ORLANDO, Fla. -- Although an expanding menu of high-definition television (HDTV) channels will certainly tax cable's bandwidth capacity, operators must also search for and find extra room to accommodate the coming digital TV transition, set to happen Feb. 17, 2009.

That is just one of several bandwidth-eaters on the horizon for cable operators, one that served as a prime topic for discussion today during the CTO panel at the Society of Cable Telecommunications Engineers (SCTE) Cable-Tec Expo.

"The [bandwidth] challenge has gotten more difficult with the stroke of the pen," said Time Warner Cable Inc. (NYSE: TWC) chief technology officer Mike LaJoie, referring to the government-mandated transition deadline.

Operators are faced with the challenge of finding room for dual must-carry (accommodating both digital and analog channels), and perhaps a "triple-cast" if required to carry those signals as well as a high-definition feed.

MSOs, LaJoie suggested, should already be determining how many off-airs there are in a given market, figure out what the broadcasters intend to do, and then take steps that enable cable operators to free up the necessary bandwidth to accommodate it all.

One component of that strategy is switched digital video (SDV), a technique that streams a linear video channel only when a customer in a given service group selects it for viewing. As one of SDV's champions, Time Warner Cable has previously said it plans to introduce the technology in half its systems by year-end.

"Broadcast is inefficient," LaJoie said. "Once you switch, bandwidth isn't an issue."

Ran Oz, the chief technology officer and founder of BigBand Networks Inc. (Nasdaq: BBND), a pioneering supplier of switched video technology, said his company has deployed the technology with three cable MSOs to a total of about 7 million homes passed. BigBand has disclosed Cablevision Systems Corp. (NYSE: CVC) as one of those customers. Time Warner Cable and Cox Communications Inc. are likely the other two.

"We've bought into [SDV] as part of our solution" to manage bandwidth, acknowledged John Schanz, the executive vice president of national engineering and technical operations for Comcast Corp. (Nasdaq: CMCSA, CMCSK), which is testing the technique in two markets: Cherry Hill, N.J., and Denver. (See Comcast Puts SDV Vendors to the Test.)

Comcast, he added, is also preparing for February 2009 with a "modest" reclamation of analog spectrum, advanced multiplexing capabilities, and sharing capacity among QAM modulators. (See Going 'Mostly' Digital .)

Although Suddenlink Communications, an MSO with about 1.4 million subscribers, is still integrating systems, completing upgrades, and segmenting nodes to address and boost capacity needs, the operator is also contemplating the introduction of SDV "in some or many" of its markets later this year, according to senior vice president and CTO Terry Cordova.

LaJoie also addressed the high-level question that continues to tail MSOs: Do cable operators have spectrum problems?

"The answer is always, 'No, we don't,' " he said, adding that capacity can be added to hybrid fiber/coax (HFC) networks as needed.

"The challenge is anticipating when you need to spend the money."

— Jeff Baumgartner, Site Editor, Cable Digital News