ORLANDO – Look for the next generation of cable's DOCSIS broadband platform to support "multi-gigabit speeds" and be backwards-compatible with earlier DOCSIS versions, according to Phil McKinney, the new president and CEO of CableLabs.
Speaking on a cable technology panel here just prior to the annual SCTE Cable-Tec Expo show, McKinney said CableLabs and its members and vendor partners began working in earnest on the new DOCSIS 3.1 specification about two months ago. Although he didn’t spell out all of the technical details about the proposed standard, he said the aim of the new initiative is to boost MSO broadband speeds well above the 1 Gbps mark.
Indeed, cable equipment manufacturers have openly mused about the idea of having the new DOCSIS 3.1 standard support downstream data speeds as high as 10 Gbps and upstream speeds as great as 2 Gbps. Currently, several cable operators, including Shaw Communications and Vidéotron, are using DOCSIS 3.0 to offer broadband services that reach or top 100 Mbps in the downstream.
McKinney argued that creating backwards-compatibility is critical to the effort because it will ensure that cable operators won’t have to carry out major plant overhauls when they upgrade to DOCSIS 3.1.
Beyond higher download and upload speeds, the proposed DOCSIS 3.1 spec will also attempt to improve the quality of cable's broadband pipes, cut latency and enhance the cable network in other ways to empower a new wave of broadband services. For instance, several panel speakers cited the cable industry's interest in delivering 4K HD services, which would provide four times the video resolution of today's HD pictures.
Further, cable technologists hope to shorten the length of time that it takes to create new broadband specs and then turn them into actual products. Up till now, the average DOCSIS spec has taken three to four years from start to finish. "We can no longer do that," McKinney said. "We have to deliver higher and higher performance." He didn't offer an estimate, however, of how long it might take to produce the final DOCSIS 3.1 spec.
While the transition to the proposed DOCSIS 3.1 spec could happen faster than the transition from DOCSIS 2.0 to 3.0, it still won't happen right away, cable engineers warned. For one thing, DOCSIS 3.1 will require new silicon, noted John Schanz, Comcast's EVP of national engineering and tech ops and chief network officer.
In addition, the DOCSIS 3.1 effort is aimed at reducing costs as broadband usage rate continue to climb. Getting costs down "is a key part of DOCSIS 3.1," said Cox Communications EVP and CTO Kevin Hart.
Cable’s pursuit of the speedier DOCSIS 3.1 standard may lead to other changes as well. Notably, engineers said on an SCTE panel here, it could lead to the industry eventually moving away from its existing 6MHz channel spacing and toward more efficient, super-wide 200MHz channels.
Currently, North American DOCSIS uses 6MHz-wide channels that each pump out about 40 Mbps. With DOCSIS 3.1, the industry hopes to squeeze out more bits per hertz by chopping 200MHz-wide blocks into thousands of small subcarriers and combining them using the orthogonal frequency-division multiplexing (OFDM) modulation scheme. Advocates argue that this approach could improve spectral frequency by at least 25%.
Engineers explained that utilizing one of those blocks would allow cable to produce a data path in the neighborhood of 1Gbps. They argued that cable operators could then bond 200MHz-wide channels together to create multi-gigabit capacities. In turn, that would let MSOs match fiber-to-the-premises (FTTP) speeds without having to extend their own fiber networks all the way to subscribers.
– Cartt.ca staff
