最新刊期
卷 ， 期 4 ， 2016
- 摘要：Multi-layer and multi-domain is the inevitable trend of the future large-scale optical interconnection networks.However,how to construct secure and reliable light-path or light-tree is a new problem under the condition of the lack of global information.In this paper,we first analyze the construction mechanism of light-path based on the Path Computation Element（PCE）architecture.Then we summarize the security threats of path computation phase and link establishment phase,which include active attack and passive attack.To deal with the issue of the identity authentication,data source authentication,encryption,digital signature and privacy protection,specific security mechanisms of the path construction of PCE communication Protocol（PCEP）and GMPLS RSVP-TE are proposed based on several technologies including Transport Layer Security（TLS）,identity-based cryptosystem,and authentication option of TCP.The proposed technique can enhance the confidentiality,integrity,authenticity,non-repudiation,freshness and privacy of the path construction of multi-domain optical networks.关键词：multi-domain optical network;PCE;light-path;security mechanism
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发布时间： - 摘要：This paper studies the frequency domain equalization scheme for single carrier optical intensity modulation direct detection system.Through theoretical analysis on the relationship between the time and frequency domain inter-symbol interference for single carrier signal,a time domain clipping based channel equalizer with new tap updating method is proposed to reduce the effect of noise.The optimal clipping position and symbol number are selected through numerical simulations.The simulation results show that compared with conventional time domain channel equalization,the required OSNR can be reduced by almost 2dB through frequency domain channel equalization after 100 km transmission of 10Gbit/s NRZ-OOK signals.关键词：optical intensity modulation;direct detection;frequency domain equalization
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发布时间： - 摘要：Aiming at the high computation load and the uncertainty of step chosen in traditional OFDM Signal-to-Noise Ratio（SNR）estimation method,a novel method is proposed to estimate the SNR of OFDM.We firstly use the correlation function to discriminate the two types of guard interval.Then we propose two different methods to estimate the SNR of OFDM signal according to the structure characteristic of two types guard interval.Finally,the result of judgment is combined with the corresponding SNR estimation method to realize the SNR estimation of OFDM.The experimental results show that the proposed method don’t need auxiliary data and the computation load is low with satisfied SNR estimation performance.关键词：OFDM;cyclic prefix;correlation function;blind recognition;SNR
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发布时间： - 摘要：LT codes are the first realization of the digital Fountain codes.LT codes using BP decoding algorithm which means the complexity is close to that of linear algorithm.However it still suffers from great delay.In order to solve this problem,we propose a decomposition and restructuring encoding algorithm.The algorithm first decomposes and regroups Kinformation packets,and then divides the packets into a plurality of sets for parallel encoding.The algorithm can effectively reduce the encoding time and operation of decoding with reduced data transmission delay.The encoding method can be applied to various modifications distribution.In the case of K = 1 000 and K = 2 000 and the same degree distribution,the simulation results show that it can achieve Non-Repetitive Encoding（NRE）algorithm performance with 75% encoding time reduction and less decoding operands.关键词：LT codes;BP decoding;degree distribution
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发布时间： - 摘要：In this paper,we propose an improved algorithm to solve the phase distortion and high bit error ratio problems during the signal transmission.Through setting the error threshold value,the algorithm can work between the CMA and LMS modes.The improved algorithm fully utilizes the faster convergence speed in CMA algorithm and LMS algorithm with good stability.The simulation results show that the proposed algorithm can increase the convergence speed of constellation points,concentrate the phase point,realize high and stable signal noise ratio high,and reduce the signal error rate to be 1/5of the previous result.关键词：PSK;adaptive filter;LMS algorithm;CMA;phase equalization
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发布时间： - 摘要：In WDM optical networks,the routing selection algorithm based on GA and wavelength assignment algorithm are widely used.In order to further optimize the routing and wavelength assignment in WDM optical network,a dynamic RWA algorithm named Double Crossover and Mutation Adaptive-Genetic Algorithm（DCMA-GA）for WDM network based on improved GA is proposed.Through simulation,the new algorithm can reduce the network blocking rate by 50% when the network load is big.The efficiency of algorithm can also be improved by 10% when compared with the normal genetic RWA algorithm.关键词：WDM;improved GA;RWA;double crossover and mutation;adaptive
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发布时间： - 摘要：<正>7月13日晚,全球权威财经杂志《财富》（中文版）发布了2016年度的中国500强榜单。烽火通信第七次荣登这一榜单。《财富》杂志是一本具有全球化影响力的杂志,1954年开始以严谨的评估推出全球最大500家企业的名单,即"世界500强排行榜"从此产生了巨大影响,以至于超越了国家、民族、文化而成为全球经济的一个标准。迄今为止,就影响力而言,没有任何一种媒体的"排行榜"能望其项背。这一排名已成世界知名企业用来
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发布时间： - 摘要：<正>据来自中国联通的官方消息,备受关注的20152016年中国联通10GPON集采结果已于近日出炉。本次集采中,烽火通信凭借技术、服务和价格等多方面的领先优势成为最大赢家,10G EPON和XGPON1两个标包均综合排名第一,分别获得60%和55%市场份额。受4K视频等高带宽业务的驱动,2016年中国联通加速超宽光网建设,这为10G PON规模部署带来新
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发布时间： - 摘要：In order to explore the key technology to extend the life of fiber mechanical,we study the optical fiber mechanical reliability and life evaluation model.The main factors affecting the mechanical life of the fiber is the crack generated under the stress corrosion and the continuous grow of the crack.According to the Weibull distribution characteristics of the fiber mechanical strength calculations and fatigue test,we establish life assessment model for optical fiber screening experiments.The use of life assessment model for OPGW line life are simulated and evaluated to extend the life of OPGW line of key technologies.The results show that the life expectancy can be improved by increasing fiber fatigue parameters and reduce the stress level.关键词：Crack;stress corrosion;Mechanism life
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发布时间： - 摘要：In this paper,we propose and study a novel structure of Photonic Crystal Fiber（PCF）with improved birefringence and single-mode propagation condition in a broad range of wavelength.The birefringence of the fundamental mode and single mode property in such a PCF is numerically investigated by Full Vector Finite Element Method（FVFEM）and Anisotropic Perfectly Matched Layers（APML）.The simulation results show that by filling the silica into one line elliptical air holes parallel to xaxis and rotated by an angle of θ=45°,and introducing one line elliptical air holes parallel to yaxis without any material and rotated by an angle of θ=45°to other direction,the birefringence can be 4.65×10-2 with good single mode condition.Obviously,the proposed PCF has the potential application in optical instruments and devices.关键词：photonic crystal fiber;birefringence;single-mode;optical devices
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发布时间： - 摘要：We study the supercontinuum（SC）generation in an As2S3-based microstructured fiber.Firstly we propose a chalcogenide（As2S3）core tellurite cladding microstructured fiber with flattened normal dispersion for ultraflat SC generation.To realize flat normal dispersion,the structure parameters are then optimized including the chalcogenide core diameter,the air hole diameter and the distance between the centers of the two neighboring air holes.It is shown that an ultraflat SC spectrum with deviations less than 4dB over an octave（from 1.4μm to 3μm）can be achieved.We also propose a chalcogenide core fluoride cladding microstructured fiber.After optimization of several parameters,a ultrawide SC（from 1.2μm to 7μm）can be generated in the microstructured fiber.关键词：nonlinear optics;supercontinuum;chalcogenide glass
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发布时间： - 摘要：Based on the rigorous coupled-wave theory and medium slab waveguide theory,an AlN wavelength tunable distributed feedback laser is designed by Periodic tunable Bragg grating.The adjustable grating is actuated by comb-drive actuator according to the Micro-Electromechanical（MEMS）technology system and simulated by COMSOL software in 1 310 nm band.The parameters of the DFB laser grating structure are evaluated by analyzing the distribution of a two-dimensional electric mode.Also,the simulation results show that the lasing wavelength and grating period have similar linear relationships,which is consistent with the theoretical analysis.Moreover,one grating period corresponds to a number of different grating heights,and it demonstrates periodic distribution in a 20 nm range.Furthermore,according to the relationship between lasing wavelength and grating period,the possibility of making 1 2901 330nm-band tunable lasers is presented in this paper.关键词：AlN;DFB-LD;wavelength-tunable;MEMS
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发布时间： - 摘要：In order to generate more stable comb,the bias control strategy based on DD-MZM for single side-band modulation is extensively studied.The effect of the criterion for bias control under non-ideal extinction ratio is analyzed theoretically and an optimum criterion for bias control is proposed.The result shows that it is more accurate using the max point of the transmitter curve as the criterion for monitoring the bias of MZM.关键词：Mach-Zehnder modulator;single side-band modulation;bias control;extinction ratio
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发布时间： - 摘要：We demonstrate theoretically an active tunable filter with a simple two-coupled-ring structure,which yields very narrow passband based on Fano resonance in the transmission spectra.The active and tunable performances of the microring filter are achieved by the pump waveguide and micro-heating device,respectively.The formulas of the resonant transmission and the ultra narrow pass-band linewidth are derived through the coupled-mode theory.Then,the relationships between the gain and the transmission and linewidth,as well as the thermo-optic effect and the resonance wavelength of the microring waveguide are simulated useing MATLAB,respectively.The numerical calculation and simulation results show that the gain can increase transmittance and compress linewidth of the microring filter.It is also shown that the thermo-optic effect can make the resonant wavelength red shift or blue shift.关键词：microring resonator;optical filter;ultranarrow passband
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发布时间： - 摘要：The transmission characteristics of the wedge-shaped SPP waveguide are analyzed through SPP superior characteristics.In this paper,we design the wedge plasma waveguide structure with embedded grating.Diffraction grating coupling is used to analyze the exciting phenomenon of SPP.The structure characteristics are obtained by changing the thickness of the metal film and the incident light angle.The calculation results show that the metal film thickness reduction will lead to fast reduction of the transmission bandwidth as well as the transmission rate.The change of the incident light angle will also lead to the variation of the transmitted light efficiency.We also simulate the wedge surface plasmon waveguide structure to obtain the film thickness change transmission curve,angle of the incident light transmittance,and the corresponding transmission rate variation.The results in this paper are significant for nanoplasmons coupling of semiconductor equipment.关键词：strip waveguide;surface plasmon;grating;metal film
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发布时间： - 摘要：In order to enhance the security of underground cultural relics protection,this paper presents an optical fiber sensing equipment for perimeter security.The equipment is principally based on optical fiber Mach-Zehnder interferometer and applied to the underground motion wave detection perimeter security.Through the study of the interference waveform,it offers sufficient information for detection,The amplitude frequency characteristics of the vibration signal can be recovered from other interference waveform.Through the application,some key features are achieved:the equipment can detect the mining region within a radius of 25 meters;the equipment can support 64probes;and the equipment can identify the warning time within2 seconds.关键词：perimeter security;interference characters filter;optical fiber sensor;underground motion wave
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发布时间： - 摘要：Optical fiber Bragg Grating（FBG）displacement sensor has many advantages such as high sensitivity,intrinsic safety and easy multiplexing,etc.However,it is difficult to obtain a large range FBG displacement sensor due to the limitations of sensitive materials.In this paper,in order to solve this problem,a large range FBG displacement sensor is proposed and demonstrated.The planetary gear train and cantilever beam composite structure are utilized in this sensor.The FBG is pasted on the cantilever beam.Through changing the rotating ratio of the planetary gear train,different range of the sensors are achieved.Finite element analysis method is used to optimize the material and structure of the cantilever.The output characteristics of the sensor in different range are experimentally studied.The results show that the sensor has a very good linear relationship between output wavelengths and displacements and its maxima range can reach 2 000 mm.关键词：displacement sensor;fiber Bragg grating;finite-element analysis;large range
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发布时间： - 摘要：Mobile fronthaul is an important part in C-RAN.With the development and evolution of modern radio access network,the rapid growth of user demand for bandwidth sets a higher requirements for network transmission rate.This paper firstly review the basic components of mobile fronthaul and C-RAN.Then the requirements of mobile fronthaul are analyzed in various aspects.Finally,we illustrate present different fronthaul solutions in detail.关键词：mobile fronthaul network;C-RAN;WDM;TDM;IFoF;SPP
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发布时间： - 摘要：In this paper,we propose a new method to reduce the computational complexity of the conventional Selective Mapping（SLM）algorithm in the Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing（MIMO-OFDM）system.The original frequency domain signals are first divided into real and imaginary parts.Then the two parts are operated by different phase rotation respectively.The corresponding time domain signals are finally obtained by using inverse fast Fourier transform operations.It can produce more candidates with different Peak to Average Power Ratio（PAPR）by different combination of real and imaginary parts in antennas.The simulation results show that the proposed method can reduce the PAPR of MIMO-OFDM signals effectively.In addition,compared with conventional SLM algorithm,the proposed method can reduce the algorithm computation complexity significantly.关键词：MIMO-OFDM;SLM;PAPR;computational complexity
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发布时间： - 摘要：In the space optical communication system,the pulse broadening effect during every incident light pulse may cause the information lost when calculating the likelihood ratio,which deteriorates the system performance.In this paper,we study the slot likelihood ratio weighted method to compensate of the effects of pulse broadening based on PPM and LDPC iterative demodulation system.When the pulse broadening obey exponential distribution and Gauss distribution,the likelihood ratio are calculated using both of the Gaussian compensation and exponential compensation.Simulation result shows that when the pulse broadening obey the 0.46 standard deviation of Gauss distribution,the likelihood ratio compensation method can improve the performance by 1.3dB.Within a certain range jitter,Gaussian compensation and exponential compensation has a very good interchangeability.关键词：space optical communication;pulse broadening;poisson channel;likelihood ratio compensation
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发布时间： - 摘要：To reduce the cost,size and power consumption of the Free-Space Optical（FSO）communications system for easy operation and maintenance,most common FSO systems use Intensity Modulation and Direct Detection（IM/DD）.This paper proposes a signal detection method based on the K- mean algorithm,and compares it with classical algorithms in terms of implementation complexity,robustness and error performance.The results show that when the data block is longer than 1 000,the performance of the proposed method can approach that of the ideal receiver.关键词：free-space optical communications;signal detection;implementation complexity;error performance analysis;K-mean algorithm
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发布时间： - 摘要：In this paper,the variation of the number of cell’s users within the cluster is studied based on Queuing theory and Markov transition model in C-RAN network.We proposes a prediction scheme to calculate the cell’s arriving rate and leaving rate by considering the history regular and the current trend.By solving the transient solution of the Markov transition model,the statistical average of the every cell’s users is achieved at different times.Considering the prediction error and the system overhead,the optimal period of the prediction is obtained.The simulation result shows that better prediction period can accurately reflect the variation of the users in the realistic environment.关键词：C-RAN;Markov transition model;predict;queuing theory;the optical prediction period;variation
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发布时间： - 摘要：For indoor visible light communication in the MIMO system,users can not enjoy fair communication service issues.In this paper,we propose a method to find the optimal value of the gain of the optical receiver concentrator to solve this problem.It can be used to optimize the multi user power distribution problems.We use an improved niche genetic algorithm establishment and node mode related to the corresponding received optical power to find a set of optimal condenser gain value in the visible light communication system.The simulation results show that the improved niche genetic algorithm performs can find a set of optimum condenser efficiently,and improve the service quality of indoor visible light communication system.关键词：visible light communication;gain of condenser;niche genetic algorithm
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发布时间： - 摘要：The past few years has witnessed the inevitable trend of the development of smart grid,where the construction of Distribution Automation Management System is a key component.This paper discusses the performances and advantages of using broadband wireless communication technology to construct the smart grid.The operation of low-voltage meter reading is based on the combination of the second generation mobile communication technique-General Packet Radio Service（GPRS）and the third generation mobile communication technique-Wideband Code Division Multiple Access（WCDMA）.Then we evaluate the system performance of smart metering application operated in GPRS system as well as WCDMA system.The simulation results can provide theoretical guidelines when smart grids are deployed in realistic network.关键词：distribution network automation;broadband wireless network;GPRS;WCDMA
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发布时间： - 摘要：<正>科技论文的引言是简要说明研究的主要目的、范围,即为什么写这篇论文以及要解决什么问题;前人在本课题相关领域内所做的工作和尚存的知识空白,作简要的历史回顾和现在国内外情况的横向比较;以及理论基础、技术路线、实验方法和手段,还有选择特定意见方法的理由;预期研究
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