🚀 go-pugleaf

On Tue, 25 Oct 2005 15:28:17 -0300, Derek Broughton
<news@pointerstop.ca> wrote:

>Jeff Liebermann wrote:
>
>> However, 
>> relocating the backhauls to 22Ghz may be a bit of a challenge.
>> considering the mesh network rule of thumb of the week of no more than
>> 3-4 hops from client to backhaul, and 100 access points per square
>> mile, that means 25-33 backhaul radios or wired connections per square
>> mile.

>I haven't really followed this discussion, and I don't know any of the
>technicalities, but surely that's more like 9 - if you've got your 100 APs
>lined up on a grid 0.1 miles apart, then you would only need your
>backhaul's to be every 0.3 to 0.4 miles, so placing them 1/3 mile apart
>should do it.

Well, I screwed up by a factor of two, by mixing radius and diameter.

The 3-4 hop assumption I made was that a mesh network client (user)
radio should not need to endure more than 3-4 store and forward hops
before hitting a backhaul to the internet.  To keep the hop count down
to 3 hops, the effective radius of coverage simply increases by a
factor of 3.  Therefore, the original 300ft radius becomes 900ft.  

Now, visualize an array of 1800ft diameter circles (cells) fitting
into a 1 mile square (5280ft on a side).  That would be about 3
circles on a side or 9 circles.  Inside each cell would need to be a
wired access point or the hop count will exceed 3.

That's still not quite right because the enlarged 1800ft diameter
cells have considerable dead area between diagonal circles.  So, they
have to be a bit smaller with some overlap to compensate for this dead
area.  My guess(tm) is about 700ft radius or 1400ft diameter.  That's
about 4 cells on a side or a total of 16 wired access points.

However, that's still not correct.  I'm assuming a cartesian 3x3 array
with a not very tight packing factor.  If the circles were arranged
for optimum packing factor (similar to the hexagonal cellular
arrangement), the number of 1800ft circles can be done with about 12
circles (including combined parts of cells).

Thanks for the correction.
(Grumble...Gone sulking.)

-- 
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558