and MNIST datasets and compared with the Adam-based SQC and the quantum support vector machine(QSVM).Furthermore,the performance of the GFO-based SQC is discussed when the rotation gate in the quantum device is under different types of *** simulation results show that the GFO-based SQC can reach a high accuracy in reduced ***,the proposed GFO algorithm can quickly complete the training process of the ***,the GFO-based SQC has a good performance in noisy environments.

关键词： single-qubit quantum classifier gradient-free parameters optimizing barren plateau quantum noise

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Cross-Modal Graph Semantic communication Assisted by Generative AI in the Metaverse for 6G

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Research 2024年第2期2024卷 19-27页

作者： Mingkai Chen Minghao Liu Congyan Wang Xingnuo Song Zhe Zhang Yannan Xie Lei Wang Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsNanjng 210003China State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced Materials(IAM) Nanjing University of Posts and TelecommunicationsNanjing 210023China

Recently, the development of the Metaverse has become a frontier spotlight, which is an important demonstration of the integration innovation of advanced technologies in the Internet. Moreover, artificial intelligence (AI) and 6G communications will be widely used in our daily lives. However, the effective interactions with the representations of multimodal data among users via 6G communications is the main challenge in the Metaverse. In this work, we introduce an intelligent cross-modal graph semantic communication approach based on generative AI and 3-dimensional (3D) point clouds to improve the diversity of multimodal representations in the Metaverse. Using a graph neural network, multimodal data can be recorded by key semantic features related to the real scenarios. Then, we compress the semantic features using a graph transformer encoder at the transmitter, which can extract the semantic representations through the cross-modal attention mechanisms. Next, we leverage a graph semantic validation mechanism to guarantee the exactness of the overall data at the receiver. Furthermore, we adopt generative AI to regenerate multimodal data in virtual scenarios. Simultaneously, a novel 3D generative reconstruction network is constructed from the 3D point clouds, which can transfer the data from images to 3D models, and we infer the multimodal data into the 3D models to increase realism in virtual scenarios. Finally, the experiment results demonstrate that cross-modal graph semantic communication, assisted by generative AI, has substantial potential for enhancing user interactions in the 6G communications and Metaverse.

关键词： modal frontier guarantee

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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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