最新刊期
卷 33 ， 期 9 ， 2017
- 摘要：According to the problem of high complexity of base station detection in large scale multiuser multiple input multiple output (MIMO) system,a low complexity multiuser variable node full information Gaussian message passing iterative detection algorithm based on forced convergence (VFI-GMPID-FC) was proposed.Firstly,the traditional Gaussian message passing iterative detection (GMPID) algorithm was improved to obtain VFI-GMPID algorithm,the detection performance of the VFI-GMPID algorithm approximates the minimum mean square error detection (MMSE) algorithm,but the complexity was considerably less than the MMSE algorithm.Then,the VFI-GMPID-FC algorithm was proposed to reduce the complexity of the algorithm and improve the detection efficiency.Finally,the simulation results show that the proposed algorithm can effectively reduce the algorithm complexity while ensuring the detection performance.关键词：large scale multiuser MIMO;Gaussian message passing iterative detection;forced convergence;low complexity698|562|0更新时间：2024-06-05
- 摘要：The high-speed mobile transportations,such as high-speed rails,pilot-less airplanes,are mostly in the open areas.Due to the existence of line of sight (LOS) propagations,the Rayleigh fading model can not describe the channels very well in these environments.The Rice fading channel model is constituted of a LOS component and a multiple-path component,which can characterize the channels more accurately.Based on the Rice model,the improved channel estimation methods and corresponding decoding methods were proposed based on the superimposed training sequences for massive multiple input multiple output (MIMO) system.The improved channel estimation methods were divided into two cases:the LOS component was known to the receiver and the other was unknown.The numerical simulation results show that the superiority of the proposed methods.关键词：massive MIMO system;Rice fading channel;superimposed training sequence;channel estimation752|1526|0更新时间：2024-06-05
- 摘要：Virtual cell is identified as one of factors affecting the system performance in ultra-dense network where the interference is complex with the increasing density of cells and the resource allocation strategies of different dimensions were coupled in overlapped virtual cells.Therefore,aiming at designing the edge weight of virtual cells,an algorithm considering the resource allocation in advance was proposed by taking interference fair power allocation,MU-MIMO operation and cooperative transmission into account simultaneously.Based on the proposed scheme of weight,the overlapped virtual cells could be formed by the proposed clustering algorithm named pairwise maximum weights.The simulation results demonstrate that the proposed algorithm can improve the sum-rate performance of the network effectively at a low complexity.关键词：ultra-dense network;virtual cell;edge weight;overlapped;clustering523|839|0更新时间：2024-06-05
- 摘要：The current researches of evolution model mainly focus on the spread of the individual topics,rarely considering the influential factors between multiple topics.A new topic evolution model was proposed by considering the interference among topics based on SIR model,which characterized by the influence of the similarity of the topic on the probability of propagation.The experimental results show that within the critical value,the similarity degree of positive and negative trends enhance or hinder the process of topic evolution,and the degree of action varies with the degree of interference nodes,which is expressed as evolutionary consistency under positive similarity and the evolutionary separability under negative similarity.When the critical value is exceeded,the effect of strengthening or hindering tends to saturation.关键词：topic evolution;multiple topics;susceptible-infective-removal model;similarity of interference517|1083|0更新时间：2024-06-05
- 摘要：In the multi-drop broadcast system,the existing research is to optimize the single-user security rate in the complete channel state information.In fact,it’s impossible that there exists only one user in the system.The base station often receives incomplete channel state information.Aiming at this problem,a robust beamforming scheme was proposed.In the multi-user case,considering the influence of channel estimation error on the system security rate,the particle swarm optimization algorithm was used to optimize the emission beamforming vector,artificial noise covariance and power split ratio to ensure that the user collects a certain energy while maximizing the safe transmission rate.The simulation results show that the proposed scheme is slightly lower than the security rate in the ideal case,but it is meaningful to the actual system,taking into account the existence of eavesdropping users and the estimation error.关键词：simultaneous wireless information and power transfer;artificial noise;estimation error;safety rate;beamforming499|1077|0更新时间：2024-06-05
- 摘要：An antenna selection scheme of space-time block coding combined with eight-beamforming (STBC-BF) in massive MIMO system was proposed.Transmit symbols were coded by space-time block coder,then the coded symbols were weighted by antenna array form eight-beam.The antenna selection technology was used to select the transmitting antenna and the receiving antenna,traditional decoding method was performed at the receiver.The proposed scheme can not only obtain the space diversity gain and array gain,but also can reduce the computational complexity by reducing the number of the RF links.Simulation results confirm the validity of the proposed scheme.关键词：massive MIMO;beamforming;space-time block coding;antenna selection659|634|0更新时间：2024-06-05
- 摘要：Sparse code multiple access technology,as a competitive non orthogonal multiple access scheme for the fifth generation wireless communication network,has a broad application prospect.However,current SCMA uplink use the flooding scheme of message passing algorithm for decoding,both the detection complexity and convergence properties are not ideal.A serial message passing algorithm which changed the information updating strategy was proposed,which performed message processing and deliveried according to the order of the variable nodes.Each of variable node simultaneously performed the reception of the verification message and the transmission of the variable message.The theoretical and simulation results show that the proposed algorithm not only maintains good performance,but also has low decoding complexity.关键词：sparse code multiple access;multiuser detection;variable node;serial message passing435|646|0更新时间：2024-06-05
- 摘要：The study of approximate k nearest neighbors query has attracted broad attention.Local sensitive hash is one of the mainstream ways to solve this problem.Local sensitive hash and its varients have noted the following problems:the uneven distribution of hashed data in the buckets,it cannot calculate the appropriate query range (for the parameter k) to build index.To tackle the above problem,a new data struct which called SLSB-forest was presented.The SLSB-forest combined the LSH and the B-tree to maintain the amount of bucket’s data in reasonable range.Two query algorithms were proposed:fast and accurate priority search.Theory and experimental results prove that query range can dynamic change during searching approximate k nearest neighbors.关键词：approximate k nearest neighbor;locality sensitive hash;high dimensionality571|1064|0更新时间：2024-06-05
- 摘要：In order to improve the spectrum sensing performance and overcome the shortcomings of the classical algorithm,a new cooperative spectrum sensing algorithm based on Wishart random matrix theory was proposed.According to the logarithmic distribution characteristics of the sampled covariance matrix eigenvalues and using the ratio of maximum eigenvalue and geometric mean eigenvalue,a simple closed-form threshold expression could be obtained,and the spectrum sensing decision could be performed depend on the threshold.The simulation results show that the proposed algorithm can get better sensing performance even under the conditions of a few number of cooperative users,low signal to noise ratio and a few samples.It is less affected by false-alarm probability and the extreme values,and has better detection performance than similar algorithms.关键词：spectrum sensing;Wishart random matrix;sample covariance matrix;geometric mean eigenvalue644|973|0更新时间：2024-06-05
- 摘要：Aiming at the problem of pilot contamination in massive MIMO system,a dynamic pilot assignment strategy based on user classification was proposed.The target cell user was divided into the central user and the edge user based on the variance of target cell user signal intensity.The central user used the maximum C/I algorithm to assign pilots to maximize the channel capacity of the central user.The edge user used greedy algorithm to assign pilots to improve the signal to interference and noise ratio of each edge user.Simulation results show that the proposed strategy can improve the channel capacity of the system while improving the signal to interference and noise ratio of the edge user.关键词：massive MIMO;pilot contamination;pilot assignment;user classification381|962|0更新时间：2024-06-05
- 摘要：Telecom users’ arrears forecasting is a classification problem of unbalanced data set.To deal with the problem that the traditional SVM on the unbalanced date set had a low detection accuracy of minority class,a novel method was proposed.Based on the fact that the position of classification plane was determined by the boundary samples,the proposed method was implemented via removing some of samples closed to the classification plane to avoid the deficiency of the traditional SVM algorithm.Finally,the proposed method was compared with other approaches on unbalanced data sets.The simulation results show that the proposed method can not only increase the detection accuracy of minority but also improve the overall classification performance.关键词：arrear;unbalance;support vector machine;boundary;under-sampling490|944|0更新时间：2024-06-05
- 摘要：Aiming at the problem of the influence of multipath channel and impulse noise on the performance of power line carrier communication system,a transceiver scheme for power line communication system was proposed which could effectively combat the influence of multipath channel and impulse noise.Firstly,the power line channel impulse response and the impulsive noise in the time domain were jointly viewed as a sparse vector.Then,the sparse Bayesian learning theory was adopted to estimate the power line channel and impulse noise jointly.The impulse noise was removed and the channel gain was compensated at the receiver.The simulation result shows that the proposed receiver scheme has better performance than traditional receiver considering channel estimation and impulse noise suppression separately.关键词：power line carrier communication;channel estimation;impulsive noise;sparse Bayesian learning779|887|0更新时间：2024-06-05
- 摘要：In high-speed environment,fast fading and non-stationary limits the channel estimation performance,so a channel estimation method for high-speed mobility in MIMO downlink was proposed.A self-feedback extended Kalman filter (EKF) was set up to track the channel response and correlation parameters.An iterative detector ＆amp; decoder receiver was adopted to deal with the problem that the observation equation is an underdetermined equation.The simulation results show that compared with least squares(LS) in high speed environment,the proposed method improves the channel estimation accuracy and performance of whole system.And it could be applied in baseband signal processing of wireless receiver in high-speed train.关键词：multiple input multiple output;orthogonal frequency division multiplexing;high-speed mobility,non-stationary channel estimation;extended Kalman filter856|1201|0更新时间：2024-06-05
- 摘要：The image encryption algorithm based on multi-direction pixel continuous folding mechanism and Radon transform was proposed.Firstly,the initial plaintext was equally segmented to get left and right sub-blocks.Then the Radon transform was used to obtain the radon projection spectrum image by processing the left and right blocks at 0～180 degrees.And Radon projection spectrum image of left block was permutated by Arnold map,while the Radon projection spectrum image of right block was permutated based on gravity model to get two su-scrambling ciphers,then the entire scrambled image is formed by combining them.To diffuse pixels from multiple directions in space,four direction continuous folding mechanism was designed to change the pixel values by using the diffusion function corresponding to four different directions for realizing image encryption.The experimental results show that this algorithm has higher security and attack resistance with more uniform of pixel distribution in output cipher compared with the current image encryption technology.关键词：image encryption;Radon transform;Radon projection spectrum;Arnold mapping;multi-direction pixel continuous folding;Gravity model390|861|0更新时间：2024-06-05
research and development
- 摘要：The evolution of optical fiber communication technology is driven by the ceaseless growth of capacity demand of Internet.Space division multiplexing (SDM) based on multi-core fiber,few-mode fiber,few-mode multi-core fibers and orbital angular momentum has become the focus of academy and industry.Key technologies and latest research progress were reviewed,including novel fiber design,spatial mode conversion,spatial channel de/multiplexing and optical amplification.Based on the comparison and analysis of four kinds of SDM technologies,their bottlenecks and potential future application were also discussed.关键词：optical fiber communication;space division multiplexing;multi-core fiber;few-mode fiber1359|2688|0更新时间：2024-06-05
summarize
- 摘要：As the social public resources,the value and function of government data has become a global consensus,but the construction of our local open government data platforms is still in a preliminary stage.Taking the Guiyang open government data platform as an example,the design and construction scheme of open government data platform was introduced from various modes,general framework,potential data acquisition mode,data quality management and metadata construction.The meaningful reference for the construction of our local open government data platform was provided.关键词：general framework;open government data;data quality;metadata1056|2062|0更新时间：2024-06-05
- 摘要：Operators are facing double pressure of the rapid development of network and the drop of telecom charges.The construction of the transport network needs to consider the long-term development.The construction plan can not only meet the business needs of the near future,but also meet the future direction of business development.By analyzing the shortage of traditional rolling planning method,oriented by planning development goals,a dynamic rolling planning method of transport network was presented.The effect of the business developing trend to the network was transformed from the artificial fuzzy thinking into quantitative calculation method,to avoid investment waste caused by inconformity of network construction and business changes.关键词：transport network;dynamic;rolling planning method;intelligent planning tool496|1097|0更新时间：2024-06-05
- 摘要：With the blowout development of cloud-computing market,start-up enterprises gradually increase the demand for cloud business.For the cost-sensitive customers,using the traditional government-enterprise PPPoE in the LSN environment could reduce the wastage of public IPv4 addresses.Meanwhile,ICT services based on cloud-computing was provided for customers.Several solutions which mixed the traditional government-enterprise gateway solution and the latest LSN scene were presented.Through the analysis of advantages and disadvantages of each scheme,reference for government-enterprise customers dialing-up to access internet in LSN environment was presented.403|1156|0更新时间：2024-06-05
- 摘要：In the scenario that a large number of small cells are deployed in the mobile communication network,the number of carriers to be detected by the user equipment (UE) in inter-frequency scanning is considerably larger than that in the conventional network deployment scenarios.This procedure may consume tremendous amounts of UEs’ energy.In order to solve this problem,a small cell discovery (SCD) scheme based on TOA fingerprint database to alleviate intensive energy consumption was proposed when the UEs try to find their potential serving small cells.The proposed scheme reduces the energy consumption of the UE by decreasing the number of unnecessary inter-frequency detection.The simulation results verifiy that the proposed scheme,compared with the existing SCD strategy using received signal strength (RSSI) based radio maps,has better anti-noise performance and higher accuracy.In addition,it can effectively help the high-speed UE avoid performing inter-frequency detection,and hence increase the rate of the UE being successfully connected to the appropriate small cell.关键词：small cell discovery;TOA;fingerprint database;inter-frequency detection;energy efficiency407|874|0更新时间：2024-06-05
- 摘要：Aiming at the shortcomings of false alarm and leakage alarm in the existing fire detection system and the complicated wiring,high cost and poor flexibility of the traditional wired fire detection system,a set of home fire detection system based on wireless multi-sensor data fusion was designed,to detect the fire safety hazards caused by kitchen equipment aging,electrical wiring aging or electrical equipment aging.The design of multi-sensor data fusion algorithm,fire detection system hardware framework and software implementation were described in detail.The simulation results show that the scheme has the characteristics of high accuracy and flexibility.关键词：multi-sensor data fusion;fire detection;CC1101;neural network;fuzzy control;STM32F407633|1387|0更新时间：2024-06-05
- 摘要：With the adoption of IMS technology system,the construction of IMS administrative switching network faces a series of planning research such as core network,bearer network,access network and so on.The problems of interconnection between headquarters and IMS network of provincial companies and public network,and the problem of telephone number resource allocation involves number transformation design.Based on the investigation status of State Grid administrative switching network,and the analysis of key technologies and architecture of IMS,combined with the characteristics of the electric power network,the transformation number design for IMS administrative switching network was presented,technological guidance was provided for the orderly evolution of switching network.关键词：administrative switching network;IP multimedia subsystem;number transformation597|1154|0更新时间：2024-06-05
- 摘要：A distributed database load balancing algorithm based on software defined networking was proposed,which separated the data,control and application to calculate the actual load of a single server in the server cluster.By querying the streams sampling record,the minimum number of server paths were determined,the request response time was reduced,the system throughput and fault tolerance were improved,and the full use of the purpose of server resources was achieved.The general load balancing technology was compared with the load balancing technology based on the software defined networking in the internal network of the distributed database experiment,the result shows that in the load state of the different server clusters,the average response time of the latter is smaller than that of the former,and can get better load balancing effect.关键词：extensible load balancing strategy;software defined networking;adaptive stream sampling;distributed server cluster583|1049|0更新时间：2024-06-05
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