EoC (EthernetoverCOAX Ethernet data is transmitted through coaxial cable)
technical standard
A lot of technologies and solutions are emerging now, and the Ethernet signal is transmitted through the coaxial cable after complex processing such as modulation and demodulation. Although some people also call it "EthernetoverCoax", it is very different from the real EoC (baseband EoC/passive EoC). The signal transmitted on the coaxial cable no longer maintains the frame format of the Ethernet signal. It is strictly technical From a perspective, it cannot be called "EoC". There are mainly the following types of such technologies: HomePNAoverCoax, HomePlugBPLoverCoax, HomePlugAVoverCoax, WiFioverCoax, MoCA-MultimediaoverCoaxAlliance, we will collectively call it "active EoC" or "modulated EoC" for the time being.
HomePNA, HomePlugBPL, HomePlugAV and WiFi (WirelessLAN, WirelessFidelity) are currently relatively mature home networking technologies. Their development has a history of several years. MoCA is a coaxial cable-based networking technology launched by MultimediaoverCoaxAlliance. It is one of the four technologies. The youngest. HiNOC is a standard EOC technology that has recently emerged in the Chinese market, and it is also a technology specifically for coaxial cables, but there is no commercial chip currently.
Folding MOCA
MoCA is the abbreviation of Multimedia over Coax Alliance (Multimediaover Coax Alliance), MoCA was established in January 2004, the founders are Cisco, Comcast, EchoStar, Entropic, Motorola and Toshiba. MoCA hopes to provide a way to transmit multimedia video information with coax (Coax); they use Entropic's technology (c-link) as the basis for the MoCA1.0 specification. MoCA members believe that the penetration rate of coaxial cable in American households is as high as 70%, and the entire infrastructure is very complete. In addition, the technology of coaxial cable transmission of multimedia video data is quite mature and stable, and it is suitable for using it to transmit multimedia video data. MoCA products can use the existing coaxial cable network, combined with optical communication technology, to use it to provide high-speed broadband access to buildings and communities.
Folding down frequency WiFi
Wireless local area network technology is one of the most promising technologies in the field of wireless communication. At present, WLAN technology has matured day by day and its applications have become more extensive. Among the many standards, the most widely known is the IEEE (American Institute of Electrical and Electronic Engineers) 802.11 series. In addition, the organizations that formulate WLAN standards include ETSI (European Telecommunications Standardization Organization) and the HomeRF working group. The standards proposed by ETSI are HiperLan and HiperLan2. , The two standards of the HomeRF working group are HomeRF and HomeRF2. Among the standards formulated by these three organizations, the IEEE 802.11 standard series has always received the most extensive support in the industry due to its Ethernet standard 802.3's influence in the industry, especially in data services. Different manufacturers implement WiFioverCoax in slightly different ways. The biggest difference lies in the different frequency bands used and whether it is frequency conversion.
MoCA development roadmap
·MoCA1.0 was released in 2007
· Frequency band: 850-1500Mhz.
Physical layer rate: 270Mbps
MAC layer rate: 130Mbps
· Number of users: 63.
·At 97% load, the MAC rate reaches 110Mpbs.
Typical delay: 3ms
Band width: 50Mhz
·MoCA1.1 was released in 2008
· Frequency band: 500-1650Mhz.
· Number of users: 63.
·At 97% load, the MAC rate reaches 160Mpbs.
Typical delay: 3ms
Band width: 50Mhz
·MAC layer rate: 175Mbps (using packet aggregation, packetaggregation)
·QoS
·Priority QoS
Parameterized QoS (PQoS)-bandwidth reservation
Corresponding products have been launched in China, such as Beijing Jinqiao Hengtai Technology, Chengdu Feiguang Communication, Chengdu Hitop Electronics, etc.
·MoCA2.0 was released in 2010
· Frequency band: 500-1650Mhz.
· Number of users: 63.
Typical delay: 3ms
·QoS
·Priority QoS
Parameterized QoS (PQoS)-bandwidth reservation
MAC layer rate: 400Mbps, 800Mbps (bandwidth is 100MHz)
Physical layer rate: 700Mbps, 1400Mbps (bandwidth is dual 100MHz)
· Backward compatibility does not affect performance
·Two low power consumption modes
·Improve PER performance
·400Mbps is already available
HomePlugAV
In March 2000, dozens of companies including Cisco, HP, Motorola and Intel jointly established the HomePlugPowerlineAlliance. The idea of setting up a local area network with power lines finally had a consistent standard and specific progress. The Home Powerline Network Alliance subsequently published the first standard for powerline networks-HomePlug1.0 in June 2001. The HomePlugAV formulation work began in February 2003. In August 2005, the Home Powerline Network Alliance approved the new HomePlugAV standard. The purpose of HomePlugAV is to build a high-quality, multi-channel media stream, entertainment-oriented network on the power line inside the home, specifically to meet the needs of home digital multimedia transmission. It uses advanced physical layer and MAC layer technology to provide a 200Mbps power line network for the transmission of video, audio and data. The physical layer of HomePlugAV uses the OFDM modulation method, which converts the information symbols to be sent through serial-to-parallel conversion to reduce the rate, thereby increasing the symbol period to weaken the influence of multipath interference. At the same time, it uses cyclic prefix (CP) as a guard interval, which greatly reduces or even eliminates inter-symbol interference, and ensures orthogonality between channels, thereby greatly reducing inter-channel interference. Of course, this also pays the price of bandwidth and brings energy loss: the longer the CP, the greater the energy loss. In OFDM, the frequency spectrum of each subcarrier has 1/2 overlap and orthogonality, which improves the spectrum utilization of the OFDM modulation method. At the receiving end, each carrier is separated through relevant demodulation technology, and at the same time, the influence of inter-symbol interference is eliminated. After removing the frequency of low-frequency interference, the EOC products based on HomePlugAV use 917 sub-carriers in the 7-30MHz frequency band; the power spectral density is programmable to meet the frequency regulation of different countries; each sub-carrier can be individually BPSK, QPSK, 8QAM, 16QAM, 64QAM, 256QAM and 1024QAM modulation; TurboFEC error checking is adopted; the physical layer line rate reaches 200Mbps, the payload is 150Mbps, and the preamble can be detected by the HomePlug1.0 device to realize the coexistence of the two, but interoperability is optional.
Now Homeplug announced that it supports IEEEP1901 and will no longer be developed separately.
EMoC
EMoC is the abbreviation of EPONMACoverCable. It adopts EPONMac layer protocol, a technology of G.hnG.9660 physical layer protocol for data transmission on the Broadcasting and Television Cable network. It is a chip of Chengdu Shuangxin Electronics. It is compatible with Deco.
Using the physical layer of G.hn, the transmission rate can reach 1.8Gbps. The MAC layer adopts the MAC layer of EPON, and the maximum transmission rate can reach 900Mbps.
ECAN
ECAN is the abbreviation of EthernetCoaxAccessNetwork, which is a technology for data transmission on the Broadcasting and Television Cable network designed after the EPON technology. It is a chip of Puran.
Deco
Deco (DatatransmissionwithEPONMACandCodedOFDM), adopts EPONMac layer protocol, G.hnG.9660 physical layer protocol, a technology for data transmission on the radio and television Cable network. It is a kind of chip of Shanghai Jingle. It is compatible with EMoC.
IEEEP1901
In July 2005, the Institute of Electrical and Electronics Engineers IEEE established the P1901 working group to unify the technical standards for power line broadband communications. The content covers the indoor networking and outdoor broadband access of power line broadband communication, as well as the interoperability of the two parts. In December 2008, IEEEP1901 passed the technical standard proposal for the physical layer (PHY) and medium access control layer (MAC) of power line broadband communication. The proposal includes three options, based on HomePlug Powerline Alliance's HomePlugAV technology, Panasonic's HDPLC technology and ITU-TG.hn's physical layer specification. In February 2010, the IEEE had completed the initial draft and released it, defining HomePlug Powerline Alliance’s HomePlugAV technology and Panasonic’s HDPLC technology as optional standards for the physical layer, giving up efforts to be compatible with G.hn. Jiangsu Cable has defined the P1901 standard as the EOC standard of Jiangsu Radio and Television in the "Jiangsu Cable EOC Technical Specifications" released in early 2010.
Passive EoC
Passive EoC (EthernetoverCoax) technology is based on a series of protocols related to IEEE802.3, which is a transmission technology that transmits Ethernet signals on coaxial cables. The frame format and MAC layer of the original Ethernet signal have not changed, except that the differentially balanced signal (twisted pair medium) will be converted into an unbalanced signal (coaxial cable medium). Its biggest feature is that the client is a passive device. The baseband coaxial transmission system occupies the 0-65MHz frequency band to provide users with a bandwidth of 10M. Using high and low pass filtering methods, all passive components are used to realize the transmission of data and cable TV signals on the coaxial. The system needs to change the original balanced transmission of the Ethernet signal into an unbalanced transmission, and also transmit and receive the Ethernet. The signal synthesizes one signal, and completes 100 ohm/75 ohm impedance transformation. The baseband EOC technology is a technology that uses frequency division multiplexing technology for the Ethernet data signal IPDATA and the cable TV signal TVRF, so that the two signals are transmitted together in the same coaxial cable. According to my country’s standard for dividing the frequency of the cable TV network in the old national standard, the IPDATA signal is transmitted in the frequency band below 35MHz, and the TVRF signal is transmitted in the frequency band above 48MHz, which can realize the common cable transmission of the two signals without affecting each other, or according to the new national standard 65 /87 split point, EOC built-in filter is easy to mass produce. In the building, the coaxial cable of the HFC network is used to directly transmit the mixed signal of IPDATA and TVRF to the user end, and then the passive separation of the mixed signal is realized at the user end. Passive EOC needs to combine the Ethernet signal and the CATV signal above 86MHz through the duplex filter. The duplex filter needs to have high isolation, high return loss, and the lowest possible insertion loss to effectively suppress Ethernet. Spurious signals generated. At the same time, the filter will produce phase nonlinearity, and the necessary equalization of the group delay is required. Therefore, the signal indicators and product process requirements are very high, otherwise it is easy to cause the signal to be blocked. Because the energy of the passive EOC is mainly concentrated in 0-20MHz, and the bandwidth of the branch distributor is generally 5 to 1000MHz, so the passive EOC cannot pass through the branch distributor.
