Ethernet over Coax (EoC) is a family of technologies that supports the transmission of

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

frames over

coaxial cable Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...

. The

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office ...

(IEEE) maintains all official Ethernet standards in the

IEEE 802 IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LANs), personal area networks (PANs), and metropolitan area networks (MANs). The IEEE 802 LAN/MAN Standards Committee (LMSC) main ...

family.

History

The first Ethernet standard, known as

10BASE5 10BASE5 (also known as thick Ethernet or thicknet) was the first commercially available variant of Ethernet. The technology was standardized in 1982 as IEEE 802.3. 10BASE5 uses a thick and stiff coaxial cable up to in length. Up to 100 stat ...

(ThickNet) in the family of

IEEE 802.3 IEEE 802.3 is a working group and a collection of standards defining the physical layer and data link layer's media access control (MAC) of wired Ethernet. The standards are produced by the working group of the Institute of Electrical and Electro ...

, specified

baseband In telecommunications and signal processing, baseband is the range of frequencies occupied by a signal that has not been modulated to higher frequencies. Baseband signals typically originate from transducers, converting some other variable into ...

operation over 50 ohm coaxial cable, which remained the principal medium into the 1980s, when

10BASE2 10BASE2 (also known as cheapernet, thin Ethernet, thinnet, and thinwire) is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. During the mid to late 1980s, this was the dominant ...

(ThinNet) coax replaced it in deployments in the 1980s; both being replaced in the 1990s when thinner, cheaper

twisted pair Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced ...

cabling came to dominate the market. The use of coaxial cable for Ethernet has been deprecated by the IEEE as of 2011.IEEE 802.3-2012 ''10. Medium attachment unit and baseband medium specifications, type 10BASE2'' Research in Ethernet transmission over coaxial cable continued, as both consumers and telecommunications operators strive to use existing 75 ohm coaxial cable installations (from cable television or CATV), to carry broadband data into and through the home, and into multiple dwelling unit (MDU) installations. Most EoC technologies are being developed for in-home or on-premises networking and are expected to be operated within the domain of a single operator.

Homeplug

HomePlug AV as well as its later extension, HomePlug AV2 both operate in a portion of the RF spectrum directly below what is commonly used for terrestrial FM radio broadcasting. HomePlug AV uses BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, and 1024 QAM modulation strategies between 2 MHz and 30 MHz while the more recent HomePlug AV2 standard extends the upper bound of its spectral use to 86 MHz.

ITU-T G.hn

The

ITU-T The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...

G.hn Gigabit Home Networking (G.hn) is a specification for wired home networking that supports speeds up to 2 Gbit/s and operates over four types of legacy wires: telephone wiring, Coaxial cable, coaxial cables, Power line, power lines and pla ...

standard provides high-speed (up to 1 Gigabit/s) local area networking over existing home wires, including coaxial cable, power lines and phone lines. It defines an Application Protocol Convergence (APC) layer for encapsulation standard 802.3 Ethernet frames into G.hn MAC Service Data Units (MSDUs). Other ITU-T standards for home networking over coaxial cable include G.9954, also known as HomePNA 3.1.

MoCA

CATV compatibility

EoC research is focused on the use of existing

cable television Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with bro ...

(CATV) infrastructure for

Internet access Internet access is a facility or service that provides connectivity for a computer, a computer network, or other network device to the Internet, and for individuals or organizations to access or use applications such as email and the World Wide ...

or broadband data transmission for the purpose of being compatible with the existing CATV (or sometimes satellite television) broadcast signals simultaneously transmitted on the same cable. The EoC technologies must operate outside the

frequency domain In mathematics, physics, electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency (and possibly phase), rather than time, as in time ser ...

currently used for CATV or for satellite receiver to set-top box transmissions. Most EoC technologies are designed to operate in

frequency band Spectral bands are regions of a given spectrum, having a specific range of wavelengths or frequencies. Most often, it refers to electromagnetic bands, regions of the electromagnetic spectrum. More generally, spectral bands may also be means in ...

s above 1 GHz, which is the upper bound of television signals and for systems designed to operate in North America using the SCTE 55-1 and SCTE 55-2 CATV transmission systems, as well as in most of Europe and portions of Asia. In many localities CATV systems operate only up to 550 MHz or 750 MHz, wherein some EoC technologies focus on using spectrum between 550 MHz or 750 MHz and 1 GHz. Though less costly, they could potentially conflict with future spectrum expansion up to 1 GHz. Some markets focus on using this 750 MHz to 1 GHz spectrum for EoC, specifically avoiding EoC bands above 1 GHz due to potential ingress noise from over-the-air transmissions and cellular systems.

References