光纤接入网技术英文文献翻译

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1、Optical fiber access network technologyThe entire telecommunication network according to network function is divided into three sections: switching, transmission,and access. Access to telecommunications business transparent to users, transmit specific, access to local switch and the user that the co

2、nnection between the parts, usually include subscriber line transmission system, reuse equipment, crossing connection device or user/network terminal equipment. And actually pick for business entity is business nodes.1. Access network development process1.1 Access Network (AN: Access by business) re

3、fers to a node interface (SNI) and related users Network interface (UNI) between a series of transmit entity (such as line facilities and transmission facilities) for transmission consisting of telecommunication business provide the required transmit load capacity, implementation system configuratio

4、ns percentile management interface via and management. Access can be seen as with business and application irrelevant transmission network, mainly finish crossing connection, reuse and transmission function, it is transparent to users of signaling.Based on modern of telecommunication network access

5、network is integrated service access, simple local voice access will be increasingly cannot meet the requirements, the voice, data and image comprehensive access is becoming access network development trend. After years of development, access network define though does not change, but its connotatio

6、n and forms has changed significantly. Superior traditional access network integrated optical fiber access network will be users access the future developing trend.Optical fiber access from SNI to UNI refers to all or part of the access network by using optical fiber as medium. ITU - T about access

7、network recommendations indicate that fiber, user access system is composed of three parts: optical line terminal(OLT), optical distribution network (ODN) and optical network unit (ONU).1.2According to the requirement of system access framework and the important characteristics, access network can b

8、e summarized as the following:1.2.1 Access to access business provides bearing capacity, achieve business transparent transfer.1.2.2. The access is transparent to users signaling, except for some users signaling format conversion outside, signaling and business processing function is still in busine

9、ss node.1.2.3 The introduction of should not be restricted access all kinds of existing access types and business, access network should through the limited standardization interface and business node connected.1.2.4Access network have independent from the business node in the network management sys

10、tem, this system through the standardized interfaces connected TMN, access network operation for implementation TMN, maintenance and management.2 .fiber structure2.1general linear structure. Refer to the public bus, fiber as each user terminals through direct connect with bus coupler network structu

11、re. Its characteristic is sharing backbone fiber, save lines to remove node investment, the demand is higher, dynamic range, interfere with each other effect is small. Defect is loss of accumulation, the backbone fiber user acceptance dependence is strong.2.2 ring structure. Refers to all share a fi

12、ber optic link node, fiber optic link its end to end the closed loop network structure. Characteristic is self-healing, namely can be realized without intervention, the network can be in a relatively short period of time to recover from failure have preached business, high reliability. Defect is han

13、ged by the number of users of monocylic limited, polycyclic interchange is relatively complex, not suitable for CATV, etc FenPeiXing business.2.3star structure. This structure is actually point-to-point way, each user terminals in the central node through with control and switch functions of the ast

14、ral couplers exchange information. Characteristics of simple structure, maintenance is convenient and easy to upgrade and expansion between, each user relatively independent, good secrecy, business adaptability. Defect is higher, networking required fiber cost of poor flexibility, high reliability r

15、equirements of central node.2.4 tree structure. Similar to the branches, a hierarchical structure, shape in transfer boxes and FenXianHe place adopts multiple optical distributor, will signal filtering down top end innings allocation, have strong control coordination. Characteristic is suitable for

16、broadcasting business. Defect is power loss is bigger, two-way communication difficulty bigger.3. The status of optical access network in the modern communicationOptical fiber in realizing national information modernization access plays a more and more important role, is an indispensable part of mod

17、ern communications network. Modern communications network basic realized based on fiber backbone transmission and exchange, and access section is still restricted modern telecommunications further development and improvement of the bottleneck, therefore, to construction of national information infra

18、structure (NII), access network is the key. Access network technology development, will result in great changes of telecommunications and information network, namely, voice, data, video, etc. Various kinds of information transmission, comprehensive business together for implementing the resources sh

19、aring, and gradually optimized communication network, greatly improving network benefits.Two optical fiber optical transmission technology access with the combination of the access technology3.1 Light transmission technology development and evolutionSince 1979, the human use of optical fiber as comm

20、unication mode, optical transmission technology experience since from analog to digital, from PDH to sdh-based WDM, from passive and active to a series of MSTP from SDH to the development and evolution process, transmission capacity and reliability, the transmission distance such indicators have rea

21、ched a very high level.The current mainstream of optical transmission technology is still SDH, STM - 1/4/16/64/256 series synchronous transfer module has been achieved, including STM -256 frame rate as high as 40Gbps. Based on SDH, fusion broadband data business multi-task transmitting platform (the

22、 MSTP) has also become the best choice for todays construction intracity networks, moreover elastic grouping ring (RPR) technology is also gradually become the direction of the development of a light transmission. The future will be optical transmission network to optical transmission network (otns)

23、 in the direction of development, many exchange, network otns choose road and other intelligent function will be implemented on light layer. Otns the intelligent network development degree can realize ASON intelligent optical network.3.2 Light transmission technology and access technology constitute

24、 fiber access networkThe needs of the user, the diversification and broadband access technology from initial made of pure narrowband access to broadband access, size, and with integrated access to transmission platform requirement light more and more is also high.Optical transmission technology and

25、access technology together constitute fiber access network system. Optical fiber access network in different stages of development of need to resort to the corresponding optical transmission means to achieve the operational load and transfer. With the light network will be dispersed access devices (

26、OLT ONU) together with organic whole, form a unified fiber access network system.4. The current development of fiber-optic access hotspotCurrently, fiber-optic access network continue presented the vigorous development momentum and various new access technology arises at the historic moment. The dev

27、elopment of better have xDSL, FTTX, dual bus size take comprehensive access technologies. In addition, HFC APON EPON, such technology is also in constant developing and perfecting.4.1 The development and application of XDSLXDSL technology refers to the ADSL (asymmetric digital subscriber loop) as a

28、representative of digital subscriber loop (DSL) the floorboard of a series of technology.By using of ground wire although more than 2Mbps broadband data transmission, but the transmission distance is very limited. XDSL and optical fiber integrated access network structure, with the UNI bounded user-

29、oriented provide narrowband normal telephone, 2Mbps line, 10Base_T and ATM broadband interface. Using fibre solve access network transmission of feeder section, XDSL solve finally hundreds meters to 3.5 kilometers (in this range, can guarantee a high rate), it is quite broadband access broadband tec

30、hnology effectively. The current market most successful is ADSL technologies, including China telecom, China netcom, China unicom, China tietong, each big telecom operators are spending heavily construction ADSL network. In the user is relatively scattered, twisted-pair cable resources under the con

31、dition of comparative energetic, ADSL can low cost to solve users network bandwidth needs. SHDSL, HDSL can provide users with broadband data line, these two kinds of digital subscriber loop in special circumstances, the technical solution to the problem of providing data line.VDSL technology is with

32、 ADSL) the development and popularization of and gradually moving towards the commercial, but because it can support distance is short, at present its popularity still far less ADSL.4.2 FTTX technologyIn all sorts of broadband access network technology, optical SDH technology adopted the access netw

33、ork system is applied the most common. SDH technology application in access network has already widespread, but still just FTTC (optical fiber to the side of the road), FTTB (fiber to the floor), the huge bandwidth optical fiber level still no to household. Therefore, to really provide broadband bus

34、iness ability, just using SDH technology solve feeder, wiring, paragraph of the broadband is not enough, still need to introduce line in part by broadband access technology combined. Can FTTB/C + used respectively FTTB/C + xDSL, Cable Modem, FTTB/C + local-area network (LAN) access methods such as r

35、esident and company respectively, enterprise users to provide business. Among them the way FTTX + LAN FTTLAN is called again, in this way our Shanghai, Beijing and other developed city new district has been widely used. The final is FTTH access development goals, but because the cost, the user needs

36、 and market and other reasons, FTTH is still a long-term task.Access the latest development direction with SDH support for IP business is, is to develop a business network platform for MSTP/RPR) (. FTTX MSTP/RPR and combining with business realized width comprehensive transfer.4.3Double (more) bus s

37、ize take integrated business access networkOptical fiber access from the preliminary narrowband integrated service access to comprehensive business access with width of the development process, had two ideas: a view by unified IP business platform realize voice and data services integrated access; A

38、nother argument is because Everything over IP technology in be used actually are still exist many problems, when in to realize comprehensive access or let narrowband service (circuit switching methods) and broadband business (packet switching mode) respectively take different channels. The former re

39、alization ways can the soft exchange to do help, then a realization way by current is most mainstream solutions - double (more) bus integrated service access network.In 1999, he launched a double before and after the comprehensive access network equipment bus model. Some manufacturers provide bus ty

40、pes according to the backboard, and puts forward four buses parlance, including: management bus, TDM business bus, group business bus, general bus. General bus is to expand business ability, or to support now still unforeseeable some business and reserved. Due to its specific also unable to estimate

41、 the design parameters usually be categorized as one of the first three bus. Management bus is to realize the management of the whole system is designed for the Lord, because the bus ability to support business types is more and more abundant, need management information more and more, now also many

42、 USES high-speed management bus bus. This so-called dual bus”, is providing the equipment backplane of the two businesses bus, namely TDM bus and packet bus.Most of the developed countries access equipment is dual bus structure. International technical development direction, adopt the most advanced

43、system structure, launched with IP for the kernel, built-in MSTP double bus type comprehensive access network equipment. Can foresee dual bus integrated access network is the development direction of access in the coming years, each big access network equipment manufacturers will strive for in this

44、huge market competitive advantage, to re-establish throughout the status of optical fiber access product market.5. Access network support business5.1 Voice class business: SPC telephone new business, magnetic card phone business, etc5.2Data class business: DDN business, packet switching, etc5.3 Imag

45、e communication class business: meeting TV business, videophone business, etc5.4 Multimedia business: home office, shopping, VOD, remote medical treatment, etc6. the development direction of future optical fiber access6.1 Broadband is changed and comprehensivizedBroadband access is market developmen

46、t trends, fiber in-home will be broadband access inevitable. XDSL, dual bus integrated access as the transition complete fibre optic access technology, will play in the next few years broadband market protagonist. Future access to achieve a single platform with various business width of comprehensiv

47、e access, achieve business and network of separation, i.e. to further to be changed to the broadband and integrated direction. Meanwhile fiber access network also must be able to support and other access flexible joint networking.6.2 To next generation network (NGN) of evolutionJudging from the tech

48、nical development, the traditional telephone network, data communications network and the technology of industry of cable television network three is gradually disappear, technology difference of fusion will further trigger network fusing, business fusion and industrial integration. Next generation

49、network (NGN) are available including voice, data and multimedia and other business integrated, open network. The trend of its development can be summarized as: network equipment of components, network communication gateway change, access technology diversification, network management integration, t

50、erminal intelligent, business exchange control functions of separation and core network group.In the future of communications-net NGN dominant, optical fiber access network will also after fusion to next generation network with them. Optical fiber access should be a continuous development, continuou

51、sly innovative open system, access network equipment can through the corresponding signaling gateway and relay gateway will narrowband service access to NGN network, through the broadband data gateway will broadband access to NGN network. With the telecommunications industry monopoly market disappea

52、r and telecommunications business market opening, telecom business functions, access technology unceasing enhancement, access is also associated with development, mainly displays in the following:6.2.1 The complexity of the access is increasing. Different access technology with comprehensive competi

53、tion between use, and require the support of large quantities of telecom business such as the complexity of that access network increases.6.2.2 Access to expand in the scope of the services. Along with the development of communication technology and communications network, a local exchange capacity

54、is expanding constantly, exchange, in decreasing number of small local in capacity, convert hubs and multiplex etc, it makes access network service scope expands unceasingly.6.2.3 The standardization level access is increasing day by day. In a local exchange gradually V5. Based on the open after X s

55、tandard interface, telecom operators more freely choose to access network technology and equipment.6.2.4 Access network should support a higher-level business. The development of market economy, prompting commercial and corporate clients demand for greater capacity for the access lines, especially L

56、AN interconnection data applications, demand reliability, short time limit of connection. Along with the optical fiber technology to users of the outspread, CATV network development to the user loop development brings opportunities.6.2.5 Support technology more diverse. Access Although currently in

57、access the content of the optical transmission in growing, but how to make better use of the existing twisted-pair cable will be taken into account, but to demand rapid construction of large capacity access lines, it can choose wireless link.6.2.6 Optical fiber technology will more applied to access

58、. As fiber-optic coverage expansion, optical fiber technology will also increasingly used to access network, from development to the perspective, SDH, ATM, IP/DWDM currently only applies to trunk cable segment and digital transmitter interface, with the bureau of business development, fiber interfac

59、e will further expand to the roadside, and finally into the home, truly realize broadband fiber access, realize unified broadband network structure, therefore, light will really become the telecommunications network information superhighway solid network foundation.光纤接入网技术整个电信网按网络功能分为三个部分：传输网、交换网和接入

60、网。接入网负 责将电信业务透明传送到用户，具体而言，接入即为本地交换机与用户之间的连 接部分，通常包括用户线传输系统、复用设备、交叉连接设备或用户/网络终端 设备。而实际上接供业务的实体就是业务结点。一. 接入网的发展历程1. 接入网（AN： Access Network）是指由业务节点接口（SNI）和相关用网络接口（UNI）之间的一系列传送实体（诸如线路设施和传输设施）所组 成的为传送电信业务提供所需传送承载能力的实施系统，可经由Q3管理接口进 行配置和管理。接入网可以被看作是与业务和应用无关的传送网，主要完成交叉 连接、复用和传输功能，对用户信令来说是透明的。基于现代电信网的接入网是 综合

61、业务接入网，简单的本地话音接入将越来越不能满足需要，语音、数据、图 像的综合接入正成为接入网的发展趋势。经过多年的发展，接入网的界定虽然没 有变，但其内涵和形式发生了很大的变化。性能明显优于传统接入网的综合光纤 接入网将是用户接入网今后的发展趋势。光纤接入网是指从SNI到UNI全部或 者部分采用光纤作为媒质的接入网。ITU-T关于光纤接入网的建议指出，用户接 入系统由三部分组成：局端设备（OLT）、光分配网络（ODN）和光网络单元（ONU）。2. 根据接入网框架和体制要求，接入网的重要特征可以归纳为如下几点：（1）.接入网对于所接入的业务提供承载能力，实现业务的透明传送。（2）.接入网对用户信

62、令是透明的，除了一些用户信令格式转换外，信令和 业务处理的功能依然在业务节点中。（3）.接入网的引入不应限制现有的各种接入类型和业务，接入网应通过有 限的标准化的接口与业务节点相连。（4）.接入网有独立于业务节点的网络管理系统，该系统通过标准化的接口 连接TMN，TMN实施对接入网的操作、维护和管理。二. 光纤的结构1. 总线形结构。指以光纤作为公共总线、各用户终端通过耦合器与总线直接 连接的网络结构。其特点是共享主干光纤，节约线路投资，增删节点容易，动态 范围要求较高，彼此干扰效小。缺点是损耗积累，用户接受对主干光纤的依赖性 强。2. 环形结构。指所有节点共用一条光纤链路，光纤链路首尾相连自

63、成封闭回 路的网络结构。特点是可实现自愈，即无需外界干预，网络可在较短的时间自动 从失效故障中恢复所传业务，可靠性高。缺点是单环所挂用户数量有限，多环互 通较为复杂，不适合CATV等分配型业务。3. 星形结构。这种结构实际上是点对点方式，各用户终端通过位于中央节点 具有控制和交换功能的星形耦合器进行信息交换。特点是结构简单，使用维护方 便，易于升级和扩容，各用户之间相对独立，保密性好，业务适应性强。缺点是 所需光纤代价较高，组网灵活性较差，对中央节点的可靠性要求极高。4. 树形结构。类似于树枝形状，呈分级结构，在交接箱和分线盒处采用多个 分路器，将信号逐级向下分配，最高级的端局具有很强的控制协

64、调能力。特点是 适用于广播业务。缺点是功率损耗较大，双向通信难度较大。三. 光纤接入网在现代通信网中的地位光纤接入网在实现国家信息现代化过程中起着越来越重要的作用，是现 代通信网不可或缺的组成部分。现代通信网基本实现了基于光纤的骨干网的传输 和交换，而接入段仍然是制约现代电信网进一步发展和完善的“瓶颈”，因此， 要建设国家信息基础结构（NII），接入网是关键。接入网技术的发展，将导致 通信信息网的巨大变化，即语音、数据、图像等各种信息业务综合一起传送，实 现资源共享，逐步优化通信网络，大大提高网络效益。光纤接入网是光传输技术 与接入技术相结合的产物1. 光传输技术的发展和演进自从1979年人类

65、使用光纤作为通信方式以来，光传输技术经历了从模拟到 数字、从PDH到SDH/WDM、从有源到无源、从SDH到MSTP的一系列发展 和演进过程，传输容量、可靠性、传输距离等指标都已经达到了相当高的水平。当前主流的光传输技术仍然是SDH，STM-1/4/16/64/256系列同步转移模 块都已经实现，其中STM-256帧速率高达40Gbps。基于SDH、融合宽带数据 业务的多业务传送平台（MSTP）也已经成为当今建设城域网的最佳选择，此外 弹性分组环（RPR）技术也逐步成为光传输发展的一个方向。未来光传输网络 将向光传送网（OTN）的方向发展，在OTN网络中很多交换、选路和其它智能 化功能将在光层

66、上实现。OTN网络的智能化发展到一定程度就可实现智能光网 络（ASON）。2. 光传输技术与接入技术共同构成光纤接入网用户需求的多样化和宽带化使得接入技术从最初的纯窄带接入发展到宽带 接入、宽窄带综合接入，因而对于光传输平台的要求也越来越高。光传输技术与接入技术融合在一起即构成光纤接入网系统。光纤接入网在不 同的发展阶段需要借助于相应的光传输手段来实现业务的承载和传送。借助于光 网络将分散的接入设备（OLT和ONU）连成有机的整体，形成统一的光纤接入 网系统。四. 当前光纤接入网的发展热点当前，光纤接入网继续呈现出蓬勃发展的势头，各种新的接入技术应运而生。 其中发展较好的有xDSL、FTTX、双总线宽窄带综合接入等技术。此外EPON、 APON、HFC等