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A Recursive DRL-Based Resource Allocation Method for Multibeam Satellite Communication Systems

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Chinese Journal of Electronics 2024年第5期33卷 1286-1295页

作者： Haowei MENG Ning XIN Hao QIN Di ZHAO State key laboratory of Integrated Services Networks Xidian University China Academy of Space Technology Institute of Telecommunication Satellite

Optimization-based radio resource management(RRM) has shown significant performance gains on high-throughput satellites(HTSs). However, as the number of allocable on-board resources increases, traditional RRM is difficult to apply in real satellite systems due to its intense computational complexity. Deep reinforcement learning(DRL) is a promising solution for the resource allocation problem due to its model-free advantages. Nevertheless, the action space faced by DRL increases exponentially with the increase of communication scale, which leads to an excessive exploration cost of the algorithm. In this paper, we propose a recursive frequency resource allocation algorithm based on long-short term memory(LSTM) and proximal policy optimization(PPO), called PPO-RA-LOOP,where RA means resource allocation and LOOP means the algorithm outputs actions in a recursive manner. Specifically, the PPO algorithm uses LSTM network to recursively generate sub-actions about frequency resource allocation for each beam, which significantly cuts down the action space. In addition, the LSTM-based recursive architecture allows PPO to better allocate the next frequency resource by using the generated sub-actions information as a prior knowledge, which reduces the complexity of the neural network. The simulation results show that PPO-RA-LOOP achieved higher spectral efficiency and system satisfaction compared with other frequency allocation algorithms.

关键词： High-throughput satellites Proximal policy optimization Deep reinforcement learning Long-short term memory High-throughput satellites Proximal policy optimization Deep reinforcement learning Long-short term memory OPTIMIZATION POWER

Layer-by-layer epitaxy growth of thickness-controllable two-dimensional tungsten disulfide

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Science China(Information Sciences) 2024年第5期67卷 302-310页

作者： Jieyuan LIANG Zixing ZOU Junwu LIANG Di WANG Biao WANG Anshi CHU Jiali YI Cheng ZHANG Lizhen FANG Tian ZHANG Huawei LIU Xiaoli ZHU Dong LI Anlian PAN key laboratory for Micro-Nano Physics and Technology of Hunan Province State Key Laboratory of Chemo/Biosensing and Chemometrics Hunan Institute of Optoelectronic IntegrationCollege of Materials Science and Engineering School of Physics and ElectronicsHunan University School of Electronic Information and Electrical Engineering Changsha University School of Physics and telecommunication Engineering Yulin Normal University Units Semiconductor Technology Co. Ltd. School of Physics and Electronics Hunan Normal University

Bilayer transition metal dichalcogenides（TMDs） balance the high mobility of single layers with the high state density of multilayers and therefore have promising application prospects in high-performance electronics. However, the layer-controlled growth of 2D materials is still confronted with challenges such as poor repeatability between different labs and a limited understanding of the growth mechanism at the atomic scale. Herein, we report a new carbon-assisted chemical vapor deposition process that can realize the growth of WS2sheets with high yield, precise thickness controllability, and repeatability. We show that carbon can act as a reducing agent and catalyst that preferentially reacts with the WO3precursor to form intermediate WO3-xproducts with low-valence state W. The resulting oxycarbide gas has a low surface adsorption energy when deposited on the surface of as-grown WS2, which provides nucleation sites for the subsequent layer of WS2growth and leads to the vertical growth of WS2sheets. The growth mechanism is thoroughly investigated. Electrical transport measurements show that the produced bilayer WS2possesses a high carrier mobility(up to 58 cm2·V-1·s-1) and small subthreshold swing（estimated to be 148 mV/decade）,which are among the best reported results for TMDs produced using CVD.

关键词： WS2 thickness-controlled growth chemical vapor deposition additive carbon

Coherence analysis of noise-like pulses generated by an erbium-doped fiber mode-locked laser

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optoelectronics Letters 2024年第4期20卷 205-210页

作者： ZHANG Ziyi WANG Chuncan LI Jing WANG Peng key laboratory of All Optical Network and Advanced telecommunication Network Ministry of EducationInstitute of Lightwave TechnologyBeijing Jiaotong University Beijing 100044China

The noise-like pulses(NLPs)with tunable fraction of the pedestal height in the whole intensity autocorrelation(AC)trace are numerically demonstrated in the designed erbium-doped fiber(EDF)mode-locked laser,which contains the saturable absorber(SA)with nonlinear polarization rotation(NPR),sinusoidal-shaped or Gaussian-shaped filter,two segments of EDFs,and two pieces of single-mode fibers(SMFs)with normal dispersion and anomalous dispersion,*** pedestal ratio of the intensity AC trace can be tuned by changing the gain saturation energies of *** results show that when the net cavity dispersion is 1.06 ps^(2),the tuning range of the pedestal ratio for the NLPs can reach its maximum values,which are 0.51—0.89 and 0.58—0.88 for the sinusoidal-shaped and Gaussian-shaped filters,*** addition,an appropriate choice of filter bandwidth is also conducive to obtain a wide range of the tuning pedestal ratio for the intensity AC trace.

关键词： fiber tuning polarization

High-efficiency Brillouin lasing in a planar GeSbS spiral-ring resonator

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Chinese Optics Letters 2024年第7期22卷 71-76页

作者： Jingcui Song Yuhang Wei Chunxu Wang Shuixian Yang Yan Li Tianhua Feng Xiaojie Guo Zhaohui Li Guangdong Provincial key laboratory of optoelectronic Information Processing Chips and Systems and School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 510006China Peng Cheng laboratory Shenzhen 518000China Department of Electronic Engineering College of Information Science and TechnologyJinan UniversityGuangzhou 510632China Guangdong Provincial key laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China College of Physics and optoelectronic Engineering Jinan UniversityGuangzhou 510632China Southern Marine Science and Engineering Guangdong laboratory(Zhuhai) Zhuhai 519000China

Stimulated Brillouin scattering in planar integrated circuits promises to realize compact and highly coherent *** we report efficient Brillouin lasing at telecommunication wavelength from a planar Ge_(25)Sb_(10)S_(65) chalcogenide(ChG)resonator with a high quality factor above 106.A low lasing threshold of 24.8 mW is achieved with a slope efficiency of 8.3%.An 8-kHz linewidth is measured for 1.56-mW on-chip output *** work offers a good opportunity to enrich the versatility and functionality of the ChG photonics on account of their intrinsic advantages of low loss,high third-order nonlinearity,and potential capacity for wafer-scale fabrication.

关键词： Brillouin lasing chalcogenide photonics planar integrated circuit high-Q resonator

Automatically identifying imperfections and attacks in practical quantum key distribution systems via machine learning

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Science China(Information Sciences) 2024年第10期67卷 359-372页

作者： Jiaxin XU Xiao MA Jingyang LIU Chunhui ZHANG Hongwei LI Xingyu ZHOU Qin WANG Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications telecommunication and Networks National Engineering Research CenterNanjing University of Posts and Telecommunications Henan key laboratory of Quantum Information and Cryptography Strategic Support Force Information Engineering University

The realistic security of quantum key distribution(QKD) systems is currently a hot research topic in the field of quantum communications. There are always defects in practical devices, and eavesdroppers can make use of the security risk points of various devices to obtain key information. To date, current types of security analysis tend to analyze each security risk point individually, thereby posing great challenges for the overall security evaluation of QKD systems. In this paper, for the first time, we employ machine learning algorithms to identify the defects of different devices and certain attacks in real time, with an accuracy of 98%. It provides a novel solution for the practical security evaluation of QKD systems, thereby addressing the bottleneck problem of multiple risk points being difficult to address simultaneously in QKD systems,thus paving the way for the future large-scale application of quantum communication networks.

关键词： quantum key distribution device imperfections eavasdropping attacks real-time detection machine learning algorithms

IP-Pealing: A Robust Network Flow Watermarking Method Based on IP Packet Sequence

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Chinese Journal of Electronics 2024年第3期33卷 694-707页

作者： Wangxin FENG Xiangyang LUO Tengyao LI Chunfang YANG State key laboratory of Mathematical Engineering and Advanced Computing key laboratory of Cyberspace Situation Awareness of Henan Province

Network flow watermarking(NFW) is usually used for flow *** actively modulating some features of the carrier traffic,NFW can establish the correspondence between different network *** the face of strict demands of network traffic tracing,current watermarking methods cannot work efficiently due to the dependence on specific protocols,demand for large quantities of packets,weakness on resisting network channel interferences and so *** this end,we propose a robust network flow watermarking method based on IP packet sequence,called as *** is designed to utilize the packet sequence as watermark carrier with IP identification field which is insensitive to time jitter and suitable for all IP based *** enhance the robustness against packet loss and packet reordering,the detection sequence set is constructed in terms of the variation range of packet sequence,correcting the possible errors caused by the network *** improve the detection accuracy,the long watermark information is divided into several short sequences to embed in turn and assembled during *** a large number of experiments on the Internet,the overall detection rate and accuracy of IP-Pealing reach 99.91% and 99.42%*** comparison with the classical network flow watermarking methods,such as PROFW,IBW,ICBW,WBIPD and SBTT,the accuracy of IP-Pealing is increased by 13.70% to 54.00%.

关键词： Protocols Packet loss Watermarking telecommunication traffic Jitter Robustness Internet

λ/20-Thick cavity for mimicking electromagnetically induced transparency at telecommunication wavelengths

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Advanced Photonics 2024年第3期6卷 42-50页

作者： Hua Lu Shouhao Shi Dikun Li Shuwen Bo Jianxu Zhao Dong Mao Jianlin Zhao Northwestern Polytechnical University School of Physical Science and TechnologyMOE Key Laboratory of Material Physics and Chemistry under Extraordinary ConditionsKey Laboratory of Light-Field Manipulation and Information AcquisitionMinistry of Industry and Information TechnologyShaanxi Key Laboratory of Optical Information TechnologyXi’anChina

Optical cavities play crucial roles in enhanced light-matter interaction,light control,and optical communications,but their dimensions are limited by the material property and operating *** planar cavities are urgently in demand for large-area and integrated optical ***,extremely reducing the planar cavity dimension is a critical challenge,especially at telecommunication ***,we demonstrate a type of ultrathin cavities based on large-area grown Bi_(2)Te_(3)topological insulator(TI)nanofilms,which present distinct optical resonance in the near-infrared *** result shows that the Bi_(2)Te_(3)TI material presents ultrahigh refractive indices of>6 at telecommunication *** cavity thickness can approach 1/20 of the resonance wavelength,superior to those of planar cavities based on conventional Si and Ge high refractive index ***,we observed an analog of the electromagnetically induced transparency(EIT)effect at telecommunication wavelengths by depositing the cavity on a photonic *** EIT-like behavior is derived from the destructive interference coupling between the nanocavity resonance and Tamm *** spectral response depends on the nanocavity thickness,whose adjustment enables the generation of obvious Fano *** experiments agree well with the *** work will open a new door for ultrathin cavities and applications of TI materials in light control and devices.

关键词： topological insulator optical nanocavity photonic crystal electromagnetically induced transparency-like effect

Building mm Wave on the Evolving C-V2X:mm Wave NR-V2X

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China Communications 2024年第1期21卷 88-101页

作者： Shanzhi Chen Xinxin He Rui Zhao Jinling Hu Xin Zhang China Information and Communication Technology Group Co. Ltd.(CICT)the State Key Laboratory of Wireless Mobile CommunicationsBeijing 100083China Beijing laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and ConvergenceBeijing University of Posts and TelecommunicationsBeijing 100876China CICT Connected and Intelligent Technologies Co. LtdChina Academy of Telecommunication TechnologyBeijing 100191China CICT Mobile Communications Technology Co.Ltd.

Since the evolving standardization of cellular V2X(C-V2X)technologies is continuously developed by 3GPP,research on new radio(NR-V2X)has been on schedule by academic and *** millimeter wave(mm Wave)frequency band is supposed to provide large transmission bandwidth,yet the development of mm Wave band in NR-V2X is still in preliminary *** this article,a comprehensive discussion of mm Wave NR-V2X is given covering trends,standardization landscape,and enabling technologies,aiming at tackling the challenge of channel modeling,directional channel access,beamforming and blockage *** vision of mm Wave NR-V2X is to fully support the development of automated driving,holographic control display and improved in-car infotainment for the future.

关键词： C-V2X enabling technologies mmWave NR-V2X

Relation between quantum NOT gate speed and asymmetry of the potential of RF-SQUID

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Chinese Physics B 2008年第2期17卷 440-444页

作者：嵇英华蔡十华胡菊菊 Department of Physics Jiangxi Normal University key laboratory of optoelectronic & telecommunication of jiangxi

This paper investigates the relationship between the speed of a quantum not gate and the asymmetry of the potential in an interactive system formed by a two-level RF-SQUID qubit and a classical microwave pulse. The RFSQUID is characterized by an asymmetric double well potential which gives rise to diagonal matrix elements that describe the interaction of the SQUID with the microwave pulse. And the diagonal matrix elements account for the interaction of the microwave pulse with the SQUID. The results indicate that, when the angular frequency of the microwave field is chosen as near resonate with the transition （0） ←→ （1）, i.e. ω1 -ω0 ≈ ωm, （1） the gate speed is decided by three factors, the Rabi frequency, the difference of the diagonal matrix elements between the two levels, and the angular frequency of the applied microwave pulse ωm; （2） the gate speed descends when the asymmetry of the potential is considered.

关键词： gate speed asymmetry microwave pulse RF-SQUID