DOCSIS 3.1 will enable cable operators to flirt with downstream capacities of 10 Gbps, and is sometimes viewed as the platform that will serve operators before they abandon HFC and ultimately go with a fiber-to-the-home approach.
According to some Arris engineers that are noodling the future, HFC’s runway could extend much longer than that, and possibly support 50 Gbps or more, when teamed with the right technical approach that involves pulling fiber even closer to the home and tapping into spectrum well beyond 1 GHz.
Arris presented its ideas in Keystone, Colo., at the recent CableLabs Summer Conference’s Innovation Showcase (Veniam, a startup that turns vehicles into mobile WiFi hotspots came away with top honors, by the way).
“10 Gigbabits per second. 15 Gigabits per seconds. Those are the numbers right now that we’re talking about as we plan to deploy DOCSIS 3.1 in this decade using 1.2 and 1.7 GHz plants,” Tom Cloonan, the CTO of Arris’s Cloud & Network Solutions unit, explained.
There are options, he said, to “maybe push DOCSIS up to 50 Gigabits per second, 100 Gigabits per second or 200 gigabits per second. Sound crazy? Maybe. But maybe not.”
He allowed that if cable did nothing new, HFC plant could “run out of gas” by the mid-2020s, based on anticipated capacity requirements shown by Nielson’s Law.
“It means we have a decent runway ahead of us, but it doesn’t run forever,” Cloonan said.
Arris’s idea (Cloonan said it’s “controversial”) focuses on extending the capacity of HFC (with DOCSIS 3.1 and its more efficient OFDM-based signals) to 6 GHz or more (today’s most advanced plant is built out to about 1 GHz), and going with a fiber-to-the-tap or fiber-to-the-curb approach that greatly shortens the length of the coax going into the home. In some ways, that borrows from the telco playbook for advances such as G.fast, a new standard platform that brings gigabit capabilities to DSL networks.
Arris’s demo ran at 6 GHz and showed the potential for 50 Gbps. When extrapolated out, the theory is that 12 GHz could deliver 100 Gbps, and 25 GHz could get to 200 Gbps, Cloonan explained.
A more thorough explanation of what Arris is chewing on is provided in this video of the brief presentation from Cloonan and Arris systems architect Ayham Al-Banna: