光纤接入网技术毕业论文外文翻译.doc

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1、一、英文原文Optical fiber access network technologyDuring the early 1980s, analog cellular telephone systems were experiencing rapid growth in Europe, particularly in Scandinavia and the United Kingdom, but also in France and Germany. Each country developed its own system, which was incompatible. The enti

2、re 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 connection between the parts, usually include sub

3、scriber 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 process 1.1 Access Network （AN: Access by business） refers to a node interface （SNI） and related us

4、ers 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 configurations percentile management interface via and ma

5、nagement. 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 network is integrated service access, simple

6、 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 connotation and forms has changed significantly. Super

7、ior 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 network recommendations indicate that fiber

8、, 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 be summarized as the following: 1.2.1 Acces

9、s 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 business node. 1.2.3 The introduction of shoul

10、d 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 system, this system through the standardi

11、zed interfaces connected TMN, access network operation for implementation TMN, maintenance and management. 2 .fiber structure 2.1general linear structure. Refer to the public bus, fiber as each user terminals through direct connect with bus coupler network structure. Its characteristic is sharing ba

12、ckbone 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 fiber optic link node, fiber optic li

13、nk 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 hanged by the number of users of monoc

14、ylic 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 astral couplers exchange information.

15、 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 requirements of central node. 2.4 t

16、ree 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 broadcasting business. Defect is

17、power loss is bigger, two-way communication difficulty bigger. 3The 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 modern communications network. Modern

18、 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 infrastructure （NII）, access network is

19、 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 sharing, and gradually optimized com

20、munication network, greatly improving network benefits. Two optical fiber optical transmission technology access with the combination of the access technology 3.1 Light transmission technology development and evolution Since 1979, the human use of optical fiber as communication mode, optical transmi

21、ssion 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 reached a very high level. The cur

22、rent 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 MSTP） has also become the be

23、st 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） in the direction of developm

24、ent, 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 fiber access network The ne

25、eds 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 access technology together

26、 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 （OLT ONU） together with org

27、anic whole, form a unified fiber access network system. 二、英文翻译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

28、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。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

29、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

30、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

31、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

32、传输技术的发展和演进自从1979年人类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

33、和其它智能化功能将在光层上实现。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。生命列车The Train Of Life 1. 不久以前，我读了一本书。书中把人生比作一次旅行。2. 人生一世，就好比是一次

34、搭车旅行，要经历无数次上车、下车; 时常有事故发生; 有时是意外惊喜，有时却是刻骨铭心的悲伤 3. 降生人世，我们就坐上了生命列车。我们以为我们最先见到的那两个人-我们的父母，会在人生旅途中一直陪伴着我们。 4. 很遗憾，事实并非如此。他们会在某个车站下车，留下我们，孤独无助。他们的爱、他们的情、他们不可替代的陪伴，再也无从寻找。 5. 尽管如此，还会有其他人上车。他们当中的一些人将对我们有着特殊的意义。 6. 他们之中有我们的兄弟姐妹, 有我们的亲朋好友。我们还将会体验千古不朽的爱情故事。7. 坐同一班车的人当中，有的轻松旅行。8. 有的却带着深深的悲哀 还有的,在列车上四处奔忙，随时准备帮

35、助有需要的人 9. 很多人下车后，其他旅客对他们的回忆历久弥新 但是，也有一些人，当他们离开座位时，却没有人察觉。10. 有时候，对你来说情深义重的旅伴却坐到了另一节车厢。你只得远离他，继续你的旅程。11. 当然，在旅途中，你也可以摇摇晃晃地穿过自己的车厢，去别的车厢找他 12. 可惜，你再也无法坐在他身旁，因为这个位置已经让别人给占了 .13. 没关系。旅途充满挑战、梦想、希望、离别 就是不能回头。因此，尽量使旅途愉快吧！14. 善待旅途上遇见的所有旅客，找出人们身上的闪光点。15. 永远记住，在某一段旅程中，有人会犹豫彷徨，因为我们自己也会犹豫彷徨。16. 我们要理解他人，因为我们需要他人

36、的理解。17. 生命之谜就是：我们在什么地方下车？坐在身旁的伴侣在什么地方下车？我们的朋友在什么地方下车？我们无从知晓 18. 我时常这样想：到我该下车的时候，我会留恋吗？我想我还是会的。和我的朋友分离，我会痛苦。让我的孩子孤独地前行，我会悲伤。 我执著地希望在我们大家都要到达的那个终点站，我们还会相聚 19. 我的孩子们上车时没有什么行李，如果我能在他们的行囊中留下美好的回忆，我会感到幸福。20. 我下车后，和我同行的旅客都还能记得我，想念我，我将感到快慰。21. 献给你, 我生命列车上的同行者, 祝您旅途愉快!1. Not long ago, I read a book, in which

37、 a mans life was compared to a journey.2. The life of a man is just like a hitchhiking，during which many times we go up and down. Now and then things will happen accidently, some of which are to be unexpected excitement，while some heart-breaking sorrows. 3. When first embraced the world，we are alrea

38、dy on the train of life. We take it for granted that the first two persons, our parents, whom we are encountered with, will accompany us all the way.4. Sadly，things do not go on as we thought.Our parents will get off the train at a certain station，leaving us, bereft and helpless.Their love and emoti

39、on to us and their irreplaceable company can be found in nowhere.5. However，there will be somebody else who will get on the train. Some of them will have special meaning to us.6. Some of them may be our siblings , relatives and friends, and we will also expereince the imperishable love.7. Some of ou

40、r travelling companions are quite light-hearted on the way.8. While some may bear immense sorrow.Still some ,back and forth, are ready to hold out their hands for others who need help.9. Some people alight off the train, yet they are still kept in the mind of the other passengers for long;some, to t

41、he opposite, leave their seats without being noticed.10. Sometimes, the one,who is dear to your heart, has huddled into another carriage. Nothing but one you can do is just to keep on going, far away from him.11. Of course, during the journey, you may stagger to another carriage to look for him.12.

42、Its a pity that you will never seat yourself beside him because the seat has been engaged by others. 13. Never mind. The journey is full of challenges,dreams, hopes and departures- but only one thing is that you cant turn back. So, have a good journey with heart and soul.14. Show your good-will to a

43、ll the passengers you are encountered with, and find the merits of theirs.15. Remeber that someone may oscillate just as we do in the journey.16. We should understand others just as we need others understanding.17. The enigma of life is：Where shall we get off the train of life?And how about the comp

44、anions beside us?And our friends?We dont know.18. Sometimes I think：When my time comes to get off the train，shall I miss it？I think I will.It is a suffering when I part with my friends.I will be sorry for leaving my kids going alone.I firmly hold that when we get to the terminal，we will have another

45、 reunion.19. When my kids get on the train of life, they have only little luggage in their travelling bags. However,if I can leave the beautiful memory in them,I will be happy. 20. After getting off the train of life, I will be content if my fellow passengers will remember me and miss me.21. To you , the companions on my train of life.May you have a good journey!