[MLB-WIRELESS] 802.11n specifications

[John McClumpha]

taken from: 
http://theage.com.au/articles/2005/06/03/1117568342243.html?oneclick=true


  Confusion over next wi-fi standard

By San Jose, California
June 3, 2005 - 1:47PM

The technology behind wireless data networks in homes and businesses is 
on the verge of a makeover that promises to fix long-standing complaints 
of spotty coverage, flaky connections and inconsistent speeds.

The next generation of Wi-Fi will be so powerful that it is expected to 
be capable of carrying everything from internet phone calls and music to 
high-definition television streams over the airwaves without a hiccup.

The problem is, the standard technically known as 802.11n does not yet 
exist. Not even a draft has been approved.

In fact, the final 802.11n specifications aren't expected to receive an 
official nod until late next year at the earliest.

But that has not stopped the makers of access points, networking cards 
and other wireless gear from launching a parade of products that claim 
the benefits and even the underlying technologies of the 
still-to-be-defined 802.11n.

The situation is setting a new standard for market confusion - even in 
an industry that plasters its boxes with claims of unobtainable speeds, 
fuzzy math and a dizzying collection of acronyms. Some products are 
labeled "Pre N," which some believe might lead consumers to think the 
equipment is upgradeable to actual 802.11n.

"It's misleading the poor consumers," said Ken Dulaney, an analyst at 
the research firm Gartner. "They walk into these technology emporiums 
and they're just snowed under by all this stuff that doesn't mean anything."

Meanwhile, equipment and chip makers are accusing each other of stealing 
names, breaking standards and causing interference with existing Wi-Fi 
networks. The companies also report that rivals' gear doesn't work well 
with equipment based on existing standards - though independent reviews 
indicate interoperability at least in slower modes.

The Wi-Fi Alliance, an industry group that certifies wireless products 
to ensure they work together, refuses to review any products for 802.11n 
inter-operability until there's actually a standard approved by the 
Institute of Electrical and Electronics Engineers.

"We just feel that there are too many moving parts," said Frank Hanzlik, 
the alliance's managing director.

Currently, two draft proposals are battling it out before the IEEE. At a 
meeting last month in Australia, one of the proposals failed to get 
enough votes to become the draft standard.

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 Airgo Networks, which now supplies the 
chips for the latest equipment from Cisco Systems's Linksys division and 
Belkin, among others.

Airgo's chief executive officer, 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, 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 gear, extends the range of a 
wireless signal by transmitting the same stream of data over multiple 
antennas. Video54's flavour 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 chief executive 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 Mr 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 neighbours' networks, said Mr Raleigh.

In any event, he contends, the debate will quickly become moot. That's 
because his flavour 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.)

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

At that point, gear from different manufacturers will inter-operate 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 neighbour, who knows? Just wait for a standard to happen."



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