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Unicast Universe

Harmonic outlined a future “video-aware router” that would enhance traditional cable radio-frequency equipment to more efficiently deliver dozens of unicast video and data streams to subscribers.

Harmonic's concept of a “HectoQAM” — still at least two years away from being a real product — would deliver the equivalent of 100 quadrature amplitude modulators (QAMs) over a single port. In a cable system, one 6-Megahertz QAM can deliver, for example, a single analog-TV signal or between 10 and 15 standard-definition digital channels.

In essence, the device would move the infrastructure necessary to combine digital services from the RF network, where it exists today, to an Internet Protocol network instead. The company presented the HectoQAM concept here at the Society of Cable Telecommunications Engineers' Conference on Emerging Technologies last week.

The HectoQAM is intended to prepare the way for the rapid growth expected for unicast services, such as video-on-demand and high-speed data, said Gil Katz, Harmonic's director of cable solutions and strategy.

“Adding more QAMs in the traditional architecture adds more cables, and it's just impossible to manage,” he said.

HectoQAM “collapses the combining network into one device … so you combine it in the IP domain before it's sent over RF,” Katz added. In this setup, analog TV channels would continue to be combined in the RF network.

The device can be thought of as “the ultimate edge QAM,” said Scopus Video Networks chief technology officer Adi Bonen, who coauthored the HectoQAM paper with Katz.

The HectoQAM is like current edge QAM devices, but would be designed to take advantage of very fast digital-to-analog converters (DACs), specialized processors that can handle various tasks in delivering services over RF.

Hypothetically, it could deliver any unicast stream to any subscriber, such as targeted advertising or network-based digital video recording services.

“If you want to repurpose, say, a broadcast QAM today, what you need to do is install new hardware,” Bonen said. “With HectoQAM, everything is already there — you just send a command and reconfigure the QAM.”

Harmonic is targeting 2010 or 2011 for delivery of a HectoQAM product, Katz said, with pricing aimed at $4,000 per port. Each port would be dedicated to a cable service group.

“It's not the price per QAM that's important anymore. It's the cost per port,” he said.

The HectoQAM would provide built-in redundancy features, so that a port failure wouldn't cause an entire neighborhood to lose access to services, Katz noted.

The company's design goal is to ensure the space required by HectoQAM servers is equivalent to the QAM infrastructure needed for video-on-demand and switched digital video today, while delivering more capacity, Katz said. A HectoQAM server could deliver up to eight ports per rack unit, or the equivalent of 800 QAMs, he said.

Also at the SCTE conference, Harmonic demonstrated “Gator,” a video-on-demand aggregation system that can deliver traditional VOD assets as well as Web video.

The Gator server (the name implies “aggregator” and “navigator”), delivers an interactive video guide composited by a headend server for accessing short clips or full-length titles without having to access a back-office VOD system.