This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programm...This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programmable gate array （FPGA） with an embedded CPU. To reduce working frequency of the FPGA, the byte-to-word conversion is proposed. Propagation delays are equalized by ranging procedure so as to avoid data collision. Implementations of synchronization, classification, as well as Linux porting are illustrated in detail. The interface between the FPGA and CPU are also presented. Experimental results show that the proposed system can properly function in a relatively low cost FPGA.展开更多
A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the ...A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.展开更多
Free Space Optical （FSO） networks, also known as optical wireless networks, have emerged as viable candidates for broadband wireless communications in the near future. The range of the potential application of FSO n...Free Space Optical （FSO） networks, also known as optical wireless networks, have emerged as viable candidates for broadband wireless communications in the near future. The range of the potential application of FSO networks is extensive, from home to satellite. However, FSO networks have not been popularized because of insufficient availability and reliability. Researchers have focused on the problems in the physical layer in order to exploit the properties of wireless optical channels. However, recent technological developments with successful results make it practical to explore the advantages of the high bandwidth. Some researchers have begun to focus on the problems of network and upper layers in FSO networks. In this survey, we classify prospective global FSO networks into three subnetworks and give an account of them. We also present state-of- the-art research and discuss what kinds of challenges exist.展开更多
In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space divis...In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.展开更多
The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ ch...The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ characteristic, technology selection, deployment consideration, network configuring, civil work evaluation and investment estimation. An example is embedded all through providing a general展开更多
为优化光纤传输质量,满足宽带接入的可控化管理需求,要严格遵循光纤传输应用控制的技术规范,有效建立基于光传送网(Optical Transport Network,OTN)技术的光纤传输接入网络,从而维系信息传输的及时性,搭建完整的技术运行框架。应从大颗...为优化光纤传输质量,满足宽带接入的可控化管理需求,要严格遵循光纤传输应用控制的技术规范,有效建立基于光传送网(Optical Transport Network,OTN)技术的光纤传输接入网络,从而维系信息传输的及时性,搭建完整的技术运行框架。应从大颗粒信息传输处理、城域核心网和干线网络、宽带用户接入、长途网应用交叉设备等方面对OTN技术的具体应用内容进行系统化分析,更好地实现网络性能的平滑升级,从而满足城域网建设的具体需求。因此,系统研究光纤传输接入网络中OTN技术的应用要点具有现实意义。展开更多
随着信息通信技术的快速发展和广泛部署,人类的生产生活以及社会治理向数字化、信息化、智能化方向不断深入演进。作为应用最广泛的无线通信技术之一,无线局域网(WLAN,wireless local area network)需要在吞吐量、可靠性、时延等关键性...随着信息通信技术的快速发展和广泛部署,人类的生产生活以及社会治理向数字化、信息化、智能化方向不断深入演进。作为应用最广泛的无线通信技术之一,无线局域网(WLAN,wireless local area network)需要在吞吐量、可靠性、时延等关键性能上进一步突破,同时还需要具备感知、智能等新特性。毫米波(mmWave,millimeter wave)巨大的频率资源为无线局域网发展注入了新动能,但同时也带来了新的技术挑战和需求。首先,回顾了无线局域网的发展历程;其次,描述了未来无线局域网的网络结构、典型应用、发展方向和性能指标要求;然后,分析了毫米波频段无线信道特性及其对无线网络设计的新要求、新挑战;最后,对能够适应这些挑战和要求的一些潜在关键技术进行了探讨和展望。展开更多
As a promising solution to efficiently achieving fiber to the home （FTTH）, Ethernet passive optical network （EPON） is currently improved to provide intercommunication among customers, together with normal traffic ...As a promising solution to efficiently achieving fiber to the home （FTTH）, Ethernet passive optical network （EPON） is currently improved to provide intercommunication among customers, together with normal traffic delivery, via optical local area network emulation. It is a new research direction and expected to enhance the normal EPON performances. The purpose of this article is to review the state-of -the-art solutions to emulating optical local area networks （OLANs） over EPON. We discuss the major problems involved, e.g., network architecture, control mechanisms, and other potential enhancements. We also outline areas for future researches.展开更多
千兆无源光网络(Gigabit Passive Optical Network,GPON)技术在宽带接入网中具有广泛的有效应用。首先介绍了GPON技术的基本原理,包括光纤传输基础知识、GPON网络结构以及下行上行传输机制。其次探讨了GPON技术的应用优势,如高带宽和高...千兆无源光网络(Gigabit Passive Optical Network,GPON)技术在宽带接入网中具有广泛的有效应用。首先介绍了GPON技术的基本原理,包括光纤传输基础知识、GPON网络结构以及下行上行传输机制。其次探讨了GPON技术的应用优势,如高带宽和高速率、长距离传输能力、共享网络资源以及低成本和高效率。最后介绍了GPON的应用模式,包括光纤到户(Fiber to the Home,FTTH)和光纤到楼(Fiber to the Building,FTTB)等。在此基础上,详细阐述了GPON技术在宽带接入网中的应用,包括提供高速宽带接入、支持多种业务和服务、实现高质量的视频和音频传输以及支持远程办公和云服务。另外,展望了GPON技术的发展趋势和未来展望,GPON技术在宽带接入网中发挥着重要的作用,并具有广阔的应用前景。展开更多
基金Project supported by Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No .04dz12045)
文摘This paper presents the design and implementation of access controller used for Ethernet passive optical network （ EPON）. As a first step to develop an ASIC product, the entire system is designed on a field programmable gate array （FPGA） with an embedded CPU. To reduce working frequency of the FPGA, the byte-to-word conversion is proposed. Propagation delays are equalized by ranging procedure so as to avoid data collision. Implementations of synchronization, classification, as well as Linux porting are illustrated in detail. The interface between the FPGA and CPU are also presented. Experimental results show that the proposed system can properly function in a relatively low cost FPGA.
文摘A new optical wireless network based on white LED lights in home area is proposed. It is a duplex channel communication system utilizing signal emitters of white LED lights in the downlink and infrared devices in the uplink. Strategies for the system construction are given. Performance for users＇ mobile access of different kinds of optical concentrators is investigated. Indoor channel band-width is analyzed considering white LED light distribution, wall reflection, and receivers field of view （FOV）. Various modulation methods are discussed. A demo point-to-point system for surfing the net is constructed using a new line code of 4B6B which is developed to stabilize the optical output, and a peak data rate of 1 Mbps is achieved. This system is built into the lighting infrastructure, therefore decreasing the cost and offering a solution for wireless access in places which are sensitive to radio frequency like hospitals.
基金This work is supported in part by the US National Science Foundation under Grants CNS-1320664, and by the Wireless Engineering Research and Education Center （WEREC） at Auburn University, Aubur, AL, USA.
文摘Free Space Optical （FSO） networks, also known as optical wireless networks, have emerged as viable candidates for broadband wireless communications in the near future. The range of the potential application of FSO networks is extensive, from home to satellite. However, FSO networks have not been popularized because of insufficient availability and reliability. Researchers have focused on the problems in the physical layer in order to exploit the properties of wireless optical channels. However, recent technological developments with successful results make it practical to explore the advantages of the high bandwidth. Some researchers have begun to focus on the problems of network and upper layers in FSO networks. In this survey, we classify prospective global FSO networks into three subnetworks and give an account of them. We also present state-of- the-art research and discuss what kinds of challenges exist.
基金supported by the National Natural Science Foundation of China(61372069)and the"111"Project(B08038)
文摘In order to apply compressive sensing in wireless sensor network, inside the nodes cluster classified by the spatial correlation, we propose that a cluster head adopts free space optical communication with space division multiple access, and a sensor node uses a modulating retro-reflector for communication. Thus while a random sampling matrix is used to guide the establishment of links between head cluster and sensor nodes, the random linear projection is accomplished. To establish multiple links at the same time, an optical space division multiple access antenna is designed. It works in fixed beams switching mode and consists of optic lens with a large field of view（FOV）, fiber array on the focal plane which is used to realize virtual channels segmentation, direction of arrival sensor, optical matrix switch and controller. Based on the angles of nodes＇ laser beams, by dynamically changing the route, optical matrix switch actualizes the multi-beam full duplex tracking receiving and transmission. Due to the structure of fiber array, there will be several fade zones both in the focal plane and in lens＇ FOV. In order to lower the impact of fade zones and harmonize multibeam, a fiber array adjustment is designed. By theoretical, simulated and experimental study, the antenna＇s qualitative feasibility is validated.
文摘The planning of wireless communication networks in underdeveloped countries is studied for landline telephone, fixed broadband wireless access and PLMN systems via investigation and discussion of the LDC networks＇ characteristic, technology selection, deployment consideration, network configuring, civil work evaluation and investment estimation. An example is embedded all through providing a general
文摘为优化光纤传输质量,满足宽带接入的可控化管理需求,要严格遵循光纤传输应用控制的技术规范,有效建立基于光传送网(Optical Transport Network,OTN)技术的光纤传输接入网络,从而维系信息传输的及时性,搭建完整的技术运行框架。应从大颗粒信息传输处理、城域核心网和干线网络、宽带用户接入、长途网应用交叉设备等方面对OTN技术的具体应用内容进行系统化分析,更好地实现网络性能的平滑升级,从而满足城域网建设的具体需求。因此,系统研究光纤传输接入网络中OTN技术的应用要点具有现实意义。
文摘随着信息通信技术的快速发展和广泛部署,人类的生产生活以及社会治理向数字化、信息化、智能化方向不断深入演进。作为应用最广泛的无线通信技术之一,无线局域网(WLAN,wireless local area network)需要在吞吐量、可靠性、时延等关键性能上进一步突破,同时还需要具备感知、智能等新特性。毫米波(mmWave,millimeter wave)巨大的频率资源为无线局域网发展注入了新动能,但同时也带来了新的技术挑战和需求。首先,回顾了无线局域网的发展历程;其次,描述了未来无线局域网的网络结构、典型应用、发展方向和性能指标要求;然后,分析了毫米波频段无线信道特性及其对无线网络设计的新要求、新挑战;最后,对能够适应这些挑战和要求的一些潜在关键技术进行了探讨和展望。
基金the National Science Fund for Distinguished Young Scholars(Grant No.60725104)the National Basic Research Program of China(Grant No.2007CB310706)+2 种基金the National High Technology Research and Development Program of China(Grant Nos.2007AA01Z246 and 2007AA01Z227)the National Natural Science Foundation of China(Grant No.60672045)the Research Fund for the Doctoral Program of Higher Education(Grant No.20060614018)
文摘As a promising solution to efficiently achieving fiber to the home （FTTH）, Ethernet passive optical network （EPON） is currently improved to provide intercommunication among customers, together with normal traffic delivery, via optical local area network emulation. It is a new research direction and expected to enhance the normal EPON performances. The purpose of this article is to review the state-of -the-art solutions to emulating optical local area networks （OLANs） over EPON. We discuss the major problems involved, e.g., network architecture, control mechanisms, and other potential enhancements. We also outline areas for future researches.
文摘千兆无源光网络(Gigabit Passive Optical Network,GPON)技术在宽带接入网中具有广泛的有效应用。首先介绍了GPON技术的基本原理,包括光纤传输基础知识、GPON网络结构以及下行上行传输机制。其次探讨了GPON技术的应用优势,如高带宽和高速率、长距离传输能力、共享网络资源以及低成本和高效率。最后介绍了GPON的应用模式,包括光纤到户(Fiber to the Home,FTTH)和光纤到楼(Fiber to the Building,FTTB)等。在此基础上,详细阐述了GPON技术在宽带接入网中的应用,包括提供高速宽带接入、支持多种业务和服务、实现高质量的视频和音频传输以及支持远程办公和云服务。另外,展望了GPON技术的发展趋势和未来展望,GPON技术在宽带接入网中发挥着重要的作用,并具有广阔的应用前景。
