Comcast Puts DOCSIS 3.1 To The Test: Report

Comcast, already a self-identified champion of DOCSIS 3.1, has begun to test the next-gen technology in the field as CableLabs prepares to rev up official testing on cable modems and cable modem termination systems that adhere to the spec, Light Readingreported Wednesday

"The target for us is to be in the field establishing network readiness in 2015," Jorge Salinger, Comcast’s VP of access architecture, said in Denver at Light Reading’s Cable Next-Gen Technologies and Strategies event.  "Our overall goal is to be able to deploy DOCSIS 3.1 and gigabit-per-second in a broad scale starting in 2016."

DOCSIS 3.1, designed to support capacities of up to 10 Gbps downstream and at least 1 Gbps upstream, will be a more efficient platform that will rely on blocks of orthogonal frequency division multiplexing (OFDM), and eschew the use of 6MHz- and 8MHz-wide channels use by today’s DOCSIS networks. When combined with low density parity-check, a forward error correction scheme that uses less bandwidth than the current Reed-Solomon approach, DOCSIS 3.1 is expected to be about 50% more efficient from a bits-per-hertz perspective than DOCSIS 3.0.

According to the report, Salinger said Comcast is starting to field-test the use of OFDM on one network and in one headend.

The current, fastest residential broadband service offered by Comcast is Extreme 505, a $399.95 per month, targeted fiber-to-the-premises product that today offers 505 Mbps downstream by 100 Mbps upstream. Following its debut in the Northeastern U.S. in the fall of 2012, Comcast has since extended the reach of the product to include systems in MSO's South Division and Central Division.  In an apparent foreshadowing to coming rollout plans, Comcast recently filed an application for the “True Gig” trademark.

Liberty Global and NBN Co, the government-owned entity that is tasked with bringing faster broadband speeds to Australia, are among others that have committed to deploy DOCSIS 3.1. Cox Communications is also expected to use D3.1 for its ambitious deployment of gigabit services.

CableLabs has been conducting DOCSIS 3.1 interops in anticipation of official qualification and certification testing. According to Light Reading, CableLabs director of network technologies Belal Hamzeh told event-goers that the goal is to start D3.1 certification testing in May, meeting a prediction made at the SCTE Cable –Tec Expo last September that those tests would be underway by the first half of 2015.

To aid the transition, the first wave of D3.1 modems will be hybrids that can support DOCSIS 3.0 traffic and OFDM-based traffic for D3.1.