CableLabs, which performs technology and specification development for the cable operators, has completed work on the specification for Full Duplex DOCSIS 3.1 (also known as FDX). The specification enables DOCSIS 3.1 hybrid fiber/coax (HFC) networks to support shared 10-Gbps transmission capabilities in both the upstream and downstream directions. The technology enables HFC networks to support similar transmission rates as XGS-PON and 10G-EPON fiber to the home (FTTH) networks, enabling cable operators to match the capabilities of telco competitors who use such PON technologies.
As its name implies, Full Duplex DOCSIS 3.1 supports symmetrical 10 Gbps by enabling upstream and downstream traffic to use the same spectrum simultaneously. What CableLabs described as "self-interference cancellation technology and intelligent scheduling" are among the approach's cornerstones. The ability to support symmetrical 10 Gbps is expected to prove particularly useful in the support of business services as cable operators target large enterprises.
Full Duplex DOCSIS 3.1 is a follow on to the original DOCSIS 3.1 specification, released in 2013, which supports 10 Gbps downstream and approximately 1 Gbps upstream (see "CableLabs releases DOCSIS 3.1 chip specifications"). Several cable operators have begun DOCSIS 3.1 roll outs. In the U.S., Comcast and a number of smaller operators have led the way (see, for example, "Comcast Business adds DOCSIS 3.1 based business services in U.S. Northeast, Mid-Atlantic"). Major operators such as Charter/Spectrum and Cox have yet to announce DOCSIS 3.1 deployments; Altice USA has said it will take an all-fiber approach rather than rely on its HFC plant with DOCSIS 3.1 (see "Altice USA to emphasize FTTH, not DOCSIS 3.1").
How quickly Full Duplex DOCSIS 3.1 deployments will begin is uncertain. Development of the necessary headend and cable modem capabilities appears to be in the very early stages. However, Hitron has announced a demonstration of Full Duplex DOCSIS 3.1 capabilities at next week's SCTE Cable-Tec Expo using its DOCSIS 3.0 modems in conjunction with Cisco's interference group capabilities. CableLabs says it expects to post the new specification, couched as an update to DOCSIS 3.1, on its website later this month.
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