最新刊期
卷 ， 期 3 ， 2014
- 摘要：Internet of Things is a network which is constituted by things connected each other to transmited and exchanged informations for satisfied we needs.Internet of Things is not a independent network,it is dependented on Internet.Internet of Things has men who control the things,but men are minority,things are majority.The sensors are the key of Internet of Things,different uses need different sensors,more dispersed.The industry of sensors are also more dispersed.关键词：Internet;sensor;Internet of things
- 6
- |
- 283
- |
- 4
发布时间： - 摘要：On the basis of the analysis of the five development trends of Optical Transport Networks（OTN）,this paper points out that the Software Defined Network（SDN）technology will have direct or indirect impacts on three of them,specifically embodied in four aspects:software defined transport plane,software defined control plane,IP and optical cross-layer cooperation and convergence and optical network resource virtualization.Research results show that SDN is an important trend of OTN beyond 100Gbit/s.关键词：OTN;SDN;beyond 100Gbit/s
- 3
- |
- 320
- |
- 13
发布时间： - 摘要：Path assignment is a core issue for optical ring networks.On the basis of the characteristics of the Genetic Algorithm（GA）,Particle Swarm Optimization（PSO）algorithm and Ant Colony Algorithm（ACA）,this paper proposes a novel hybrid ACA algorithm incorporating PSO and ant GA and searches the optimal ring path in optical networks.Simulation results indicate that the proposed algorithm outperforms the basic ACA and the hybrid GA and PSO algorithm in terms of convergence speed and the search results,confirming its effectiveness.关键词：optical network;optimal ring;ACA;PSO algorithm;GA
- 2
- |
- 87
- |
- 4
发布时间： - 摘要：High-order external modulation and coherent detection technology are generally used in long-haul optical communication systems to improve the overall system transmission capacity.However,a low-cost direct modulation-direct detection technology tends to be more used in short-haul optical communication systems.In this case,it is necessary to adopt advanced multilevel modulation to realize high-rate large-capacity transmission.Currently,there are three principal modulation schemes considered internationally,i.e.Pulse Amplitude Modulation（PAM）,Direct Detection-Orthogonal Frequency Division Multiplexing（DD-OFDM）modulation,Carrierless Amplitude/Phase（CAP）modulation.This paper analyzes and compares their principles and performances,hoping to use them as the basis for the design of future short-haul large-capacity optical communication systems.关键词：short-haul optical communication;PAM;CAP modulation;DD-OFDM
- 2
- |
- 350
- |
- 7
发布时间： - 摘要：In order to reduce the use of PLL as much as possible in the process of demapping,this paper designs a sync circuit. On the basis of the uniform gaps in the clock produced by a sync clock,the sync circuit is used to realize deframing,de-FEC and demapping from OTU2to ODU2.Simulation and FPGA test results verify the correctness of the circuit functions,indicating that this circuit can accomplish demapping from OTU2to ODU2in real-time and accurately.关键词：gap in the clock;deframer;asynchronous mapping
- 2
- |
- 52
- |
- 0
发布时间： - 摘要：In view of the problems in traditional and intelligent communities,this paper presents the architectures of next generation cloud platform-based intelligent communities,which have the advantages of fully breaking down the barriers between data and bringing about such characteristics as energy saving,low loss,fast deployment,high stability,safety and easy maintenance.Practical cases show that cloud platform-based intelligent communities solve the problems of the traditional communities and optimize the existing IT environment.Finally,it summarizes the prospects of the integration of cloud computation with people’s living.关键词：cloud platform;intelligent community;information service
- 2
- |
- 578
- |
- 14
发布时间： - 摘要：This paper simulates and analyzes four modulation formats,i.e.Duobinary Return to Zero（DRZ）,Modified Duobinary Return to Zero（MDRZ）,Carrier Suppressed Return to Zero（CSRZ）and Return to Zero DPSK（RZ-DPSK）in 40Gbit/s single-channel transmission systems by using Optisystem.On the basis of the spectrum diagram,eye diagram and Qfactor,it analyzes the performances of these four modulation formats in long-range transmissions.关键词：fiber-optic communication;modulation format;performance analysis;spectrum diagram;eye diagram
- 2
- |
- 138
- |
- 1
发布时间： - 摘要：On the basis of the property and features of equideviate matrixes,a novel method for constructing Quasi-Cyclic LowDensity Parity-Check（QC-LDPC）codes is presented in this paper.The LDPC codes constructed in this method are easy for effective encoding and decoding,have good girth properties and can avoid the girth-4effectively,which prevents the generated codes from short cycle interference.Furthermore,it can save the storage space in terms of hardware implementation.The simulation results show that when the bit error rate reaches 10-7,the net coding gain of the high code-rate QC-LDPC（3780, 3542）constructed this way is improved by about 2.1dB as compared with that of the RS（255,239）code in ITU-T G.975, proving that the code has a better error correcting performance,and by 0.35dB as compared with that of regular QC-LDPC（4221,3956）code.关键词：equideviate matrix;QC-LDPC codes;net coding gain
- 2
- |
- 53
- |
- 0
发布时间： - 摘要：This paper presents a theoretical model for evaluating the standard deviation of Four-Wave-Mixing（FWM）noise in multi-span dispersion managed WDM systems with Differential Phase-Shift-Keying（DPSK）modulation.This model takes into consideration the effects of the randomness of bit sequence and initial phase of the pulses in each channel.Using this model,it analyzes some practical cases.The results show that with the same average power,the noise deviation ratio of DPSK modulated signals is smaller than that of On-Off Keying（OOK）modulated signals,that the variations of bit rates have little effect on the noise deviation value of the DPSK modulated signals,while the average power has great influence.With the increase of the latter,the voice deviation value increases almost exponentially.关键词：WDM;dispersion managed;FWM;DPSK
- 4
- |
- 61
- |
- 1
发布时间： - 摘要：When the hash lookup table is used to construct the filtering database defined by the VLAN-aware bridges in IEEE 802.1Qprotocol,the hash bucket is usually used to resolve the hash collisions caused by multiple keywords corresponding to the same storage address.The traditional hash bucket is low in efficiency as it acquires the resources of the entire learning table with only one hash address.This article presents an optimization method to improve collisions of the hash table,i.e.constructing the hash table by dual hash buckets and an overflow bucket and performs address learning in a balanced learning approach. When the dual bucket overflow occurs,it stores the overflow-entry in the overflow bucket temporarily and notifies the CPU to release the location of collision-entry and move the overflow-entry.The simulation results show that this new algorithm minimizes the hash collisions effectively,and improves the utilization rate of the storage space of the hash table.关键词：hash bucket;hash collision;balance learning
- 2
- |
- 44
- |
- 0
发布时间： - 摘要：Dynamic Routing and Wavelength Assignment（RWA）is a key issue to Intelligent Optical Networks（ION）,and heuristic algorithms represented by the Ant Colony Optimization（ACO）algorithm is one of the most preferred schemes for such issues.This paper proposes an Adaptive Ant Colony Optimization（ADACO）algorithm-based RWA mechanism,which realizes state adjustment for the global pheromone updating by adopting adaptive strategies.Theoretical analysis and numerical simulation results show that compared with Dijkstra+FF algorithm,the improved ADACO+FF algorithm effectively lowers the network blocking probability and the optimal blocking probability improvement in regular MESH and NSFNET topology scenario is up to 0.3and 0.2,respectively.关键词：ION;dynamic RWA;heuristic algorithm;ADACO algorithms;adaptive strategy
- 2
- |
- 88
- |
- 4
发布时间： - 摘要：To solve the problem of spectrum fragmentation,this paper proposes a modulation format-based spectrum reconstruction algorithm taking into consideration the feature of variable service modulation format in elastic optical networks and compares in simulation this algorithm with the shortest-path reconstruction algorithm.The results show that the proposed algorithm more flexibly changes the allocation of spectrum subcarriers and effectively improves the utilization of spectrum resources under the same network conditions.关键词：elastic optical networks;modulation format;spectrum resource reconstruction
- 2
- |
- 197
- |
- 8
发布时间： - 摘要：The localization of access network services has enabled Network Coding（NC）to be more and more broadly applied in Passive Optical Networks（PON）.However,data packets with different lengths result in the waste of bandwidth in the transmission of encoding packets.In order to improve the bandwidth utilization rate and reduce the energy consumption at the Optical Line Terminal（OLT）,this paper proposes a novel encoding scheme for packets queue and its implementation.Simulation results show that the proposed encoding and implementation scheme improves the bandwidth utilization rate,effectively reduces the occupation of ONU memory by the decoding packets and optimizes the system downlink throughput and the energy efficiency of the OLT.关键词：NC;PON;encoding scheme;energy efficiency
- 2
- |
- 76
- |
- 9
发布时间： - 摘要：This paper introduces the framework of EPON and proposes the solution to its link data acquisition.Furthermore,it discusses in-depth the module design of the hardware and software and analyzes the encryption algorithm for EPON and the package format of the protocol frame.It is verified that this design can efficiently acquires the specified real-time data.关键词：EPON;data acquisition;protocol frame;link layer
- 2
- |
- 55
- |
- 2
发布时间： - 摘要：Future telecommunication networks are expected to be flat-structured and support a variety of traffic demands.In line with the diversified demands,the Mixed Line Rate（MLR）is applied to the metro OTN traffic grooming algorithm,grooming services at the different bit-rates.A heuristic algorithm is proposed for the service grooming in large and medium-sized networks.Then this algorithm is applied to metro networks and the results in MLR and Single Line Rate（SLR）networks are compared,which show that this algorithm applied in MLR OTN metro networks can reduce the network construction cost.关键词：OTN;traffic grooming;metro network;mixed line rates
- 2
- |
- 45
- |
- 4
发布时间： - 摘要：Using a single-fiber bidirectional system is an effective solution to the capacity expansion of the fiber-optic communication system and the simulation study of its performances is important to its practical applications.This paper presents an effective scheme,i.e.using the wavelength shifting technology to lower the reverse Rayleigh scattering in the system and using OptiSystem to set up a simulation model for the QPSK modulation-based bidirectional transmission system.When the transmitting power is 3dBm and the transmission distance is 360km,the Q factor of the proposed system is improved by 1.5times and the BER is reduced to 10-170 as compared with the traditional unidirectional WDM system.In addition,when the Q factor is over 6,the maximum transmission distance can reach 1 600km.Research results show that when the transmission capacity is the same,the bidirectional system can reduce the use of one fiber and its transmission performance is also somewhat improved.关键词：QPSK;wavelength shifting;bidirectional transmission
- 2
- |
- 82
- |
- 1
发布时间： - 摘要：Fiber lasers have huge advantages compared with the traditional lasers.This paper proposes a novel all-solid squarelattice Yb3+-doped Photonic Crystal Fiber（PCF）for the development of fiber lasers with still better output characteristics and simulates its structure and properties by using the Finite Element Method（FEM）.By designing defect positions and optimizing the sizes of B2O3-doped rods,it enables the Mode Field Area（MFA）of the fundamental mode of this fiber to reach 4 405μm2 at 1.06μm and satisfy the conditions for single-mode transmissions and low bending loss properties at the same time,i.e.maintaining single-mode transmissions when the bending radius is larger than 8cm.This PCF can be used as a gain fiber in high power fiber lasers.关键词：PCF;mode field area;confinement loss;bending loss
- 2
- |
- 131
- |
- 0
发布时间： - 摘要：In order to timely discover and differentiate the faults in optical fiber composite submarine cables,a novel multi-scale wavelet analysis-based detecting and diagnosing method is proposed in this paper.By this method,the Brillouin scattering frequency shifts in submarine cable fibers are first measured by using a Brillouin optical time-domain reflectometer and then the fault spots are detected and analyzed by using the dual-threshold method.The grounded faults are diagnosed by using the threshold method,but the ungrounded faults are decomposed in 8scale by using coif2wavelet basis.The research results indicate that anchor damage and overheating faults caused by partial discharges in plastic sheath can be effectively diagnosed by using the sensitivity of high frequency coefficient scale of wavelet decomposition to spatial distance.On the basis of analyzing the features of submarine cable faults,the effectiveness of this approach is verified by setting up the simulation data of submarine cable faults.关键词：optical fiber composite submarine cable;fault detection and diagnosis;Billouin optical time domain reflectometer;wavelet analysis
- 4
- |
- 393
- |
- 10
发布时间： - 摘要：The microelectronic technology,which uses electrons as its information carrier,is currently running into the bottleneck of development.As optical communication is characteristic of broad bandwidth and high transmission rate,it is an inevitable trend for the development of future information transmission to integrate photonic carriers with electronic carriers.The highly-efficient coupling between waveguides and fibers is the key to realizing photoelectronic integration.This paper reviews the latest advances in the development of several typical couplers at home and abroad,including the tapered coupler,Gradient Refractive Index（GRIN）lens coupler and vertical grating coupler.In addition,it compares and analyzes their performance indexes,advantages and disadvantages and predicts the feasibility of further improving their coupling efficiencies.The results show that with the advantages of high coupling efficiency,wide bandwidth,mature technology,large process tolerance and simple coupling steps,vertical granting couplers have a broad prospect of applications in the fields of optical communication and integrated optoelectronics.关键词：silicon-based photonics;coupler;coupling efficiency
- 4
- |
- 285
- |
- 2
发布时间： - 摘要：An auto test system is designed in this paper,which can test all the specifications of the MEMS-based Variable Optical Attenuators（VOA）expediently and enable the optical spectrum analyzer to share the test results with the polarization controller.By programming,data are displayed and curves are plotted in real-time,and data can be stored in the database automatically.Compared with the normal test instruments,this system is low in manufacturing cost,high in measuring accuracy and has high application values.关键词：MEMS-VOA;auto test system;database
- 2
- |
- 45
- |
- 0
发布时间： - 摘要：In time-phase modulation systems,the aliasing signals of multi-channel time-phase modulation signals received at the multiple sensor ports are separated into relatively independent segments by adopting the fast Independent Component Analysis（ICA）algorithm so that their phase abrupt features can be extracted and their detection and demodulation accomplished.Simulation results indicate that this technique can extract the phase abrupt features of time-phase modulation signals with distinct effects.关键词：time-phase modulation;ICA;abrupt phase;feature extraction
- 2
- |
- 36
- |
- 1
发布时间：
- Postal code：430205
- Technical support is provided by Beijing Founder electronics co., LTD 鄂ICP备2022010197
鄂公网安备 42011202002092号 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
- Total Visits：75845
0