Advertisement
Articles
Advertisement

DOCSIS 3.1 takes center stage at Cable-Tec Expo

Wed, 11/21/2012 - 9:56am
Brian Santo and Mike Robuck

The new DOCSIS 3.1 specification makes its debut in Orlando, with CCAP and the cable industry's migration pathway to IP in the spotlight, as well.

There were plenty of buzz-worthy topics during the most recent edition of the SCTE Cable-Tec Expo, but the official debut of the DOCSIS 3.1 specification made the biggest splash in Orlando outside of Sea World.

The next iteration of DOCSIS was largely foreshadowed at The Cable Show in Boston earlier this year, but a panel provided some insights on DOCSIS 3.1 during a standing-room-only panel at Expo. The DOCSIS 3.1 specification is a work in progress, but the game plan is to complete at least the hardware portions of the spec by early next year so that equipment, which most likely will start with cable modems, can be offered in 2014.

With the spec still a work in progress, Jeff Walker, director of CMTS product marketing for Motorola Mobility, said the panel introduced the “speeds and feeds” of the DOCSIS 3.1 specification, but there was “plenty more work to be done.”

DOCSIS 3.1 will use a new modulation scheme, along with a more sophisticated forward error correction (FEC). It will also support transmission speeds up to 10 Gbps downstream and 1 Gbps upstream, and it assumes operators will reallocate as much as 160 MHz of downstream bandwidth for use on the upstream.

DOCSIS 3.1 will rely on orthogonal frequency division multiplexing (OFDM), used in DSL, LTE, Wi-Fi and MoCA, among other technologies. It will also replace the commonly used Reed-Solomon FEC with far more efficient low-density parity check (LDPC) codes.

During the Expo panel, DOCSIS 3.1 was introduced by Jeff Finkelstein, senior director of network architecture for Cox; Howard Pfeffer, senior vice president of broadband engineering and technology for Time Warner Cable; Jorge Salinger, vice president of access architecture for Comcast; and Matt Schmitt, director of DOCSIS specifications for CableLabs, each of whom has participated in every version of DOCSIS to date.

Salinger, referring to his fellow panelists from the “DOCSIS 3.1 specification and standard development” session, said: “I don’t know that any of us thought we’d be doing it again. It’s exciting.”

DOCSIS 3.1
The details of DOCSIS 3.1 were heavily telegraphed in a paper called “The mission is possible,” co-written by leading technologists at Arris, Cisco, Intel and Motorola and delivered earlier this year at The Cable Show.

That paper presented almost every option under consideration and said LDPC error correction showed great promise, so use of that in DOCSIS 3.1 could have been expected. It said that continuing to use single carrier modulation was not going to be practical, and though several modulation schemes were considered, the virtues of OFDM in particular were extolled.

The authors of the paper said that denser modulation schemes would be inevitable. Many of their examples were of 1024-QAM, but they suggested that 4096-QAM be studied. The MSO panel at Cable-Tec Expo consistently speculated about going on to 4096-QAM.

As of The Cable Show, various spectrum splits were on the table, expanding the high end of the upstream band from 42 MHz to as high as even 500 MHz. DOCSIS 3.1 will only go to 200 MHz.

To replace the spectrum lost to the upstream, the options were to expand beyond 1 GHz to as high as 1.7 GHz. DOCSIS 3.1 would top off at 1.1 GHz or 1.2 GHz.

At The Cable Show, the impression given was that downstream data rates of 2 Gbps were likely to be considered, but the MSOs said they want support in the 3.1 spec for up to 10 Gbps downstream and 1 Gbps upstream.

“We’re looking at eight, 10, even 12 bits per hertz,” Finkelstein said. “That’s an astounding number.”

The combination of new technologies is expected to lead not only to extraordinary transmission speeds, but also significantly reduced cost per bit, “otherwise, there’s no reason to do this,” Schmitt said.

That will be due in part because OFDM will enable MSOs to use their spectrum more efficiently. There is also the possibility that cable will be able to leverage economies of scale (as OFDM is widely used elsewhere), as well as leverage the innovation potential inherent in a larger vendor community.

The MSOs were adamant that any transition to 3.1 will be smooth, with backwards-compatibility with previous generations of DOCSIS assured. “This has to start with zero plant investment,” Schmitt noted.

Salinger said he expects that MSOs will install DOCSIS 3.1 CPE first, then implement 3.1 on the downstream, and then finally on the upstream.

The capabilities cable will have when 3.1 is fully deployed will be formidable. John Chapman, CTO of Cisco’s Cable Access Business Unit and a co-author of The Cable Show paper, said 3.1 might end up being the last iteration of DOCSIS. On the show floor, Chapman said DOCSIS 3.1 would be the final springboard to full spectrum, but new technologies, such as new silicon, need to be developed.

Stan Brovont, Arris' senior vice president of marketing and business development, said not to underestimate the cable operator industry’s ability to continue to innovate on HFC, and that DOCSIS 3.1 could have a shelf life of up to 10 years.

Several vendor employees pointed out that the demand for DOCSIS 3.1 equipment will vary by operator, but Chapman said cable operators can start seeding the field with the 3.1 modems when they become available in order to future-proof their investments.

The SCTE said that while CableLabs is helping to define the 3.1 spec, it is already working in parallel with its sister organization to develop training, certification and other support services.

To that end, the SCTE formed a Special Working Group to develop best practices and requirements to prepare HFC networks for higher-capacity signaling schemes, including DOCSIS 3.1. Jack Moran, fellow of the technical staff for Motorola Mobility’s Home Business, was named chair.

CCAP on the show floor, in trials
Moving in a parallel path with the migration to IP video, and now DOCSIS 3.1, the Converged Cable Access Platform (CCAP) was also in the spotlight during Expo. While Casa Systems introduced its CCAP platform at The Cable Show, Arris, CommScope and Harmonic were showing their wares in Orlando, while Motorola and Cisco were providing views of their respective CCAP platforms behind closed doors.

Not surprisingly, the vendors’ approaches were based largely on their own history and culture, which meant that Cisco and Arris were able to tout their cable modem termination system (CMTS) and edge QAM platforms, while CommScope, through its purchase of LiquidxStream Systems, and Harmonic took the edge QAM approach in the early stages of their CCAP product development.

Over in the “whisper suite” section of its booth, Cisco was offering previews of its CCAP cBR-8, which will be available next year. Out in the public eye, Cisco was showing 3G60 and DS384 line cards on its uBR10k CMTS, which gives it a CCAP-compliant product on the uBR10k’s installed base.

Building on its universal edge QAM experience, Harmonic showed its CCAP-compliant product, the NSG Pro, at Expo for the first time. Harmonic’s Asaf Matatyaou, director of cable edge and access solutions, said the vendor would integrate a CMTS into the NSG Pro in the future, but the current version delivered on CCAP’s goals of lower cost and high densities. Harmonic has the NSG Pro in at least one trial and plans on making it commercially available in the first quarter.

Arris’ E6000 Converged Edge Router was also on display for the first time. The E6000 is starting out as a bigger, better version of the company’s C4 CMTS platform before eventually migrating to an integrated CCAP platform that will combine the edge QAM and CMTS features in one box. Arris didn’t say when it would integrate the edge QAM features, but the CMTS version supports up to 1,792 downstream DOCSIS channels in a 16-rack-unit chassis, and it will be commercially available early next year.

Arris’ Brovont said the E6000 would allow cable operators more flexibility and greater efficiencies as they move toward IP architectures.

CommScope’s entry into the CCAP sweepstakes, which is called the Converged Services Platform (CSP), comes in two form factors: the 14-rack-unit CSP 1280 and the nine-rack-unit CSP 640. The CSP product line takes the company’s current edge QAM solution – Universal Wideband – and adds support for DOCSIS upstream and MAC (media access control), native IP processing, and EPON/EPOC (EPON over Coax) support in a denser and more scalable platform.

Tom Anderson, CommScope's broadband optical solutions product strategist, said the CSP units are slated for labs and trials by the end of the year, with commercial availability also by early next year.

On the operational side of CCAP, Comcast’s Salinger went over some of the issues that cable operators need to be aware of when deploying CCAP during the Expo session “CCAP trial: The verdict,” as well as a rundown of Comcast’s CCAP trial that started last year.

“It's not just about dropping in another box,” Salinger said. “It’s a different beast to manage and deploy. It’s a different ballgame when all of your revenue is running through one box. You have to be careful.”

Salinger said Comcast’s trial was all about operational readiness. The trial used equipment that wasn’t fully CCAP-compliant, since that type of equipment hasn’t become available until this year, but it gave Comcast the opportunity to see what kinds of tools, including traps and alarms, were needed in the CCAP environment.

Salinger said CCAP would be “massively deployed” next year, but there’s still work to be done around creating a foundation for CCAP. From an organizational standpoint, Salinger said training needs to occur between the DOCSIS and video groups that previously operated separately prior to CCAP. Training should start at the engineering level to create a pyramid of learning from a smaller group to a larger group, Salinger said.

From an equipment standpoint, cable operators may not be ready to jump in with both feet on a full CCAP rollout of equipment, but cable operators can still take advantage of the CCAP-enabled edge QAM capabilities as they expand their narrowcast services. According to Salinger, this approach doesn’t “strand the investment” in the short term, and it allows cable operators to migrate to full CCAP at a later date.

CCAP also provides an easy transition from one technology to another. When DOCSIS 3.1 lifts off, cable operators, in theory, won’t need to make any hardware changes; they’ll just need to swap out line cards.

On the tools front, Applied Broadband CEO Jason Schnitzer spoke about DCE, which is a system he developed with Comcast. DCE is an XML-based protocol for configuration management in CCAP. DCE provides a modeling environment with a device configuration emulator.

Motorola Mobility’s John Holobinko, vice president of strategy and business development, spoke about service group alignments for CCAP. Holobinko said cable operators need to plan for the alignment of video and data service groups, which differ in size. With CCAP and edge QAMs providing a new level of economics, old methods, such as QAM striping, are no longer viable, according to Holobinko.

Points to ponder on the IP migration path
When it comes to IP video migration, there’s no one-size-fits-all for cable operators, but there are plenty of options to consider. The Expo workshop “Great ways to migrate: Making the move to all-IP video” laid out some of those options for cable operators. Tom Gonder, Time Warner Cable’s chief architect, focused on three migration options for linear TV, which were hybrid set-top boxes with downloadable security, hybrid home gateways and multicast-to-HTTP conversion at the cable modem.

“The point is there’s no clear standout winner amongst the three,” he said. “What it comes down to is how fast do you want to go? No one is anxious to make the wrong move. Operators have different starting points. Some have SDV (switched digital video), some have DTAs (digital terminal adapters), so where they stand today on how they manage their spectrum is significant.

“Easy, gradual migration is the key, and pay close attention to your viewership.”

Holobinko highlighted the advantages and disadvantages of using multicast or unicast streams. Accounting for which shows customers will view the most is hard to do based on one-time events, such as the Super Bowl, or a reoccurring event, such as “America’s Got Talent.”

Holobinko said a hybrid unicast/multicast implementation looks to be the best option, because it is consistent with the IP video vision of supporting multi-screen experiences and personalization of services; it makes efficient use of bandwidth because high-speed data and unicast ABR efficiently share bandwidth; and it enables rapid deployment across legacy DOCSIS 3.0 modems – down to four channels, without truck rolls.

Customers can also hook up IP devices directly via a wireless router because they are unicast, while IP set-top boxes can be linked via Ethernet cable.

Rounding out the panel, Arris’ Charles Cheevers, chief technology officer for CPE solutions, touted the benefits of combining the faster DOCSIS networks – which are expected to scale to 1 Gbps, and even 10 Gbps – and cloud-based services. Home gateways with 1 Gbps of wide area network capability are a customer premises equipment platform with a shelf life of well into 10 years, according to Cheevers.

In the meantime, IP video transition plans have to support some type of interim augmentation strategy for the legacy devices before going to a full-service gateway. Some cable operators may opt for a standalone transcoding device in the home for the customers that don’t want the full-service gateway.

While there are various home networking options floating about, Cheevers said the first MoCA-based mini gateways, which cost less because they don’t have CableCards, could connect to Smart TVs and IP set-top boxes before the full-service gateways are deployed.

With CCAP, cable operators will be able to deliver the 1 Gbps network that will connect home networks to the cloud and enable HTML5 for better user experiences and interfaces, Cheevers said.

“The new weapon is faster speed on the IP network, and gateways with more memory can improve efficiencies of service delivery,” Cheevers said.

Small ops, women in technology panels
The SCTE had a strong lineup of opening day keynotes and panels at this year’s Expo, including the “Women in Technology Panel” and the “Mid-size insights: Challenges faced by Tier 2 and 3 cable operators – CTO Panel.”

Women in Technology Panel

During the “Women in Technology Panel,” Cablevision’s Yvette Kanouff, executive vice president of engineering and technology, spoke about her company’s recent launch of its Onyx user interface, which is known to consumers as the Optimum Program Guide. Before launching the guide to set-top boxes, Cablevision rolled Onyx out on iPhones, Macs, PCs and the Kindle Fire. Kanouff said the advanced interactive user guide gave Cablevision’s subscribers the same look and feel across multiple platforms.

Kanouff also said that Cablevision, which is already a big proponent of cloud-based services, plans to launch more cloud-based features and services next year.

Charlotte Field, senior vice president of infrastructure and operations at Comcast Cable, said her company’s new guides have also been well-received, but the cable industry needs to have a much quicker development cycle.

“We can’t wait two years for a guide change,” she said. “We’re doing that not because of the traditional competition, but because we want to be like the next Apple. We have to make sure our customers get content anywhere on any device.”

The small cable ops panel delved into the successes and frustrations of not being Comcastic. On the cutting-edge side, Armstrong Group of Companies CTO Mike Giobbi said his company kicked the tires in rural areas of Pennsylvania with a fiber-to-the-home service in 2006.

Being a smaller cable operator also means being more inventive, and on that note, Buckeye CableSystem CTO Joe Jensen said his company came up with a toolkit for the technicians that were doing the home networking installs.

Massillon Cable technical operations manager and general manager Kelly Rehm said his company has a project in place next year to go to 85 MHz on the upstream return path, which will be one of the first forays into the 85 MHz mid-split range.

Next up
While the warm 80-degree days of Orlando are turning into a distant memory, the foundation for DOCSIS 3.1 was laid at this year’s Expo. The SCTE’s Cable-Tec Expo 2013 will take place Sept. 18-20 at the Ernest N. Morial Convention Center in New Orleans. Kevin Hart, executive vice president and CTO of Cox Communications, will serve as Program Committee chairman for next year’s event.

Cable’s backup plan might include Stirling engines
Deka Research's Stirling engineCould the Stirling engine, a 200-year-old technological curiosity, be a timely solution to the cable industry’s power backup concerns? Dean Kamen, inventor of the Segway, thinks it can, and Mike LaJoie, CTO of Time Warner Cable, is giving Kamen a shot to prove it.

The Stirling engine, conceived in 1816, is in essence a heat engine operating by cyclic compression. Though Stirling engines have been successfully used, successful commercial implementations are rare.

They have several drawbacks, most notably a practical limitation on how big they can be in terms of energy output. Furthermore, in most circumstances, energy from Stirling engines will be far more expensive than energy from almost every other extant power generation system.

On the positive side, Stirling engines are highly efficient generators and can be run not only with any energy source, but they can be run with different energy sources changed on the fly – kerosene, diesel, alcohol … it doesn’t matter – Kamen noted, because it relies on external combustion. They are quiet, and they can run anywhere.

And unlike almost every other power generator, Stirling engines can be run continuously for long periods – possibly even years – with minimal wear. Kamen is fond of comparing the Stirling engine to another heat-exchange device: the refrigerator. The Stirling engine, he said, is like a refrigerator running backwards, and think about how long refrigerators last.

Kamen is wiry and wired, alert with an enthusiasm that never flags, even when he dives into the details of his Stirling engine design. It has no pistons, and therefore no seals, which means they lack the single most common point of failure of most other Stirling engines. Kamen’s acts as a brushless DC motor, with wires the only thing inserted in the cylinder chamber to draw off the electricity generated, he explained to a group of journalists after his keynote at Expo.

But in order to make it all practical, he and his company, Deka Research, need economies of scale. Kamen said it costs about $250,000 to build one generator today, essentially on a custom basis; he thinks that with volume, they could be made for as little as $10,000 each.

So Kamen is looking for an application where the advantages of his Stirling engines can be exploited and the disadvantages do not apply. And that’s where the cable industry might – might – come in. The industry might represent a total of 1,400 hubs and more than 100,000 nodes that all need backup power, LaJoie noted. Most of them sit idle 90 percent of the time. What if those generators were replaced with Kamen’s 10 kW Stirling engines?

A cable operator could run the generator on whatever fuel is the cheapest available at the time. Furthermore, they don’t rely in any way upon the grid; they will be absolutely reliable in a power outage, as long as the fuel holds out. And remember: It can run on any fuel, even alcohol.

The U.S. utility industry is talking about building more than 100 new power plants in the next 10 years, each at the approximate cost of $100 million. What if cable operators volunteered to run their Stirling engine “backup” generators to help satisfy peak power demand, thereby alleviating new energy plant requirements?

“We are constantly dealing with the problem of backup energy,” LaJoie said. “Dean has a system, and if it has downstream benefits? I’m thrilled. How are we going to use it? I don’t know yet. But we have his guys and our guys crawling all over the plant to see if we can find a way to make it work.”

Advertisement

Share This Story

X
You may login with either your assigned username or your e-mail address.
The password field is case sensitive.
Loading