最新刊期
卷 ， 期 3 ， 2017
- 摘要：With the development of microwave photonics technology,great achievements have been achieved in solving the function that cannot be directly realized in the traditional RF field,and the development of optoelectronic communication technology is greatly promoted.However,microwave photon technology is still facing new challenges:the existing optical communication system consists of discrete optical/electrical,electrical/optical components,smaller size of devices and systems in the constant pursuit of higher speed,higher bandwidth,higher processing power of communication systems,lower power consumption and stronger anti-interference ability.Therefore,by silicon integrated technology and microwave photonic technology combined with microwave photonics system chip integration,thus reducing the cost,smaller size,lower power consumption of the whole system,is the inevitable developing trend of microwave photonics.This paper summarizes the development of microwave photonic integrated technology and silicon-based photonic devices.It is pointed out that tunable and programmable silicon-based microwave photonic chips will become the key technology to limit the development of military and civilian fields.关键词：microwave photon integration;silicon-based photon;integrated chip
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发布时间： - 摘要：This paper first reviews the fundamental principle of Visible Light Communication（VLC）system,considering the limited modulation bandwidth of VLC system.Two methods with high Spectrum Efficiency（SE）is proposed to make full use of the limited bandwidth in VLC system.The paper then introduce two modulation techniques for its realization:Orthogonal Frequency Division Multiplexing（OFDM）and Nyquist-shaped Single-Carrier（N-shaped SC）and their principles.We simulate and compare the performances of OFDM and N-shaped SC in VLC system.The Bit Error Rate（BER）performance and SE of the two systems are analyzed and compared.It is shown that both of the OFDM-based VLC and N-shaped SC-based VLC have high SE,but N-shaped SC is more robust and suitable to the implementation of the VLC system.关键词：VLC;OFDM;N-shaped SC
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发布时间： - 摘要：In Intensity Modulation Direct Detection（IM/DD）optical transmission system with Carrierless Amplitude and Phase modulation Quadrature Amplitude Modulation（CAP-16QAM）,the system capacity is limited due to the power fading effect caused by the dispersion and chirp of intensity modulator.In this paper,we use optical domain equalization scheme based on optical Fiber Bragg Grating（FBG）to realize the optical Vestigial Sideband（VSB）filtering.The simulation results show that the 40Gbit/s CAP-16 QAM system performance after 60 km transmission have been improved by using the proposed equalization scheme,which mitigate the power fading effect efficiently.关键词：optical communication system;short distance;carrierless amplitude phase modulation;equalization scheme
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发布时间： - 摘要：The optical transmission network is often involved in the problems of network nodes.After selecting the source and sink,the network should also designate the central site,which will establish a shortest path for business requirement.In this paper,we propose a new algorithm based on improved genetic algorithm.The algorithm generates a random tree based on the nodes.In the random spanning tree,we choose two nodes among the selected nodes.The sub-path of the node and the selection probability of the sub-path are used to dynamically adjust the crossover and mutation of the adaptive mechanism to improve the search efficiency.Therefore,the genetic algorithm is improved which can be applied to solve the necessary network node problem.Finally,the simulation results show that the proposed algorithm can meet the application.关键词：optical transmission network;PTN;improved genetic algorithm;necessary node
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发布时间： - 摘要：In order to ensure the dynamic monitoring of equipment time synchronization of the new intelligent substation,we analyze the fragility of the central switch device’s time synchronization.Based on the colored Petri network,we build the model of its equipment time synchronization’s operation process of new intelligent substation,and show the attack model of colored Petri network for central switch device’s time synchronization.According to the equation of state to verify the attack accessibility through the linear algebra math analysis tools,we find the time synchronization vulnerability points,and propose solution accordingly.关键词：new intelligent substation;center switch;colored Petri network;time synchronization of vulnerability;equation of state;the accessibility of attack
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发布时间： - 摘要：With the rapid development of cloud computing,big data and Internet applications,datacenters which are regarded as the important infrastructure have also obtained rapid construction and development.Optical interconnect technology which holds the advantages of large capacity,high speed,and low energy has been widely applied to the inter-datacenter networking.With the frequent occurrence of natural disasters and human-made intentional attacks,datacenters and optical datacenter networks are facing an enormous threat.How to design a disaster-resilient optical datacenter network has attracted more and more attention.In this paper,we analysis the current development situation of optical datacenter networks and compare the commonly used survivability technologies.Based on the current situation of optical datacenter networks,we present the development direction of the survivability of the next-generation optical datacenter network.关键词：optical datacenter networks;survivability;content connectivity;natural disasters
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发布时间： - 摘要：The temperature sensing characteristics of the Total Internal Reflection Photonic Crystal Fiber（TIR-PCF）with the air hole as the positive nine side shaped periodic array is investigated by using the full vector finite element method.The effects of different air hole arrangement,duty cycle and wavelength on the temperature characteristics are analyzed and compared with the photonic crystal fiber with hexagonal structure.The result shows that the PCF mode field distribution changes significantly with the change of temperature.The effective refractive index and the limitation of the size of the air hole is inversely proportional to the temperature of the air hole in the positive nine shape periodic arrangement.Keeping the distance between the holes constant,the results show that the larger the duty cycle or the longer the input wavelength,the higher the sensitivity will be.Then,we propose a kind of the positive nine side shaped periodic array and fusion point for cone SMF-PCF-SMF（Single-Mode Fiber,SMF）Mach-Zehnder Interferometer（MZI）temperature sensor.The result shows that when the wavelength is 1 550 nm and the duty cycle is 0.6,the temperature range from-20 to 80℃,and the temperature sensitivity of the sensing structure is0.112 2nm/℃.关键词：photonic crystal fiber;Mach-Zehnder interferometer;temperature sensing characteristics
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发布时间： - 摘要：In order to obtain the mechanical properties of pulling force on each layer,this paper establishes cable tension model by finite element method.The geometric model of single core fiber composite submarine cable is established by combining the outer and inner layer shielding and water blocking tape with similar mechanical properties.The model also neglects the outer layer with small thickness and strength.The same structural rigid body ensures the displacement synchronization between the submarine cables.We then simulate the engineering practice of laying and apply the segmented force load to submarine cable.Finally,the mechanical data of stress,strain and plastic strain of submarine cable are obtained.The results show that the stress and strain of each layer structure increase with the increase of stress,and the copper conductor reaches the yield state first.The data provides a reference for the submarine cable laying work.关键词：optical fiber composite submarine cable;laying;stretch;stress/strain;finite element
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发布时间： - 摘要：In order to solve the problem of high precision measurement of grating pitch in three-dimensional grating measurement,an adaptive three-dimensional object grating pitch measurement method is presented in this paper.Its implementation processes are as follows:obtain the object outline based on a large pitch grating;according to the achieve outline,divide the target area by non-Unicom zoning laws;adjust the partition grating pitch and take second projection;according to the divided target area,reconstruct the three-dimensional object to achieve high-precision measurement regionally.The simulation results show that compared to the traditional four-step phase shift method,the measurement accuracy of the proposed method（with the adaptive grating pitch）is increased by 6.78%,indicating that the proposed method can achieve the three-dimensional object measurement more accurately,which also has good practical value.关键词：three-dimensional measurement;grating pitch;adaptive;region division
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发布时间： - 摘要：In order to improve the efficiency and accuracy of the channel calibration,a full channel automatic calibration system is developed to investigate the 3D MOEMS optical switch array.Through the test of the calibration search process and the analysis of the search algorithm,this paper proposes a combined search method of fine search based on genetic algorithm and rough search based on hill search algorithm.Then,full-channel automatic calibration system is proposed based on a series of test experiments.Finally,the variation rule of the optimal voltage and the number of channels and rows are summed up in the test of the whole channel search scheme.The experimental results show that the full channel search scheme has higher feasibility and search efficiency than conventional methods.关键词：full-channel automatic calibration system;genetic algorithm;hill-climbing algorithm
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发布时间： - 摘要：Based on 1Drandom medium and waveguide theory,we design a multi-layer random laser 2D waveguide structure composed of gold particles and ZnO random medium.We use the quantum theory to analyze the model of the output laser gain particle number and inversion of particle number.The dynamic characteristics of the quantum theory analysis system are caused by a series of relaxation ultra-fast response,and the response time is 100fs.The experimental results show:the model of gold particles fill rates between 25%30%can achieve the output laser more effectively.The peak of the design of 2Drandom laser model can reach 104 V/m order of magnitude.关键词：laser;high latitudes random medium;quantum theory;strong feedback
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发布时间： - 摘要：Under the premise of low Bit Error Rate（BER）,in order to obtain larger code capacity,a new two-dimensional Optical Orthogonal Code（OOC）named ESPC/QCHC is constructed with Extend Square Prime Code（ESPC）as time spreading sequence and Quadratic Congruence-Hop Code（QCHC）as wavelength hopping sequence.The cross-correlation mean value is deduced by analyzing the performance of ESPC/QCHC.The word capacity of the code is theoretically analyzed,and the BER of the code is simulated by MATLAB.The results show that lower BER can be achieved by increasing the number of frequencies when the same code weight（or code length）is given.This code has lower BER and larger code capacity when compared with other two dimensional OOC which constructed by the prime number as time spreading sequence.The simulation results in the Optical Code Division Multiple Access（OCDMA）system have shown that the BER performance ESPC/QCHC is better.关键词：OCDMA system;ESPC;QCHC;bit error rate
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发布时间： - 摘要：In current Vehicle Ad-hoc Networks（VANET）,the existing roadside-aided with location based routing algorithms introduce a large number of redundant control packets and it is easy to fall into local maximum by using greedy forward method.To solve these problems,we propose an Efficient Routing with Message Aggregation（ERMA）.By aggregating control packet and piggybacking mechanism of data,ERMA can reduce the number of sending control packets and deal with the local maximum problem efficiently.The simulation shows that ERMA can efficiently improve the packet deliver ratio,reduce the end to end delay and control the overhead.关键词：vehicle Ad-hoc networks;GPSR;RSU-aided routing;message aggregation
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发布时间： - 摘要：With the rapid development of Internet applications and the increasing demand of data services,there are great challenges in wireless networks.In this paper,the optimization model of joint base-station association,power allocation and channel allocation is proposed.The optimization objective is to maximize the throughput of the network,and to ensure the fairness of the user under the constraints of the individual user quality-of-service.An iterative algorithm is proposed to solve the optimization model,and the simulation results show that the proposed algorithm can effectively improve the network throughput.关键词：base-station association;power allocation;channel allocation;fairness of the user;iterative algorithm
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发布时间： - 摘要：In the traditional Zigbee network,the data forwarding frequency in each layer is not uniform and the path selection is achieved by route request message RREQ flooding.As a result,the energy dissipation of the nodes in the network is not uniform and the network die prematurely.In this paper,a Zigbee routing algorithm IZRA-AODVjr based on the node energy balance mechanism is proposed.Through controlling intermediate low energy nodes to forward RREQ data packet and balancing the energy level of each node in the network,the proposed algorithm divides the energy state of the node according to the dynamically established global node energy metric to solve the disadvantages of the traditional routing algorithm,which considers the node energy protection and extends the network lifecycle.The simulation results show that the proposed algorithm can effectively reduce the overall energy consumption of the network and improve the node survival rate.关键词：Zigbee network;AODVjr routing;energy balance
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发布时间： - 摘要：The third generation mobile communication technology and wireless LAN are required to integrate effectively.In order to have the most effective integration,this paper proposes a new multi-objective decision algorithm based on Vague set.Firstly,this paper proves the uniqueness of the proposed algorithm.Then,according to each parameter value in heterogeneous network and its characteristic,we use different formulas to deal with parameters,and use the proposed algorithm to calculate and simulate data.Finally,the simulation results are compared with those of the traditional fuzzy switching algorithms.By comparing the simulation results,we find that the proposed algorithm is more intelligent,and can effectively reduce the ping-pong effect in a heterogeneous network switch in the integration.关键词：heterogeneous network;swith;Vague sets;ping-pong effect
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发布时间： - 摘要：According to the problem of Orthogonal Frequency Division Multiplexing（OFDM）systems are very sensitive to carrier frequency offset,we analyze the performance of decision feedback algorithm.By mathematical deduction the phase rotation value of adjacent symbol data in frequency domain,a Non-Data-Aided（NDA）method without the pilot signals is proposed for correct the Residual Frequency Offset（RFO）.The method correct the RFO for the received signal in time domain.The pilot subcarriers are not required to achieve high efficiency.Simulation results show that,the proposed algorithm can track the frequency offset effectively in multipath channel and the tracking range is 5% of the subcarrier space,which has high practical application value.关键词：OFDM system;residual frequency offset;blind tracking;non-data-aided
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发布时间： - 摘要：In the traditional use of Distributed-Space Time Block Codes（D-STBC）in the relay system,matrix relay nodes generated code words need to control message overhead without changing the relay node number,which is not suitable to the practical communication scenarios.In order to solve the problem,we propose a new method of D-STBC coding.The method introduces D-STBC in traditional multiple input multiple output system and uses the AF forward agreement.The Relay nodes don’t require the control message when generating code word matrix and cooperating with other nodes.Therefore,the adaptability of the communication system of collaboration and performance of the system can be improved.Finally,the MATLAB simulation results show that the method has more superior performance in full diversity and full rate conditions with low decoding complexity.关键词：D-STBC;full-diversity;amplify-and-forward;relaying networks
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发布时间： - 摘要：A dual-band patch antenna operating in the Terahertz regime is presented.By loading the double T-type radiation slots,the surface current path on the patch is modified,which results in the dual-band operation of the antenna.Simulation results indicate that the designed antenna can operate on the bands of 300 and 670GHz simultaneously with a maximum gain of7.13 dB.Featured with a simple structure,easy fabrication and stable performance,the dual-band antenna can be applied in Terahertz communication systems.The proposed design scheme has certain significance to the design of dual-band patch antenna.关键词：dual-band antenna;Terahertz;return loss;directive gain
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