IEEE Meeting Ends Again Without Decision on 802.11g

By Bob Liu

July 13, 2001

Modulation proponents believe OFDM will become the standard for 802.11g by September when IEEE reconvenes in Seattle.

For a second straight time, the Institute of Electrical and Electronics Engineers (IEEE) has held off on determining the technological standard to extract data and deliver it wirelessly through the unlicensed airwaves of the 2.4 GHz spectrum at rates of 20+ megabits per second (Mbps), prolonging the rollout of all chipsets for next-generation 802.11g wireless LAN (WLAN) products.

However, after weeklong meetings in Portland, Ore., that were described as "at times very contentious," the .11g Task Group of the IEEE's 802.11 Working Group has laid the foundation for the IEEE to ratify Intersil's Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme at its next regularly scheduled meetings in September, which will take place in Seattle.

Analysts concur that while the latest decision does translate to a longer wait before next-generation product comes to market, it still validates the nascent 802.11 WLAN industry by providing a blueprint to IT managers who will eventually need to upgrade wireless networks. Currently, 802.11b -- which is based on a modulation scheme known as Complementary Code Keying (CCK) -- transmits data through the 2.4 spectrum at 11 Mbps, although actual demonstrations a few weeks ago at the TechXNY trade show in New York only exhibited data rates of 1 Mbps at best.

"It's important for enterprise customers to see a technology roadmap. They want to see that the technology won't die out," said Greg Collins, a director at Dell'Oro Group, a Redwood City, Calif.-based market research firm. Recent history.

The Portland meeting was the first time that IEEE members discussed the 802.11g specification since a ran corous debate during the May meeting in Orlando, Fla. At that time, Intersil's OFDM modulation scheme beat out Texas Instruments' spec, known as Packet Binary Convolution Coding (PBCC) technology. But support for Intersil's technology failed to reached the 75-percent ratification threshold and a subsequent bipartisan debate erupted on how to proceed with voting.

"We're really pleased to see they've gotten through the political nonsense," said Chris Henningsen, vice president of marketing at Irvine, Calif.-based Intersil.

On Thursday, the Task Group reached a compromise that, as Intersil indicates, offers very favorable terms for confirmation. Come September, the group would vote on the Intersil proposal in multiple rounds eliminating one dissenting opinion after another until the 75 percent threshold was reached.

"We certainly believe in the September meeting it will go through the rounds of meetings and finally achieve the 75 percent threshold," Intersil spokesman John Allen told InternetNews.com.

Take the 802.11a Train
Intersil previous stated it could supply chipsets operating at 36 Mbps by the fourth quarter and ramp up to the 54 Mbps by the second quarter of 2002. The company's rollout plans won't be affected by the ratification delay, Henningsen said in a telephone interview.

Even though industry participants are forging with their rollout plans, many industry observers still maintain the notion that .11g is merely a migration path toward the ultimate goal of wireless connectivity via 802.11a -- data transmission at 54 Mbps in the uncluttered 5 GHz spectrum as opposed to the 2.4 GHz spectrum which is filled with microwave signals that may interfere with data transmissions.

"I think the industry right now is trying to grapple with [the questions of] how significant is the .11g vote and how it will affect migration to .11a. In general, the industry consensus continues to hold that .11a represents the long-term future of wireless LAN. The question is: is .11g going to represent a pitstop on the way to that future or a longer resting place?" said Navin Sabharwal, vice president of residential and networking technologies at Allied Business Intelligence (ABI), an Oyster Bay, NY-based think tank.

"Over time, everything will migrate to [802.11]a," Collins concurred.

But what prevents a direct migration to 802.11a from the current 802.11b standard isn't simply an increase in data rates but the adoption of a modulation scheme. As it was originally approved by the IEEE in 1999, 802.11b supported CCK and Texas Instrument's PBCC, which was later was added as an alternative. In fact, that was the entire argument behind TI's push for PBCC at the higher data rates of 802.11g -- backwards compatibility with 802.11b.

But at around the time of the last IEEE meeting in May, the FCC issued an unusual (and, to many, surprising) mandate, allowing for new wave forms to increase data transmission rates in the 2.4 GHz spectrum. The news greatly undercut TI's argument for PBCC and opened the door for Intersil because, prior to the FCC ruling, OFDM had no precedence in that part of the spectrum. OFDM, though, is widely used in the 5 GHz space.

"Essentially what Intersil and other OFDM proponents are arguing is regardless of what happens with the .11g vote, OFDM technology makes too much sense to not play in the 2.4 GHz band. The question is: will OFDM be a proprietary extension to 802.11b or will it be a standardized .11g standard?" Sabharwal explained.

However, TI officials believe that type of zeal for OFDM in the end won't be good for consumers because it focuses on the technology of tomorrow rather than what is available today. Since that ruling, TI has char ged full-speed ahead with its rollout of products to support the 802.11b standard and has applied to increase PBCC's data rates. It also has ongoing development efforts using OFDM in the 5 GHz space.

"Making the choice of modulation is exactly the kind of thing that the customer doesn't cares about. What's important is your ability to ship ever-better product to an ever-hungrier customer base," said Mike Hogan, general manager of TI's Wireless Networking Business Unit.

"Hanging too much on [OFDM] too early doesn't help anything. The reason we like PBCC is we have it now. Customers are already using it. It's like letting your technical side get ahead of your marketing side."



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