U.S. airlines, airports battle over Wi-Fi spectrum: (Baz, Blitz)

<< I don't get this. 802.11 interference usually comes from other non 
802.11 sources, like cell phones and
microwave ovens. From my 20 story roof, downtown San Francisco, I can 
see 150+ 802.11 networks.
Never had an interference problem. I assume this is because the CSMA 
collision avoidance spec
works pretty well.>>

I have begun doing some 802.11 interference surveys in public places 
(downtown San Jose and along El Camino in Burlingame so far); in no 
case have I yet found offered loads exceeding about 2% of the channel 
capacity:  that is, there is no interference to speak of coming from 
802.11 networks.   My highest AP count was about 25.  Anecdotal reports 
from my colleagues at Tropos Networks indicate that high-power cordless 
phones are the biggest interference offenders.   However, it is worth 
noting that other published data shows that network speeds do slow down 
when about 7 simultaneous high-rate downloads are proceeding from 1 AP, 
and presumably similar result would be obtained from collocated AP's 
run by differing organizations (since the medium is common):  if the 
airport networks were HEAVILY used they would indeed clash.

The better question to ask is:  why should the Federal government 
regulate what is essentially a local matter?  The property owner, the 
airport authority, should have the right to specify what sort of 
equipment and activities are permitted on the airport, subject to 
contractual obligations to their tenants.  If they are being 
unreasonably avaricious (as seems to be the case here), it is something 
to be taken up with the local political establishment, since airports 
are usually run by a port authority or related local jurisdiction.  The 
folks who use the airport ought to be making the call about the 
benefits of additional revenues vs. the risks of losing service, rather 
than the FCC.  This is actually an issue of some importance in the long 
run:  the FCC and other regulatory agencies were born out of an 
environment in which most communications were very long-wave and 
high-power, with huge ranges so that interference was an inevitable 
issue and regulation needed to span borders.  It is much less clear 
that such as assumption is valid for current and future short-range, 
low-power emitters, but if we can't develop alternative mechanisms to 
deal with disputes like this one, we might be stuck with the 
inefficient, awkward centralized regulatory model we use today.

Daniel M. Dobkin
Enigmatics
1-408-314-2769
[email protected]

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