Description and Application of Broadband Access Technology Optical Fiber Access Technology

It is said that China Netcom wants fiber optic access

Optical fiber access technology is a future-oriented Broadband Network Access Technology for optical fiber to the roadside (HTTC) and optical fiber to the household (HTTH. Fiber-optic access network (OAN) is currently the most rapidly developed Access Network Technology in China Telecom. It not only focuses on effective access to narrowband services such as telephone, it can also solve the access problems of broadband services such as high-speed data services and multimedia images.

OAN refers to a system from a vswitch to a user that allows access by optical fiber. In addition to HFCs, the optical fiber access methods are as follows:

(1) optical digital loop carrier system l

The DLC system uses fiber-optic transmission instead of feeder and wiring, and then connects to the user with twisted pair wires. The PDH quasi-synchronous time-division multiplexing technology is used for transmission of narrowband services. Asynchronous Transfer Mode (ATM) and SDH synchronous time-division multiplexing technology are used for transmission of broadband services. The network structure is commonly seen in point-to-point, link-type, or ring-type network structures. The transmission rate ranges from 34Mbps-155Mbps. The transmission distance can be from several thousand meters to hundreds of kilometers. The DLC technology can be used to implement fiber-to-road (FTTC) and fiber-to-household (FTTH) phases. The system has mature technologies, high reliability, and is easy to popularize and apply. Many domestic manufacturers have launched mature products, and the most practical online applications.

(2) ATM-based Passive Optical Network

Passive Optical Network (PON) is an access technology that uses fiber branches to achieve point-to-point multi-point communication. It can support iSDN base groups or businesses of the same rate. Each optical network unit (ONU) can connect several to dozens of users. APON is a PON that uses an ATM cell transmission mode. It can be a symmetric system with the same upstream and downstream speeds, or an asymmetric system with different upstream and downstream speeds, bandwidth requirements for iSDN and B-I iSDN services can meet the common requirements of various telecom services and full service networks (FSN. APON represents the latest development direction of broadband access technology. Currently, it has been applied in the UK, Germany, and so on. It is considered as a better method to implement FTTC and FTTH. The advantage of APON is that it can save the cost of optical fiber and optical equipment, and realize the network transmission between the broadband data service and the CATV service. The disadvantage is that the cost is high. How to Implement bidirectional high-quality transmission economically is still a problem to be studied.

(2) switched digital video technology

SDV is a network access technology that uses wavelength division multiplexing (WDM) or optical fiber splitting technology to share optical fiber lines on CATV networks. SDV is a system that uses digital transmission technology and a system that uses analog technology. Therefore, SDV has a good transmission quality and is easy to upgrade and has a long-term development prospect. SDV uses optical fiber access systems and ATM technologies to provide telephone, data, and video signal transmission in hierarchical mode. The first layer uses the traditional optical fiber access system to transmit telephone and data services. The second layer uses SDH-Based ATM cells to support interactive broadband services such as digital videos.