3ComHFC Data Network Solution

I. Overview

1. Current status and progress of domestic CATV network

Radio and television is the largest media in China, it provides radio and television broadcasting services from wireless to cable, has the largest number of information audiences, is the biggest advertising, economic, market, entertainment and cultural information collection, production, dissemination and provider. By 1999, CCTV and more than 20 provincial-level television stations nationwide have opened satellite digital TV channels, China's radio and television system has begun to change to digital television.

With the continuous development of China's CATV industry, the radio and television departments are also infiltrating the digital transmission, using the CATV network to carry out the multi-functional application of data Services has become the development direction of CATV, but also become one of the key points of urban informatization construction.

2. New opportunities brought by data communication business

Currently access to Internet services and enjoy the convenience of the network has become a part of the public life, distance education, E-commerce and other emerging network services have been maturing, in China has 15,000 kinds of websites and nearly tens of millions of internet users; in Shanghai alone, 3 per thousand of the enterprises have access to the Internet through a dedicated line, At the end of the year, hundreds of thousands of residents will access the Internet via broadband, while online supermarkets and online e-commerce in Beijing have brought hundreds of millions of sales to service providers, and 4.7 billion of the turnover has been achieved online in Chongqing Merchants Bank.

At present, for the unit or residents to provide broadband network access, so that users really enjoy the fun of surfing the Internet at all levels of operation service providers, Guang door has unparalleled advantages, mainly focused on:

More than 90% of the city's line coverage advantages, the majority of residents have access to cable television network, the optical fiber coaxial network has been built to the majority of residents access to cable TV lines bandwidth advantage, the focus of the integration of multiple networks, line equipment maintenance advantages, operating services, advertising advantages, publicity management advantages.

The cable TV broadband Integrated Services Network offers:

TV Reception--basic service to provide dozens of sets of high quality TV signals for users
Internet interconnection--provide online browsing, retrieval and publishing information services for users in the network
Private line access--provide Internet service for group and unit users
Relay Service--Provides a point-to-point connection or other relay service to the user
Web Home--provides home page space for users in addition to the WWW home page
Data retrieval--providing public information and special information services for government departments
Mail Service----providing mail service to facilitate user interaction
Graphic TV--providing securities economic information and other services through TV system
Conference TV--making use of network and digital video technology to realize remote conference
IP telephony-Global IP telephony users grow at a rate of 239% a year, and the development of IP telephony has become a new business growth opportunity
Other value-added services-distance education, E-commerce, electronic fees, telemedicine, online games, etc.
3. HFC Network data communication technology
The HFC network, as the network that transmits image information, has a bandwidth of 5MHz---1000MHz, and usually a TV channel uses 6MHz or 8MHz, such as PAL and NTSC. Data transmission is also the use of a channel's bandwidth as carrier-borne modulation, so a channel to transmit data information and a transmission of image programs in the physical equivalent to the channel. Information for more efficient transmission requires the use of appropriate technology for format conversion. The following table lists the devices that are required for analog and digital information to be transmitted on both analog and digital carriers respectively.

Carrier
Information simulation numbers
Analog Sensors/Amplifiers codec (CODEC)
Digital Band Modem (modem) baseband modem (DSU/CSU)

In the case of HFC network transmission data, the digital information is converted to the analog carrier which is suitable for transmission through the modulation technology, the device that completes this task is called the cable modem (Cablemodem, abbreviated cm). Cable modulation and demodulation technology combined with amplitude and phase modulation can get high data load density, common QAM256, QAM64, QAM16 and QPSK.

CATV system has rich broadband resources, and its use has been stipulated accordingly. In the PAL format, as shown in the following figure, the 5mhz-65mhz is the uplink return bandwidth, and the 65mhz--1000mhz is the downlink bandwidth.

At present, the mainstream standard of data transmission in HFC is DOCSIS, which is made up by the forum MCNs of the major manufacturers in the industry. Compliance with standards and CABLELAB-certified equipment ensures interoperability. The performance of HFC network constructed in different periods is different, the network with early construction does not have the ability of uplink return, so it needs to be reformed to implement bidirectional transmission. For the one-way and bidirectional cable network, DOCSIS has put forward a complete implementation scheme. Using the telephone system as the uploading channel, the data service can be provided on the one-way downlink network.

4, the content and steps of CATV data network construction

The HFC network operator constructs the data application system to include the following several parts, compared with the traditional HFC network service, because of its service diversity and the complexity, causes the comprehensive consideration aspect to be more complex.