计算机相关专业毕业设计用+英文翻译(没有论文只有中英文翻译).doc

Wide band optical fiber access network trend of developmentAuthor: Liu Jinhai article source: Computer universal time: 2005-3-8This article first is brief introduced the world broadband access network develops the condition and the main application, next narrated the wide band optical fiber access network merit. With emphasis has once more analyzed the wide band point-to-point active Ethernet optical fiber system and the wide band to the passive optical fiber system characteristic and the application. Meets down proposed our country optical fiber access network sends chem. possible to surmount APON, BPON and the EPON stage, starts from the wide band point-to-point Ethernet optical fiber system and GEPON, finally and even transits to the GPON stage preliminary idea. Finally analyzed the optical fiber communications technology trend of development from each angle.The broadband access network develops condition and main applicationIn fact, looking from the telecommunication development history, when the network number of users achieves certain scale. Each kind of application meets the nature production; this also is so-called steps the Cuff law might to be at especially. In the history one kind of technology since birth has not been having a big pile of application, regardless of is the mobile communication or the Internet, on its short note, the browsing, the net chats and so on the key applications all is develops certain degree after the user scale to produce naturally, but is not sedulously designs beforehand plans. Since has entered for the 21st century, the whole world broadband access network entered the big development phase. To 2004 years end, the total number of users already achieved 150,000,000, became in the electricity reliable historical account to develop one of quickest telecommunication services, and even was also quicker than the mobile service. For example the whole world mobile service from 10,000,000 developed to 100,000,000 has spent for 5.5 years, but the broadband access service has only used for 3.5 years. According to the IDC forecast, in 2007 the global wide band total user may achieve 209,000,000, in which 9.9, namely about 20,000,000 users for optical fiber access network. The Asian and Pacific area, specially South Koreas and Japan were the broadband access develop the swiftest most and violent country, the South Korean wide band user total already break through 10,000,000, the wide band popular rate occupied the world first, hold family 7 Internet 90%. Japanese Government also vigorously advances the wide band development through each measure, plans in 2005 to enhance the wide band user total to 30,000,000, in which FTTH achieves 1 10,000.US still is the world biggest broadband access market, the total number of users surpasses 30,000,000.American FOC the wide band service localization is one of 2003-2008 year six big goals, in fact the broadband access is becoming the American universal service the next goal. The US broadband access is primarily develops by the cable television and ADSL, because the telecommunication control policy encouragement uses the new technical construction network (e.g. FCC stipulation operation business construction optical fiber access network to be possible not limited the pressure which in local ring circuit non-colligation policy) as well as the competition and the service grows, recently leads the operation business to be extremely positive to the optical fiber to the station (FTTP) development.Speaking of the optical fiber access network, specially the optical fiber to station (FTTP) or optical fiber proficient (FTTH), the whole world already started to enter the unloading phase, only US had 270 FTTP projects, was mostly the local authority, the public company, the property developer and the non-leading telecommunication operation business project. Leading operation business also starts to enter this domain, in which Version plans in 2005 to complete 3,000,000 FTTP; SBC in the plan plans in 2007 in its huge “speed of light” to reach 18,000,000 FTTN, each household has speed 20-39Mb/s, provides the end-to-end tertiary service colligation (trite play) the service. Japan is in the world advances the FTTH most radical country, 2.004 years its optical fiber on already understood more than 18,000,000 households families, but the user development lag, probably was 2,000,000, in 2005 plans develops 10,000,000.Europe quite is steady conservatively, FTTH altogether has laid to 2004 500,000, some 167 small projects or the experimental project are carrying on.Our country broadband access network extremely is also rapid in the near two year development, according to the preliminary statistics, to 2004 years end our country wide band user is 25,000,000, becomes is inferior to USs second big broadband access market, in which leadership technology is only ADSL, probably accounts for about 70%, next is the Ethernet technology, but also has few wide band wireless turning on and electric cable modem turning on, also occupies regarding the FTTH technology the track stage, the minority developed city already was also starting to consider and to experiment each kind of FTTHI technology. Looking from the wide band application that, according to the American Mai Kenxi Companys newest analysis, the initial period wide band application mainly is the high speed surfer, may make the surfer the time to increase approximately 30%.Hereafter, along with the service large-scale development, develops the power which the new service becomes continues to develop. According to American BHK Corporation demonstrated in 2004 investigation result that, in 2003 the American first five wide band expense was on the net gambles, the adult program, the game, music downloading and the selection and broadcast television, had obviously to the expense class incline tendency.Needs to point out that, discusses needs to pay attention to in a basic understanding using the actuation the erroneous zone, namely cannot place hopes in artificially studies beforehand develops 12 items so-called “the Assassins mace application”, promoted application. In fact, looking from the telecommunication development history, when the network number of users achieved certain scale, each kind of application meets the nature production; this also is so-called steps the Cuff law might to be at especially. In the history one kind of technology since birth has not been having a big pile of application, regardless of is the mobile communication or the Internet, on its short note, the browsing, the net chats and so on the key applications all is develops certain degree after the user scale to produce naturally, but is not sedulously designs beforehand plans.Wide band optical fiber access network superiorityAlong with the optical fiber in the toll network, the metropolitan area network and even the access network branch section massive applications, the logical trend of development will be continues to the access network to match the line segment and to direct the inlet part to extend, the key is advances the speed quickly? This will be decided by many kinds of factors, including the market demand, the competition need, the application stimulation, the technical progress, the cost drop and necessary will transport Augur system development and so on. Our country in 2008 will hold the Olympic Games and in 2010 holds world expo these two big events to a certain extent to be able to advance the wide band optical fiber access network the developmentBelow mainly will analyze several kind of main wide band optical fiber turning on technology from the system technology angle the characteristic, the question and the trend of development. Certainly, besides the system technology, affects its application the factor to be very many, mainly is the service and the application as well as the control policy. In addition, each kind of necessary primary device technology and the placing installment test technology extremely is also essential. At present the low cost photo source hopefully has realized, 850nm VCSEL only several US dollars, 1310nm VOSEL had the breakthrough, the speed reaches 10Gb/s.The PLC mix integration technology, the high density low cost optical cable and the correlation technology, uses the optical fiber to the curving insensitive room in, the low cost passive component, work the technology, the automatic light operation test system and so on also all is affects the light access network promotion application the key aspect, needs to have the properly solution.The point-to-point active Ethernet Because system the cost, the quality, the management, the security and so on many kinds of factors, the Ethernet still had further to improve as the public network turning on way.The traditional Ethernet belongs to the user in network (cPN).However its application actually in to include the access network other public network domain expansion. In the history, regarding business user application environment, the Ethernet technology always is the most popular method, at present has become only definitely in the power supply receptacle second big housing and the office public facility connection. Uses the Ethernet is had the huge network foundation and the long-term experience knowledge, at present all popular operating system and the application as the business user turning on method primary cause also all is with the Ethernet compatible, the performance price compared to good, the extendibility, easy to install the clear as well as redundant reliable and so on.Regarding the public network housing user application environment, the point-to-point active Ethernet system uses the active service focus point to substitute the passive point-multipoint system the passive component, enables the transmitting range to be possible to expand to 1 20 kilometer far. The main merit is special-purpose turning on, the band width has the guarantee, each user may monopolize 100Mb/s and even 1dbs; Bureau end equipment simple cheap; The transmitting range is long, the service area is big; But the cost the linearity increases along with the number of users actual growth, does not need to plan, the investment risk is low, thus disperses the local cost in the low density user to be low. The shortcoming is the both sides equipment and the optical fiber facility special-purpose, the user cannot share the bureau end equipment and the optical fiber, when the demand fast growth also the user are very crowded, optical fiber and both sides equipment quantity and cost as well as spatial demand also along with it rapid increase, thus not too suits the high crowded user region. The influence choice Ethernet technology another factor is the traditional video frequency service provides the way, for example American Place Bell Company all pledged provides the tradition to simulate the RF video frequency program, but the Ethernet and the simulated video program mix is very difficult. This aspect PON technology quite is easy.Because the cost, the quality, the management, the security and so on many kinds of factors, the Ethernet still had further to improve as the public network turning on way. Mainly is the Ethernet technology inherent mechanism does not provide the end-to-end package time delay, the package loss rate, the band width control, supports the real-time service with difficulty the grade of service, lacks the safety mechanism guarantee and so on.Point-multipoint passive, light network systemAlong with IP rising with the development, some people proposed the EPON concept, this thought obtained the positive response in the Ethernet, has already formed the GEPON standard in under the IEEE 802.3ah flag.1. Passive light networkingPassive light network (PoN) is one pure medium network, its main characteristic has removed the active equipment in the access network, thus has avoided the electromagnetic interference and the thunder and lightning influence, reduced line and the external instrumentation failure rate, reduced correspondingly has transported the Augur cost. Next, the PON service transparency is good, the band width is wide, suitably in any service pattern and the speed signal, can support the simulation broadcast television service quite economically, has tertiary service function (triple-play).Finally, as a result of its game of end equipment and optical fiber by user sharing, thus the line cost compares other point-to-point mailing address to have to be low, the construction cost also may reduce obviously. Especially day by day advances along with the optical fiber to the user, its synthesis superiority is more and more obvious. But the PON each user cost along with shares OLT the user quantity increase to drop rapidly, thus most suits in the dispersible small business and the inhabitant user, these user region is specially dispersible, but each region user relative centralism small area crowded user area, in particular newly built region. Finally, after considered uses the PON technology quite to be easy to continue to provide traditional the simulated video program, thus, most American Place Bell Company favors the PON technology, but is not the light Ethernet technology.The PON main shortcoming is the disposable investment cost is high, because bureau end light line terminal OLT is very expensive, the optical fiber and the shunt and so on the passive infrastructure must an arriving, when like this the number of users are few or the user distribution surpasses some definition is away from, each users cost is very high. Moreover, its tree branch topology caused the user not to have the protection function or the protection function cost is high, has affected the large-scale development.2. APON AND BPONThe early narrow band passive light network is based on TDM, the performance price compared not well, already naturally withers away. An ATM passive light network (APON/BPON) may use ATM the centralism and the statistics multiplying, the recombination passive shunt to the optical fiber and the light line terminal sharing function, enable the performance price compared to have the important improvement, at present in countries and so on US and Japan already started commercial.However, the actual APON/BPON service adaptive provides at present very complex, provision of service ability is limited, the data transmission rate and the efficiency are not high, the cost is high, but its market prospect as a result of ATM decline dim. Finally, looking from the long-term service trend of development that, the APON available band width was still insufficient. Take FTTC as the example, although the typical branch downward speed may reach 622Mb/s, after but because the by-pass, actual as separable greatly will reduce as each users band width. According to 32 groups computations, each branch available band width only remains 19.SMb/s, again presses 10 user sharing, then each user only can obtain approximately the 2Mb/s band width. Obviously, such performance price compared to is unable to satisfy the network and the service long-term development needs.3. EPON/GEPONAlong with IP rising with the development, some people proposed the EPON concept, namely in with APON and the BPON similar structure and in the O.983 foundation, tries to retain its essence part - physics level PON; But replaces ATM by the Ethernet to take the link level agreement, constitutes one to be possible to provide a greater band width, the Low cost and wider professional ability new marriage - EPON. This thought obtained the positive response in the Ethernet; in IEEE802.Under the 3ah flag has already formed the GEPON standard. In reality, EPON and the GEPON basic difference is the standardization, the former often Refers to the non-sign equipment, the latter refers conforms to IEEE 802.3ah, standard equipment. Moreover, the GEPON transmitting range and the by-pass compare have compared to EPON reduce.EPON/GEPON and the traditional point-to-point Ethernet main different place lies in the work in the point-multipoint mailing address. Its downward direction work in the TDM way, the data stream changes the long Ether frame way to broadcast ONU, each ONU basis ether frame MAC address, decision choices. The upward direction work in the TDMA way, Comes from the different time slot ONU data stream to gather the public optical fiber facility and OLT. In addition, the traditional Ethernet work in the continual optical transmission pattern, is receiving and dispatching two directions both is the continual bit class, therefore receives the end fixed time easily to realize with the decision. But the EPON/GEPOkI ONUpward bit class is the sharp-edged data packet which transmits in turn, the OLT receive timing recovery, the decision threshold establishment, the range finder and the time delay compensation quite is complex.Looked from the EPON/GEPON structure that, its essential merit Enormously simplified the traditional multi-layered overlapping network Structure, the main characteristic included:- - Eliminated ATM and the SDH level, thus reduced the initial cost and the movement cost; - - The downward service speed reaches as high as 1Gb/s, the permission support multi-user, each users band width may be higher, and can provide video frequency professional ability and good QOS- - The hardware is simple, does not need outdoor electronic installation, and enables the installment deployment work to simplify;- - May use the Ethernet technology mature chip massively, the realization is simple, the cost low- - improved the electric circuit to refer to the coordination service nimbly provision with the reshuffle ability.IEEE 802.3ah the standard GEPON technology standards is good, on the downward wave length is 1310 and 1490nm, on the downward speed is 1.25Gb/s, the trans