Electric vehicles (EVs) are an emerging type of mobile intelligent power consumption devices in Smart Grid as new green transport tools. In order to provide a powerful automation and intelligence support for wide area...Electric vehicles (EVs) are an emerging type of mobile intelligent power consumption devices in Smart Grid as new green transport tools. In order to provide a powerful automation and intelligence support for wide area electric vehicles energy service network, we analyze the network infrastructure and communications demands of various terminals, devices and monitoring systems distributed in wide area electric vehicle energy service network. According to interactive user services scenarios and energy operations intelligent monitoring, we propose multimode communication integration architecture for wide area electric vehicle energy service network by means of the fusion of the Internet of Things (IoT) technology. Then, we design different networking schemes in access networks and backbone transmission networks meeting multi-scene and multi-operation interaction requirements. The networking schemes will provide efficient technical support to implement intelligent, cross-regional, interactive energy services for electric vehicle users.展开更多
The use of Global Navigation Satellite Systems (GNSS) for positioning has revolutionized the way location data is be- ing collected. The NAVigation System with Time And Ranging Global Positioning System (GPS), which i...The use of Global Navigation Satellite Systems (GNSS) for positioning has revolutionized the way location data is be- ing collected. The NAVigation System with Time And Ranging Global Positioning System (GPS), which is a principal component of the global navigation satellite system (GNSS);is a satellite-based radio navigation system that provides positions of points of interest and time information to users. GPS positional accuracy can be improved by using differential corrections obtained through a technique called Differential GPS (DGPS), which is known to provide the most accurate positioning results. Differential correction can be applied in real time at the data collection phase or in the of- fice, at the post-processing phase. DGPS is generally used for positioning purposes through static or kinematics GPS surveys. In static GPS surveys, one receiver is placed at a point whose coordinates are known and the other receiver is placed over a point whose coordinates are desired. In kinematic surveys, one receiver remains at one point (base station) normally with known coordinates, and the other receiver (rover) moves from point to point in the project area. Kinematic surveys in which points positions are computed on-the-fly (OTF) are known as real-time kinematic (RTK). RTK surveys provide real-time locations of points of interest needed in many applications. Positioning with wide-area GNSS networks is basically based on the DGPS and RTK concepts. Observables from a network of a finite number of GPS receivers over an area are processed by a server at a central location (network server) and made available to the users of the network later or in real-time through radio-based, satellite, or wireless communications. This article provides a review of the concept and application of positioning with wide-area GNSS networks.展开更多
With the rapid development of information technology,the scale of the network is expanding,and the complexity is increasing day by day.The traditional network management is facing great challenges.The emergence of sof...With the rapid development of information technology,the scale of the network is expanding,and the complexity is increasing day by day.The traditional network management is facing great challenges.The emergence of software-defined network(SDN)technology has brought revolutionary changes to modern network management.This paper aims to discuss the application and prospects of SDN technology in modern network management.Firstly,the basic principle and architecture of SDN are introduced,including the separation of control plane and data plane,centralized control and open programmable interface.Then,it analyzes the advantages of SDN technology in network management,such as simplifying network configuration,improving network flexibility,optimizing network resource utilization,and realizing fast fault recovery.The application examples of SDN in data center networks and WAN optimization management are analyzed.This paper also discusses the development status and trend of SDN in enterprise networks,including the integration of technologies such as cloud computing,big data,and artificial intelligence,the construction of an intelligent and automated network management platform,the improvement of network management efficiency and quality,and the openness and interoperability of network equipment.Finally,the advantages and challenges of SDN technology are summarized,and its future development direction is provided.展开更多
As the revolutionary change in electric power industry begins with the latest communication infrastructure, it is on the verge of a revolutionary transformation to develop a smart grid to meet the requirements of our ...As the revolutionary change in electric power industry begins with the latest communication infrastructure, it is on the verge of a revolutionary transformation to develop a smart grid to meet the requirements of our digital society. Wide Area Power System is made up of plentiful automated transmission and distribution systems with strong communication infrastructure, all operating in a coordinated, proficient and reliable mode. This paper is fretful with the wide area power system load protection scheme and ensuing design requirement that enhances stability as well as control. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, server, connected loads, and protection devices using WIMAX. The main theme of the paper is on the use of information technology to obtain more flexibility and smartness in the Wide Area Power System Load Protection by designing the Communication channel using WIMAX. Faults detected in Local area networks and Information regarding the faults of Local Areas is communicated to Load Area Manager (LAM) which takes required control action to handle it. Finally the paper shows islanding operation through WAM for the areas that becomes intensive faulty. Results have been verified in MATLAB/ SIMULIMK.展开更多
Research on wide area ad hoc networks is of great significance due to its application prospect in long-range networks such as aeronautical and maritime networks,etc.The design of MAC protocols is one of the most impor...Research on wide area ad hoc networks is of great significance due to its application prospect in long-range networks such as aeronautical and maritime networks,etc.The design of MAC protocols is one of the most important parts impacting the whole network performance.In this paper,we propose a dis-tributed TDMA-based MAC protocol called Dynamic Self Organizing TDMA(DSO-TDMA)for wide area ad hoc networks.DSO-TDMA includes three main features:(1)In a distributed way,nodes in the network select transmitting slots according to the congestion situation of the local air interface.(2)In a selforganization way,nodes dynamically adjust the resource occupancy ratio according to the queue length of neighbouring nodes within two-hop range.(3)In a piggyback way,the control information is transmitted together with the payload to reduce the overhead.We design the whole mechanisms,implement them in NS-3 and evaluate the performance of DSO-TDMA compared with another dynamic TDMA MAC protocol,EHR-TDMA.Results show that the end-to-end throughput of DSO-TDMA is at most 51.4%higher than that of EHR-TDMA,and the average access delay of DSO-TDMA is at most 66.05%lower than that of EHR-TDMA.展开更多
This paper presents the design of a small printed ultra wideband antenna with Band Notched characteristics. Both the free space and on-body performances of this antenna were investigated through simulation. The newly ...This paper presents the design of a small printed ultra wideband antenna with Band Notched characteristics. Both the free space and on-body performances of this antenna were investigated through simulation. The newly designed UWB antenna is more revised small form factor sized, with the ability to avoid interference caused by WLAN (5.15 - 5.825 GHz) and WiMAX (5.25 - 5.85 GHz) systems with a band notch. The return loss response, gain, radiation pattern on free space of the antenna were investigated. After that, the on-body performances were tested on 3-layer human body model with radiation pattern, gain, return loss, and efficiency at 3.5, 5.7, 8, 10 GHz and all the results were compared with free space results. As the on-body performance was very good, the proposed antenna will be suitable to be used for multi-purpose medical applications and sports performance monitoring.展开更多
面向智能配电网的通信需求,长距离广域网(Long Range Wide Area Network,LoRaWAN)因长距离、低功耗特性备受关注,但其在实时性、网络容量及安全性等方面仍存在不足。以智能配电网为应用场景,通过分析LoRaWAN通信架构的局限性,设计一种...面向智能配电网的通信需求,长距离广域网(Long Range Wide Area Network,LoRaWAN)因长距离、低功耗特性备受关注,但其在实时性、网络容量及安全性等方面仍存在不足。以智能配电网为应用场景,通过分析LoRaWAN通信架构的局限性,设计一种分层优化的通信架构。研究结果表明,该优化架构加快了故障响应速度,增强了并发处理能力,显著扩展了网络容量,提升了数据传输的安全性。展开更多
We analyze the development of quantum cryptography communication,including analyze the problems lie in the existent literatures and give the resolve methods according to these problems.Then discuss the quantum cryptog...We analyze the development of quantum cryptography communication,including analyze the problems lie in the existent literatures and give the resolve methods according to these problems.Then discuss the quantum cryptography communication for wireless networks and also point out the shortcoming of current research and the future of quantum wireless networks.展开更多
跨数据中心网络是处于不同地区的数据中心网络(Data Center Networks,DCNs)通过广域网(Wide-Area Network,WAN)连接组成的网络,分布式应用通常基于该网络为用户提供高质量的服务。DCNs和WAN的缓冲区大小、往返时延存在显著差异,这导致...跨数据中心网络是处于不同地区的数据中心网络(Data Center Networks,DCNs)通过广域网(Wide-Area Network,WAN)连接组成的网络,分布式应用通常基于该网络为用户提供高质量的服务。DCNs和WAN的缓冲区大小、往返时延存在显著差异,这导致现有的Cubic拥塞控制算法在跨数据中心网络场景下出现降速不准确、丢包率过高以及与其他拥塞控制算法兼容性差等问题。针对以上挑战,提出了一种通过匹配不同发送速率模式的改进Cubic算法Cubic+。具体地,Cubic+整合了网络中的时延、ECN(Explicit Congestion Notification)和丢包信号。当拥塞发生在浅缓冲交换机时,Cubic+会周期性地排空队列;当拥塞发生在深缓冲路由器时,Cubic+会快速减少堆积的数据包。基于大规模NS3仿真实验结果表明,在跨数据中心网络流量模型下,Cubic+与现有流行算法相比,平均流完成时间最多减少了20.77%,第99百分位流完成时间最多减少了15.88%,为跨数据中心网络提供了一种高吞吐的拥塞控制算法。展开更多
广域长距离高性能传输技术在中国“东数西算”工程构建全国一体化算力网背景下具备重要的战略价值。3个趋势对广域分布式算力协同范式提出新需求:对算力资源要求极高的人工智能(AI)大模型智能应用的兴起;高端高性能图形处理单元(GPU)芯...广域长距离高性能传输技术在中国“东数西算”工程构建全国一体化算力网背景下具备重要的战略价值。3个趋势对广域分布式算力协同范式提出新需求:对算力资源要求极高的人工智能(AI)大模型智能应用的兴起;高端高性能图形处理单元(GPU)芯片被禁运限制单中心算力资源;中国各地建设的算力集群形成算力分散分布态势。广域长距离高性能传输技术是上述新范式的关键技术。从支撑广域分布式算力协同新范式、技术路线、承载网络、研究难点、成本5个方面进行讨论,结合深圳到宁夏中卫2100 km实网实验结果,将现有远程直接内存访问(remote direct memory access,RDMA)技术基于广域全光网进行长距离优化的方案是短期内可行性高、成本低且利于开展研究的最佳方案之一,通过优化基于融合以太网的远程直接内存访问(RDMA over Converged Ethernet,RoCE)可以在广域全光网上实现“广域光数直达”逼近物理层通信性能指标。展开更多
文摘Electric vehicles (EVs) are an emerging type of mobile intelligent power consumption devices in Smart Grid as new green transport tools. In order to provide a powerful automation and intelligence support for wide area electric vehicles energy service network, we analyze the network infrastructure and communications demands of various terminals, devices and monitoring systems distributed in wide area electric vehicle energy service network. According to interactive user services scenarios and energy operations intelligent monitoring, we propose multimode communication integration architecture for wide area electric vehicle energy service network by means of the fusion of the Internet of Things (IoT) technology. Then, we design different networking schemes in access networks and backbone transmission networks meeting multi-scene and multi-operation interaction requirements. The networking schemes will provide efficient technical support to implement intelligent, cross-regional, interactive energy services for electric vehicle users.
文摘The use of Global Navigation Satellite Systems (GNSS) for positioning has revolutionized the way location data is be- ing collected. The NAVigation System with Time And Ranging Global Positioning System (GPS), which is a principal component of the global navigation satellite system (GNSS);is a satellite-based radio navigation system that provides positions of points of interest and time information to users. GPS positional accuracy can be improved by using differential corrections obtained through a technique called Differential GPS (DGPS), which is known to provide the most accurate positioning results. Differential correction can be applied in real time at the data collection phase or in the of- fice, at the post-processing phase. DGPS is generally used for positioning purposes through static or kinematics GPS surveys. In static GPS surveys, one receiver is placed at a point whose coordinates are known and the other receiver is placed over a point whose coordinates are desired. In kinematic surveys, one receiver remains at one point (base station) normally with known coordinates, and the other receiver (rover) moves from point to point in the project area. Kinematic surveys in which points positions are computed on-the-fly (OTF) are known as real-time kinematic (RTK). RTK surveys provide real-time locations of points of interest needed in many applications. Positioning with wide-area GNSS networks is basically based on the DGPS and RTK concepts. Observables from a network of a finite number of GPS receivers over an area are processed by a server at a central location (network server) and made available to the users of the network later or in real-time through radio-based, satellite, or wireless communications. This article provides a review of the concept and application of positioning with wide-area GNSS networks.
文摘With the rapid development of information technology,the scale of the network is expanding,and the complexity is increasing day by day.The traditional network management is facing great challenges.The emergence of software-defined network(SDN)technology has brought revolutionary changes to modern network management.This paper aims to discuss the application and prospects of SDN technology in modern network management.Firstly,the basic principle and architecture of SDN are introduced,including the separation of control plane and data plane,centralized control and open programmable interface.Then,it analyzes the advantages of SDN technology in network management,such as simplifying network configuration,improving network flexibility,optimizing network resource utilization,and realizing fast fault recovery.The application examples of SDN in data center networks and WAN optimization management are analyzed.This paper also discusses the development status and trend of SDN in enterprise networks,including the integration of technologies such as cloud computing,big data,and artificial intelligence,the construction of an intelligent and automated network management platform,the improvement of network management efficiency and quality,and the openness and interoperability of network equipment.Finally,the advantages and challenges of SDN technology are summarized,and its future development direction is provided.
文摘As the revolutionary change in electric power industry begins with the latest communication infrastructure, it is on the verge of a revolutionary transformation to develop a smart grid to meet the requirements of our digital society. Wide Area Power System is made up of plentiful automated transmission and distribution systems with strong communication infrastructure, all operating in a coordinated, proficient and reliable mode. This paper is fretful with the wide area power system load protection scheme and ensuing design requirement that enhances stability as well as control. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, server, connected loads, and protection devices using WIMAX. The main theme of the paper is on the use of information technology to obtain more flexibility and smartness in the Wide Area Power System Load Protection by designing the Communication channel using WIMAX. Faults detected in Local area networks and Information regarding the faults of Local Areas is communicated to Load Area Manager (LAM) which takes required control action to handle it. Finally the paper shows islanding operation through WAM for the areas that becomes intensive faulty. Results have been verified in MATLAB/ SIMULIMK.
文摘Research on wide area ad hoc networks is of great significance due to its application prospect in long-range networks such as aeronautical and maritime networks,etc.The design of MAC protocols is one of the most important parts impacting the whole network performance.In this paper,we propose a dis-tributed TDMA-based MAC protocol called Dynamic Self Organizing TDMA(DSO-TDMA)for wide area ad hoc networks.DSO-TDMA includes three main features:(1)In a distributed way,nodes in the network select transmitting slots according to the congestion situation of the local air interface.(2)In a selforganization way,nodes dynamically adjust the resource occupancy ratio according to the queue length of neighbouring nodes within two-hop range.(3)In a piggyback way,the control information is transmitted together with the payload to reduce the overhead.We design the whole mechanisms,implement them in NS-3 and evaluate the performance of DSO-TDMA compared with another dynamic TDMA MAC protocol,EHR-TDMA.Results show that the end-to-end throughput of DSO-TDMA is at most 51.4%higher than that of EHR-TDMA,and the average access delay of DSO-TDMA is at most 66.05%lower than that of EHR-TDMA.
文摘This paper presents the design of a small printed ultra wideband antenna with Band Notched characteristics. Both the free space and on-body performances of this antenna were investigated through simulation. The newly designed UWB antenna is more revised small form factor sized, with the ability to avoid interference caused by WLAN (5.15 - 5.825 GHz) and WiMAX (5.25 - 5.85 GHz) systems with a band notch. The return loss response, gain, radiation pattern on free space of the antenna were investigated. After that, the on-body performances were tested on 3-layer human body model with radiation pattern, gain, return loss, and efficiency at 3.5, 5.7, 8, 10 GHz and all the results were compared with free space results. As the on-body performance was very good, the proposed antenna will be suitable to be used for multi-purpose medical applications and sports performance monitoring.
文摘面向智能配电网的通信需求,长距离广域网(Long Range Wide Area Network,LoRaWAN)因长距离、低功耗特性备受关注,但其在实时性、网络容量及安全性等方面仍存在不足。以智能配电网为应用场景,通过分析LoRaWAN通信架构的局限性,设计一种分层优化的通信架构。研究结果表明,该优化架构加快了故障响应速度,增强了并发处理能力,显著扩展了网络容量,提升了数据传输的安全性。
基金supported by the National High Technology Research and Development Program of China(863 Program)(No. 2006AA01Z208)Nataral Sci-ence Foundation of Jiangsu Province(No. BK2007236)Six Projects Sponsoring Talent Summits of Jiangsu Province(No. SJ207001)
文摘We analyze the development of quantum cryptography communication,including analyze the problems lie in the existent literatures and give the resolve methods according to these problems.Then discuss the quantum cryptography communication for wireless networks and also point out the shortcoming of current research and the future of quantum wireless networks.
文摘广域长距离高性能传输技术在中国“东数西算”工程构建全国一体化算力网背景下具备重要的战略价值。3个趋势对广域分布式算力协同范式提出新需求:对算力资源要求极高的人工智能(AI)大模型智能应用的兴起;高端高性能图形处理单元(GPU)芯片被禁运限制单中心算力资源;中国各地建设的算力集群形成算力分散分布态势。广域长距离高性能传输技术是上述新范式的关键技术。从支撑广域分布式算力协同新范式、技术路线、承载网络、研究难点、成本5个方面进行讨论,结合深圳到宁夏中卫2100 km实网实验结果,将现有远程直接内存访问(remote direct memory access,RDMA)技术基于广域全光网进行长距离优化的方案是短期内可行性高、成本低且利于开展研究的最佳方案之一,通过优化基于融合以太网的远程直接内存访问(RDMA over Converged Ethernet,RoCE)可以在广域全光网上实现“广域光数直达”逼近物理层通信性能指标。
