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IEEE to Determine 802.11g WLAN Specification

The Institute of Electrical and Electronics Engineers (IEEE) on Wednesday will determine key specifications that would essentially double the current data transmission rates over the much-ballyhooed wireless local area network (WLAN) environment, enabling true wire-free multimedia content streaming.

The vote by the IEEE's 802.11 Working Group, which is currently convened in Orlando, Fla., pits Texas Instruments (TI) and its Packet Binary Convolution Coding (PBCC) technology against Intersil's Orthogonal Frequency Division Multiplexing (OFDM) modulation. Both specifications are hoping to gain acceptance as the industry standard to be used on chipsets for all next-generation 802.11g products -- which will transmit data at rates at 20+ megabits per second (Mbps).

"The implications for the industry are significant," said John Allen, spokesman for Irvine, Calif.-based Intersil. "We believe OFDM makes sense because it is the same modulation technique already adopted [for other spectrum space] and it would allow much faster speeds than the PBCC proposal brought forward by TI."

But on the flipside, TI contends that its technology is more compatible with existing standards -- an issue known as backward compatibility. "I certainly hope it all goes our way. It would be great for the market. And we would make it easier for the market to get the technology," TI's Wireless Networking Business General Manager Mike Hogan told InternetNews.com in a telephone interview.

And this time around, industry observers aren't taking comments like these as pure hype. Unlike the promises of next-generation technologies in the cellular spectrum, analysts conceded that Wednesday's vote means a new era of wireless networking in both the home and office and could spell make-or-break for either TI or Intersil.

"Data rates are extremely critical," said Kurt Scherf, vice president of research at Parks Associates, a Dallas-based market research and consulting firm. "As 802 applications move from the office to the home, it means multimedia applications become more realistic for the home."

Parks Associates estimated that, while 5 percent of U.S. households currently have a PC network in place, as many as 15 percent will have one in five years. Of that, wireless networking will account for 40 percent of all those home networks, Scherf said.

"I think [the IEEE decision is] very important. It's surprising to me how little attention it's gotten," said Navin Sabharwal, vice president of residential and networking technologies at Allied Business Intelligence (ABI), an Oyster Bay, NY-based think tank.

The promises and the real world

And just how much does Texas Instruments have invested in tomorrow's vote? TI's Hogan explained, for example, the company last summer spent at least $300 million of its own stock to acquire Alantro Communications, which has done much of the heavy lifting in the PBCC specs' development.

"Our intent would be to support whatever standard is out there, but we would be hard-pressed to come up with a definitive availability date for the other proposal," Hogan added.

One day before the decision, shares of Texas Instruments were at 37.03, up 24 cents, while Intersil's stock was at 30.30, up 30 cents, in Tuesday trading.

Much of the reason for the heightened interest in the IEEE vote is related to the limitations of current 802.11b technology. Since the 802.11b specification was finalized by IEEE in 1999, many networking companies from Intel to Compaq have quickly adopted it -- only to find its theoretical transmission speeds of 11 Mbps a bit of a misnomer. Due to legacy synchronization issues, 802.11b only nets about 7 Mbps of throughput.

"In the real world, it doesn't have the necessary data rate to support a DVD stream or an MPEG stream," Sabharwal said.

About 150 IEEE members will participate in the 802.11g vote. The 802.11 Working Group is also working on other specifications such as .11e (for voice transmission and security) and .11a (which promises data rates of 54 Mbps). But as a result of the non-profit organization's glacial pace of standard adoption only via consensus, no other technologies will make their way to chipsets sooner than 802.11g.

Of course, IEEE's main criterion for evaluating the two 802.11g specifications is a matter of which one will perform better. But IEEE members also must account for the Federal Communications Commission, which governs the spectrum.

"They will look at which one will perform better. But the other thing they look at is which one they think the FCC will be more receptive to," Sabharwal explained.

And to that extent, the FCC has sent very mixed signals.

The politics of spectrum

Every specification must comply with current FCC rules for operating in the unlicensed 2.4GHz spectrum space. As a general condition, devices operating in the unlicensed spectrum may not cause harmful interference with authorized services and must work around any interference that may be received from phones, microwaves or other RF devices.

To operate within the 2.4GHz spectrum, the FCC mandates that a device must operate in one of two ways:

  • Frequency Hopping Spread Spectrum (FHSS) -- transmit bits of data by hopping along various frequencies. These data signals are transmitted and received using the same algorithm, which allows the sender and recepient to follow the signal along the various frequencies.
  • Or Direct Sequence Spread Spectrum (DSSS) -- the data signal is broken up into sequences and transmitted to the receiver, which reassembles the sequences into the data signal.

Neither OFDM or PBCC has won a ringing endorsement from the FCC. But, while the federal agency last week indicated its desire to shift development away from frequency hopping, it also granted waivers to companies (such as Wi-Lan Inc. of Calgary, Canada), which have submitted technologies that don't qualify under the direct sequencing rules.

Meanwhile, TI claims its technology will meet current FCC rules, and analysts such as Sabharwal agree PBCC is closer to the FCC's idea of direct sequencing than OFDM.

"If you look at 11b today, the PBCC proposal just extends that to higher data rates...we're kind of a more pure extension of the current technology," TI's Hogan said.

This takes us back to performance issues such as backward compatibility. Both Sabharwal and TI officials claim that Intersil's OFDM spec is spread further across the spectrum using more of the precious airwaves; hence, it will more likely interfere with other burgeoning specifications such as 802.11b or Bluetooth. Intersil officials weren't available to address these opinions.



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