Wireless Routing, Position Inference (was Re: CNN.com - WiFi activists on free Web crusade)

Major Variola (ret) mv at cdc.gov
Mon Dec 2 08:24:03 PST 2002

At 02:57 PM 12/2/02 +0000, Peter Fairbrother wrote:
>What I don't understand is how a node knows the location of a person
>moves about in the first place.
>Also, I don't like the idea that my location is known by the location
of my
>equipment. But I know very little about geographical routing.

I'll bite.  Lets think about fundamentals, and play the adversary game.

If I know that you can receive in *any wireless* system, then I know
something about your location.

This includes nets with huge 'cells', like a 100,000 watt commercial
broadcast station
(are you listening to KFOO or WFOO?),
and nets with smaller cells, like the 'cellular' phones and 802.11foo
meshes.  The
only difference (albeit a significant one) is the size of the cell
---the smaller your cells
the more bits I get about your location.  (Barring cypherpunk jokesters
who make cell calls
from the foci of dishes to hit another base station...)

Of course if you're needing to transmit, you give your location.

If you're needing to receive, and you roam beyond the diameter of a
single 'cell',
you are going to have to transmit your location (think cell phones) for
routing XOR
the system has no routing and must broadcast to all cells (think pagers)
(you might consider the physical
cells merged into a large single virtual cell in this case.).  This
latter doesn't scale.

Got Yagis?

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