With the advent of video on demand, network games and IPTV and other high bandwidth services, the user's demand for access bandwidth will increase further, the existing ADSL-oriented broadband access method has been difficult to meet the user's high bandwidth, two-way transmission capabilities and security requirements. Faced with this dilemma, telecom operators in various countries have turned their attention to FTTH, planning to use the optical fiber as the best transmission medium to break through the "bottleneck" of access, FTTH is regarded as the next generation of broadband access technology representatives, is the future "last kilometer" final form.
Realization of FTTH by passive optical Network (PON) technology
In more than 10 years of development, FTTH technology continues to introduce new, from the active access mode to passive access mode, from Point-to-Point (peer-to-peer) mode of MC (Media Converter) to develop point to apon, Epon and gpon pon (passive optical network) technology. The PON technology has become the preferred solution for FTTH today.
Pon system consists of optical line terminals (OLT), Optical Network Unit (ONU)/Optical Network terminal (ONT) and optical distribution network (ODN), the so-called "passive", refers to all ODN by passive optical splitter and optical fiber and other passive optical components, excluding any active nodes. The PON technology uses a point to a multi point topology, and the downlink light signal emitted by Olt is broadcast through a passive optical splitter to each onu/ont through a single fiber. Different data link layer technology and physical layer PON technology combine to form different PON technology, such as Atm+pon formed Apon,ethernet+pon formed Epon,atm/gem+pon then formed Gpon, which is the biggest difference between various PON technologies.
PON technology has the following advantages: ODN is composed of passive optical devices, there is no expensive active electronic equipment between Olt and Onu/ont, which reduces the possibility of equipment being damaged by lightning and radiated interference, and can be flexibly composed of tree-shaped, star-shaped, bus-shaped topological structure, typical topological structure is tree-shaped, each onu/ Ont can share the optical fiber between the olt and the optical splitter, save the fiber laying quantity, the business transparence is good, in principle can be applied to any system and rate signal, the network is easy to expand, the Operation management maintenance is simple. (Computer science)
The development of FTTH in foreign countries
A number of international research advisory bodies have maintained a fairly optimistic view of the FTTH Outlook, and all considered that the 2005 ~2008 years were a year of rapid application and promotion of FTTH technology. In general, the development of FTTH in foreign countries has a strong regional nature. Japan has the best development, North America and Europe lagging behind.
Japan is currently the most active FTTH application of the country, due to fierce market competition and government policy incentives, Japan's major operators have been large-scale promotion of FTTH applications, currently providing FTTH services operators are mainly Ntteast, Nttwest and SoftBank. The business of FTTH in Japan can be divided into three kinds of high-speed data, high speed data + voice and high speed data + Voice + video (Tripleplay), which embodies the trend of FTTH business development--three nets in unity. In terms of technology choices, Japan has renounced the early adoption of the MC approach and has shifted vigorously to the use of PON, especially Apon and Epon technologies.
South Korea, which is very popular in ADSL/VDSL, announced in 2003 that it would progressively develop FTTH to replace the existing DSL network, in accordance with its government's "IT839 Strategic Plan", and planned to promote 300,000 FTTH users by 2005, with FTTH family penetration of more than 70% by 2007. South Korea has become the only country in the world where DSL users have fallen.
The United States is the world's largest broadband access market, according to Rendervanderslice and associates data, from the end of September 2005 to March 31, 2006, 350,000 U.S. households have new access to optical networks. One of the most radical is the number of verizon,2004 years of its FTTH users for 1 million households, and 2005, the surge to 3 million households, user bandwidth reached 30m/households.
The development of FTTH in Europe is very slow, mainly due to the recession in Europe and the poor operation of major operators, and the government does not have a corresponding policy issued. About 500,000 users were deployed in Europe in 2004 and most FTTH projects are in the pilot or small-scale trial commercial phase.
The development of FTTH in China
FTTH currently in the domestic market start-up phase, from large-scale commercial deployment is still a long distance. From the current development situation, there are mainly the following development models: Government intervention, the implementation of real estate developers, user-resident network operators and real estate developers or property cooperation implementation, telecommunications operators leading and implementation of equipment manufacturers to promote commercial testing.
Under the impetus of the national "863" High-tech program, the research on EPON technology was carried out during the "XV" period. 2003 began the dissemination of FTTH, 2004 with the "863" Epon project completed, the country in Wuhan, Chengdu and other countries to establish a FTTH test network. At the same time, the major operators, developers of FTTH attitude positive, many cities have given corresponding policy support, at present, more than 20 cities have built a FTTH test network. China Telecom has conducted pilot work in cities such as Wuhan, Beijing, Shanghai and Guangzhou, and the Chinese netcom began to carry out experiments in the business center and high-grade residential areas in Beijing. The resident network operators, such as Tyrone, based on the established experimental network, also strive to expand and explore new business delivery and operation models. Real estate developers will be FTTH as a selling point of high-end real estate, in order to improve sales value-added, speed up sales. All of these have facilitated the popularization of FTTH access technology in China.
From the experience of FTTH application at home and abroad, the development of FTTH in China is confronted with the following problems: The lack of "killer application"; The cost must be further reduced; it brings huge bandwidth pressure to the metropolitan area network. These problems have restricted the development of FTTH in our country to a great extent.
The FTTH market in China needs to be nurtured and patient as well as confident in FTTH. From the perspective of telecom operation, it is necessary to consider many factors, such as technical factors, cost factors, control policy factors and so on, to apply FTTH to the actual network environment, which needs the common attention and joint efforts of the whole industry, and deepen and develop gradually in the continuous experience accumulation.