Cable CTOs: DOCSIS 3.1 Will Handle Bandwidth Crunch

WASHINGTON — The emerging DOCSIS 3.1 specifications will save cable operators time and money by leveraging their existing upstream spectrum and avoiding more costly bandwidth-enhancing alternatives.

DOCSIS 3.1 and its use of orthogonal frequency-division multiplexing (OFDM) “is a godsend in the upstream,” Comcast executive vice president and chief technology officer Tony Werner said last Monday (June 10) during a Cable Show panel that covered a broad range of technology topics.

OFDM, a technology that’s already popular in the wireless world and is tagged for the new DOCSIS 3.1 specs, will make existing spectrum about 50% more efficient. That could help cable operators avoid an operationally tricky “mid-split” that would widen the current upstream spectrum range from today’s 5-42 Megahertz to 5-80 MHZ.

“I don’t think we’ll have to widen the upstream,” Mike LaJoie, Time Warner Cable’s executive vice president and chief technology officer, said. He said cable continues to develop tools that enable MSOs to adapt the network and stay ahead of potential bandwidth crunches.

Execs also talked about when they expect to deploy DOCSIS 3.1, a platform that has designs on supporting downstream capacities of 10 Gigabits per second and upstream speeds of up to 2 Gbps. CableLabs is expected to complete the specs this year.

Werner said he sees DOCSIS 3.1 trials starting in 2014, and expects commercially-ready products becoming available by late 2014 or early 2015. Comcast, he said, will start purchasing DOCSIS 3.1 modems as soon as it makes financial sense and, as a future-proofing measure, expects to deploy those devices even before the networks are upgraded for the new platform. The first D3.1 modems are expected to be hybrid versions that also support DOCSIS 3.0.

“As soon as we can get modems at the right [cost] delta, we’ll be buying DOCSIS 3.1 modems,” Werner said. He wouldn’t say what that magical price point is, but said, “If they’re twice as much, you have a hard time future-proofing.”

He also said he liked that DOCSIS 3.1’s use of OFDM will make the service more resilient to interference with Long-Term Evolution (LTE) signals. “It’s an evolution that has a lot to like about it.”

Cox Communications has not identified when it will support DOCSIS 3.1, but executive vice president and chief technology officer Kevin Hart said the MSO is already starting to do the kind of network preparation required to “free up channels to enable this capability.”

“We’re all excited about doing more with what we have,” Yvette Kanouff, executive vice president of technology at Cablevision Systems, said.

Panelists also stressed that cable will be prepared when 1-Gig speeds to the home are needed.