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 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

“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

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

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