EoC (EthernetoverCoax) technology is currently the most economical, more mature technology, suitable for NGB broadcast and television network and a faster development technology. This article briefly introduces the NGB broadcast and television network, and makes a brief study of EoC technology, and puts forward its own views on the application prospects of EoC technology.
1. Next Generation Broadcast and Television Network (NGB) Technology
The Next Generation Radio and Television Network (NextGeneraTIonBroadcasTIng, referred to as NGB) was proposed by the State Administration of Radio, Film and Television and the Ministry of Science and Technology in the agreement between the National High-Performance Broadband Technology Network and China's Next Generation Radio and Television Network. Using the existing cable TV digitization and mobile multimedia broadcasting as the basic technology platform, and supported by the core technology of the "high-performance broadband information network", a next-generation broadcast and television network suitable for China's national conditions has been developed. The national new generation information infrastructure NGB broadcast and television network with triple play as the basic feature can meet the technical requirements of triple play, wired and wireless integration, and full network. The NGB core transmission speed is required to reach 1000kM / S, and the user access speed is 40M / S, which can provide high-definition digital TV, high-speed data access and voice call services, that is, to achieve three networks in one; at the same time, it also has a high reputation service guarantee And manageable features, can meet the overall requirements and strategic goals of national information network construction in the next few decades.
2. EoC technology research
EoC technology meets the requirements of the NGB broadcast and television network, and can provide users with modern digital broadcast and television services at a very low operating cost. EoC technology is divided into passive EoC technology, low frequency active EoC technology and high frequency active EoC technology. Among them, passive EoC technology is regarded as a more promising technology with low cost and high bandwidth.
2.1 Passive EoC technology
IPData (Ethernet Data Signal) and TVRF (Cable TV Digital Signal) are used to realize coaxial cable transmission with frequency division multiplexing technology, and the mixed signal of IPData and TVRF is directly transmitted to the client using the HFC network, and then the client signal processing system The separated TVRF radio frequency signal is sent to a TV or DVB set-top box; the separated IPData signal is sent to a computer. IPData and TVRF mixed signals can also be directly transmitted to the dual-mode set-top box. The dual-mode set-top box is used to realize IPTV and other TV services. At the same time, an Ethernet interface is provided on the set-top box to provide broadband Internet access for the computer. The basic topology of passive EoC networking is shown.
The passive EoC system supports a single user's 10M / S rate and is highly standardized, following the Ethernet protocol; the client is a passive terminal, the operation and maintenance costs are reduced, and the system stability is improved; there is no need to re-lay the line during the installation process. It effectively solves the problem of the difficulty of re-laying cables in the building, and the construction cost is greatly reduced.
2.2 Introduction of Low Frequency Active EoC Technology
The low-frequency active EoC technology uses a frequency of 5MHz to 30MHz, and a transmission speed of 85M / S to transmit a distance of 500m. The low-frequency active EoC technology can work in the low frequency band through the distributor, and the network adaptability is better; but the user needs at least one active device, and the cost is higher.
2.3 Introduction of High Frequency Active EoC Technology
The high-frequency active EoC technology uses the frequency band of 800MHz ~ 1500MHz, each channel has a bandwidth of 50MHz, and a total of 29 channels. The maximum transmission rate of each channel is 135M / S; the transmission distance is 300m ~ 600m. The high-frequency active EoC technology can coexist with existing analog TV, DVB digital TV, IPQAM, etc .; it can directly transmit data through coaxial cable; the network structure is highly adaptable, and it can be built step by step in combination with the EPON system. However, high-frequency active EoC technology needs to replace high-quality distributors and cables, and requires at least one active device at the user end, which is costly.
2.4H3C passive EoC technology and Aolan Elink series passive EoC technology comparison
Huasan Passive EoC system consists of a data / TV signal synthesizer and a data TV signal separator. Among them, the data / TV signal synthesizer can be used by 6/12 users at the same time. The H3C passive EoC system TV signal uses a high-end frequency of 47MHz to 860MHz, and the Ethernet baseband data signal uses a low-end frequency of 0.1MHz to 20MHz. The Ethernet data signal and the TV signal are transmitted to the user switch through two independent networks. The distributor is divided into 6 / 12-channel signals, and then enters the household by the 6 / 12-channel coaxial cable. Finally, the EoC terminal equipment in the user's home separates the data signal and the TV signal to realize Internet access and watch TV programs.
The Aolan Elink system uses the EoC equipment to transmit the Ethernet data signal and the TV signal using the frequency division multiplexing technology to coaxially transmit the two signals. According to China's TV network frequency division standard, Ethernet data signals are transmitted in the frequency band of 65MHz or below 45MHz, and TV signals are transmitted in the frequency band of above 87MHz, and the two sets of mixed signals are directly transmitted to the user terminal via the client access device HFC, and then the user's EoC terminal equipment ETH separates data signals and TV signals to achieve Internet access and watch TV programs.
The two passive EoC technologies make full use of the existing coaxial network resources, without the need to re-reform and wire the home cable, and the user terminal is directly embedded in the cable TV, without the need for other auxiliary equipment and active equipment, the network operation is safe and stable, Operation and maintenance are simple and convenient, and the cost is low. However, the two passive EoC solutions are only suitable for point-to-point applications, and there are obvious deficiencies in the future requirements for high-speed video on demand and 10M / S Ethernet rate.
3. Prospect of EoC technology application
EoC technology is relatively mature, and its related products have been industrialized. With the deepening of China's NGB radio and television network construction, FTTB is considered to be the most feasible way to achieve NGB radio and television networks, and in all three network integration technologies, various EoC technologies are undoubtedly the lowest cost option to achieve realistic goals. Under the trend of "three network convergence", EoC technology is the best choice to reduce the cost of two-way network access. Especially passive EoC technology, while having a low cost, up to 10M / S bandwidth, low network reconstruction project is also its most competitive advantage, and EoC technology can fully achieve 100M / S home bandwidth. Compared with high-cost fiber-optic homes, adopting EoC technology is the best choice to realize the digitization of China's NGB broadcast and television networks.
In terms of development content, China ’s NGB broadcast and television network provides high-definition digital TV, digital audio programs, high-speed data access and voice call services, providing a comprehensive service for education, business, culture, technology, health and other industries Information service platform. Through the development of the NGB radio and television network, its rich video, audio and video content can better serve the people and improve the quality of life of the people. The NGB radio and television network has the most valuable information resources in the coming decades. In the process of achieving the integration of the three networks, the informatization and the two-way network are inseparable. The two are interdependent and promote each other. Since its birth, EoC technology can meet the requirements of triple play, and is suitable for star network, convenient access, simple operation, low failure rate and other characteristics. The low cost advantage of EoC has laid the foundation for its large-scale promotion and use. Making full use of the existing radio and television network resources, and through new technological upgrades, in a relatively short period of time, at a low cost to achieve the digitalization of China's radio and television networks, also in line with the basic principles of China's current economic development.
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