With the arrival of data era and the diversification of the requirements of user services, like internet surfing, popularization of smart phones, Internet of things and so on, people already can not live their daily life without internet, and single digital television service of HFC network of operators can not meet the demand of end-user anymore, by applying telecom LAN or FTTH solution to solve this requirement of users, operators need to rebuild a data network that costs highly, and in the last kilometer to the home, there are all kinds of difficulties like power problem, which makes it difficult for data accessing to the home and become a lingering question.
In the construction of two-way access network of broadcast television, with years of practice and characteristics of low cost, high stability and high bandwidth that are widely acknowledged, PON and EOC have become the main technical solution of access network of broadcast television. Solution of PON + EOC can implement the transmission of CATV, voice, computer data in two-way HFC network at the last few hundred meters. By combining the technology of EPON, GPON and EOC with technology of HFC, it will greatly promote the development of application of two-way access of HFC digitization and three-in-one network. The core of this solution is that based on the existing resources of HFC (Hybrid Fiber-Coax) network that has been built, to construct manageable and maintainable HFC multimedia broadband access network in telecommunication level, and by sufficiently combining unique advantages of telecom industry and HFC accessing of broadcast television, to develop service of broadband internet, VOIP, video-on-demand of IPTV and so on.
EOC (Ethernet Over Coax) is network that transmits Ethernet signal in coaxial-cable between two points or among multiple points, which carries Ethernet network by coaxial-cable in user’s home and provides return channel for interactive services like digital television. Cable television broadband access network based on cable access technology (EOC) consists of device in local side, terminal device in user side, cable, branch distributor and so on.
EOC has various technical solutions, in which technology of Home Plug AV has highest stability, low two-way reconstruction cost and high rate in physical layer, so it is most widely applied and has become industry application standard in reality. The EOC technology stated in this solution all refers to low frequency EOC technology of Home Plug AV standard.
Home Plug is an enterprise alliance co-founded by tens of enterprises like Cisco, HP, Motorola and Intel with the aim of building local area network based on electric-power line. In August 2005, the organization released standard of Home Plug AV. Data transmission in electric-power line, telephone wire, and cable-coaxial can be implemented in Home Plug AV. Comparing with electric-power line network, coaxial network of cable television has better channel quality. Coaxial network resources can be sufficiently used and excavated by applying Home Plug AV technology in coaxial network of cable television.
Introduction of PON+EOC
PON+EOC is an efficient combination of PON network and EOC access mode with PON network as input of data interface of EOC. Network structure of PON+EOC as shown following figure 1:
Figure 1 Network Structure of PON+EOC
With fiber of PON as transmission medium at front part, abundant coaxial network resources as transmission medium at end part, it can well solve the objective limits of limited bandwidth and mass noise of traditional coaxial-cable under CMTS accessing mode. Moreover, communication system of EPON offers bandwidth of more than 1Gbps, GPON system offers bandwidth of up to 2.5Gbps in downstream, transmission distance reaches to 20km, and EOC offers bandwidth of up to 300Mbps on each service area, so PON+EOC system has a greater advantage on service providing capability and deployment flexibility.
No need for additional wiring, changing for original coaxial-cable or devices, and two-way reconstruction of cable television, PON+EOC solution realized functions of two-way reconstruction of cable television, which means high speed surfing is accomplished by coaxial-cable without affecting the transmission of cable television signal, so PON+EOC is acknowledged as an advanced broadband access and two-way reconstruction solution.
PON+EOC broadband access system has following remarkable advantages:
- Transmission Distance
Transmission range of PON access part can reach to 20Km, which can easily accomplish the coverage from head-end room to access point. In EOC access part, the system will not affect existing television channel signal as it adopts low frequency from 7.5MHz～65MHz for transmission. Comparing with high frequency signal, low frequency signal has better anti-attenuation performance, which can adapt to coaxial distribution network in communities, and can get to the ideal transmission bandwidth in 40dB link.
- Anti-Interference Capability
There adopts fiber transmission technology in PON access part, so it will not be interfered by electrical signal. In EOC access part it avoids low frequency area with high interference from 0MHz to 7MHz, and also applies advanced modulation technique of OFDM (Orthogonal Frequency Division Multiplexing) and Turbo FEC error checking, which greatly improves the capability of anti-interference.
- High Bandwidth and Multi-User Access Capability
EPON access supports two-way bandwidth of 1.25Gbps, GPON supports bandwidth of 2.5Gbps in downstream, 1.25Gbps in upstream. In EOC access part, head-end device supports 600Mbps physical layer bandwidth and 300Mbps MAC layer bandwidth, TDMA (Time Division Multiple Access) technology is applied in downstream and upstream, which can meet the requirements for developing high density users and high bandwidth services.
- Web Mastering
PON and EOC device both support remote management and control
- Advantage of “investment step by step, save costs”
Firstly PON+EOC does not need to reconstruct complex lines of fiber to the building and fiber to the home in existing broadcast television HFC network, but only needs to rebuild the lines of fiber to the node. Besides, on the situation of moderate number of access users in a community, it can meet the needs when deploying one head-end device in optical node that can provide 300Mbps shared bandwidth. As the number of access users is increasing, the option that can be considered is to increase the number of head-end device in optical node, access bandwidth will be increased by 300Mbps when adding one local side EOC device, which is enough for then requirements of multi-service from massive users.
EPON+EOC solution provided by C-Data as shown following figure 2:
Figure 2 EPON+EOC Solution
Introduction of PON+EOC solution:
OLT of local side (Machine room) is the core of PON system, provides uplink interfaces with high speed for information accessing like voice, data, and PON interfaces for passive optical distribution network. OLT is also the control center of PON system, by which network management system can accomplish operations, management and maintenance of PON system.
EDFA of local side (Machine room) amplifies received CATV front signal then transmit it, its uplink interface connects CATV front-end optical transmitter, downlink interface connects input port of WDM device.
Node OR (Optical Receiver) device converts CATV optical signal from fiber into RF (Radio Frequency) signal received by STB (Set Top Box), then RF signal will be transmitted to EOC head-end.
EOC head-end device multiplexes data signal and CATV radio-frequency signal in the same coaxial-cable by frequency band division, then forward to EOC terminals.
EOC terminal device separates data signal and television signal from EOC head-end, then transmits signals to STB (Set Top Box) and computer respectively.
There is ODN network between OLT and ONU, which is passive optical distribution network consisting of optical splitter and optical fiber with the function of distributing and converging optical signals. ODN network forwards downstream data to each ONU terminal and aggregates upstream data into OLT device, based on the actual application environment, multi splitters solution can be realized in ODN, one splitter solution is recommended.
C-Data EPON+EOC Product:
EOC products are mainly for the access from optical node to user in broadcast television network. C-Data provides various EOC products assembled with HFC optical receiver module, ONU module, fiber optical transceiver and EOC head-end module corresponding to different user scenario, which is the best choice for EOC access network construction with low investment for operators.
This product is developed and designed by C-Data company independently with complete intellectual property, it integrates multiple technologies including passive optical network, Ethernet, analog optical transmission, Internet security and network management, which can meet the needs for operators to provide high quality and reliable network services for users. With modularized product design, there are various product modalities by combining different function modules. Main function module includes: EOC Master function module, ONU function module, OR function module and MC function module. There are many types according to the functions and applications of EOC products in local side, like corridor type, outdoor type, integration type, all-in-one machine. EOC terminal has 4FE type, 4FE+WIFI type. With rich variety of products, the needs of various application scenarios of broadcast television will be met.
|EOC Master Function Module
|Based on HomePlug AV and IEEE1901 standard, co-uses with EOC terminal device, builds layer 2 Ethernet data transmission channel in coaxial network of cable television, provides broadband access service based on coaxial network for users|
|ONU Function Module
|Standard EPON network unit in user side, completely meet international standard IEEE802.3.ah and standard of technical requirements for China telecom EPON device, supports interconnection with third party OLT, provides connection for data services|
|Standard GPON network unit in user side, completely meet international standard G.984 and standard of technical requirements for China telecom GPON device, supports interconnection with third party OLT, provides connection for data services|
|OR Function Module
|Standard HFC optical node, completely meet the requirements of GY/T143-2000 of SARFT (State Administration of Radio, Film and Television), accomplishes transmission of cable television signal, transforms optical signal of cable television into radio frequency electrical signal|
|MC Function Module
|Standard Ethernet fiber optical transceiver module, can connect the fiber optical transceiver products of our company or third party, provides connection for data services|
EOC Head-End: EOC-only, EOC+ONU, EOC+ONU+OR
EOC Terminal: Data + CATV, data + CATV + WiFi