I agree that we don't want to make perfect the enemy of better.
A lot of the issues I'm calling out can be simulated/enhanced with different
power levels.
over wifi distances, I don't think time delays are going to be noticable (we're
talking 10s to low 100s of feet, not miles)
David Lang
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fair enough, but for this "RF emulator device" being able to support
distance matrices, even hollow symmetric ones, is much better than what's
typically done. The variable solid state phase shifters are 0-360 so don't
provide real time delays either.
This is another
symmetry is not always (or usually) true. stations are commonly heard at much
larger distances than they can talk, mobile devices have much less transmit
power (becuase they are operating on batteries) than fixed stations, and when
you adjust the transmit power on a station, you don't adjust
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The distance matrix defines signal attenuations/loss between pairs. It's
straightforward to create a distance matrix that has hidden nodes because
all "signal loss" between pairs is defined. Let's say a 120dB attenuation
path will cause a node to be hidden as an example.
I guess it depends on what you are intending to test. If you are not going to
tinker with any of the over-the-air settings (including the number of packets
transmitted in one aggregate), the details of what happen over the air don't
matter much.
But if you are going to be doing any tinkering
that matrix cannot create asymmetric paths (at least, not unless you are also
tinkering with power settings on the nodes), and will have trouble making hidden
transmitters (station A can hear station B and C but B and C cannot tell the
other exists) as a node can hear that something is
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I found the following talk relevant to distances between all the nodes.
https://www.youtube.com/watch?v=PNoUcQTCxiM
Distance is an abstract idea but applies to energy into a node as well as
phylogenetic trees. It's the same problem, i.e. fitting a distance matrix
using some
These cases are what my student, Fouad Tobagi and I called the Hidden Terminal
Problem (with the Busy Tone solution) back in 1975.
Len
> On Aug 2, 2021, at 4:16 PM, David Lang wrote:
>
> If you are going to setup a test environment for wifi, you need to include
> the ability to make a fe
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We find four nodes, a primary BSS and an adjunct one quite good for lots of
testing. The six nodes allows for a primary BSS and two adjacent ones. We
want to minimize complexity to necessary and sufficient.
The challenge we find is having variability (e.g. montecarlos)
On 8/2/21 4:16 PM, David Lang wrote:
If you are going to setup a test environment for wifi, you need to include the ability to make a fe cases that only happen with RF, not with wired networks and
are commonly overlooked
1. station A can hear station B and C but they cannot hear each other
2.
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That distance matrices manage energy between nodes. The slides show a 5
branch tree to realize 4 nodes (and that distance matrix) and a diagram for
11 degrees of freedom for 6 nodes (3 BSS) The python code will compute the
branch attenuations based on a supplied distance
If you are going to setup a test environment for wifi, you need to include the
ability to make a fe cases that only happen with RF, not with wired networks and
are commonly overlooked
1. station A can hear station B and C but they cannot hear each other
2. station A can hear station B but
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