1 Introduction
FTTX is a way to access the networking. In the access network, optical fiber is mainly used to be close to users. The transmission space capacity of optical fiber is huge. As a high-quality transmission method, it also has extremely high reliability; as a main transmission medium, optical fiber access has become a fixed broadband A new direction for access. With the development of technology and the application of commercial scale, the cost of FTTX is also decreasing, which will help the popularization of FTTX technology and further enter our daily life. In the triple play, the application of FTTX technology has played a very important role.
2 Technical development of FTTX
In FTTX technology, passive optical network technology is the most dominant. It uses optical fiber as the medium and can passively split optical transmission throughout the whole process. Especially in terms of management operation and maintenance, comprehensive service provision, etc., its advantages are more significant, making it comparable to other technologies. more prominent than advantage. The passive optical network system can be divided into three parts, namely optical line terminal, optical fiber distribution network and optical network unit. Here, the optical line terminal is the core part of the system, which provides a high-speed interface for the access network and the core network, and can also be used as a point-to-multipoint network interface to provide information to other optical network units by broadcasting. The optical network unit mainly accesses data and voice services and plays a role at the user end. Optical fiber distribution network is an optical fiber distribution network, the main component is passive optical fiber splitter, such an optical fiber transmission broadband can be shared by many optical network units, of course, the premise is that this broadband interface is a passive optical network.
The concept of passive optical network technology was first proposed in 1990. After development and changes, it has been continuously matured and gradually improved, forming two standards, namely the EPON standard and the GPON standard. EPON is based on Ethernet. We all know that passive optical network has a unique network structure advantage, and Ethernet has low cost, and EPON has the advantages of both. The main technology of GPON is ATM encapsulation technology. Under this premise, GEP84 encapsulation is selected, which has higher quality and shows great support for TDM services.
Network technology is constantly developing, and the competition between new technologies is becoming more and more fierce. As the most influential technologies in passive optical network technology, EPON and GPON have always been compared with each other. These two technologies have their own advantages. GPON has significant advantages in terms of uplink and downlink speed, optical splitting ratio, and network management functions. Compared with EPON, GPON launched the standard later, so it is more comprehensive; compared with GPON, EPON's industrial chain It should be more mature and perfect, and the cost is much lower. In addition, the EPON standard is more relaxed than the latter, so that manufacturers have more room to play in product development.
3 Practical application of FTTX
Ten years ago, operators used XPON technology to test FTTX. With the end of this process, market cultivation and related technology preparations began a new stage. Since then, FTTX based on XPON technology has officially started commercialization. A new stage of scale application. Now, the optical network unit is divided into three types, which are single-port optical, multi-port optical and integrated optical network unit. According to the different positions of the optical network unit in the passive optical network access network, there are three types in total, namely fiber-to-the-home, fiber-to-the-building, and fiber-to-the-road, all called FTTX.
3.1 FTTH
The optical network unit is usually installed in the user's home in a single-port manner, and the optical line terminal at the central office is installed in the communication room, and the transmission equipment is used as a carrier to connect and transmit relevant information of voice and data networks. The connection between the optical line terminal and the passive fiber optic splitter is mainly done by the trunk fiber optic cable. From the passive fiber optic splitter to the user's house, a leather cable with a small number of cores is placed, and from the user's optical network unit. Five types of lines and twisted pairs, so as to facilitate access to broadband and voice services.
3.2 Fiber to the building
This kind of optical network unit is multi-port, generally placed inside the building, and usually has the function of combining the passive optical network and the local area network. Most of the splitters are placed in the module office computer room, and some are in the fiber optic distribution device of the community computer room. The number of multi-port optical network units is calculated by the total number of users per unit in the residential building. At this time, it is generally The optical network unit will be placed in the vertical shaft, and the power box is also included, so that the power supply can be easily introduced. The optical network unit usually uses Category 5 lines to the homeowner’s home, and a character-style panel is installed on the wall of the house to connect the computer to the Category 5 line, and to connect the optical modem and the twisted pair interface.
3.3 Fiber to the curb
Its optical line terminal is installed in the computer room of the central office, and a passive optical fiber splitter is installed in the office. This kind of network unit with high comprehensive performance, this technology is often used for network transformation and upgrading in areas where users are scattered, and can make full use of the covered area The network has the characteristics of low cost and fast improvement of user perception. The three forms of XPON have their own characteristics. The speed of fiber-to-the-home is very fast and the maintenance is very convenient. However, it is relatively expensive to install an optical network unit device in each home. With the continuous decline in the cost of single-port optical W network units, the cost of optical network unit equipment and optical leather cables, fiber-to-the-home has become the most important application mode.
4 Epilogue
Through the continuous development of FTTX technology, we can see its development prospects in real life. This technology will also affect the development of network technology and new business expansion in the future; the changing needs of users also promote the continuous evolution of FTTX technology and development, the future FTTX technology will be more comprehensive, more flexible, more practical, and more stable in performance
