最新刊期
卷 30 ， 期 3 ， 2014
- 摘要：Standardization aspects of IoT were discussed. After identified the definition of IoT in China, challenges of IoT were put forward. Somebody considered those challenges mainly came from the lack of standards, according to the definition of IoT, different technologies and standards must be included in IoT. It was pointed out that instead of standardization, abstract methods should be the most effective way to make the inclusion. As an example, the sensor and actuator platform built by NUPT was briefly introduced.关键词：Internet of things;standardization;framework and method;sensor network;system abstract784|1347|0更新时间：2024-06-05
Viewpoint focusing
- 摘要：Long term evolution technology（LTE）is a new generation of wireless communications technology. LTE has experienced a rapid development process since 2010. And by the end of 2013, 260 LTE networks has been launched. Chinese government also issued TD-LTE licenses on Dec. 2013. It was specified that LTE was the hot technology based on current wireless markets and technology development. Current LTE development status and challenge it faced were analyzed. Also the positive impaction to TD-LTE globalization brought by Chinese TD-LTE license issuing was analyzed. Based on the analysis, some perspects on LTE development in future were conducted, especially in 2014.关键词：LTE;TD-LTE;4G;VoLTE;commercial network deployment658|1787|0更新时间：2024-06-05
- 摘要：An evaluation of vertical sectorization in LTE field trial was conducted. The field trial results show that the performance of vertical sectorization will be decreased due to the co-frequency interference between the inner and outer cells. Furthermore, some practical suggestions on the deployment of vertical sectorization in LTE network were proposed.关键词：LTE;active antenna system;field test763|1060|0更新时间：2024-06-05
- 摘要：With release of TD-LTE license in China, how to deploy LTE becomes the primary problem for network operators. Techniques of both WCDMA and LTE network were analyzed in detail, and LTE construction thoughts of China Unicom were elaborated from the viewpoints of brand convergence, network convergence and mobile terminal convergence, which aimed to promote combination of 3G and 4G to fulfill the best mobile broadband network.关键词：WCDMA;LTE;3G/4G convergence640|1487|0更新时间：2024-06-05
- 摘要：Both LTE and WLAN are quite important networks for China Mobile in the near future. So it reserves to research on how to improve the cooperation efficiency and flexibility of these two networks, make full utilization of operator's resources, as well as offer better service for subscribers. First, existing LTE-WLAN cooperation mechanisms were discussed and the necessity of radio interworking method was analyzed.Then the radio interworking mechanisms and standardization progress were introduced. Finally some views on future work were proposed.关键词：LTE;WLAN;wireless;interworking668|925|0更新时间：2024-06-05
- 摘要：Doppler frequency offset can severely impact the performance of uplink in LTE-based high-speed railway telecommunication system. Frequency offset pre-compensation in transmitter combined with residual frequency offset compensation in receiver was proposed to solve this problem. The simulation results demonstrate that this scheme can improve the uplink performance for high-speed railway telecommunication system.关键词：high-speed railway;Doppler frequency offset;long term evolution;frequency offset pre-compensation738|1867|0更新时间：2024-06-05
- 摘要：The carrier aggregation and enhanced MIMO for enhancing throughout,CoMP and eICIC for interference suppression,eSON for improving SON efficiency were introduced in detail. The technology industry status, simulation and test results were also described.关键词：TD-LTE-Advanced;carrier aggregation;eMIMO;CoMP;relay;eSON;eICIC500|1044|0更新时间：2024-06-05
- 摘要：MIMO enhancement was studied and investigated out of five key technologies in LTE-Advanced system. Based on the technique theory, algorithm implement and test trail of transmission mode 9 were well disscussed. The utilization method, performance advantages and network compatibility of transmission mode 9 were also analyzed. Furthermore, all downlink transmission modes of LTE and LTE-Advanced were compared, and some suggestions were provided for network planning.关键词：LTE-Advanced;MIMO;transmission mode;beamforming550|1563|0更新时间：2024-06-05
- 摘要：In dense heterogeneous wireless network, the large-scale small cell deployment can substantially increase not only the complexity of the interference environment but also the network energy consumption. Based on the system model and deployment scenario of small cell enhancement, the energy efficiency in dense heterogeneous wireless network was analyzed and simulated from the sight of system level under different scenarios with different pico numbers. The evaluation has profound guiding significance for the future energy efficiency analysis and optimization in dense heterogeneous wireless network.关键词：dense heterogeneous wireless network;energy efficiency;system level simulation451|771|0更新时间：2024-06-05
- 摘要：Cloud radio access network（C-RAN）has been proposed as one of the most promising solutions to meet the service requirements of the fifth generation（5G）wireless communication systems. The published achievements indicate that C-RAN has many advantages, which can improve the spectrum efficiency and energy efficiency simultaneously. The state-of-the-art research achievements, system architecture and key technology challenges in C-RAN were studied. Furthermore, the performance gains over the traditional systems were introduced as well.关键词：cloud radio access network;5G;system architecture;technology evolution620|1743|0更新时间：2024-06-05
Topic: 4G＆5G
- 摘要：The technologies and features of airborne wireless systems for public mobile communication were analyzed, applications in different states were compared. At last, the issues that need attention were indicated that frequency assignment and radio station using must coexist with other airborne systems, which could influence the safety of the aircraft.关键词：airborne public mobile communication;mobile satellite service;air-to-ground station communication system382|1620|0更新时间：2024-06-05
- 摘要：For the large scale Ad Hoc network with single-type or multi-type users, the percolation-based connectivity problem was addressed. Firstly, from the Boolean model point of view, single-type and multi-type user network connectivity was analyzed. For the single-type users, the sufficient condition under which percolation was achieved in clustered networks was formulated under the disk model. For multi-type user network, under the Poisson distributed cognitive radio model, the necessary condition for network connectivity was analyzed. The existence of a communication link between two secondary users depends on not only the distance between them, the transmitting and receiving activities of nearby primary users, but also the neighboring user's type. Then from random connection model point of view, the product rule was introduced to decide which two users could be connected, thus delaying or accelerating the occurrence of percolation. Various simulations show that the percolation is effective both in theory and practice in guidance of the deployment of cognitive radio network.关键词：heterogeneous wireless network;percolation;cognitive radio418|828|0更新时间：2024-06-05
- 摘要：The universal in-network caching, as a prominent feature of information centric networking（ICN）, plays important roles in the demonstration of ICN's advantages over other architectures. But so far, many people still have different perception of it. The specific roles that in-network caching can play should be first explored before it can be taken full advantage were argued. Such exploration by pointing out three levels of in-network caching were argued, explained how the three-level in-network caching play roles in error-recovery, flash crowd relief, DDoS attack prevention, popular content hosting and commission service, and stating issues related to these roles.关键词：in-network caching;information-centric networking;error recovery;flash crowd relief;DDoS attack prevention;popular content hosting;commission service455|835|0更新时间：2024-06-05
- 摘要：A simulation system and hardware platform based on IEEE 802.11p proposal was established. Then, key technologies of system design include OFDM parameter bandwidth and data rate choice, pilots' structure design, synchronization and channel estimation design, were presented. A novel channel estimation method to eliminate the disadvantage in vehicle environment was proposed. The vehicle communication system based on IEEE 802.11p was realized on FPGA hardware platform. The processing speed, storage and performance on the platform were appraised, and then a demo about the vehicle control traffic light in vehicle-to-roadside environment on the platform was realized.关键词：IEEE 802.11p;DSRC/WAVE;system design;hardware realization469|1645|0更新时间：2024-06-05
- 摘要：Reliability is an important issue for emergency message broadcast services in vehicular Ad Hoc network （VANET）. Most investigations of such broadcast in VANET focus on multi-hop connectivity, taking all one-hop links for granted. But potential emergency applications of broadcast in VANET include collision avoidance warning, intersection coordination, etc. Usually direct one-hop broadcast is demanded due to the stringent delay requirements in high mobility scenario. Three reliability metrics, which were the packet reception rate（PRR）, PRR with distance d from the sender（PRR（d））and the node packet delivery probability（PDP）, were evaluated for one-hop broadcast at an intersection in 2-D VANET analytically. Expressions of these metrics were derived with consideration of the hidden terminal problem and collisions caused by concurrent transmissions. The impact of carrier sensing and interference ranges, the packet size, the back-off window size and the density of nodes on the reliability were investigated and discussed. Finally, some important observations to the broadcast at an intersection in 2-D VANET were provided, such as the PRR, PRR（d）and PDP were getting worse with the traffic density increase.关键词：vehicular Ad Hoc network;broadcast;reliability;hidden terminal;concurrent transmission296|617|0更新时间：2024-06-05
- 摘要：The large-scale involvement of the large-scale access convergence router was described for the significance of application of multiple access networks.In the background of network convergence,the role of ACR in the network was analyzed.Based on the thought of forwarding and control element separation（ForCES）of distributed system, the PPPoE protocol principle and process were analyzed, and the PPPoE access technology was achieved in ACR.The test results show that,the implementation of PPPoE based on a distributed system can meet the requirement of large-scale access application scene,and ACR can support high bandwidth for thousands of concurrent.关键词：ACR;distributed system;PPPoE320|910|0更新时间：2024-06-05
- 摘要：In order to improve the broadcast reception rate in VANET, the conclusion that the relationship between collision probability and minimum contention window size and the relationship between expiration probability and minimum window size were reached by building Markov model. According to this conclusion, a minimum contention window size adjustment back-off algorithm called CEB was proposed, it is on the basis of the relative size between the number of expiration beacons and pre-set threshold. Simulations were done to compare the performance of CEB, RBEB and BEB, and the results show that the performance of the new proposed algorithm is better than that of RBEB and BEB.关键词：vehicular Ad Hoc network;back-off algorithm;beacon information;expiration probability;collision probability259|1008|0更新时间：2024-06-05
- 摘要：Traditional spectrum sensing based on compressed sensing assumes that the sparsity is known, in fact,it is unknown and time-varying. To solve the problem, a sparsity adaptive algorithm for wideband spectrum sensing was proposed. First, the distributed compressed sensing and restricted isometry property principle were adopted to estimate an initial sparsity value. Then the confidence coefficient was used to update the sparsity and the spectrum support set was obtained, which was occupied by a primary user. Simulation results show that the proposed method has better spectrum detection performance than the spectrum sensing method with a known sparsity, and losses spectrum availability a little in low SNR, and its complexity is small.关键词：compressed sensing;spectrum sensing;sparsity estimation;restricted isometry property;confidence coefficient286|609|0更新时间：2024-06-05
- 摘要：Based on the observation of frequency spectrum of navigation signal, an improved FFT acquisition algorithm was proposed which could reduce the capturing time of GNSS receiver, the threshold of the algorithm was also modified. Simulation results show that the new algorithm can shorter capturing time. The complete tracking channel of the GNSS receiver was also designed, and the MATLAB simulation results verify the correctness of the proposed tracking channel.关键词：signal acquisition;tracking;GNSS receiver;acquisition algorithm365|1258|0更新时间：2024-06-05
research and development
- 摘要：Firstly, the inevitable trend was discussed that the available spectrum of the future mobile communication systems would be found in the higher frequency band, since the gap between the future spectrum requirements and the current planned total spectrum in the low-band was considerable. Then the status of the development of global hig h frequency wireless communications were introduced, in terms of high frequency band planning, related standardization and organization activities. Next, the propagation characteristics of high frequency bands were analyzed and summarized. Finally, the advantages and challenges of future high-band communications were proposed from potential available bands, transmission technologies, networking technologies, and radio frequency technologies.关键词：spectrum requirement;high frequency band;wireless communication;5G377|1490|0更新时间：2024-06-05
- 摘要：Applications of the cognitive radio technology based on cross-layer in green networks with the aim of saving energy were explored. A variety of key technologies on cognitive radio based on cross-layer protocol in green network were collected and discussed. First, the spectrum of architecture and cross-layer structure on cognitive radio network were discussed; second, a large number of cognitive radio cross-layer solutions were discussed to make energy-saving target contrast; third, the key challenges were pointed out and possible solutions for cross-layer cognitive radio technology in green network were provided.关键词：cognitive network;cross-layer design;green network551|1067|0更新时间：2024-06-05
Overview
- 摘要：The unified communication（UC）industry was reviewed and nine European and American operators' UC practices were analyzed from six perspectives: services and bundle, deployment model, marketing strategy, industry partners,service support and portal.Operators'UC strategies were also discussed based on the key findings.关键词：unified communication;collaborative commumcation;enterprise service453|996|0更新时间：2024-06-05
- 摘要：To comply with the maintenance reformation requirement of ＂intensive management＂, China Telecom Corporation, while initiating a power and environment management platform on the provincial level, is starting a normalized and standardized setup of all the signals in the power and environment supervision system. On the basis of an analysis of the existing faults with the power and environment supervision system of Jiangsu Branch of China Telecom Co., Ltd., an easily replicable mode, through unifying names of stations, facilities, and signals and attributes of signals was found; a detailed analysis of the convergence mode of the provincial power and environment management platform and the function of each unit was carried out, which may contribute to a great extent to the establishment of the criteria for the power and environment system.关键词：power and environment monitoring system;standardization;convergence mode;province supervision center335|1541|0更新时间：2024-06-05
- 摘要：The application scale of 240 V direct current power supply system and modular UPS is expanding continuously. The advantage and characteristics of the two power supply systems were studied, the user acceptance, the availability of power supply system, and the total cost of the whole life cycle were comparatively analyzed. Some specific concerns regarding the application in data center were raised, such as load adaptability testing, redundancy allocation principle, and so on.关键词：240 V direct current power supply system;modular UPS;load adaptability;availability of power supply system;total cost of the whole life cycle353|1010|0更新时间：2024-06-05
- 摘要：The development of mobile internet caused the significant changes of mobile communication industry and advanced the integration of mobile communication, internet and media industries. In this progress, mobile operators had the marginalization and channelization risks. To help mobile operators cope with the challenges, the main characteristics of the industry was researched and the challenges of mobile operators in the application field were closely analyzed. Five strategies, such as optimizing basic network, constructing core competitive power in content and application fields etc, were put forward to create mobile operators' value in the change of industry.关键词：mobile internet;reconstruction of industry chain;operator's strategy309|930|0更新时间：2024-06-05
- 摘要：The smart home application development and deployment requirement of operators were analyzed. Through comparing technical characteristics between the international mainstream open architecture platform OSGi and Android, an open service platform which can dynamically load and run third-party applications was proposed. On the basis, the function module design of home gateway supporting OSGi and control process definitions were also proposed. Finally, the future direction of research and development were summarized.关键词：smart home;open services gateway initiative;Android;inteligent control;home automation;ITMS+1042|990|0更新时间：2024-06-05
- 摘要：The present TMN architecture and the solutions of telecommunication international standards organization will not meet the requirements of management. Besides of that, the improving business＆service requirements, and the increasing demands in the intensive intelligent and automatic network management are the elements that push original network management system to face enormous challenges. In order to get to the root of this matter, the concept of intelligent gateway element in transmission network was put forward. It abandoned the original TMN EMS architecture, and increased a part of intelligent network management functions in the basis of the original transmission gateway element function. In the meantime substrate transport properties were shielded, the upward interface was opened to build a newly open effective network management architecture following the IT models, which satisfied the management requirements of network and service and quickly realized end-to-end unified controls in the multi-specialized field.关键词：transmission network;network management system;intelligent;intensive311|821|0更新时间：2024-06-05
- 摘要：Data resource is the core asset of telecom operators, under the environment of the data surging, opening data service ability is advantage to the operator to increase the value and revenue of pipeline, but it also need higher requirements of the operating capacity. On the basis of researching the requirements of data service ability open business under the environment of big data, the data service content was clearly introduced, the construction ideas, system architecture and open mechanism of the data service ability open platform were put forward.关键词：big data;data service;open ability429|1465|0更新时间：2024-06-05
- 关键词：optical access network;access network gridding;holographic grid system;ODN programming213|487|0更新时间：2024-06-05
- 摘要：Combination with the smart grid communication needs, LTE 230 system is customized development based on the LTE core technology and uses 230 MHz frequency band. Compared with the high frequency, the signal of 230 MHz frequency spread far and has strong diffraction capability. It greatly improves the covering capacity of system. The covering capacity of the system can reach more than 4 km in the dense urban area. Based on the Okumuram-Hata model and the precise link budget, the theory covering capacity of LTE 230 system was given. At the same time, according to the testing results of the LTE 230 experimental network which Shenzhen Power Supply Bureau has built in Shenzhen Futian district, the LTE 230 system is verified that the actual coverage ability correspond with the theoretical value in dense urban environment.关键词：smart grid;wireless private network;LTE 230 system;wide coverage316|768|0更新时间：2024-06-05
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