The runway for the hybrid fiber/coax (HFC) community simply acquired a bit longer.
CableLabs stated at present that it has revealed the bodily layer specs for an enhancement to DOCSIS 4.0 designed to pump out downstream speeds of 25 Gbit/s. That milestone arrives roughly a 12 months after Phil McKinney, the outgoing CableLabs CEO, introduced the initiative finally 12 months’s SCTE TechExpo in Washington, DC.
These specs – at the moment known as DOCSIS 4.0 “operational annex” – name for spectrum on the HFC community to be prolonged to 3GHz. By comparability, the preliminary model of DOCSIS 4.0 helps spectrum as much as 1.8GHz. At considerably current CableLabs interops, present D4.0 expertise has been proven to ship about 14 Gbit/s downstream because the platform is additional optimized to assist larger and better modulations.
The present D4.0 specs additionally present a pair of choices: one which retains upstream and downstream spectrum working in separate, devoted spectrum (Prolonged Spectrum DOCSIS, or ESD); and a second, led by Comcast), that allows each upstream and downstream visitors to function on a Full Duplex (FDX) band. Each choices will proceed to be supported within the new specs.
If D4.0 non-compulsory annex is deemed financially and technically possible and suppliers and operators transfer to undertake it, a shift to 3GHz may additional prolong the lifetime of HFC networks and delay the necessity for cable operators to overbuild elements of their HFC networks with PON or go together with widescale upgrades to PON.
In fact, such evaluation is already underway at present within the early phases of the DOCSIS 4.0 period. Whereas some operators, together with Comcast, Spectrum and Mediacom Communications, have D4.0 squarely of their sights, others are leaning on DOCSIS 3.1+ as an interim step, or biting the bullet and going with fiber-to-the-premises (FTTP) upgrades. Operators corresponding to Cable One are exploring all of them earlier than figuring out which course to finally go.
A technical (and interoperable) roadmap to 3GHz
CableLabs famous that the brand new 3GHz specs outline downstream necessities for nodes and distant PHY gear and cable modems. The specs additionally contact areas such because the MAC and OSS layers. The brand new specs will proceed to depend on 192MHz-wide orthogonal frequency-division multiplexing (OFDM) downstream channels.
From a excessive stage, CableLabs specs are there to drive interoperability between a number of distributors of DOCSIS buyer premises gear (CPE) and sure community components corresponding to distant PHY units and cable modem termination methods (CMTSs).
A number of work forward
The brand new specs will present CPE and community gear and software program suppliers with a technical roadmap for product improvement, though it is going to seemingly be years earlier than 3GHz-capable merchandise are prepared for prime time. However that hasn’t stopped some suppliers from creating pre-market 3GHz prototypes. Utilized Optoelectronics Inc. (AOI), for instance, will present a 3GHz proof-of-concept amplifier at this week’s SCTE TechExpo in Atlanta.
Taking HFC to 3GHz will current some particular challenges, together with potential amplifier respacing and the potential use of booster amplifiers to handle the upper ranges of energy required to function alerts in these larger frequencies.
This newest wave of 3GHz exercise stems largely from a CableLabs DOCSIS 4.0 PHY Working Group that covers a number of expertise and product areas, together with the notion of amplifier hybrids and new optical nodes, RPD silicon, cable modems, faucets, cables and connectors.
“Utilizing this info, the group developed cable plant fashions able to supporting operation to 3GHz. This evaluation helped the working group decide what’s technically possible at frequencies as much as 3GHz with at present’s expertise,” two engineers at CableLabs – Richardo Villa, lead bodily layer applied sciences architect; and Karthik Sundaresan, distinguished technologist and director of HFC options – defined in a press release.
Subsequent cease: 6GHz?
CableLabs stated D4.0 operational annex specs additionally feed into analysis underway that’s exploring potential operations on plant upgraded to 6GHz, which theoretically may ship downstream speeds within the neighborhood of fifty Gbit/s. This week’s present will characteristic displays from execs with CableLabs, Aurora Networks, Sercomm and AOI centered on the challenges offered by 6GHz expertise and potential 6GHz migration methods and architectures that will not require a full community alternative.
In an interview forward of this week’s present, Mark Bridges, the incoming CEO of CableLabs, stated the 6GHz exercise continues to be within the explorational phases, however he burdened that it may sometime present the trade with one other stage of optionality.
Bridges, who at the moment serves as president and CTO and can turn out to be CEO of the group in January, additionally famous that work is underway to discover the conduct of the community at 6GHz and a deal with product improvement, together with new amplifier and faucet designs. He added that work is the furthest together with respect to 6GHz-capable faucets.
