Wireless networks on verge of makeover

Impostor technology
Much of the controversy surrounds an advance called MIMO, an acronym for "Multiple Input, Multiple Output," which refers to the use of several antennas to improve overall wireless performance. It's a major part of both 802.11n proposals under consideration.

In that definition, multiple antennas and radios are used to send different streams simultaneously on the same data channel. At the receiving end, antennas pick up the signal, which is then deciphered. The result is an increase in range and data rate.

The technology was pioneered by the Palo Alto startup Airgo Networks Inc., which now supplies the chips for the latest equipment from Cisco Systems Inc.'s Linksys division and Belkin Corp., among others.

Airgo's CEO, Greg Raleigh, wrote papers describing it as far back as the mid-1990s while a student at Stanford University. But now, he says other companies are trying to derail his company's momentum and confuse consumers by using MIMO to describe other technologies.

"There's been a lot of impostor technology that's piggybacked on the MIMO bandwagon," he said.

Atheros Communications Inc., a larger maker of wireless networking chips, uses a much broader definition.

"What (MIMO) refers to is any wireless system that has multiple antennas at both ends of the connection," said Craig Barratt, Atheros' chief executive. "The way in which those antennas can be used is quite varied."

Atheros' MIMO, found in some D-Link Corp. gear, extends the range of a wireless signal by transmitting the same stream of data over multiple antennas. Video54's flavor also uses multiple antennas but relies on software to instantly alter their configuration to improve the signal.

Both companies defend their usage of MIMO and bristle at being called impostors.

"Their accusation is so ridiculous that it's not worth even fighting," said Video54 CEO Selina Lo. "MIMO started in the research community way before Greg was even involved."

Video54's first customer is Netgear, which also sells business-class equipment based on Airgo's chip. For consumers, though, it's offering Video54 combined with Atheros chips in a product line it calls RangeMax. One reason: it's cheaper.

Airgo is "very envious of our business with RangeMax," said Vivek Pathela, head of Netgear's consumer product management and marketing. "They're getting furious because they're seeing their costs are so much higher. We can be a lot more competitive."

Airgo's Raleigh points out that RangeMax, in its fastest mode, uses a speed-boosting technology that bonds data channels. By contrast, Airgo's single-channel approach makes more efficient use of the airwaves. As a result, Airgo's "True MIMO" — a term the company has trademarked — won't affect neighbors' networks, said Raleigh.

In any event, Raleigh contends, the debate will quickly become moot. That's because his flavor of MIMO is capable of moving beyond today's theoretical maximum of 108 megabits per second — while "impostors" will be unable to boost their performance any further. (Actual data rates hover just below 50 megabits per second.)

Gartner's Dulaney says most consumers are best served by waiting for 802.11n's official certification.

At that point, gear from different manufacturers will interoperate even in the fastest modes — the ultimate speeds of which might leave today's offerings in the dust.

"It's a good technology, and it will be there in time," he said. "Wait until it settles down. Maybe what you buy today will be deemed in conflict with what eventually gets approved. You might be screwing up your neighbor, who knows? Just wait for a standard to happen."

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