Vyyo’s wireless upstream traffic gets ‘hexed’

(Telephony) What goes down must come up. In the case of fixed broadband wireless transmission, that is not necessarily an equitable deal--systems using 6 MHz of spectrum downstream often have only 400 to 800 KHz in the upstream band.

To deal with this inequity, Vyyo has introduced a “hex card” that handles multiple upstream signals and increases system capacity without the need to add more chassis to a headend or hub rack.

“You need to aggregate quite a few of those [upstream channels] in order to have some semblance of symmetry,” said Peter Jew, vice president of marketing & business development for ADC’s broadband wireless access business unit.

In a residential high-speed situation with “best effort” delivery, symmetry is a minor distraction. As fixed broadband wireless operators move toward serving business customers and telephony services, upstream speeds become as important as downstream speeds.

To even things out today, wireless providers must aggregate upstream signals one at a time in a hub location, consuming valuable rack space and adding to the overall system cost.

The Vyyo hex card, which ADC is testing as part of its full fixed broadband wireless system, supports six upstream channels. Each channel can be configured independently to support various deployment configurations and channel sizes from 400 KHz to 1.6 MHz, an important consideration in determining what types of services to offer.

“If you’re talking about voice traffic, it’s more symmetrical,” Jew said. “Business traffic may not be totally symmetrical, but it’s more symmetrical than residential traffic.”

The hex card also helps service providers maximize their downstream, Jew continued.

“You broadcast at 6 MHz, but you don’t want to have too many customers, because you don’t have a way to carry more upstream traffic,” he said. “If you know you can add more upstream traffic, you can take advantage of the full downstream traffic.”

ADC is testing the Vyyo hex card as part of its overall system with the intent to release it to its customers “sometime in the second quarter,” Jew said.

“It’s one of these things that does not add a new functionality, but it makes life a lot easier.”