CableLabs hails symmetrical multi-Gigabit DOCSIS development

Belal Hamzeh

Cable technology standards body CableLabs has begun work on a new technology initiative to support symmetrical multi-Gigabit services.

CableLabs used last week’s winter conference in Orlando to unveil plans for a ‘Full Duplex’ DOCSIS technology, tapping techniques currently used by wireless networks to combine upstream and downstream bandwidth rather than having a dedicated upstream channel.

In a blog posting, Belal Hamzeh, vice-president wireless, research and development and Dan Rice, senior vice-president, research and development at CableLabs, said that the technology could deliver up to 10Gbps of symmetrical bandwidth on 1GHz HFC network, with the potential for even higher performance by using spectrum above 1GHz.

In their blog posting, the pair outlined how the technology could double the capacity available for upstream traffic by simultaneously using the same spectrum, unlike current technologies such as frequency division duplexing – currently used by DOCSIS – and time-division duplexing, used by Wi-Fi and G.Fast networks.

“In frequency division duplexing, upstream and downstream – or uplink and downlink in the terms of the wireless world – traffic operate separately in dedicated parts of the spectrum. In current DOCSIS network deployments, the lower part of the spectrum is dedicated for upstream traffic and the upper part of the spectrum is dedicated for downstream traffic,” said the pair.

“In time division duplexing, the upstream and downstream traffic share the same spectrum, but take turns in using the spectrum, similar to how Wi-Fi, or DSL, operate. In Full Duplex communication, the upstream and downstream traffic use the same spectrum at the same time, doubling the efficiency of spectrum use. A DOCSIS 3.1 Full Duplex network provides the peak speeds and flexibility of time division duplex solutions, but one-ups both time division duplex and frequency division duplex with double the capacity.”

Hamzeh and Rice said that, by using a combination of passive HFC networks and DOCSIS 3.1-based self-interference cancellation and intelligent scheduling, CableLabs had built a solution that proved the technology was viable.

The pair said that a Full Duplex network would support backward compatibility and co-existence with previous generations of DOCSIS deployments.

They said that that CableLabs would engage with members and vendors to validate the technology over the next few months, potentially transitioning to an R&D project afterwards.