检索结果-南通市图书馆

量子定位系统在沙尘暴背景下的最优纠缠度自适应策略

在线全文

学校读者我要写书评

暂无评论

光电子．激光 2024年第8期35卷 861-867页

作者：马虎森聂敏杨光张美玲孙爱晶裴昌幸西安邮电大学通信与信息工程学院陕西西安710121 西安电子科技大学综合业务网理论及关键技术国家重点实验室陕西西安710071

量子定位系统(quantum positioning system,QPS)具有定位精度高、安全系数高的特点,然而沙尘暴会使得光量子纠缠度产生较大变化,进而影响到量子定位系统的定位误差。为了降低这种误差,本文基于双卫星星地链路切换策略提出了抵抗沙尘暴... 详细信息

量子定位系统(quantum positioning system,QPS)具有定位精度高、安全系数高的特点,然而沙尘暴会使得光量子纠缠度产生较大变化,进而影响到量子定位系统的定位误差。为了降低这种误差,本文基于双卫星星地链路切换策略提出了抵抗沙尘暴干扰的最优纠缠度自适应(optimal entanglement degree adaptive,OEDA)策略。建立了沙尘暴各参数、传输距离与纠缠度之间的关系,并且将沙尘暴整体特征对系统的定位误差在自适应调整前后进行对比。仿真结果表明,当沙尘暴整体特征聚合因子为10,传输距离为10 km时,采用OEDA算法后,系统定位误差由0.14 m缩减至0.02 m,因而可知经过OEDA策略后可以提高沙尘暴天气下QPS的精确度。

关键词：量子光学量子定位系统纠缠度沙尘暴自适应

ML and MAP Channel Estimation for Distributed OneWay Relay Networks with Orthogonal Training

在线全文

学校读者我要写书评

暂无评论

China Communications 2015年第12期12卷 84-91页

作者： YAO Chenhong ZHANG Shun pei changxing State Key Laboratory of Integrated Services Networks Xidian University Xian University of Architecture and Technology

In this letter,we investigate the individual channel estimation for the classical distributed-space-time-coding(DSTC) based one-way relay network(OWRN) under the superimposed training *** resorting to the composite channel estimation,as did in traditional work,we directly estimate the individual channels from the maximum likelihood(ML) and the maximum a posteriori(MAP) *** derive the closed-form ML estimators with the orthogonal training *** to the complicated structure of the MAP in-channel estimator,we design an iterative gradient descent estimation process to find the optimal *** results are provided to corroborate our studies.

关键词： posteriori iterative estimator likelihood relay descent variance assumed iteration posed

Perfect quantum controlled teleportation via a novel threeparticle partially entangled channel

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2015年第6期22卷 45-50页

作者： Chen Na Quan Dongxiao Yang Hong pei changxing State Key Laboratory of Integrated Services Networks Xidian University

Recently Li et al. proposed special partially entangled states serving as quantum channel in quantum controlled teleportation, while there are some limitations in their scheme. Based on that, we present a possible improvement in this paper. We construct a novel three-particle partially entangled state which is suitable for perfect controlled teleportation. A simple quantum circuit is designed to obtain this state. We evaluate quantum controlled teleportation from three points of view： teleportation fidelity, success probability and the controller＇s power. Detailed calculations and simulation analyses show that the constructed state is a suitable channel for controlled teleportation of arbitrary qubits, unit teleportation fidelity and 100% success probability can be achieved. Meanwhile, as long as channel＇s entanglement degree equals to or greater than 3/4, the controller＇s power can be guaranteed.

关键词： quantum controlled teleportation three-particle partially entangled state quantum circuit

Average fidelity estimation of twirled noisy quantum channel using unitary 2t-design

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第1期28卷 223-231页

作者： Linxi Zhang Changhua Zhu changxing pei State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710071China Science and Technology on Communication Networks Laboratory Shijiazhuang 050081China

We propose a method to estimate the average fidelity using the unitary 2t-design of a twirled noisy channel, which is suitable for large-scale quantum circuits. Compared with the unitary 2-design in randomized benchmarking, the unitary2t-design for the twirling of noisy channels is more flexible in construction and can provide more information. In addition,we prove that the proposed method provides an efficient and reliable estimation of the average fidelity in benchmarking multistage quantum gates and estimating the weakly gate-and time-dependent noise. For time-dependent noise, we provide a scheme of moment superoperator to analyze the noise in different experiments. In particular, we give a lower bound on the average fidelity of a channel with imperfect implementation of benchmarking and state preparation and measurement errors(SPAM).

关键词： quantum channel average fidelity unitary 2t-design

Effect of non-spherical atmospheric charged particles and atmospheric visibility on performance of satellite-ground quantum link and parameters simulation

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2017年第6期24卷 39-48页

作者： Shi Li Nie Min Yang Guang pei changxing School of Communication and Information Engineering Xi'an University of Posts and Telecommunication School of Electronics and Information Northwestern Polytechnical University State Key Laboratory of Integrated Service Networks Xidian University

In order to study the relationship between the non-spherical atmospheric charged particles and satellite-ground quantum links attenuation. The relationship among the particle concentration, equivalent radius, charge density of the charged particle, the attenuation coefficient and entanglement of the satellite-ground quantum link can be established first according to the extinction cross section and spectral distribution function of the non-spherical atmospheric charged particles. The quantitative relationship between atmospheric visibility and communication fidelity of satellite-ground quantum link were analyzed then. Simulation results show that the ellipsoid, Chebyshev atmospheric charged particle influences on attenuation of the satellite-ground quantum link increase progressively. When the equivalent particle radius is 0.2 gm and the particle concentration is 50 μg/m^3, the attenuation coefficient and entanglement of the satellite-ground quantum link is 9.21 dB/km, 11.46 dB/km and 0.453, 0.421 respectively; When the atmospheric visibility reduces from 8 km to 2 kin, the communication fidelity of satellite-ground quantum link decreases from 0.52 to 0.08. It is shown that the non-spherical atmospheric charged particles and atmospheric visibility influence greatly on the performance of the satellite-ground quantum link communication system. Therefore, it is necessary to adjust the parameters of the quantum-satellite communication system according to the visibility values of the atmosphere and the shapes of the charged particles in the atmosphere to improve reliability of the satellite-ground quantum link.

关键词： satellite-ground quantum link non-spherical atmospheric charged particles atmospheric visibility degree of quantum entanglement

层积云背景下量子干涉雷达最优平均光子数自适应策略

在线全文

学校读者我要写书评

暂无评论

激光杂志 2024年第1期45卷 26-32页

作者：聂敏张政杨光张美玲孙爱晶裴昌幸西安邮电大学通信与信息工程学院西安710121 西安电子科技大学综合业务网国家重点实验室西安710071

量子干涉雷达(Quantum Interference Radar,QIR)是以量子力学为基础,利用量子纠缠效应进行目标探测的一种新型雷达体制,QIR探测光子数的变化会对雷达分辨率和系统生存函数产生影响。为了降低层积云液态水含量对QIR探测性能的影响,提出... 详细信息

量子干涉雷达(Quantum Interference Radar,QIR)是以量子力学为基础,利用量子纠缠效应进行目标探测的一种新型雷达体制,QIR探测光子数的变化会对雷达分辨率和系统生存函数产生影响。为了降低层积云液态水含量对QIR探测性能的影响,提出了基于诱骗态量子密钥协议的最优平均光子数自适应(Photon Number Adaptive,PNA)调整策略。建立了层积云液态水含量、传输距离与最优平均光子数之间的关系,对自适应调整前后的QIR分辨率和信道生存函数进行了比较。理论分析和仿真结果表明,当脉冲信号波长一定,层积云粒子浓度为1.579×10^(4)cm^(-3),层积云液态水含量为0.5 g/cm3时,采用PNA策略之后,QIR角度分辨率值由1.289下降至1.028,QIR系统角度分辨率和空间分辨率均得到有效提高;当层积云液态水含量为0.1034 g/cm^(3)时,采用PNA策略之后,信道生存函数由0.2292提高到0.4167。因此,通过PNA策略自适应地调整系统发送端信号脉冲所含的平均光子数,能够提高QIR在层积云背景下探测的可靠性。

关键词：量子光学量子干涉雷达层积云平均光子数自适应调整

PROOF OF CERTIFICATELESS MIP REGISTRATION PROTOCOL BASED ON PCL

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 2010年第2期27卷 273-278页

作者： Zhang Manjun pei changxing The State Key Laboratory of lSN Xidian University Xi＇an 710071 China Xi＇an University of Posts ＆ Telecommunications Xi＇an 710121 China

Security protocols are the basis of many mobile communication systems,thus it is important to ensure protocol property correct. Using Protocol Composition Logic (PCL),this paper proves a Mobile IP (MIP) registration protocol that is based on certificateless public key signature without pairing between home agent and foreign agent,which minimizes the registration time and cost as well as improves the security compared with the identity-based and certificate-based registration protocol. Analysis and proof shows that the proposed protocol provides users security and authentications,moreover,the anonymity property is proved correct.

关键词： Mobile IP (MIP) Registration Certificateless Protocol Composition Logic (PCL)

BER ANALYSIS OF A GMSK SYSTEM USING DECISION FEEDBACK

在线全文

学校读者我要写书评

暂无评论

Journal of Electronics(China) 2008年第4期25卷 544-551页

作者： He Xiandeng pei changxing The State Key Lab of Integrated Services Networks Xidian University Xi＇an 710071 China

There are considerable literatures on the Bit Error Rate(BER)evaluation of DifferentialDetection of Gaussian Minimum Shift Keying(DDGMSK)system using Decision Feedback(DF),butmost of them give the performance based on the Monte Carlo Error Counting(MCEC)*** probability distribution of the phase angle between two vectors perturbed by Gaussian noises,theformulae of BER are derived for the performance analysis of DDGMSK system with DF in this *** the m-bit dock-tailed sequence,the new formulae of Gaussian Minimum Shift Keying(GMSK)modulated phase and the Time-Varying Signal to Noise Ratio(TVSNR)of the demodulatedsignal are presented,and it is proved that the relationship between the TVSNR of the demodulatedsignal and the size of eye opening is not *** results show that the theoretical in-vestigation gives analogous results with the MCEC *** formulae presented are useful for theperformance analysis of systems using GMSK as modulating and demodulating method,for instance,the analysis of synchronous performance of frequency-hopping communication system.

关键词： Gaussian Minimum Shift Keying (GMSK) Differential detection Decision Feedback (DF) Bit Error Rate (BER)

Internet end-to-end delay dynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2006年第3期17卷 685-691页

作者： Zhu Changhua pei changxing Li Jiandong Chen Nan Yi Yunhui State Key Laboratory of Integrated Services Networks Xidian Univ. Xi'an 710071 P. R. China

End-to-end delay is one of the most important characteristics of Internet end-to-end packet dynamics, which can be applied to quality of services （OoS） management, service level agreement （SLA） management, congestion control algorithm development, etc. Nonstationarity and nonlinearity are found by the analysis of various delay series measured from different links. The fact that different types of links have different degree of Self-Similarity is also obtained. By constructing appropriate network architecture and neural functions, functional networks can be used to model the Internet end-to-end nonlinear delay time series. Furthermore, by using adaptive parameter studying algorithm, the nonstationarity can also be well modeled. The numerical results show that the provided functional network architecture and adaptive algorithm can precisely characterize the Internet end-to-end delay dynamics.

关键词： Internet end-to-end delay functional network nonlinear system.