最新刊期
卷 33 ， 期 7 ， 2017
- 摘要：In the past few years,the development of big data technologies has brought new opportunities and challenges in many business sectors.As an important contributor in the telecommunications industry,China Tower has its unique advantages in data.Firstly,the industrial structure of big data was expounded,then the data assets of China Tower were introduced.Finally,the application of big data of China Tower was prospected.关键词：big data application;data sharing;data opening453|1068|0更新时间：2024-06-05
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- 摘要：Deploying dense network in 5G system increases the number of nodes,which leads to a sharp increase in power consumption of wireless communication system,aggravates the economic burden of mobile network operator and exacerbates the emission of CO2.Therefore,considering the number of candidate base station (BS) group and the relative position of the BS supplied by new energy,a comprehensive power consumption model in wireless communication system was investigated in terms of the power consumption and economical level.A base station sleep algorithm based on power consumption and energy cost balance was proposed to achieve a tradeoff between them,which selected candidate groups according to the corresponding power consumption and then determined the active group by choosing the cheapest ones.Simulation results show that the proposed algorithm can significantly reduce energy cost of communication bases system although it leads to a negligible increase in power consumption.关键词：5G;energy saving;green network;resource allocation;sleep mechanism457|623|0更新时间：2024-06-05
- 摘要：Achievable sum rate was investigated for the massive multiple input multiple output (MIMO) uplink system with channel aging in the high-speed mobile scenario,and the effect of both channel aging and the Ricean factor on the power scaling law was characterized.Theoretical analysis and simulation results show that the transmit power of each user is scaled down by 1/M for the time varying Rican fading channel indicating that the Ricean factor affects the power scaling law and sum rate,and achievable channel aging only leads to a reduction of the sum rate.Moreover,the effect of channel aging on the sum rate can be ignored compared with that of the Ricean factor in the time varying Ricean fading channel.关键词：high-speed mobile scenario;massive multiple input multiple output;time varying Ricean fading channel;channel aging;achievable sum rate;power scaling law415|186|0更新时间：2024-06-05
- 摘要：In order to solve the problem of the pilot contamination in multi-cell massive multiple input multiple output (MIMO) system,a dynamic pilot allocation scheme was proposed by analyzing the error of MMSE channel estimation.Users living in the fringe regions between the target cell and adjacent cells adopt the dynamicpilot allocation scheme,the rest of users are randomly pilot allocation to increase the average achievable sum rate of the downlink.The simulation results show that the proposed method can not only apparently improve the performance of the channel estimation,but also effectively improve the achievable sum rate of the downlink in the whole system.关键词：massive MIMO;pilot contamination;pilot allocation;achievable sum rate82|289|0更新时间：2024-06-05
- 摘要：Among the uplink signal detection algorithms for massive MIMO systems,the minimum mean square error (MMSE) algorithm can achieve the near-optimal linear detection performance.However,conventional MMSE usually involves high complexity due to the required matrix inversion of large-size matrix,which makes it hard to implement in realistic applications.Based on joint steepest descent (SD) algorithm and Gauss-Seidel iteration,a low complexity hybrid iterative detection algorithm was proposed.The SD algorithm was employed to obtain an efficient searching direction for the following Gauss-Seidel to speed up convergence.Meanwhile,an approximated method was also proposed to compute the bit log-likelihood ratio (LLR) for soft channel decoding.Simulation results verify that the proposed algorithm can converge rapidly and achieve its performance quite close to that of the MMSE algorithm with only a small number of iterations.Meanwhile,the complexity is reduced by an order of magnitude,which is kept consistently of O(K 2).关键词：massive MIMO;minimum mean square error;matrix inversion;steepest descent;Gauss-Seidel interative;soft-output57|106|0更新时间：2024-06-05
- 摘要：Due to the high cost and power consumption of some mixed signal components at mmWave frequencies,the conventional full digital precoding technique encounters the problem of high hardware complexity.Consequently,the hybrid analog-digital precoding architecture has attracted the attentions from both academy and industry.Based on this,an orthogonal beam codebook based hybrid precoding algorithm for mmWave MIMO systems was proposed,which utilized the orthogonality of beam codebook to design the analog beamforming vector of each radio frequency (RF) chain in parallel.As a result,the large computational complexity of the conventional orthogonal matching pursuit (OMP) algorithm and the hardware complexity could be greatly reduced.关键词：mmWave;hybrid precoding;beamforming68|172|0更新时间：2024-06-05
- 摘要：Distributed denial of service (DDoS) is a special form of denial of service (DoS) attack based on denial of service(DoS).It is a distributed,collaborative large-scale network attack.A DDoS detection method based on deep learning was presented.The method included two stages:feature processing and model detection:feature extraction,format conversion and dimension reconstruction of the input data packet was performed in feature processing stage;in the model detection stage,the processed features were input to the depth learning network model to detect whether the input data packets was DDoS attack packet.The model was trained by the ISCX2012 dataset,and the model was validated by real-time DDoS attack.The experimental results show that DDoS attack detection method based on deep learning has high detection precision,little dependency on hardware and software equipment,and the model of depth learning network is easy to update.关键词：distributed denial of service;denial of service;deep learning436|532|0更新时间：2024-06-05
- 摘要：The random foreat regression algorithm was introduced to solve the shortcomings of neural network in predicting the PM2.5 concentration,such as over-fitting,complex network structure,low learning efficiency.A novel PM2.5 concentration prediction model named RFRP was designed by analyzing the 22 characteristic factors including the meteorological conditions,the concentration of air pollutants and the season.The historical meteorological data of Xi’an in 2013—2016 were collected to verify the effectiveness of the model.The experimental results show that the proposed model can not only predict the PM2.5 concentration effectively,but also improve the operating efficiency of the model without affecting the prediction accuracy.The average run time of the proposed model is 0.281 s,which is about 5.58% of the neural network prediction model.关键词：PM2.5 concentration prediction;random forest regression analysis;back propagation neural network167|552|0更新时间：2024-06-05
- 摘要：Predictable network performance is critical for cloud applications and can be achieved by providing tenants a dedicated virtual data center (VDC) with bandwidth guarantee.The embedding problem of oversubscribed data center in physical data center network was studied.Compared with the general virtual data center,the traffic pattern between the virtual machines in the over-subscription virtual data was more complicated.Therefore,the flow model and the embedding problem were described.A heuristic algorithm with lower time complexity was proposed for the embedding problem of virtual machine-packet perturbation algorithm.Finally,the simulation algorithm was used to compare the packet perturbation algorithm with the algorithm proposed in the previous work and the famous first-fit.The experiment result shows that the proposed algorithm improves the embedding success rate while reducing the complexity of the algorithm.关键词：data center;virtualization;embedding algorithm;perturbation110|261|0更新时间：2024-06-05
- 摘要：Adaptive modulation technology is an important research content of AMC technology in LTE-Advanced system.The β value of new MCS levels were studied,in which the higher order modulation 256QAM was used,then the general β value of new MCS levels by the iterative algorithm in several different channel models were obtained,according to the convexity of the mean square error function,and compared with the traditional MCS levels.The simulation results show that the new MCS levels provide higher system performance when SNR is high,and the optimized β value makes CQI calculation more accurately.关键词：adaptive modulation technology;LTE-Advanced system;new MCS level;β value102|915|0更新时间：2024-06-05
- 摘要：Since the approach of analyzing statistical resolution limit (SRL) based on generalized likelihood ratio test (GLRT) has the problems of high computational complexity and isn’t easy to get the analytical formula of the detection statistics,a method for the analysis of the SRL based on Rao test was proposed.The unidimensional SRL of azimuth under the cases of known and unknown noise variance,two-dimensional SRL of azimuth and elevation under the case of known noise variance were analyzed.The Rao test detection statistic and the minimum SNR required for the corresponding SRL were derived,the detection performance and the computational complexity of the Rao test were analyzed and compared with the GLRT method.Simulation results verify the validity of the Rao test.关键词：statistical resolution limit;statistical test;parameter estimation;Rao test;generalized likelihood ratio test164|266|0更新时间：2024-06-05
- 摘要：Source cell-phone identification has become a hot topic in multimedia forensics.A novel cell-phone identification method was proposed based on the silent segments of recorded speech.Firstly,the silent segments were obtained using adaptive endpoint detection algorithm.Then,the mean of Mel frequency coefficients (MFC) was extracted as the characteristics for device identification.Finally,the CfsSubsetEval evaluation function of WEKA platform was selected according to the best priority (BestFirst) search,and support vector machine (SVM) was used for classification.Twenty-three popular models of the cell-phones were evaluated in the experiment.Experimental results show that the proposed method is feasible and the average recognition rates are 99.23% and 99.00% on the TIMIT database and the CKC-SD database.At the same time,the proposed feature performs was demonstrated better than the MFC features and the Mel frequency cepstrum coefficients (MFCC) features of the speech segments.关键词：audio forensics;source cell-phone identification;silent segment;Mel frequency coefficient390|1426|0更新时间：2024-06-05
- 摘要：At present,people’s daily life has been seriously affected by an endless stream of harassing calls.To prevent the adverse social influence,a harassing calls recognition method based on the analysis of users’ feedbacks was proposed,which could make people look insight into the features of harassing calls by data mining.Also,the random forest algorithm was applied to identify the suspected harassment numbers.In this way,the recognition rate of harassment source has been enhanced greatly,and a comprehensive control in harassing calls can be achieved by integrating the portable interceptor.Simulation results also show its good performance.关键词：harassing call;random forest algorithm;big data81|576|0更新时间：2024-06-05
- 摘要：A new configuration of the low noise figure C+L-band erbium-doped fiber amplifier was proposed and demonstrated.In the proposed configuration,a preamplifier was used to reduce the noise figure,and an improved double-pass configuration with a fiber bragg grating was employed to enhance the L-band gain and while to reduce the noise figure.The experiment results demonstrate that the noise figure in the new broad-band amplifier was improved by −2 dB,and the gain was enhanced up to above 25 dB over the region from 1 525～1 605 nm.关键词：erbium-doped fiber amplifier;C-band;L-band;wideband76|318|0更新时间：2024-06-05
- 摘要：Multi-antenna technology is the key technology of high speed broadband wireless access network,it has a broad application prospect in the fourth generation mobile communication systems.Indoor coverage is the main business for mobile communication.It is very important to use the MIMO technology to solve the problem of indoor wireless communication.Focused on the theme of wireless MIMO technology in the indoor coverage,MIMO channel capacity,indoor channel modeling,indoor coverage systems were mainly analyzed.关键词：MIMO;indoor coverage;indoor channel model94|338|0更新时间：2024-06-05
- 摘要：A compact and wideband microstrip patch antenna for multi-band wireless communications was proposed and designed.The antenna is fed by co-plane capacitive coupling method to compensate the inductance of the feeding probe,using stacked substrate of FR4 and air,an E-E or half E-E shaped radiating patch to reduce the size of the antenna.The results show that the bandwidths of the E-E and half E-E shape microstrip antennas are 1.85～2.57 GHz (relative bandwidth 32.6%) and 1.85～2.50 GHz (relative bandwidth 29.9%),respectively.Compared with ordinary E-shaped microstrip antenna,the area of E-E and half E-E microstrip antenna reducts by 47% and 61% patch.关键词：microstrip antenna;E-E-shaped patch;half E-E-shaped patch;co-plane coupling feed;wireless communication205|227|0更新时间：2024-06-05
research and development
- 摘要：Through the reduction of the hardware reliability which was caused by the introduction of NFV,the reliability issue of introducing NFV into telecommunication network was introduced.Through the analysis of reliability and availability of NFV,the typical fault scenarios,fault detection mechanism and processes of NFV architecture,and the NFV’s unique cross-layer detection mechanism and deployment advice was proposed.Finally,the NFV reliability requirements and design recommendations were proposed.关键词：network function virtualization;reliability;availability;core network44|350|0更新时间：2024-06-05
- 摘要：Based on the research results of Monte-Carlo simulation technology,the service-aware air port rate guarantee threshold was established.Based on the research of Monte-Carlo simulation technology,the design method of user distribution model and business model in perceptive simulation planning was obtained,and on the basis of this,the specific simulation planning analysis ideas was given.Taking the actual planning of a certain area as an example,the method of perceived planning based on simulation was feasible and effective,and it had good promotion value by comparing the business perceived rate and service success rate before and after the planning.关键词：4G;user perception;Monte-Carlo;simulation;network planning;capacity199|498|0更新时间：2024-06-05
- 摘要：In view of the problem that network congestion which caused by the uneven distribution in large traffic data,a priority-aware dynamic network traffic scheduling mechanism was proposed.By using the token bucket algorithm,different buckets of different rates were assigned to different services according to the service priorities.The priorities of the service and the remaining buffer space of the user nodes was taken into account to deal with different services.At the same time,the traffic arrival factor,service factor and node cache were regarded as target to define a network traffic scheduling mechanism performance indicator:packet loss rate.The numerical results show that the proposed mechanism can rationally divide the service priorities in the network,effectively utilize the network resources,prevent the network congestion,enhance the network performance,and provide the users with more stable and reliable network service.关键词：network congestion;traffic scheduling;token bucket;node cache;packet loss rate189|279|0更新时间：2024-06-05
- 摘要：Customer perception of mobile video service not only depends on the quality of the network,but also depends on the role of “end,pipeline,cloud,platform”.It is urgent to change the quality assurance mechanism based on the network itself to the end-to-end horizontal integration of customer perception.To solve these problems,the design and implementation of a mobile video service quality analysis system was introduced.The analysis model was established from service,flow direction,area,network element,community and terminal in order to analyze the data source in each part of the mobile video service; key KQI and changing trend of video services was presented,constant performance monitoring was carried out; the problem was found from the users’ perspective,trend analysis of performance deterioration,cause analysis of performance deterioration; automatic or manual processing of the identified problems by distribution work order was carried out,the problems were solved by antomatically or manual dispatch,closed-loop management mechanism was established.This system could improve the management level of mobile video service quality and reduce the cost notably significantly.The framework of the system and the realization of main function part was introduced in detail,and examples of system applications were described.关键词：mobile video service;quality analysis;design and implementation58|307|0更新时间：2024-06-05
- 摘要：The design of network architecture for IMS bearer network of State Grid was studied and analyzed,including the backbone of the network architecture and transition network architecture.And according to the network architecture,media flow and signaling flow,the IMS switching network on the data communication network backbone side,access side of the bandwidth requirements and measurement methods were put forward,which have a guiding significance for the construction of IMS bearer network of State Grid.关键词：IMS bearer network;design of network architecture;method of bandwidth measure82|136|0更新时间：2024-06-05
- 摘要：With the rapid development of big data and cloud computing technology,and successful practice in domestic and foreign enterprises,how to introduce the cloud computing technology,to innovate the traditional test mode,to achieve the conversion of the traditional software testing to the cloud model test mode,become the key to software quality assurance for the enterprise.For cloud platform has strong processing ability,large storage capacity,safety and reliability,moderate distribution capacity,grid cloud testing service platform will meet the advanced,practical,safety and other characteristics,to provide internal and external cloud testing services for enterprises.The application of mobile testing in the cloud platform was enumerated,the availability of the grid cloud testing service platform was verified,the advantages of the platform were analyzed.关键词：cloud computing;grid cloud;software testing33|56|0更新时间：2024-06-05
- 摘要：The direction finding technology based on spatial spectrum estimation is widely used due to its’ ultra-high resolution,high sensitivity,high accuracy and plays a leading role in radio management.Based on the theoretical study of spatial spectrum estimation,the algorithm was put forward and the algorithm was simulated.Finally,the practicability and superiority of the spatial spectrum estimation system were demonstrated.关键词：spatial spectrum estimation;multiple signal classification algorithm;radio direction finding66|260|0更新时间：2024-06-05
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