通信專(zhuān)業(yè)外文翻譯---基于epon的三網(wǎng)融合接入網(wǎng)技術(shù)

1、<p>　　基于EPON的三網(wǎng)融合接入網(wǎng)技術(shù)</p><p><b>　　1引言 </b></p><p>　　信息社會(huì)的發(fā)展使人們?cè)絹?lái)越離不開(kāi)網(wǎng)絡(luò)技術(shù)提供的便利，經(jīng)過(guò)最近20年的快速發(fā)展，我國(guó)電信網(wǎng)、有線(xiàn)電視網(wǎng)和互聯(lián)網(wǎng)都已經(jīng)成為世界第一。目前，我國(guó)有線(xiàn)廣播電視網(wǎng)已有333萬(wàn)km光纜線(xiàn)路，1000萬(wàn)km同軸電纜線(xiàn)路，有線(xiàn)電視用戶(hù)數(shù)達(dá)到1.75億戶(hù)，其中數(shù)字信

2、號(hào)電視用戶(hù)6500萬(wàn)，模擬信號(hào)電視用戶(hù)超過(guò)1億戶(hù)，有線(xiàn)電視網(wǎng)絡(luò)提供的寬帶接入用戶(hù)數(shù)300多萬(wàn)戶(hù)。2009年，基礎(chǔ)電信企業(yè)的互聯(lián)網(wǎng)寬帶接入用戶(hù)凈增2034.7萬(wàn)戶(hù)，達(dá)到10322.6萬(wàn)戶(hù)，寬帶網(wǎng)民數(shù)達(dá)到3.46億。通過(guò)對(duì)比可以發(fā)現(xiàn)，最大程度地利用現(xiàn)有網(wǎng)絡(luò)資源，用較小的投資進(jìn)行雙向改造，迅速發(fā)展寬帶用戶(hù)，是廣電行業(yè)面臨的巨大挑戰(zhàn)和歷史機(jī)遇。 </p><p>　　隨著國(guó)務(wù)院對(duì)三網(wǎng)融合政策的批復(fù)，有線(xiàn)電視網(wǎng)向前演進(jìn)為下

3、一代廣播電視網(wǎng)（NGB）的浪潮已經(jīng)不可阻擋，NGB的骨干網(wǎng)和內(nèi)容平臺(tái)都已經(jīng)有相對(duì)成熟的解決方案，接入網(wǎng)絡(luò)的建設(shè)由于解決方案的復(fù)雜性和占總體投資比例的重要性而成為當(dāng)前NGB建設(shè)的重點(diǎn)和難點(diǎn)。 </p><p><b>　　2接入網(wǎng)技術(shù)方案 </b></p><p>　　EPON技術(shù)由于高帶寬、易維護(hù)、遠(yuǎn)距離覆蓋的特點(diǎn)成為當(dāng)前FTTx的主流承載技術(shù)，目前產(chǎn)業(yè)鏈發(fā)展完善，是

4、電信運(yùn)營(yíng)商接入網(wǎng)絡(luò)建設(shè)的首選技術(shù)。但是由于在駐地網(wǎng)層面采用光纖直接到戶(hù)的成本較高，傳統(tǒng)電信運(yùn)營(yíng)商基本上采用了FTTB+LAN或FTTB＋DSL的方案，這樣在盡量節(jié)約駐地網(wǎng)投資的前提下，獲得了最佳的網(wǎng)絡(luò)性能。 </p><p>　　廣電運(yùn)營(yíng)商長(zhǎng)期專(zhuān)注于HFC網(wǎng)絡(luò)的建設(shè)，擁有著龐大的HFC接入網(wǎng)絡(luò)，利用HFC作為入戶(hù)媒介可實(shí)現(xiàn)最大的實(shí)用性和經(jīng)濟(jì)性。廣電HFC網(wǎng)絡(luò)中的同軸電纜網(wǎng)是一種理想的數(shù)據(jù)傳輸媒介，尤其在最后100

5、m的帶寬支持能力遠(yuǎn)遠(yuǎn)高于五類(lèi)線(xiàn)或電話(huà)線(xiàn)資源。因此，在廣電網(wǎng)絡(luò)雙向改造中如何融合光纖和HFC兩種介質(zhì)，深入挖掘現(xiàn)有網(wǎng)絡(luò)價(jià)值，被廣電運(yùn)營(yíng)商所關(guān)注。目前比較經(jīng)濟(jì)可行的雙向改造技術(shù)方案有3種：CMTS，EPON+LAN和EPON+EoC。 </p><p>　　2.1 CMTS適合稀疏模式網(wǎng)絡(luò)覆蓋區(qū)域 </p><p>　　CMTS利用現(xiàn)有的有線(xiàn)電視網(wǎng)絡(luò)，通過(guò)對(duì)信號(hào)進(jìn)行QPSK/QAM調(diào)制，在HF

6、C低頻端進(jìn)行雙向傳輸。CMTS的優(yōu)點(diǎn)是技術(shù)較成熟，網(wǎng)管能力強(qiáng)，可實(shí)現(xiàn)大規(guī)模雙向覆蓋。缺點(diǎn)是CMTS噪聲匯聚效應(yīng)影響系統(tǒng)的帶寬和性能，同軸電纜及接頭質(zhì)量要求較高，后續(xù)維護(hù)工作量較大；對(duì)于大多數(shù)有線(xiàn)電視運(yùn)營(yíng)商而言，上行噪聲是一個(gè)普遍存在的問(wèn)題，尤其是在低頻帶。CMTS設(shè)備包轉(zhuǎn)發(fā)能力弱，無(wú)法滿(mǎn)足日益增長(zhǎng)的高帶寬業(yè)務(wù)需求，可承載業(yè)務(wù)有限，無(wú)法提供全業(yè)務(wù)承載，后續(xù)系統(tǒng)擴(kuò)容成本巨大。CMTS的Cable接入屬于共享線(xiàn)路方式，如果只作寬帶接入和上網(wǎng)，

7、在用戶(hù)數(shù)量不太多的情況下比較適合廣電開(kāi)展數(shù)據(jù)業(yè)務(wù)。對(duì)于目前國(guó)內(nèi)用戶(hù)集中居住，用戶(hù)需要長(zhǎng)時(shí)間占用網(wǎng)絡(luò)、大流量吞吐數(shù)據(jù)，單位帶寬下降明顯，不利于高帶寬業(yè)務(wù)的開(kāi)展，采用CMTS實(shí)現(xiàn)大范圍的用戶(hù)寬帶接入不夠經(jīng)濟(jì)。 </p><p>　　2.2 EPON+LAN適合于高密度用戶(hù)新建小區(qū) </p><p>　　EPON+LAN方案是通過(guò)EPON網(wǎng)絡(luò)接入到樓宇，通過(guò)ONU提供以太網(wǎng)接口，用戶(hù)接入通過(guò)以太

8、網(wǎng)五類(lèi)線(xiàn)實(shí)現(xiàn)。采用這個(gè)方案實(shí)現(xiàn)用戶(hù)語(yǔ)音和互聯(lián)網(wǎng)接入，有線(xiàn)電視信號(hào)仍通過(guò)HFC線(xiàn)路實(shí)現(xiàn)。它的優(yōu)點(diǎn)是技術(shù)成熟，設(shè)備商較多，接口和標(biāo)準(zhǔn)規(guī)范。該方案適合于高密度用戶(hù)和大帶寬業(yè)務(wù)需求新建小區(qū)的第一次綜合布線(xiàn)時(shí)一次完成，而對(duì)于已經(jīng)開(kāi)通有線(xiàn)電視的老用戶(hù)需要重新進(jìn)行布線(xiàn)，小區(qū)樓道和入戶(hù)布線(xiàn)施工難度較大，用戶(hù)一般不愿意接受。 </p><p>　　2.3 EPON＋EoC適合現(xiàn)有CATV用戶(hù)的首選技術(shù) </p>&l

9、t;p>　　EPON＋EoC技術(shù)是在現(xiàn)有的HFC網(wǎng)絡(luò)基礎(chǔ)上構(gòu)造一個(gè)適用于廣電網(wǎng)絡(luò)系統(tǒng)的數(shù)字帶寬用戶(hù)接入網(wǎng)絡(luò)，它在不影響現(xiàn)有的CATV正常工作的前提下，以先進(jìn)的調(diào)制解調(diào)技術(shù)，將以太網(wǎng)信號(hào)合成在同軸電纜中與原有的CATV信號(hào)一起傳輸，用于承載基于IP的數(shù)據(jù)、語(yǔ)音和視頻等業(yè)務(wù)。它以較少的改造成本和工程量將原來(lái)單向的有線(xiàn)電視網(wǎng)絡(luò)改造成為一個(gè)雙向的、能夠承載多種業(yè)務(wù)的雙向?qū)拵ЬW(wǎng)絡(luò)。采用EoC技術(shù)具有良好的適應(yīng)性和靈活的組網(wǎng)方案，充分利用了廣

10、電原有的同軸接入網(wǎng)資源，節(jié)省了入戶(hù)部分的線(xiàn)路投資。 </p><p>　　將EPON技術(shù)和EoC技術(shù)相結(jié)合，統(tǒng)一網(wǎng)管，組成整體解決方案，可以為廣電三網(wǎng)融合NGB的發(fā)展提供接入網(wǎng)絡(luò)的最佳技術(shù)。EPON＋EoC可提供數(shù)據(jù)、視頻、語(yǔ)音于一體的三種播放的綜合承載，通過(guò)一張接入網(wǎng)提供過(guò)去多張網(wǎng)絡(luò)的功能。該方案在開(kāi)發(fā)過(guò)程中充分考慮中國(guó)國(guó)情和當(dāng)前廣電網(wǎng)絡(luò)的實(shí)際情況，在駐地網(wǎng)層面利用廣電網(wǎng)已有的Cable網(wǎng)絡(luò)作為傳輸介質(zhì)，節(jié)約了

11、大量的綜合布線(xiàn)成本和運(yùn)維投資，兼具高性能和低成本。EPON＋EoC技術(shù)滿(mǎn)足了廣電數(shù)字電視的雙向改造和國(guó)家三網(wǎng)融合的需要，將推動(dòng)NGB產(chǎn)業(yè)在中國(guó)的深入發(fā)展，是面向廣電運(yùn)營(yíng)商N(yùn)GB網(wǎng)絡(luò)接入層首選技術(shù)。 </p><p>　　3 EPON和EoC組網(wǎng)技術(shù) </p><p>　　3.1 EPON技術(shù) </p><p>　　光纖作為傳輸高速率、大容量、多業(yè)務(wù)的最佳媒質(zhì)，早已在

12、骨干網(wǎng)和城域網(wǎng)中得到了廣泛的應(yīng)用，在接入網(wǎng)層面，光纖也已經(jīng)得到了普及與應(yīng)用。光纖具有壽命長(zhǎng)、可靠性高、抗干擾性強(qiáng)的優(yōu)點(diǎn)，光傳輸具有很強(qiáng)的帶寬擴(kuò)展能力，并且容易實(shí)現(xiàn)各種業(yè)務(wù)平臺(tái)的融合。 </p><p>　　EPON技術(shù)是將以太網(wǎng)與無(wú)源光網(wǎng)絡(luò)相結(jié)合的技術(shù)，按照IEEE802.3ah國(guó)際標(biāo)準(zhǔn)可以支持1.25Gbit/s對(duì)稱(chēng)速率。作為光纖接入網(wǎng)的重要解決方案，EPON技術(shù)具有ADSL，LAN等無(wú)法比擬的特性，也比APO

13、N，BPON，GPON等技術(shù)更為高效地滿(mǎn)足了“EverythingoverIP”的多業(yè)務(wù)接入需求。EPON接入網(wǎng)絡(luò)具有投資成本低、操作和維護(hù)簡(jiǎn)單等優(yōu)勢(shì)，為運(yùn)營(yíng)商解決“最后一公里”問(wèn)題提供了一種非常經(jīng)濟(jì)有效的寬帶接入解決方案。目前，EPON技術(shù)已經(jīng)在國(guó)內(nèi)外得到了大規(guī)模的應(yīng)用，得到國(guó)內(nèi)外運(yùn)營(yíng)商和廠(chǎng)商的支持和認(rèn)可。 </p><p>　　通過(guò)EPON系統(tǒng)設(shè)備，利用FTTH/FTTB光纖網(wǎng)絡(luò)覆蓋家庭、企業(yè)用戶(hù)可以提供最大

14、帶寬達(dá)1Gbit/s的傳輸速率。運(yùn)營(yíng)商可以用經(jīng)濟(jì)的造價(jià)和極少的光纜線(xiàn)路投資，方便地實(shí)現(xiàn)高速上網(wǎng)，IPTV組播/點(diǎn)播等高帶寬IP數(shù)據(jù)業(yè)務(wù)的傳送。 </p><p>　　EPON系統(tǒng)主要由OLT（OpticalLineTerminal，光纖線(xiàn)路終端）和ONU（OpticalNetworkUnit，光纖網(wǎng)絡(luò)單元）以及分離器（Splitter）構(gòu)成，OLT提供到IP城域網(wǎng)，IPTV承載網(wǎng)，NGN軟交換網(wǎng)上行接口。針對(duì)最終

15、用戶(hù)不同的業(yè)務(wù)需求，運(yùn)營(yíng)商可靈活選擇終端ONU設(shè)備，滿(mǎn)足FTTH/FTTB/FTTC/FTTC+EoC等多種應(yīng)用場(chǎng)景。典型的EPON組網(wǎng)方案如圖1所示。 </p><p>　　圖附-1 EPON典型組網(wǎng)方案</p><p>　　Fig attached-1 EPON typical network scheme</p><p>　　3.2 EoC技術(shù) </p&

16、gt;<p>　　EoC是指在同軸電纜上傳輸以太網(wǎng)數(shù)據(jù)的技術(shù)。EoC系統(tǒng)由頭端、終端、同軸分配網(wǎng)等部分組成。頭端一般放在光節(jié)點(diǎn)位置，起分發(fā)上層以太網(wǎng)數(shù)據(jù)、匯聚終端設(shè)備的作用；終端放在用戶(hù)家里接入用戶(hù)電腦或互動(dòng)機(jī)頂盒；同軸分配網(wǎng)絡(luò)是從有線(xiàn)電視網(wǎng)光節(jié)點(diǎn)位置到用戶(hù)家里的網(wǎng)絡(luò)，除了同軸線(xiàn)纜以外，還包括有源放大器，EoC跳接器，分支/分配器等設(shè)備。 </p><p>　　目前常用的EoC頭端設(shè)備是基于Home

17、PlugAV技術(shù)的有源調(diào)制的接入?yún)R聚設(shè)備，它的主要功能是將數(shù)據(jù)基帶信號(hào)以O(shè)FDM方式調(diào)制到7～30MHz頻段，再與有線(xiàn)電視網(wǎng)絡(luò)信號(hào)進(jìn)行混合后在有線(xiàn)電視HFC網(wǎng)的同軸電纜上傳輸。常用的EoC用戶(hù)端設(shè)備是基于HomePlugAV技術(shù)的用戶(hù)端的調(diào)制解調(diào)設(shè)備，其主要功能是將各類(lèi)用戶(hù)終端設(shè)備電腦，機(jī)頂盒，IP話(huà)機(jī)等，接入到EoC系統(tǒng)中，實(shí)現(xiàn)以同軸電纜為介質(zhì)的雙向?qū)拵Ы尤搿?</p><p>　　針對(duì)廣電運(yùn)營(yíng)商的EPON和E

18、oC技術(shù)，OLT放置在網(wǎng)絡(luò)系統(tǒng)的前端，ONU放置于樓層，連接EoC（EthernetoverCable）局端設(shè)備，通過(guò)HFC入戶(hù)。用戶(hù)通過(guò)有線(xiàn)電視同軸電纜線(xiàn)傳輸和接收數(shù)據(jù)信號(hào)，同時(shí)不影響有線(xiàn)電視信號(hào)的傳輸和接收。EoC主機(jī)最大帶寬可達(dá)80M以上，最多可帶64個(gè)從機(jī)，多個(gè)從機(jī)共享主機(jī)帶寬。主機(jī)在連接一定數(shù)目從機(jī)的情況下，從機(jī)的帶寬可自動(dòng)調(diào)節(jié)，用QoS可設(shè)置從機(jī)的帶寬，主機(jī)可進(jìn)行SNMP網(wǎng)絡(luò)管理。橋接器可以延伸有線(xiàn)電視信號(hào)的傳輸距離，跨接各

19、種有線(xiàn)電視信號(hào)放大器，實(shí)現(xiàn)數(shù)據(jù)雙向傳輸，真正實(shí)現(xiàn)數(shù)據(jù)信號(hào)和電視信號(hào)一線(xiàn)傳輸。 </p><p>　　目前EoC主流產(chǎn)品采用HomePlugAV/BPL技術(shù)，EoC頭端設(shè)備為纜橋交換機(jī)，纜橋交換機(jī)是同軸數(shù)據(jù)網(wǎng)中對(duì)有線(xiàn)電視單向放大器跨接的設(shè)備，它將混合后的信號(hào)通過(guò)頻率分割的方式，使數(shù)據(jù)信號(hào)不經(jīng)過(guò)放大器，有線(xiàn)電視信號(hào)經(jīng)放大后通過(guò)跨接器再次與數(shù)據(jù)信號(hào)混合。 </p><p>　　纜橋交換機(jī)采用模塊

20、化設(shè)計(jì)，主要模塊有CATV模塊，ONU模塊，EoC頭端模塊，主控交換模塊。這些模塊都作為可選模塊配置在相應(yīng)的機(jī)箱里。其中主控交換模塊只有在多端口纜橋交換機(jī)中才有應(yīng)用。模塊化設(shè)計(jì)的好處在于，可以更加靈活地滿(mǎn)足廣電運(yùn)營(yíng)商不同時(shí)期的需求和遠(yuǎn)期的靈活擴(kuò)展，最大限度地降低投資成本，獲得高回報(bào)。 </p><p>　　不同地區(qū)的運(yùn)營(yíng)商可根據(jù)經(jīng)濟(jì)發(fā)展情況、用戶(hù)密度、覆蓋率、開(kāi)通率和用戶(hù)的帶寬需求情況，選購(gòu)不同接口數(shù)量的纜橋交換

21、機(jī)，安裝場(chǎng)合可以選擇室內(nèi)或室外。用戶(hù)終端設(shè)備按網(wǎng)絡(luò)接口的數(shù)量主要分單接口、雙接口和四網(wǎng)絡(luò)接口。EoC頭端模塊數(shù)量可以根據(jù)需要進(jìn)行配置，每個(gè)模塊提供一路電視信號(hào)輸入和一路Cable混頻口，可同時(shí)傳輸和接收數(shù)據(jù)信號(hào)和有線(xiàn)電視信號(hào)的混合信號(hào)。CATV接入模塊支持單CATV接入口，提供一路有線(xiàn)電視接口，可傳輸有線(xiàn)電視信號(hào)。 </p><p>　　主端通過(guò)耦合器可以支持多路下連同軸通道。采用高性能的光器件，分光比為1：32

22、時(shí)覆蓋距離達(dá)到20km，分光比為1：64時(shí)覆蓋距離達(dá)到10km。分光比為1:64時(shí)平均帶寬可以達(dá)到15Mbit/s，滿(mǎn)足用戶(hù)的帶寬需求。 </p><p>　　3.3 EPON+EoC組網(wǎng)應(yīng)用 </p><p>　　采用EPON和EoC技術(shù)對(duì)傳統(tǒng)有線(xiàn)電視網(wǎng)絡(luò)進(jìn)行技術(shù)改造，可利用EPON設(shè)備完成光纜干線(xiàn)的雙向改造、用戶(hù)同軸電纜接入網(wǎng)雙向改造，使用有源EoC進(jìn)行組網(wǎng)，在ONU下接有源EoC頭端

23、，覆蓋光節(jié)點(diǎn)之下的所有用戶(hù)，對(duì)有雙向需求的用戶(hù)使用EoC用戶(hù)端接入。這樣將單向廣播式傳輸網(wǎng)建設(shè)為雙向傳輸網(wǎng)絡(luò)。 </p><p>　　EPON＋EoC的典型應(yīng)用組網(wǎng)方案如圖2所示，纜橋交換機(jī)放置于樓道或室外，覆蓋一幢大樓或一個(gè)單元。現(xiàn)網(wǎng)已鋪設(shè)光節(jié)點(diǎn)，纜橋交換機(jī)不用配置CATV模塊，通過(guò)射頻電纜接入到纜橋交換機(jī)，ONU模塊配置在纜橋交換機(jī)，實(shí)現(xiàn)數(shù)據(jù)或互動(dòng)電視信號(hào)的回傳。 </p><p>　

24、　圖附-2 EPON＋EOC應(yīng)用組網(wǎng)方案</p><p>　　Figure attached-2 EPON + EOC application network scheme</p><p>　　如果現(xiàn)網(wǎng)由于光接收機(jī)下移，纜橋交換機(jī)需要集成光接收功能。這時(shí)纜橋交換機(jī)需要配置CATV模塊，通過(guò)光纖將電視信號(hào)接入到纜橋交換機(jī)。ONU模塊配置在纜橋交換機(jī)，實(shí)現(xiàn)數(shù)據(jù)或互動(dòng)電視信號(hào)的回傳。另外一種情況

25、，如果現(xiàn)網(wǎng)已鋪設(shè)光節(jié)點(diǎn)，ONU放置在樓外，接入幾個(gè)單端口的纜橋交換機(jī)，數(shù)據(jù)信號(hào)通過(guò)線(xiàn)纜接入到纜橋交換機(jī)，實(shí)現(xiàn)數(shù)據(jù)或互動(dòng)電視信號(hào)的回傳，電視信號(hào)通過(guò)射頻電纜接入到纜橋交換機(jī)。 </p><p><b>　　4結(jié)束語(yǔ) </b></p><p>　　廣電運(yùn)營(yíng)商采用EPON和EoC技術(shù)有助于綜合利用網(wǎng)絡(luò)資源，快速完成NGB接入層的建設(shè)，實(shí)現(xiàn)數(shù)字化雙向化改造，減少大量重復(fù)建設(shè)，

26、節(jié)約建設(shè)和運(yùn)維成本。采用EPON＋EoC方案，用戶(hù)無(wú)需對(duì)室內(nèi)布線(xiàn)做任何更改，只需增加CNU終端設(shè)備就可以實(shí)現(xiàn)雙向、交互、多功能、多業(yè)務(wù)，享受三網(wǎng)融合帶來(lái)的豐富內(nèi)容。EPON＋EoC方案能夠全面提升有線(xiàn)電視網(wǎng)絡(luò)技術(shù)水平和業(yè)務(wù)承載能力，發(fā)揮有線(xiàn)電視網(wǎng)頻帶寬、低成本、易普及的優(yōu)勢(shì)，使有線(xiàn)數(shù)字電視成為進(jìn)入千家萬(wàn)戶(hù)的多媒體信息平臺(tái)。 </p><p>　　雙向改造后的有線(xiàn)電視網(wǎng)絡(luò)是承載、提供三網(wǎng)融合業(yè)務(wù)最重要的網(wǎng)絡(luò)，將成為

27、現(xiàn)代社會(huì)活動(dòng)中最重要的信息通信基礎(chǔ)設(shè)施。廣電網(wǎng)經(jīng)過(guò)雙向改造，采用光纖加同軸電纜的接入方式能為每個(gè)家庭用戶(hù)提供可擴(kuò)展的寬帶接入，可以滿(mǎn)足標(biāo)清和高清電視節(jié)目的帶寬需求，用戶(hù)欣賞到的畫(huà)面質(zhì)量將更銳麗逼真，圖像更清晰。通過(guò)這條“高速路”用戶(hù)可以快速方便地處理日常的信息，暢享信息社會(huì)的便捷服務(wù)。 </p><p><b>　　附錄C 外文文獻(xiàn)</b></p><p>　　Bas

28、ed on the three nets fusion EPON access network technology</p><p>　　1 introduction</p><p>　　The development of the information society to make people more and more from the network technology pr

29、ovides convenience, and over the last 20 years of rapid development, China telecom network, cable television and the Internet are all has become the world's first. At present, our country has 3.33 million km cable ra

30、dio and television network fiber optic cable line, 10 million km coaxial cable line, cable TV subscribers of 175 million users, including digital signal television subscribers 65 mil</p><p>　　With the state

31、council on three nets fusion policies written reply to a subordinate body, cable TV networks broadcast TV networks for the next generation forward evolution (NGB) has been unstoppable tide, NGB backbone and content of th

32、e platform has a relatively mature solution, access network construction because of the complexity of the solution and overall investment proportion of the importance of the construction of NGB and become the key and dif

33、ficult.</p><p>　　2 access network technology solutions</p><p>　　Due to high bandwidth EPON technology, easy maintenance and long distance covered become the mainstream of FTTx characteristics of

34、 bearing technology, at present developed industry chain, telecom operators access network construction is the first choice of technology. But because the local nets level by using optical fiber to the home directly the

35、cost is higher, the traditional telecom operators basically used FTTB + LAN or FTTB + DSL solutions, such as saving in local nets investment, under th</p><p>　　Radio and television operators long-term focus

36、on the construction of HFC network, with huge HFC access network, use of HFC as entering a media can achieve maximum practical and economical efficiency. Radio and television HFC network of coaxial cable nets is a kind o

37、f ideal data transmission medium, especially in the final 100 m bandwidth support ability is far higher than the five kinds of line or telephone line resources. Therefore, in radio and television networks two-way renovat

38、ion of optica</p><p>　　CMTS 2.1 for sparse network coverage area mode</p><p>　　CMTS use of the existing cable TV network, through to the signal QPSK/QAM modulation, the low frequency in a two-wa

39、y HFC transmission. CMTS is the advantage of technology are more mature, network management ability is strong, can realize large-scale two-way covered. Defect is CMTS noise gathering effect system bandwidth and performan

40、ce, coaxial cable and joint quality the demand is higher, the follow-up maintenance larger workload; For most cable TV operator speaking, uplink noise is a widesprea</p><p>　　2.2 EPON + LAN suitable for high

41、 density users new district</p><p>　　EPON + LAN scheme is through the EPON Internet access to the building, through the ONU provide the Ethernet interface, user access through the Ethernet five kinds of line

42、 realized. Using the methods of speech and user access to the Internet, cable TV signal is still through the HFC circuit implementation. Its advantages are mature technology, equipment business more, interface and standa

43、rds. The plan suitable for high density users and big business needs the new bandwidth first comprehensive wir</p><p>　　2.3 EPON + EoC for the existing CATV users first choice of technology</p><p&

44、gt;　　EPON + EoC technology is in the existing HFC network structure is based on a in the radio and television network system of digital bandwidth users access network, it has no impact on the existing CATV normal work, u

45、nder the premise of with advanced demodulation technology, will Ethernet signal synthesis in the coaxial cable with the original CATV signals in together the transmission, and used to carry based on IP data, voice and vi

46、deo business. It for less transformation cost and the original bi</p><p>　　Will EPON technology and EoC technologies, unified net, made up of the whole solution, can radio fusion of three nets NGB provide ac

47、cess network of the best technology. EPON + EoC can provide data, video, voice in one of the three broadcast the overall carrying, through a access network for the past more than one the function of network The scheme in

48、 the development process of fully considering China's national conditions and the actual situation of the radio and television networks, in local ne</p><p>　　3 EPON EoC and network technology</p>

49、<p>　　3.1 EPON technology</p><p>　　Optical fiber transmission as a high rate, high capacity, many of the best media business, have already been backbone in man and a wide range of applications, in the a

50、ccess network level, optical fiber has also got the popularization and application. Optical fiber has long life, high reliability, robust of the advantages of the optical transmission < http://info.broadcast.hc360.com

51、/list/cpzt_gldl.shtml > has strong ability to expand the bandwidth, and easy to realize the integration of various b</p><p>　　EPON technology is passive optical network of Ethernet and combination of tech

52、nology, according to the international standard IEEE802.3 ah can support 1.25 Gbit/s symmetric rate. As an important solution of optical fiber access network, EPON technology has ADSL, LAN and incomparable characteristic

53、, also than APON, BPON, GPON technology more efficient to meet the "EverythingoverIP" business needs more access. EPON access network has investment low cost, simple operation and maintenance the advant</p&g

54、t;<p>　　Through the EPON system equipment, use of optical fiber network cover/FTTB FTTH family, the enterprise users can provide maximum bandwidth of 1 Gbit/s transmission rate. Operators can use economic cost of

55、investment and few fiber optic cable line, realized high-speed Internet access, IPTV < http://info.broadcast.hc360.com/list/wlds.shtml > multicast/demand high bandwidth IP data service delivery.</p><p>

56、;　　EPON system mainly by the OLT (OpticalLineTerminal, fiber optic lines terminal) and ONU (OpticalNetworkUnit, optical fiber network units) and separator (Splitter), which provide to IP OLT man, IPTV bearing network, NG

57、N soft switching uplink interface. According to the end user of the business needs of different, operators can choose freely ONU terminal equipment to meet FTTH/FTTB/FTTC/FTTC + EoC and so on many kinds of application sc

58、enarios. The typical EPON network schemes shown as show in figu</p><p>　　Fig attached-1 EPON typical network scheme</p><p>　　3.2 EoC technology</p><p>　　It is to point to in the EoC

59、 coaxial cables transmission Ethernet data of the technology. The way the EoC system, terminals, coaxial FenPeiWang components. The head of general on light node location, the distribution of upper Ethernet data, gatheri

60、ng terminal equipment role; Terminal on the home user's computer user access or interactive set-top box; Coaxial cable television network distribution from light to users of the position node home network, in additio

61、n to coaxial cable, but also includi</p><p>　　Now commonly used EoC head end equipment is based on HomePlugAV technology of active modulation access convergence equipment and its main function is to data bas

62、eband signal to OFDM way to 7 ~ 30 MHz modulation frequency band, again with the cable TV network in the mixed signals in catv HFC network coaxial cables transmission. Commonly used EoC client equipment is based on HomeP

63、lugAV technology users demodulation equipment, its main function is to all kinds of user terminal equipment computer, s</p><p>　　According to the cable operators EPON and EoC technology, OLT placed in the fr

64、ont of the network system, ONU placed in the floor, connecting EoC (EthernetoverCable) bureau end equipment, through HFC door. The user through cable TV coaxial cable transmit and receive data signal, and do not affect t

65、he cable TV signal transmission and reception. The biggest EoC host up to 80 M above the bandwidth, at most, can bring 64 from machine, more from sharing host machine bandwidth. The host in connection a</p><p&

66、gt;　　At present the EoC mainstream product HomePlugAV/BPL technology, EoC head end equipment for cable bridge switches, cable bridge switches is coaxial data networks on cable television in the one-way amplifier jumper e

67、quipment, it will be the mixed signals through the frequency of segmentation method, the data signals don't through amplifier, cable TV signal after enlargement through the jumper again and data signals is mixed.<

68、/p><p>　　Cable bridge switches modular design, the main module has CATV module, ONU module, EoC head end module, exchange control module. These modules are as optional module configuration in the corresponding

69、case. One master control module in ports exchange only cable bridge switches to be used. Modular design of the benefit that can be more flexible cable operators to meet the needs of different periods and the expansion of

70、 the flexible, maximize reduce investment cost, earn higher returns.</p><p>　　Different regions of the operators can according to economic development conditions, the user density, coverage, KaiTongLv and us

71、er bandwidth demand, the choose and buy different interface number of cable bridge switches, installations can choose indoor or outdoor. The user terminal equipment according to the number of network interface the main p

72、oints of the interface, double interface and single four network interface. The EoC head can need according to the number of module configuration, each</p><p>　　The Lord by coupler may support more under way

73、 even coaxial channel. Using the high performance optical devices, spectral than for knowing the cover up to 20 km distance when, than for all four was covered up to 10 km distance. For all 4 when spectrometer than avera

74、ge bandwidth up to 15 Mbit/s, meet the user's bandwidth needs.</p><p>　　3.3 EPON + EoC networking applications</p><p>　　The EoC technology on traditional EPON and cable TV network technical

75、reform, can use EPON equipment to finish the main lines of fiber optic cable transformation, the two-way user coaxial cable access network two-way transformation, using active EoC in networking, in the active ONU EoC hea

76、d end, to cover all the users under light node, the performance requirements of users use have EoC client access. This will GuangBoShi one-way transmission network construction as the two-way transmission netwo</p>

77、<p>　　EPON + EoC the typical application of network scheme as shown in figure 2 shows, cable bridge switches placed in the corridor or outdoor, covering a building or a unit. Now the network has laid light node, c

78、able bridge switches don't configuration CATV module, through the radio frequency cable access to cable bridge switches, ONU module configuration in cable bridge switches, realize data or interactive television signa

79、l of the opponents.</p><p>　　Figure attached-2 EPON + EOC application network scheme</p><p>　　If now nets caused by the receiver down, cable bridge switches need integrated light receives functi

80、on. Then cable bridge to switch configuration CATV module, through the optical fiber cable TV signal will access to bridge switches. ONU module configuration in cable bridge switches, realize data or interactive televisi

81、on signal of the opponents. Another thing, if now nets have laid light node, ONU placed on the floor, access the cable bridge several single port switches, the data signals through</p><p>　　4 last word</p

82、><p>　　The cable operators EPON EoC and comprehensive utilization technology which network resources, done quickly NGB access layer, the construction of the digital two-way transformation, reduce a lot of repet

83、itions construction, saving building and operation and maintenance costs. Using EPON + EoC scheme, users need to indoor wiring do any change, need to increase CNU terminal equipment can realize two-way, interactive, mult

84、i-function, many business, enjoy 3 nets fusion bring rich content. EPON + EoC</p><p>　　Two-way after the transformation of the cable TV network is bearing, offer three nets fusion business the most important

85、 network, will become the modern social activities in the most important information communications infrastructure. Wide power grid after two-way transformation, by using optical fiber and coaxial cable access styles for