最新刊期
卷 ， 期 1 ， 2012
- 摘要：This paper first studies in depth the key technologies for and transmission of 100 Gbit/s Ethernet and then analyzes the present status of the commercially available high-rate photoelectronic devices.Finally,it reviews the research advances and results achieved by Fiberhome Telecommunication Co.,Ltd.in 100 G Ethernet interfaces and equipment and the progress in the 50 km error-free transmission of 4×5 Gbit/s signals over the conventional G.652 and G.657 optical fibers.The research results indicate that 100 GE technology is mature and suitable for commercial applications.关键词：100 Gbit/s Ethernet;100 Gbit/s interface;time delay correction;MAC/PCS layer
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发布时间： - 摘要：In the coherent optical communication systems at 100 Gbit/s and higher rates using high-order phase modulation,laser phase noise and dispersion effects in fiber-optic transmissions are the major factors that affect the system performance.To compensate for these effects,this paper proposes a method for the combined use of electric channel equalization and carrier phase estimation modules in the electric domain.The phase estimation is completed after the electric channel equalization,the results of which are also used in updating the tap coefficients of the equalizer.This method can effectively reduce the requirements for the step-size in the equalization,conducive to acquiring lower bit error rate,more stable error performance and longer transmission distance.
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发布时间： - 摘要：Burst contention is a key problem in Optical Burst Switching（OBS） networks.As an effective solution to contention,deflection routing is extensively studied.This paper proposes a Congestion Avoidance-based Pre-Deflection Routing（CAPDR） algorithm.In this algorithm,on the basis of the periodically fed back information about network congestion,the algorithm deflects in advance parts of the burst packets according to a certain probability,thus realizing congestion avoidance and network load balancing.Simulation results show that the proposed algorithm outperforms the conventional shortest path deflection routing algorithm in terms of Burst Loss Ratio（BLR）,throughput and average link utilization.关键词：optical burst switching;congestion avoidance;burst contention;deflection routing;load balancing
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发布时间： - 摘要：The Passive Optical Network（PON） system,represented by EPON and GPON,is widely used in optical access networks at home and abroad.The sleep mode of ONU becomes an important power-saving scheme for PON.This paper reviews the working principles,sleeping actions and influences on protocols of four kinds of sleep modes and analyzes and compares their characteristics in respect of power consumption,device support,service performance and user experience,providing useful references for the research and applications of energy-saving in PON.关键词：PON;sleep;energy-saving
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发布时间： - 摘要：Network management and maintenance has always been an important means for ensuring normal network operation and improving customer perception.As a principal technology for broadband access,Passive Optical Network（PON） is widely adopted by major operators.Therefore,the effective management and maintenance of PON become a major focus of attention and that of Optical Distribution Networks（ODN） is of first priority.Starting with the faults in ODN and the problems in its operation and maintenance,this paper introduces the general situation of the existing ODN,discusses the existing fault diagnosis techniques and analyzes the advantages and disadvantages of various technical schemes and the suitable networking modes and location effects.关键词：network management;maintenance;fault diagnosis;PON;ODN
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发布时间： - 摘要：With the rapid development of Wave Division Multiplexing（WDM） transmissions,100 Gbit/s communication systems are about to be brought into commercial operations,so the Polarization Mode Dispersion（PMD） effects in optical fibers will become more prominent.This paper first describes the causes of PMD generation and the necessity of its mitigation.Then it introduces six PMD mitigation schemes and analyzes and studies their classifications and application principles.Finally,it points out that three of them: PMD compensation,new stable modulation codes and Forward Error Correction（FEC） have good application prospects in terms of technological performances.关键词：PMD;FEC;coding;WDM
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发布时间： - 摘要：The QoS in the carrier Ethernet has been a key issue of concern.When entering the network,traffic can be well controlled by using the traffic control strategies so as to reduce network congestions as much as possible and improve the network performance.In this paper,an improved single-rate three-color token bucket algorithm is presented.It is found in analysis and comparison that this algorithm can improve bandwidth efficiency and reduce the packet loss to a certain extent.关键词：traffic control strategy;token bucket algorithm;single-rate three-color marker
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发布时间： - 摘要：As the existing Virtual Local Area Network（VLAN）-based automatic learning schemes,i.e.Virtual Terminal Protocol（VTP）and GARP VLAN Registration Protocol（GVRP） have their respective deficiencies,the automatic learning functions of VLAN are restricted in practical applications.This paper analyses the working principles and shortcomings of these two VLAN-based learning schemes and presents an improved one,which can resolve the problems of VTP and GVRP in practical applications so that the VLAN automatic learning functions can be better applied.关键词：VLAN;VTP;GVRP
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发布时间： - 摘要：On the basis of the study on the major problems encountered in building large-capacity heterogeneous network management systems,this paper presents a process-based dynamic scalable software architecture using the divide-and-conquer strategy.In this architecture,it uses the nested hierarchical service management model and object dynamic memory management technology to solve the major problems encountered in the management of subnet-level large-capacity heterogeneous networks.关键词：heterogeneous;large capacity;divide-and-conquer;service management model;dynamic memory management
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发布时间： - 摘要：A novel side-hole Highly Birefringent Photonic Crystal Fiber（HB-PCF） is proposed.Its phase modal birefringence at 1.55 μm in free space is as large as 2.916×10-3,the sensitivity of its phase modal birefringence to hydrostatic pressure is as high as-2.444×10-5 MPa-1 and the maximum measurable hydrostatic pressure value is 119.3 MPa.In addition,with ultra-low sensitivity to temperature,it is believed to be an excellent candidate for future applications in hydrostatic pressure measurement.关键词：photonic crystal fibers;birefringence;pressure sensitivity;pressure measurement
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发布时间： - 摘要：The layer stranded Submarine Optical Fiber Cable（SOFC） has the advantage of large communication capacity and crush resistance is one of its most important properties.In this paper,anti-crush simulation is performed on two types of typically structured SOFC by using the finite element software and the results are compared and analyzed,which make clear the factors affecting the SOFC anti-crush property and the conclusion has considerable significance to the design of the layer stranded SOFC.关键词：layer stranded SOFC;crush;stainless steel tube
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- 161
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发布时间： - 摘要：With the formulation of IEEE802.3ba standard,100 Gbit/s Ethernet technologies have been verified and standardized and 400 Gbit/s Ethernet and OTN standards become the next focus of concern.This paper discusses the relevant technologies,such as 2SC-DP-16QAM,coherent-detection array,for 400 Gbit/s Ethernet and OTN optical modules on the basis of the current 100 Gbit/s standard.关键词：400 Gbit/s Ethernet;2SC-DP-16QAM;coherent-detection array
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发布时间： - 摘要：The thermal expansion of fiber Bragg grating generates chirps,which are enhanced by the stress produced by its aluminum plate,thus realizing a novel wideband tunable fiber grating dispersion compensator.This compensator has two operating modes,tuning the group time dispersion without central wavelength detuning and tuning the central wavelength without dispersion detuning.The group delay dispersion can be tuned from-350 ps/nm to-690 ps/nm with a center wavelength at 1 551.25 nm.On the other hand,the center wavelength can be shifted by 1 nm with a GVD value around-660 ps/nm.关键词：optical communication;fiber grating;dispersion compensation;tuning;wideband
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发布时间： - 摘要：A new Fiber Bragg Grating（FBG）sensor for simultaneous measurement of temperature and pressure is reported in this paper.A part of a single FBG（about one half of a grating） is securely affixed to an open-loop to form a FBG sensor.When the temperature is raised and pressure applied to the open loop,both the temperature and pressure can be measured simultaneously by using a single FBG.Good linear responses to temperature and pressure are achieved in the measurable temperature range of 2282 ℃ and pressure range of 010 N.关键词：FBG;open loop;temperature measurement;pressure measurement
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发布时间： - 摘要：This paper analyzes and studies two classical packet scheduling algorithms,Max C/I and PF,which support non-real time services in the High Speed Downlink Packet Access（HSDPA） system.In view of the lack of system fairness in these algorithms,this paper proposes a HSDPA-based fast fairness packet scheduling algorithm.While ensuring both the instantaneous channel condition and average system throughput,this algorithm provides the users,whose average throughput is below a certain threshold,with opportunities for priority in service.Simulation results show that this algorithm can ensure long-term fairness among the users.关键词：HSDPA;packet scheduling algorithm;instantaneous channel condition;system fairness
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发布时间： - 摘要：In this paper,we propose a scheme for a smooth handover in the LTE system from the angles of the control and user plane signaling flows.With the coordination among all the modules in the eNodeB,we achieve smooth intra-eNodeB handovers including data forwarding and ensure no packet loss in the course of the handovers.We conduct practical intra-eNodeB handover tests between two cells and present practical results.关键词：intra-eNodeB handover;LTE;data forwarding;smooth handover
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- 278
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发布时间： - 摘要：Synchronization is very important to OFDM systems.In view of timing obscurity of the S&C and Park algorithms,we propose an improved symbol synchronization algorithm.The new method first identifies the probable initial position of the OFDM symbol by correlating the received signals with the known training sequence,and then further identifies its accurate initial position by filtering the correlation operation result.Simulation results show that the timing metric of the improved algorithm has an impulse-shaped peak in the conditions of low SNR and multi-path fading channel and smaller Mean Square Error（MSE） in timing than the conventional methods.关键词：OFDM;symbol synchronization;training symbol;multi-path fading channel;MSE
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发布时间： - 摘要：In order to improve the communication quality in high-speed trains,a scheme for in-train repeaters in the high-speed mobile environment is presented.In this paper,the characteristics of the in-train repeater scheme are briefly introduced.Then,the advantages of this scheme in overcoming the penetration loss and alleviating the fast handoff are studied from the angle of wave propagation.Finally,the substantial role of the in-train repeaters with AFC functions in improving the signal quality is explained theoretically and on the basis of the testing results.关键词：in-train repeater;penetration loss;fast handoff;Doppler frequency shift;AFC
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发布时间： - 摘要：Receiving aperture can effectively improve the BER performance of optical wireless communication links.Starting with the averaging effect of apertures,this paper compares the averaging factor differences between annular apertures and circular apertures and analyzes their impacts on the system BER.The simulation results reveal that,when receiving aperture diameter D<8 cm,there are fairly great differences between the averaging factors of the two shapes of apertures and the relative errors of the BER are fairly large.However,when D≥8 cm,their averaging factors are basically identical and the relative errors are little or negligible.关键词：optical wireless communications;aperture averaging effect;aperture averaging factor;BER
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发布时间： - 摘要：Frequency Correction Channel（FCCH） detection is very important to the synchronization of GSM frequency hopping digital repeaters and the demodulation of broadcast information from the base station.This paper analyses the structures of FCCH and Synchronization Channel（SCH） pulses in GSM public control channels and introduces a FFT-based algorithm for the fast FCCH detection method.Simulation results indicate that this method can accurately capture FCCH and reduce the range of SCH search so as to synchronize the system quickly.关键词：GSM;digital repeater;FCCH
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发布时间： - 摘要：<正>不久前,工业和信息化部、财政部及中国企业联合会在北京人民大会堂召开全国企业技术创新大会。中共中央政治局委员、国务院副总理张德江出席会议并作重要讲话,中国企业联合会会长王忠禹、工业和信息化部部长苗圩、国务院有关部门的负责同志、地方工业和信息化主管部门负责人、国家技术创新示范企业的
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