标题: Wide band optical fiber access network trend of development [打印本页] 作者: 季风风风 时间: 2011-6-1 10:23 标题: Wide band optical fiber access network trend of development
al fiber access network trend of development
The broadband access network develops condition and main application
In 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 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 Looking from the wide band application that, according to the American Mai Kenxi Company's 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 Assassin's 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 superiority
Along 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 development
Below 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 system
Along 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 networking
Passive 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.
