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Bessel–Gaussian beam-based orbital angular momentum holography

Chinese Physics B 2024年第1期33卷 407-413页

作者：季佳滢郑志刚朱家龙王乐王新光赵生妹 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 National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Orbital angular momentum(OAM), as a new degree of freedom, has recently been applied in holography *** to the infinite helical mode index of OAM mode, a large number of holographic images can be reconstructed from an OAM-multiplexing hologram. However, the traditional design of an OAM hologram is constrained by the helical mode index of the selected OAM mode, for a larger helical mode index OAM mode has a bigger sampling distance, and the crosstalk is produced for different sampling distances for different OAM modes. In this paper, we present the design of the OAM hologram based on a Bessel–Gaussian beam, which is non-diffractive and has a self-healing property during its propagation. The Fourier transform of the Bessel–Gaussian beam is the perfect vortex mode that has the fixed ring radius for different OAM modes. The results of simulation and experiment have demonstrated the feasibility of the generation of the OAM hologram with the Bessel–Gaussian beam. The quality of the reconstructed holographic image is increased, and the security is enhanced. Additionally, the anti-interference property is improved owing to its self-healing property of the Bessel-OAM holography.

关键词： orbital angular momentum holography Bessel–Gaussian beam OAM-multiplexing hologram

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Lasing mode manipulation in a Benz-shaped GaN cavity via the Joule effect of individual Ni wires

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NANOtechnology 2023年第28期34卷 285208-285208页

作者： Qin, Feifei Ji, Xin Yang, Ying Li, Meng Li, Xin Lin, Yi Lu, Kerui Wang, Ru Wang, Xiaoxuan Wang, Yongjin Zhu, Gangyi Nanjing Univ Posts & Telecommun GaN Optoelect Integrat Int Cooperat Joint Lab Jian Collegeof Telecommun & Informat Engn Nanjing 210003 Peoples R China Nanjing Univ Posts & Telecommun Key Lab Broadband Wireless Commun Sensor Network Technol Minist Educ Nanjing Peoples R China Huaiyin Inst Technol Fac Math & Phys Huaian 223003 Peoples R China Southeast Univ State Key Lab Bioelect Nanjing 210096 Peoples R China

Silicon-based gallium nitride lasers are considered potential laser sources for on-chip integration. However, the capability of on-demand lasing output with its reversible and wavelength tunability remains important. Herein, a Benz-shaped GaN cavity is designed and fabricated on a Si substrate and coupled to a Ni metal wire. Under optical pumping, excitation position-related lasing and exciton combination properties of pure GaN cavity are studied systematically. Under electrically driven, joule thermal of Ni metal wire makes it easy to change the temperature of the cavity. And then, we demonstrate a joule heat-induced contactless lasing mode manipulation in the coupled GaN cavity. The driven current, coupling distance, and excitation position influence the wavelength tunable effect. Compared with other positions, the outer ring position has the highest lasing properties and lasing mode tuning abilities. The optimized structures demonstrate clear wavelength tuning and an even mode switch. The thermal reduction of the band gap is identified to account for the modification of the lasing profile, but the thermo-optic effect is non-negligible under a high-driven current.

关键词： GaN microcavity optically pumped lasing mode tuning joule thermal effect

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Demonstration of Einstein–Podolsky–Rosen Steering with Multiple Observers via Sequential Measurements

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Chinese Physics Letters 2022年第11期39卷 1-5页

作者： Jian Li Yang Zhou Qin Wang Institute of Quantum Information and Technology 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 Engineering Research Center of Telecommunication and Networks Nanjing University of Posts and TelecommunicationsNanjing 210003China

Quantum correlation is a fundamental property that distinguishes quantum systems from classical ones,and is also a fragile resource under projective ***,it has been shown that a subsystem in entangled pairs can share nonlocalities with multiple observers in *** we present a new steering scenario where both subsystems are accessible by multiple *** results show that the two qubits in a singlet state can be simultaneously steered separately by two sequential observers.

关键词： Einstein projective subsystem

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Intelligent routing method based on Dueling DQN reinforcement learning and network traffic state prediction in SDN

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wireless networkS 2024年第5期30卷 4507-4525页

作者： Huang, Linqiang Ye, Miao Xue, Xingsi Wang, Yong Qiu, Hongbing Deng, Xiaofang Guilin Univ Elect Technol Sch Comp Sci & Informat Secur Guilin 541004 Peoples R China Guilin Univ Elect Technol Guangxi Key Lab Wireless Wideband Commun & Signal Guilin 541004 Peoples R China Fujian Univ Technol Fujian Prov Key Lab Big Data Min & Applicat Fuzhou 350118 Fujian Peoples R China

The traditional routing method makes use of limited information on the network links to make routing decisions, which makes it difficult to adapt to the dynamic and complex network and adjust the router's forward strategy. To address these issues, this paper proposes an intelligent routing method based on the Software Defined network (SDN), Dueling DQN (a Deep Reinforcement Learning algorithm) and network traffic state prediction. First, the global network awareness information is obtained with the SDN network measurement mechanism, which is converted into a traffic matrix consisting of multiple network link status information such as bandwidth and delay, etc. Then, the optimal forwarding route under the current network state is generated by predicting the network traffic matrix and the Dueling DQN. The experimental results show that: (1) compared with the traditional Dijkstra and OSPF routing methods, the proposed method significantly improves the network throughput and effectively reduces the network delay and packet loss rate;(2) comparing with the reinforcement learning algorithms DDPG and PPO, the proposed approach achieves a faster convergence state, which improves the efficiency of network routing.

关键词： Software defined network Intelligent routing method Deep reinforcement learning network traffic state prediction

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Analysis of Channel Uncertainty in Trusted wireless Services via Repeated Interactions

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IEEE Journal on Selected Areas in communications 2025年第6期43卷 2248-2265页

作者： Chen, Bingwen Ling, Xintong Cao, Weihang Wang, Jiaheng Ding, Zhi Southeast University National Mobile Communications Research Laboratory Nanjing211189 China Purple Mountain Laboratories Nanjing210023 China University of Maryland Department of Electrical and Computer Engineering College ParkMD20742 United States University of California at Davis Department of Electrical and Computer Engineering DavisCA95616 United States

The coexistence of heterogeneous sub-networks in 6G poses new security and trust concerns and thus calls for a perimeterless-security model. Blockchain radio access network (B-RAN) provides a trust-building approach via repeated interactions rather than relying on pre-established trust or central authentication. Such a trust-building process naturally supports dynamic trusted services across various service providers (SP) without the need for perimeter-based authentications;however, it remains vulnerable to environmental and system unreliability such as wireless channel uncertainty. In this study, we investigate channel unreliability in the trust-building framework based on repeated interactions for secure wireless services. We derive specific requirements for achieving cooperation between SPs and clients via a repeated game model and illustrate the implications of channel unreliability on sustaining trusted wireless services. We consider the framework design and optimization to guarantee SP-client cooperation, given the worst channel condition and/or the least cooperation willingness. Furthermore, we explore the maximum cooperation area to enhance service resilience and reveal the trade-off relationship between transmission efficiency, security integrity, and cooperative margin. Finally, we present simulations to demonstrate the system performance over fading channels and verify our results. © 1983-2012 IEEE.

关键词： Fading channels

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760 Mbps ultraviolet wireless communication based on a transmitter with AlGaN/InGaN MQWs

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APPLIED OPTICS 2022年第29期61卷 8600-8605页

作者： LI, Xin Chen, Meipeng Wang, Xu Hu, Fangchen Han, Mingyu LI, Yun Wang, Yongjin Nanjing Univ Posts & Telecommun GaN Optoelect Integrat Int Cooperat Joint Lab Jian Nanjing 210003 Peoples R China Nanjing Univ Posts & Telecommun Key Lab Broadband Wireless Commun & Sensor Network Minist Educ Nanjing 210003 Peoples R China Fudan Univ Key Lab Informat Sci Electromagnet Waves MoE Shanghai 200433 Peoples R China

III-nitride LEDs offer a solution for ultraviolet (UV) high-speed communication as a transmitter with high performance. This paper focuses on a transmitter with AlGaN/InGaN multi-quantum wells (MQWs) for UV com-munication. The transmitter is realized on a GaN-on-silicon platform by a double etching process. The emission region of the transmitter with a small area is beneficial for improving the data rate of UV communication. The emission peak keeps stable at 376.48 nm in the UVA band. The transmission with 300 Mbps is obtained in a UV communication system setup with on-off keying (OOK) modulation. We realize a digital signal transmission up to 760 Mbps by bit-loading discrete multi-audio (DMT) modulation. (c) 2022 Optica Publishing Group

关键词： Bit error rate Diode lasers Optical wireless communication Signal transmission Solar radiation Ultraviolet radiation

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An Innovative Linear wireless sensor network Reliability Evaluation Algorithm

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sensorS 2025年第1期25卷 285-285页

作者： Ma, Tao Guo, Huidong Li, Xin Shenyang Univ Technol Coll Informat Sci & Engn Shenyang 110167 Peoples R China Shenyang Key Lab Adv Comp & Applicat Innovat Shenyang 110167 Peoples R China

In recent years, wireless sensor networks (WSNs) have become a crucial technology for infrastructure monitoring. To ensure the reliability of monitoring services, evaluating the network's reliability is particularly important. sensor nodes are distributed linearly when monitoring linear structures, such as railway bridges, forming what is known as a Linear wireless sensor network (LWSN). Although existing evaluation methods, such as enumeration and Binary Decision Diagram (BDD)-based methods, can be used to assess the reliability of various types of networks, their efficiency is relatively low. Therefore, we classified network states based on the number of failed nodes located at the network's ends and analyzed the arrangement characteristics of nodes under different network states. This paper proposed a new reliability assessment method for LWSNs. This method is based on the combinatorial patterns of nodes and uses the concept of integer partitions to calculate the total number of states at different performance levels, applying probability formulas to assess network reliability. Compared to Multi-Valued Decision Diagram (MDD)-based evaluation algorithms, this method is suitable for large-scale LWSNs and offers lower time complexity.

关键词： LWSNs reliability evaluation performance level failure probability number splitting

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A survey of secure semantic communications

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JOURNAL OF network AND COMPUTER APPLICATIONS 2025年 239卷

作者： Meng, Rui Gao, Song Fan, Dayu Gao, Haixiao Wang, Yining Xu, Xiaodong Wang, Bizhu Lv, Suyu Zhang, Zhidi Sun, Mengying Han, Shujun Dong, Chen Tao, Xiaofeng Zhang, Ping Beijing Univ Posts & Telecommun State Key Lab Networking & Switching Technol Beijing 100876 Peoples R China Peng Cheng Lab Dept Broadband Commun Shenzhen 518066 Guangdong Peoples R China Beijing Univ Technol Sch Informat Sci & Technol Beijing 100124 Peoples R China Beijing Univ Posts & Telecommun Natl Engn Lab Mobile Network Technol Beijing 100876 Peoples R China

Semantic communication (SemCom) is regarded as a promising and revolutionary technology in 6G, aiming to transcend the constraints of "Shannon's trap" by filtering out redundant information and extracting the core of effective data. Compared to traditional communication paradigms, SemCom offers several notable advantages, such as reducing the burden on data transmission, enhancing network management efficiency, and optimizing resource allocation. Numerous researchers have extensively explored SemCom from various perspectives, including network architecture, theoretical analysis, potential technologies, and future applications. However, as SemCom continues to evolve, a multitude of security and privacy concerns have arisen, posing threats to the confidentiality, integrity, and availability of SemCom systems. This paper presents a comprehensive survey of the technologies that can be utilized to secure SemCom. Firstly, we elaborate on the entire life cycle of SemCom, which includes the model training, model transfer, and semantic information transmission phases. Then, we identify the security and privacy issues that emerge during these three stages. Furthermore, we summarize the techniques available to mitigate these security and privacy threats, including data cleaning, robust learning, defensive strategies against backdoor attacks, adversarial training, differential privacy, cryptography, blockchain technology, model compression, and physical-layer security. Lastly, this paper outlines future research directions to guide researchers in related fields.

关键词： Semantic communication wireless security Privacy 6G

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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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Game-Theoretic Deep Reinforcement Learning for Task Offloading in Heterogeneous MEC Systems 16

Game-Theoretic Deep Reinforcement Learning for Task Offloadi...

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16th International Conference on wireless communications and Signal Processing, WCSP 2024

作者： Yu, Han Dou, Haie Xu, Xinmian Cui, Jingwu Wang, Lei Liu, Chen Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing210003 China

ISBN: (纸本)9798350390643

The emergence of new applications has increased the demand of mobile users for edge computing. Therefore, the optimization of base station load balancing and task offloading is particularly important. In this paper, a two-tier heterogeneous mobile edge computing (MEC) system based on Stackelberg Game (SG) is studied. The introduction of SG can improve user association flexibility while reducing base station load. The introduction of network slicing can classify users according to different types, which increases the universality of the proposed framework. To solve the above problem, we map an optimization problem of efficiency, computation delay and computation energy consumption. Due to the non-convexity of the optimization problem, the Multi-agent Deep Deterministic Policy Gradient (MADDPG) algorithm based on SG is proposed in this paper. The gradient descent strategy can converge faster and obtain the optimal solution of user association policy and unload policy. Through simulation, it is verified that the proposed scheme can obtain lower computation delay and computation energy consumption on the basis of solving the problem of base station overload. © 2024 IEEE.

关键词： Deep reinforcement learning

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