IP: Is Wi-Fi Getting Too Crowded?

[Dave Farber <dave@farber.net>]

------ Forwarded Message
From: Dewayne Hendricks <dewayne@warpspeed.com>

[Note:  This week reader Tim Pozar gets the same treatment from the
same reporter who did an article for '802.11-Planet' on me last week.
<g>  DLH]

Is Wi-Fi Getting Too Crowded?
By Ed Sutherland
<http://www.80211-planet.com/columns/article/0,4000,1781_1122641,00.html>

Breaker breaker, good buddy. Remember the CB radio -- one of the
preeminent fads of the 1970s and 1980s? The communication method of
choice for gear-grinders and grandmas may be heading for an update.
802.11b "will end up being the Citizens Band of this era," according
to Bay Area Wireless Users Group. Such ubiquity may not be all good,
however.

Tim Pozar, spokesman for the San Francisco-based wireless group, says
that an influx of myriad wireless makes the unlicensed 2.4GHz
spectrum "certainly more unusable."

While the most notable resident of 2.4GHz is wireless networks, the
bandwidth is also home to millions of devices ranging from magnetic
resonance instruments (MRIs) to microwave ovens. Pozar says 802.11b
is also used by cordless phones, home spy cameras -- even industrial
paint driers.

"Already many licensed users, such as the microwave video
transmission links, that share the band with 802.11b, are finding the
band too crowded and are moving off," Pozar says.

A Federal Communications Commission (FCC) spectrum advisory group
plans to recommend opening the 2.4 GHz to less interference-prone
devices. The move was prompted by complaints from licensed amateur
radio users reporting Wi-Fi gadgets interrupting the increasing
number of amateur television broadcasts.

"The aggregate noise levels of what the FCC calls 'intentional and
unintentional radiators' will increase on the 2.4 GHz [wavelength],"
Pozar says.

Also a potential threat to any harmony within the 2.4GHz band is
Bluetooth, the short-range personal area network technology. Industry
market research firm In-Stat/MDR expects 644 million Bluetooth
devices will be in use by 2006. Pozar believes Bluetooth's use of
Frequency Hopping Spread Spectrum (FHSS) transmission technology may
be a larger problem than 802.11b.

FHSS "hops" a signal over more than 75 frequencies. By permitting
only devices transmitting at the same time over the same frequency,
interference is reduced. Wi-Fi, on the other hand, employing Direct
Sequence Spread Spectrum (DSSS), divides data transmitted while
duplicating the bits of information, allowing a signal to survive
interference.

"Many features that would reduce interference, like frequency
coordination and automatic power limits were not built into [Wi-Fi or
FCC regulations]," Pozar says. Even 802.11a, with its more expansive
5.8GHz home does not include the features, according to Pozar.

Allen Nogee, a wireless network analyst at In-Stat/MDR, says 802.11b
has plenty of room. "Because 802.11b has three channels, I really
don't know of many instances where that hasn't been adequate, maybe
outside a few corporate installations with very large networks."

Up the West Coast from Pozar in Portland, Oregon, is the Personal
Telco Project, another community-based public wireless network. Nigel
Ballard, a spokesman for the group, spoke from steamy New Orleans,
where the Cable2002 trade show was taking place.

"Thanks to one of the exhibitors leaving their 802.11b access points
wide open, I'm able to log onto the net and check my e-mail. Gotta
love this technology," Ballard said.

"What's the future?" asked Ballard. "We'll slowly migrate to 802.11g,
but there is a ton of life left in 802.11b."

May 15, 2002


------ End of Forwarded Message

For archives see:
http://www.interesting-people.org/archives/interesting-people/