最新刊期
卷 ， 期 3 ， 2011
- 摘要：As most of the static traffic grooming technology is,as reported in relevant literature,not applicable to large-scale optical networks,this paper presents an effective clustering-based static traffic grooming algorithm.When this method is applied,the network is decomposed into clusters of different hierarchical levels,and one node in every cluster is chosen as the head-node in charge of inter-and intra-traffic grooming.Simulation results show that this algorithm performs better than other known static traffic algorithms.关键词：WDM networks;inter-domain traffic grooming;clustering
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发布时间： - 摘要：An auto theft proof system based on the Internet of Things is analyzed and designed.Active dual-frequency RFID with low energy consumption is used for high-speed information collection.The geographical location of the reader is used to locate and track vehicles.Middleware technology is applied to eliminate data redundancy.The secure and reliable Public Security Network and ubiquitous Mobile Communication Network are used as the access network,ensuring the security and reducing the implementation cost.关键词：the Internet of Things;auto theft proof;public security network;RFID
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发布时间： - 摘要：In respect of the upstream TDM mechanism in EPON systems,this paper presents a multi-queue scheduling EPON Dynamic Bandwidth Allocation（DBA） algorithm on the basis of the least mean square prediction.Simulation results show that this scheme can accurately predict the flow of high-priority services and reasonably distribute bandwidth on the basis of the predictions,thus fundamentally avoiding light load penalty and reducing the delay of high priority services.关键词：EPON;DBA algorithm;least mean square prediction;quality of service
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发布时间： - 摘要：In accordance with the characteristic that OSPF routing protocol networking is applied in networking in communication networks,the Neighbor Discovery（ND） mechanism in the protocol is studied and improved in this paper.On this basis,the management and assignment scheme for the IP and threshold for network stations are redesigned,which enables the newly established stations to be identified and supervised automatically,satisfying the need for large-scale station building in communications networks.关键词：OSPF;ND;dynamic routing
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发布时间： - 摘要：Low Density Parity Check（LDPC） code can reduce the signal error codes produced in fiber channel transmission and it can be used in the military fiber-optic communication system that has special requirements on accuracy and real-time performance of information transmission.In view of the performance demand of usual military fiber optic communication systems,the structure of LDPC code is analyzed.The quasi-below triangle check matrix strategy is applied to realize the encoding of LDPC code and the LLR-BP arithmetic is adopted for decoding.The encoder design is implemented in a chip of Field Programmable Gate Array（FPGA）.The results indicate that the design possesses much fine error correcting performance and can meet the demand of high accuracy and reliability for information transmissions of military fiber optic communication.关键词：LDPC code;fiber optic communication;encoder;decoder
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发布时间： - 摘要：This paper studies an improved algorithm for jitter buffer-based adaptive clock recovery in TDMoIP technology.In the original algorithm,the clock frequency at the receiver end is adjusted in accordance with fixed period length,while in the improved algorithm it is adjusted according to the variable period length.Simulation and comparison indicate that the improved algorithm overcomes the contradictions in the original algorithm.Finally,the analysis of the performance of the improved algorithm further verifies its superiorities theoretically.关键词：TDMoIP;jitter buffer;clock recovery algorithm
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发布时间： - 摘要：At the initial link of carrier recovery,a type of carrier blind frequency offset estimation algorithm based on nonlinear transformation is discussed and a simplified algorithm for the scenario of medium and high SNR is proposed by analyzing the estimated minimum mean square error.And then slight frequency and phase offsets are tracked by using PLL technology.Simulation results verify the feasibility and effectiveness of this algorithm,thus obtaining a simplified carrier recovery method for high-order QAM.关键词：carrier recovery;blind estimation algorithm;polarity decision PLL;soft simulation
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发布时间： - 摘要：With the increase of the transmission rate in optical fiber channel transmission,Polarization Mode Dispersion（PMD） has become the main factor in limiting the transmission range of fiber-optic communication systems and electronic dispersion compensation technology is one of the solutions,but it is restricted by the hardware complexity and computing speed.In this paper,parallel processing with Block LMS（BLMS） algorithms is used in PMD compensation,providing a new approach for the application of this technology in high-rate communication systems.关键词：PMD compensation;parallel processing;BLMS algorithm
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发布时间： - 摘要：This paper introduces a few important nonlinear effects in fiber-optic communication systems,such as Stimulated Brillouin Scattering（SBS）,FWM and SPM and analyzes the mechanism for their generation and the effects on the system performances in practical applications.On the basis of the basic principles of the above effects,it investigates the primary factors by theoretical analysis in combination with numerical simulation.Finally,it gives the appropriate methods for suppressing and eliminating them.关键词：nonlinear effect;SBS;FWM;SPM
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发布时间： - 摘要：According to the attributes of Extensible Markup Language（XML）,detailed study is made of the protocol formulation,device modeling and the data output of the northbound interfaces and specific examples are given.The results show that XML can be a descriptive language for a lightweight CORBA and can describe the northbound interface model distinctly.关键词：XML;northbound interface;Information model;WSDL;MTOSI
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发布时间： - 摘要：This paper focuses on the design of an electrical wire and optical fiber composite cable,which enables the provision of power and optical signals simultaneously for the Remote Radio Unit（RRU）.Additionally,it presents the test results of its performances.Test and project results show that this is a low-cost and effective solution to remote power feeding,especially showing good stability and security in remote power feeding systems in underdeveloped areas.关键词：electrical wire and optical fiber composite cable;optical fiber cable;TD-SCDMA;remote DC power-feeding
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发布时间： - 摘要：A high birefringence Photonic Crystal Fiber（PCF） with a new structure for pressure sensing is presented.With the external lateral pressure,the effective refractive indexes of its two polarization states change and its birefringence alters accordingly.Pressure sensing is achieved by measuring the variations of the polarization state brought about by that of birefringence.Simulation results show that the birefringence PCF changes significantly under the lateral pressure,to the extent of as 0.7×10-5/MPa.关键词：photonic crystal fiber;finite element method;birefringence change;pressure sensing
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发布时间： - 摘要：In this work,the design approach for terahertz layered one-dimensional photonic crystal fibers is theoretically studied by using the transfer matrix method and the compound materials of As2Se3 and Teflon for PCF structure presented.The study shows that when its transmission center frequency is 1 THz,the optimum photonic bandgap material match is as the following: the high refractive index materials is As2Se3 and the layer thickness is 168.3 μm;the low refractive index materials is Telfon,the layer thickness is 359.7 μm and the optimum number of periods is 25.关键词：photonic crystal fiber;THz frequency field;photonic bandgap
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发布时间： - 摘要：To further study the characteristics of self-similar evolution of the ultra-short pulses in nonlinearity-increasing fibers,the influences of incident pulse energy,pulse width and equivalent gain coefficient on the evolution are analyzed by using the numerical simulation method.The results show that both the incident pulse energy and equivalent gain coefficient have obvious influences on the self-similar evolution,in that the evolution speed increases when pulse energy or equivalent gain coefficient is increased,i.e.the characteristic length that the evolution needs is shortened,while the influence of pulse width is feeble.关键词：nonlinear optics;self-similar parabolic pulse;linear chirp;pulse compression
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发布时间： - 摘要：This paper introduces the key technologies for Optical Network Unit（ONU） modules in 10 Gbit/s Ethernet Passive Optical Network（EPON） systems and describes the design of optical burst transmitter/receiver module that conforms with the standard.The test results show this module in the case of burst mode has the function of launching optical power and extinction ratio with short turn on/off delay and remain constant over a wide range of temperature.Furthermore,its indexes fully satisfy the requirements of IEEE Stanard.802.3av.关键词：10 Gbit/s EPON;asymmetric;symmetric;burst-mode transmission
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发布时间： - 摘要：Optical Add-Drop Multiplexer（OADM） is one of the key devices of Wavelength Division Multiplexing（WDM） optical networks.This paper presents a novel OADM based on Fiber Bragg Grating（FBG） and describes the principle of its multiplexing/demultiplexing.The device has the advantages of low insertion loss,high flexibility,low crosstalk and so on.To verify its structural design and theoretical analysis,we simulate this new structure of OADM with OptiSystem software.The simulation results show that the side mode suppression ratio of the drop wavelength is up to 20dB,and the new structure has good performance and flexibility.关键词：FBG;OADM;circulator
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发布时间： - 摘要：This paper designs three kinds of graded photonic crystal structures by changing the gaps between dielectric columns,radius of dielectric columns and dielectric constant,calculates the transmission spectrum by using the Finite Difference Time Domain（FDTD） method and compares and analyzes photonic crystal structures with different forms of graded combinations.Simulation results show that different combinations have different effects on photonic bandgap and can obtain still larger bandgap width than one-dimensional photonic crystals.关键词：graded photonic crystal;THz;FDTD method;transmission spectrum
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发布时间： - 摘要：This paper first analyzes the variations of the interjection of spectrum-sliced Amplified Spontaneous Emission（ASE） source into wavelength-locked Fabry-Perot Laser Diodes（FP-LD） spectrum with seed light power.Then,the variations of the gain due to the injection and Side-Mode Suppression Ratio（SMSR） with injected ASE light power,and FP-LD injected current are experimentally investigated.Finally,comparisons are made among the transmission characteristics of the light signals injected in different spectrum-slicing approaches in WDM-PON systems.关键词：spectrum-sliced ASE;injection wavelength-locked;FP-LD
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发布时间： - 摘要：This paper presents an optical interleaver that is based on a ring resonator and a Sagnac loop,which is constructed by coupling a ring resonator with single polarization properties in the conventional Sagnac loop.The phase latency property of the polarization light is changed by using the nonlinear phase property of the ring resonator,thus realizing a polarization-independent optical interleaver with approximate rectangular structure.关键词：ring resonator;Sagnac interferometer;interleaver
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发布时间： - 摘要：Timing recovery is one of the key technologies for all digital receivers.On the basis of the conventional theory of Gardner timing recovery,a modified timing recovery method is studied.An improved interpolation configuration is proposed and the controller is modified.This configuration is simulated and verified on QPSK signals as examples,indicating that the proposed scheme is a good solution to timing recovery and effective to the cost reduction for system implementation.关键词：all digital receiver;timing recovery;interpolator;Gardner algorithm
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发布时间： - 摘要：In order to improve the efficiency of the preamble detection in random access,this paper proposes a frequency domain detection-based invariable threshold algorithm,which detects the signature preamble sequence on the basis of frequency domain detection by supposing the invariable threshold.Compared with the traditional time-domain detection algorithm,it reduces the complexity and is still simpler in the choice of threshold.Simulation results prove that this method shows good performances in various wireless channels.关键词：LTE;random access;preamble detection;threshold
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发布时间： - 摘要：On the basis of the application scenarios of the TD-LTE random access process,this paper introduces in detail the fundamental principle of the competition-based random access process,taking network end as an example,designs an appropriate flow of the random access process Media Access Control（MAC） sub-layer.It generates its Message Sequence Chart（MSC） by SDL and TTCN co-simulation,verifying the correctness of the signal flow design and data.This design flow has been applied to the development of TD-LTE wireless integrated test instrument.关键词：TD-LTE;random access;SDL;TTCN
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发布时间： - 摘要：<正>日前,烽火通信在国内率先推出规模商用的单芯片1∶128光分路器,为FTTH（光纤到户）大分路比应用场景提供了强力支撑,符合现有以及下一代PON（无源光网络）技术演进趋势。同时,烽火通信正在投入1∶256分路比单芯片光分路器的研发,有望在该领域率先推出相关产品。
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发布时间： - 摘要：<正>1、内容要求本刊主要刊登通信领域内的学术和技术类文章,主要内容包括通信网络、通信系统、无线通信系统、光纤光缆、光器件、技术应用等。其特点是"前沿学科"与"基础研究"相结合;"核心技术"与"支撑技术"相结合。
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发布时间： - 摘要：<正>是以提供文献内容梗概为目的,不加评论和补充解释,简明、确切地记述文献重要内容的短文。包括:（1）目的——研究、研制等的目的,所涉及的主要范围;（2）方法——所用的原理、理论、条件、工艺手段
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