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Squeezing new gear into existing headends

Tue, 08/31/1999 - 8:00pm
Craig Kuhl, Contributing Editor

Space may not be the cable industry's final frontier, but for operators trying to find more of it for their headend equipment, it's close.

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Overhead ladder racking

The advent of advanced services and technologies, including network monitoring, high-speed data, Internet access and more, is bringing with it on-going challenges to cable operators to squeeze more hardware and sophisticated components into an already shrinking headend space.

Add to the mix network lasers, digital equipment and IP telephony paraphernalia yet to be determined, and the average size of today's headend soars to nearly 6,000 square feet, with some reaching 10,000. Just a few years ago, a 200-square-foot headend was the norm. With the average cost of a headend today at about $2.5 million for the structure or facility, and $1 million for electronic equipment, the trend is toward "superheadends" which can reduce the need, and cost, for smaller remote sites.

Yet many operators are getting smarter about the efficient use of existing headend space, and requiring their vendors to focus on the shrinking space issue as early as the research and development stage of headend components. "We're making equipment smaller, but there are certain limitations on how tightly you can pack some boards. You can only get so small," says Clayton Dore, VP of sales and marketing for Digitrans, a provider of digital equipment for headend and satellite receivers. "We have to keep pace with rapidly-changing markets, however. And there's definitely a headend space issue in terms of dollar-saving packages and space."

Dore notes that his company's DTE-7100 IRD (Integrated Receiver Descram-bler), which costs about $1,800, is only 1.75 inches high, but the next generation DTE will be half that size. "Operators will be able to fit eight units in five inches of vertical rack space. The trend is toward vertical rack-mounted systems, which makes it very challenging to reduce the size and packaging of technology," he says.

Packaging digital and CMTS (cable modem termination system) equipment is adding to the space crunch, according to Dean Rockwell, director and general manager of headend systems for Scientific-Atlanta (S-A).

"It's a real issue because of the cost of construction and buildings," Rockwell says. "The trend will be for services to be centralized at one superheadend, and pushed out to the hubs, like video file servers, CMTS and cable modem equipment."

S-A is developing its "Quad Qam" four-pack of QAM modulators for its Explorer 2000 platform, Rockwell adds, which is designed to reduce headend space. And, its Continuum headend system reduces the typical rack space requirements by more than 50 percent, with a chassis five rack units high, holding up to eight application modules and one controller, enabling 40 mono or 20 stereo channels per pack, according to S-A. "We are very sensitive to space efficiency in our design of headend equipment like Continuum and our next-generation RF Signal Manager," he notes. Squeezing new digital and telephony equipment into a shrinking headend space adds to the challenge. "With advanced equipment like CMTSs and HDTs (host digital terminals), there's lots of processing in them," says Keith Kreager, vice president of technical operations for Antec Corp., a manufacturer of laser transmitters, receivers, optical nodes and other headend equipment.

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S-A's Continuum

Some operators, Kreager says, are now housing their remote headend equipment in underground Controlled Environmental Vaults (CEVs), which range from 10 to 24 feet long and house up to 20 racks of equipment. "They're the same as a hub site and can house expensive, sophisticated equipment," he notes.

Even though smaller continues to be better for cable operators, Kreager cautions, there's bound to be a point of diminishing returns. "Our LaserLink chassis has been out there for seven years in embedded bases. Now, we can get 14 return receivers in a space designed for seven. But even with laser technology, diodes can only get so small, and fans will be needed to cool new telephony equipment. Space will always need to be planned for carefully."

A growing number of cable operators are now acknowledging that reducing the size of headend equipment can only get them so far. Planning for headend expansion—from floor to ceiling—is a 21st century attitude which more operators are displaying.

"Taller racks aren't working for operators, so the best thing is to plan your engineering, and plan every rack," suggests John Coons, senior director of real estate and construction management for Jones Intercable/Comcast. "Figuring out signal flow and determining the number of racks and the growth factors are extremely important in reducing headend space." Coons recalls a recent headend project at Jones' Alexandria, Va. system as a case-in-point. "We recommended a 3,000-square-foot headend, and they thought we were nuts. Two years later, it was too small," Coons says.

The key to efficient use of headend space, Coons insists, lies in the design and planning stage. "From a physical design standpoint, it's like a sandwich. First the underfloor, then floor, then racks, lighting, fire protection. You have to marry all of those levels together, because when you lay out a headend, you always need more vertical space."

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Digitrans' DTE-7100

Building an efficient, space-saving headend in a sequential manner sounds simple, Coons notes, but there are caveats. "Headends must have room for duct work and efficient distribution of air, because there is lots of conduit from fiber, telephone equipment, satellite dishes and nodes. And all of these components must stay dry," he says.

And each additional headend component fills space, and adds expense. "It costs around $250 per square foot for a headend, so it takes a concert of architects and engineers—mechanical, electrical, structural and construction—to make a team. The bottom line is in planning and design. It means a functional headend down the line. If not, you'll have problems," Coon says.

Engineering those potential problems out of the design upfront can eliminate more headaches down the road, says Tom Osterman, president of Comm/Net Systems Inc., a Seattle-based communications power systems integrator and engineering firm. "Our customers want more integrated, managed packages. But they must be heavily engineered upfront because of the expense and complexity, not just piecemeal. The new facilities are a combination superheadend, telephony central office and computer/data center." And while additional services may be presenting new revenue opportunities for cable operators, they're also presenting powering and reliability challenges. With the need for more power, how does a cable operator wedge sizable, and growing, power units, air conditioning units and generators close to the headend?

Comm/Net, Osterman admits, is routinely asked that question by cable operators. "Because of the added services like telephony, data and digital, power requirements (equate to) significantly larger units and batteries for backup time, and those take up space. Then there are air conditioning systems and generators that are requiring more power. It's like a snowball effect," he says.

Once telephony, digital and related services are deployed, operators must not only consider space issues, but protecting expensive and sensitive equipment required for unfamiliar services such as IP telephony and others.

"The trend toward consolidation of space and the need for power to protect expensive, sophisticated new headend equipment is to prioritize the protection," says Eric Wentz, director of marketing for Alpha Technologies, a manufacturer of powering solutions for voice, video and data communications systems.

"Headend equipment can be protected selectively or facility-wide," Wentz says. "We obviously recommend facility-wide because you don't want a loss of data or service. In any case, the level of power protection is through the roof."

And raising the roof may be the most efficient space-saving idea yet. Says Dore: "When Discovery Channel calls and says it's changing to digital, you can put the same amount of digital equipment in the same amount of rack space. But when you have 60 channels, that can get very tall."

Whether through the roof, or under the floor, headends will continue to eat up space as they expand to carry new services. And with that expansion, expensive, sensitive and sophisticated equipment and hardware will follow.

Just where a cable operator puts it all, and how space-efficient a headend can be, industry experts say, will depend on good planning and design. Concludes Rockwell: "We'll push the limits in space efficiency. But if there's another space crunch, we'll just need more room."

E-mail: cakuhl@compuserve.com

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