外文翻譯--光纖接入網(wǎng)技術(shù)

1、<p><b>　　中文1866字</b></p><p><b>　　附 錄</b></p><p><b>　　一、英文原文</b></p><p>　　Optical fiber access network technology</p><p>　　Duri

2、ng 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, w

3、hich was incompatible. </p><p>　　The entire telecommunication network according to network function is divided into three sections: switching, transmission,and access. Access to telecommunications business t

4、ransparent to users, transmit specific, access to local switch and the user that the connection between the parts, usually include subscriber line transmission system, reuse equipment, crossing connection device or user/

5、network terminal equipment. And actually pick for business entity is business nodes. </p><p>　　1. Access network development process </p><p>　　1.1 Access Network （AN: Access by business） refers

6、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 prov

7、ide the required transmit load capacity, implementation system configurations percentile management interface via and management. Access can be seen as with business and application irrelevant transmission network, mainl

8、y finish </p><p>　　Based on modern of telecommunication network access network is integrated service access, simple local voice access will be increasingly cannot meet the requirements, the voice, data and i

9、mage 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. Superior traditio

10、nal access network integrated optical fiber access network will be users access the future d</p><p>　　Optical fiber access from SNI to UNI refers to all or part of the access network by using optical fiber a

11、s medium. ITU - T about access 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.

12、2According to the requirement of system access framework and the important characteristics, access network can be summarized as the following: </p><p>　　1.2.1 Access to access business provides bearing capac

13、ity, achieve business transparent transfer. </p><p>　　1.2.2. The access is transparent to users signaling, except for some users signaling format conversion outside, signaling and business processing functio

14、n is still in business node. </p><p>　　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 int

15、erface and business node connected. </p><p>　　1.2.4Access network have independent from the business node in the network management system, this system through the standardized interfaces connected TMN, acce

16、ss network operation for implementation TMN, maintenance and management. </p><p>　　2 .fiber structure </p><p>　　2.1general linear structure. Refer to the public bus, fiber as each user terminals

17、 through direct connect with bus coupler network structure. Its characteristic is sharing backbone fiber, save lines to remove node investment, the demand is higher, dynamic range, interfere with each other effect is sma

18、ll. Defect is loss of accumulation, the backbone fiber user acceptance dependence is strong. </p><p>　　2.2 ring structure. Refers to all share a fiber optic link node, fiber optic link its end to end the clo

19、sed 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 reliab

20、ility. Defect is hanged by the number of users of monocylic limited, polycyclic interchange is relatively complex, not suitable for CATV, etc FenPeiXing business. </p><p>　　2.3star structure. This structure

21、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. Characteristics of simple structure, maintenance is convenien

22、t 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 c

23、entral node. </p><p>　　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 e

24、nd innings allocation, have strong control coordination. Characteristic is suitable for broadcasting business. Defect is power loss is bigger, two-way communication difficulty bigger. </p><p>　　3．The status

25、of optical access network in the modern communication</p><p>　　Optical fiber in realizing national information modernization access plays a more and more important role, is an indispensable part of modern co

26、mmunications 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 o

27、f the "bottleneck", therefore, to construction of national information infrastructure （NII）, access network is the key. Access network t</p><p>　　Two optical fiber optical transmission technology a

28、ccess with the combination of the access technology </p><p>　　3.1 Light transmission technology development and evolution </p><p>　　Since 1979, the human use of optical fiber as communication mo

29、de, 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

30、 and reliability, the transmission distance such indicators have reached a very high level. </p><p>　　The current mainstream of optical transmission technology is still SDH, STM - 1/4/16/64/256 series synchr

31、onous 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 best choice for toda

32、y's construction intracity networks, moreover elastic grouping ring （RPR） technology is also gradually become the direction of the development of a light transmission. The fut</p><p>　　3.2 Light transmis

33、sion technology and access technology constitute fiber access network </p><p>　　The needs of the user, the diversification and broadband access technology from initial made of pure narrowband access to broad

34、band access, size, and with integrated access to transmission platform requirement light more and more is also high. </p><p>　　Optical transmission technology and access technology together constitute fiber

35、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 networ

36、k will be dispersed access devices （OLT ONU） together with organic whole, form a unified fiber access network system.</p><p><b>　　二、英文翻譯</b></p><p><b>　　光纖接入網(wǎng)技術(shù)</b></p

37、><p>　　整個電信網(wǎng)按網(wǎng)絡(luò)功能分為三個部分：傳輸網(wǎng)、交換網(wǎng)和接入網(wǎng)。接入網(wǎng)負責將電信業(yè)務(wù)透明傳送到用戶，具體而言，接入即為本地交換機與用戶之間的連接部分，通常包括用戶線傳輸系統(tǒng)、復用設(shè)備、交叉連接設(shè)備或用戶/網(wǎng)絡(luò)終端設(shè)備。而實際上接供業(yè)務(wù)的實體就是業(yè)務(wù)結(jié)點。</p><p>　　一．接入網(wǎng)的發(fā)展歷程</p><p>　　1.接入網(wǎng)（AN：Access Network

38、）是指由業(yè)務(wù)節(jié)點接口（SNI）和相關(guān)用</p><p>　　網(wǎng)絡(luò)接口（UNI）之間的一系列傳送實體（諸如線路設(shè)施和傳輸設(shè)施）所組成的為傳送電信業(yè)務(wù)提供所需傳送承載能力的實施系統(tǒng)，可經(jīng)由Q3管理接口進行配置和管理。接入網(wǎng)可以被看作是與業(yè)務(wù)和應(yīng)用無關(guān)的傳送網(wǎng)，主要完成交叉連接、復用和傳輸功能，對用戶信令來說是透明的?；诂F(xiàn)代電信網(wǎng)的接入網(wǎng)是綜合業(yè)務(wù)接入網(wǎng)，簡單的本地話音接入將越來越不能滿足需要，語音、數(shù)據(jù)、圖像的綜合

39、接入正成為接入網(wǎng)的發(fā)展趨勢。</p><p>　　經(jīng)過多年的發(fā)展，接入網(wǎng)的界定雖然沒有變，但其內(nèi)涵和形式發(fā)生了很大的變化。光纖接入網(wǎng)是指從SNI到UNI全部或者部分采用光纖作為媒質(zhì)的接入網(wǎng)。ITU-T關(guān)于光纖接入網(wǎng)的建議指出，用戶接入系統(tǒng)由三部分組成：局端設(shè)備（OLT）、光分配網(wǎng)絡(luò)（ODN）和光網(wǎng)絡(luò)單元（ONU）。</p><p>　　2. 根據(jù)接入網(wǎng)框架和體制要求，接入網(wǎng)的重要特征可以歸

40、納為如下幾點： </p><p>　?。?）接入網(wǎng)對于所接入的業(yè)務(wù)提供承載能力，實現(xiàn)業(yè)務(wù)的透明傳送。 </p><p>　?。?）接入網(wǎng)對用戶信令是透明的，除了一些用戶信令格式轉(zhuǎn)換外，信令和業(yè)務(wù)處理的功能依然在業(yè)務(wù)節(jié)點中。 </p><p>　?。?）接入網(wǎng)的引入不應(yīng)限制現(xiàn)有的各種接入類型和業(yè)務(wù)，接入網(wǎng)應(yīng)通過有限的標準化的接口與業(yè)務(wù)節(jié)點相連。 </p>

41、<p>　?。?）接入網(wǎng)有獨立于業(yè)務(wù)節(jié)點的網(wǎng)絡(luò)管理系統(tǒng)，該系統(tǒng)通過標準化的接口連接TMN，TMN實施對接入網(wǎng)的操作、維護和管理。 </p><p><b>　　二．光纖的結(jié)構(gòu)</b></p><p>　　1.總線形結(jié)構(gòu)。指以光纖作為公共總線、各用戶終端通過耦合器與總線直接連接的網(wǎng)絡(luò)結(jié)構(gòu)。其特點是共享主干光纖，節(jié)約線路投資，增刪節(jié)點容易，動態(tài)范圍要求較高

42、，彼此干擾效小。缺點是損耗積累，用戶接受對主干光纖的依賴性強。 </p><p>　　2.環(huán)形結(jié)構(gòu)。指所有節(jié)點共用一條光纖鏈路，光纖鏈路首尾相連自成封閉回路的網(wǎng)絡(luò)結(jié)構(gòu)。特點是可實現(xiàn)自愈，即無需外界干預(yù)，網(wǎng)絡(luò)可在較短的時間自動從失效故障中恢復所傳業(yè)務(wù)，可靠性高。缺點是單環(huán)所掛用戶數(shù)量有限，多環(huán)互通較為復雜，不適合CATV等分配型業(yè)務(wù)。</p><p>　　3.星形結(jié)構(gòu)。這種結(jié)構(gòu)實際上是點對點

43、方式，各用戶終端通過位于中央節(jié)點具有控制和交換功能的星形耦合器進行信息交換。特點是結(jié)構(gòu)簡單，使用維護方便，易于升級和擴容，各用戶之間相對獨立，保密性好，業(yè)務(wù)適應(yīng)性強。缺點是所需光纖代價較高，組網(wǎng)靈活性較差，對中央節(jié)點的可靠性要求極高。 </p><p>　　4.樹形結(jié)構(gòu)。類似于樹枝形狀，呈分級結(jié)構(gòu)，在交接箱和分線盒處采用多個分路器，將信號逐級向下分配，最高級的端局具有很強的控制協(xié)調(diào)能力。特點是適用于廣播業(yè)務(wù)。缺點

44、是功率損耗較大，雙向通信難度較大。</p><p>　　三．光纖接入網(wǎng)在現(xiàn)代通信網(wǎng)中的地位</p><p>　　光纖接入網(wǎng)在實現(xiàn)國家信息現(xiàn)代化過程中起著越來越重要的作用，是現(xiàn)代通信網(wǎng)不可或缺的組成部分。現(xiàn)代通信網(wǎng)基本實現(xiàn)了基于光纖的骨干網(wǎng)的傳輸和交換，而接入段仍然是制約現(xiàn)代電信網(wǎng)進一步發(fā)展和完善的“瓶頸”，因此，要建設(shè)國家信息基礎(chǔ)結(jié)構(gòu)（NII），接入網(wǎng)是關(guān)鍵。接入網(wǎng)技術(shù)的發(fā)展，將導致通信信

45、息網(wǎng)的巨大變化，即語音、數(shù)據(jù)、圖像等各種信息業(yè)務(wù)綜合一起傳送，實現(xiàn)資源共享，逐步優(yōu)化通信網(wǎng)絡(luò)，大大提高網(wǎng)絡(luò)效益。光纖接入網(wǎng)是光傳輸技術(shù)與接入技術(shù)相結(jié)合的產(chǎn)物</p><p>　　1．光傳輸技術(shù)的發(fā)展和演進</p><p>　　自從1979年人類使用光纖作為通信方式以來，光傳輸技術(shù)經(jīng)歷了從模擬到數(shù)字、從PDH到SDH/WDM、從有源到無源、從SDH到MSTP的一系列發(fā)展和演進過程，傳輸容量、

46、可靠性、傳輸距離等指標都已經(jīng)達到了相當高的水平。</p><p>　　當前主流的光傳輸技術(shù)仍然是SDH，STM-1/4/16/64/256系列同步轉(zhuǎn)移模塊都已經(jīng)實現(xiàn)，其中STM-256幀速率高達40Gbps。基于SDH、融合寬帶數(shù)據(jù)業(yè)務(wù)的多業(yè)務(wù)傳送平臺（MSTP）也已經(jīng)成為當今建設(shè)城域網(wǎng)的最佳選擇，此外彈性分組環(huán)（RPR）技術(shù)也逐步成為光傳輸發(fā)展的一個方向。未來光傳輸網(wǎng)絡(luò)將向光傳送網(wǎng)（OTN）的方向發(fā)展，在OTN

47、網(wǎng)絡(luò)中很多交換、選路和其它智能化功能將在光層上實現(xiàn)。OTN網(wǎng)絡(luò)的智能化發(fā)展到一定程度就可實現(xiàn)智能光網(wǎng)絡(luò)（ASON）。</p><p>　　2．光傳輸技術(shù)與接入技術(shù)共同構(gòu)成光纖接入網(wǎng)</p><p>　　用戶需求的多樣化和寬帶化使得接入技術(shù)從最初的純窄帶接入發(fā)展到寬帶接入、寬窄帶綜合接入，因而對于光傳輸平臺的要求也越來越高。</p><p>　　光傳輸技術(shù)與接入技術(shù)融