Hybrid Fiber-Coaxial network (HFC), also called coaxial network, is the telecommunication network architecture that combines fiber cable and coaxial cable to carry broadband content to users. Coaxial cable was invented by Oliver Heaviside, who patented the design in 1880. The hybrid network was globally used by cable television operators until the 1990s. Since then, the HFC architecture evolves to Next-Generation Access (NGA) networks, supporting also internet, telephony, and multimedia services. The network supports the transmission in both directions and the largest optical distance between the cable modem termination system and the farthest cable modem is 160 km.
Legacy HFC DOCSIS 3.0 cable networks use a tree topology with the analog transmission in an RF bandwidth 1 between 50 and 1,000 MHz, serving customers through a shared physical environment, with a downstream capacity until 1.2 Gbit/s. The 3.1 and the new DOCSIS 4.0 allows a downstream of 10 Gbit/s.
Benefits of Coaxial
While fiber is trendy in greenfields, coaxial still the most rational and economical option for brownfields, because the technology will continue to involve up to 10Gbps connectivity in the next years. Besides the good bandwidth, the coaxial network allows a great channel capacity, can be easily modified and has noise immunity due to the low error rate. Another benefit of the use of coaxial cables is the electromagnetic field carrying the signal exists only in the space between the inner and outer conductors, this means the coaxial cable can be installed next to metal objects without losing power, unlike other types of transmission lines.
HFC is used for delivering content like video, telephony, TV, digital TV, data and other interactive services over coaxial and fiber optic cables are using frequency-division multiplexing. In a Hybrid Fiber-Coaxial Cable System, the television channels are sent from the cable system's distribution facility, the headend, to local communities through optical fiber subscriber lines. At the local community, a box called an optical node translates the signal from a light beam to radio-frequency (RF) and sends it over coaxial cable lines for distribution to subscriber residences.
Coaxial cable or coax cable is an indispensable element of the Hybrid Fiber-Coaxial Network (HFC). It is a type of electrical cable which transmits radio frequency (RF) signals from one point to another. Usually, the coaxial cable is made of 4 parts: copper core, dielectric insulator, metallic shield, and plastic jacket. There are some types of coaxial cable and they have different uses, ones are indicated to residentials and others for commercial projects.
There are different types of coaxial cables that differ according to the purpose of use. For example, the Hard Line Coaxial Cables are often used for high signal strength applications, as with radio transmitters. The RG cables cover most of the high-frequency data and signal transmission requirements. Semi-Rigid Coaxial Cables are less flexible because they have a harder shielding metal. There also exist Tri-Axial Cables, Twin-Axial Cable, and others.
Coaxial cable lines only offer one signal to power a singular device. If there is more than one device that requires a signal, this can be problematic. Coaxial splitters are used exactly for these situations when there’s more than one device that requires a signal. Before choosing a cable splitter it’s important to know your device to understand the signal strength it might need. There exist 4 types of cable splitters: passive cable splitter, active cable splitter, diplex cable splitter, and multi-switch cable splitters.
Depending on the type of coax cable, they may have a single shield, double shield, triple-shield or quad shield. The most commons ones are double and triple shields, they are a low loss at high frequency for cable television, satellite television and cable modems. For special uses, like long drops and underground conduits, quad shields are more appropriate.