Chipping Away at Cable Bandwidth Crunch

How to get rid of those pesky, bandwidth-hogging analog channels?

Silicon Valley startup BroadLogic Network Technologies claims it has developed a chip to answer the riddle that has vexed cable operators for years. With a new “headend on a chip,'' the company claims that operators can eliminate the need to broadcast analog signals in their networks.

Under this approach, all programming would be carried over the cable network digitally, which makes it possible to pack more channels into available bandwidth.

The two-inch-square TeraPix chip would then convert 80 channels of programming coming in as an MPEG-2 digital stream into analog format.

The startup's pitch: A cable operator would install small gateway devices with the Tera-Pix processor at subscribers' homes, either inside a house or bolted onto the outside.

That would allow operators to shut off the analog signal across an entire node, freeing up a vast tract of spectrum — between 450 and 500 Megahertz, according to BroadLogic—that could be used for other purposes, such as expanding data or voice services, high-definition channels or video-on-demand services.

Delivering analog channels digitally over a hybrid-fiber coaxial network is far more efficient. In a digital-cable transmission, about 10 analog channels can be squeezed into a 6-MHz band. An analog signal requires 6 MHz for each channel.

Could this be a silver bullet for operators? “They've found a way to recover massive quantities of spectrum with a cost-effective approach that allows us to transition to an all-digital network,” said Wayne Davis, the former chief technical officer at Charter Communications. He's a technical consultant to BroadLogic, and said he has received some equity in the company in exchange for services.

BroadLogic demonstrated the chip privately at the CableLabs summer camp in Keystone, Colo., in August, to some operators and equipment makers. But it hasn't been deployed in a real cable network.

“The approach is unproven in the field,” said Michael Wolf, a research director at consumer-electronics analyst firm ABI Research. “Much of the cost saving and the actual real-world performance has yet to be proven in a scaled deployment.”

The San Jose, Calif.-based company also doesn't have any announced customers for the TeraPix yet. Jeff Huppertz, BroadLogic's vice president of marketing and business development, said the company is working with major operators with field trials expected in the second half of 2007 and commercial deployments slated for 2008.


So if this is such a great idea, why hasn't anyone put a digital-to-analog converter at the home before?

It's been too expensive to assemble all the pieces necessary to do that using off-the-shelf equipment, according to Huppertz. Now, by performing those functions in a single piece of silicon, TeraPix provides lower-cost, more reliable video conversion in the field, he said.

“It does what used to take a whole headend to do, in a single chip,” Huppertz said.

Obviously, it can't do everything a headend does. But the TeraPix BL80000, which is an application-specific integrated circuit, provides several advanced features in a palm-sized package. It can process a 600 Megabit-per-second MPEG-2 stream, or the equivalent of an 80-channel analog lineup, into National Television Standards Committee (NTSC) analog video.

TeraPix can also pass through the rest of the digital signal, for subscribers with a digital set-top box. “We have to be able to allow the HD box to access the digital signal,” Huppertz said. The chip is able to selectively take up to 16 slices of bandwidth technically known as quadrature amplitude modulation (QAM) signals and remap them to different frequencies “without adulterating the QAMs themselves.”

One alternative cable operators have to get to an all-digital cable network is to roll out digital set-top boxes across an entire service area. But cable operators don't necessarily know how many TVs are connected to the analog network. At $150 per box, “the operational implications of putting a digital set-top box on every outlet will scare you,” said Davis, Charter's ex-CTO.

Plus, the digital-tier-or-nothing proposition introduces the risk that subscribers will defect. “Going to all digital set-tops is very subscriber-unfriendly,” Huppertz noted.


It's uncertain what the actual price tag will be for deploying TeraPix devices. BroadLogic is selling sample chips at $300 apiece, and Huppertz said an integrated gateway device would be roughly “the cost of one to two set-top boxes.”

But that doesn't address deployment costs. A truck roll would be necessary at every home where an operator wanted to continue to provide analog service. In addition, a device with a TeraPix chip would need power; Huppertz said that an operator could power it by sending direct current over the coax.

All things considered, though, Huppertz claimed the TeraPix approach would still be cheaper than trying to switch every subscriber to a digital set-top. “I don't mean to minimize the challenges,” he said. “But if you're talking about multiplying set-tops by six times your existing installed base, that's a substantial cost for the operators.”

BroadLogic, with 30 employees, has received $32 million in two rounds of funding from Cisco Systems, Intel, Time Warner and several venture-capital firms. Mike Hayashi, Time Warner Cable's senior vice president of advanced engineering, sits on BroadLogic's board.

One other detail of note: BroadLogic on Oct. 10 appointed a new president and CEO, Danial Faizullabhoy, a partner with venture-capital firm Walden International, which is one of the company's investors. Faizullabhoy replaced previous CEO Tony Francesca.

Asked why Francesca left the company, Faizullabhoy responded, “I think the board really wanted me to come on board and increase the volume, and the commercialization of the TeraPix product line.”