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Thanks for the intro.
First, let me say, when
I submitted a proposal
for to talk here, I didn't expect
to be put into a room with
with such a big audience in front of me.
Uh, yeah.
Anyway, now I'm here.
And first of all,
this is not a talk address to
open up to developers.
So the technical level is
it's really on a more abstract
and almost sometimes philosophical
level here.
But I thought about it and
I really I
made the decision that this is the this
is the most important point I want to
get across here to you
and.
And.
I think I'm preaching to the choir here
in when I say that
we are all interested to
keep developing technologies,
communication technologies.
That allow us to communicate more
directly and more authentically.
So we need more of
the things on the right side and
less dependency on the thing on the
infrastructure. It looks like on the
left side here.
Problem is, for example,
wireless mesh networks where this is very
easy to do or we will see
it's an interference limit
problem that we run into quite fast.
So it's not
the performance of the network is not
dependent on.
Creating distances that are small enough
to get at least some
signal to the receiver, it's more or less
the interdependencies of
multiple transmissions in a shared
common medium.
And actually, every
wireless network.
Eventually becomes an interference
limited network
with a growing node density.
It's even analogous to society itself,
because right now we are starting to live
in a society that is attention limited,
the relation
attention interference is
pretty strong if you look at it,
obviously, the technology that we like to
use to build measures.
We refer to it as I
believe it's 11 W land, or most
people nowadays, globally, say WI,
although it's a trademark term from
the wi fi alliance.
And the link speeds
that these protocol families
offer are sort of growing
like.
Monotonously, it's really
strange to look at the throughput figures
that some vendors now give in the range
of, I don't know, seven gigabits per
second or something like that, although
the hardware itself starts to look really
ridiculous.
But anyway, this is
the most suitable technology that we now
have.
It's it's becoming, thanks
to Moore's Law, extremely cheap,
extremely powerful.
But it needs one thing to work, which is.
Free channels.
And especially when a gear
is directed toward five gigahertz
usage and if you look, for example,
in North America in
order to get these gigabit speeds,
we must use channel with
in the order of 80 or 160 megahertz
even.
And then we have the same situation that
we know from years ago, indicus
and 2.5 gigahertz band.
So I'm a fan of wireless networks.
In the previous talk, we heard
what great things we can do with
meshes and.
This this person.
Cause me to look into ways how to improve
the overall performance of meshes of
true measures.
And there are many spots
you can look at in proving.
This is just one way to
categorize, so
I looked at, right, controlling
and
power controlling.
So these are things that are not really
standardized.
So there is room for improvement, room
for optimization for mesh networks.
I also looked at rather
sort of fancy things like network coding
for some time.
And I also had the chance to look at
congressional control because I
worked for a project that
defines to distribute congressional
control in the vehicular communication
field. So like.
It is tough if you'd like to call this.
And when I did all this.
Over the years, he came to me that there
is one strange thing
missing here, actually, which
is we know that these
networks are interference, limited
mostly, or they all become interference
limited in the end.
But where exactly can I measure this
interference anywhere when I'm
participating in such a network?
So I'm actually making trying to
make the point here that in
order to make the distributed
system, um, robust
enough or.
At least more robust,
um, we need
to implement some
way that lets us.
Directly observe what are
the resources that are
available currently in the channel in
that room, like right now
in here, there are probably lots of
there's the
2.5 gigahertz band is buzzing
because of probe requests.
And I don't know,
uh, the normal,
uh, activity with the access points in
here.
Where where, you know, in our devices.
Can we see that?
And most people think, yes, it's
possible because basically you just
looking at the information that is
decoded by your by the
radio front-end, and then you can sort
of assume
that you have a very good correlation
with. Exactly. This is the activity that
is actually
taking place right now.
But the thing is, because it's a
distributed coordination
that is done when accessing the
medium, actually, it's called
distributed coordination function.
So pretty straightforward in the
standard.
Which is.
More or less the equivalent of
so it's mimicking human communications
in a sense that if you put several polite
people in a room and they want to have a
discussion, they do exactly that.
So they listen, if the medium is free,
if it's not free to back off and wait
until the person
who is currently speaking has finished a
sentence or appears to have finished
the sentence.
So.
And since this is distributed over space,
every receiver has a different perception
of exactly what is the medium
now, active or not?
Am I allowed to speak or not?
And eight to 11 works in a
way where it just defines sort
of a sort of a power threshold
or most 99 percent of the devices
work like this.
There's a power threshold,
for example, in a way, for them it's only
a power threshold.
And so there's a power threshold defined.
And every note
that is waiting to get the
next opportunity to transmit is basically
waiting until the channel power
goes below the threshold.
This is a very simplistic
shortcut now, but essentially
that's the way it works.
So, for example, this should be
a visualization of instantaneous
power at the antenna input
of a Wi-Fi radio.
And this
is this is not a real
measurement. This is basically something
that I
try, um, I try
to come
up with a visualization as it as
it actually looks like, but cleaned it up
a little bit more. So this is not this is
not the real measurement data here.
But you see that there are these blocks
and these blocks correspond to individual
with the frame transmission's around
the place.
And the green line is is the,
uh, the line from which a.
So this could be sort of the Karasinski
threshold at at our current receiving
device and
what happens is that you see
there, I mean, it's not perfectly
clear, but there are multiple
overlapping all the time.
So there is not like a slot structure
because it's a distributed phenomenon and
everybody has a different perception.
It's really like if we want to have a
clear discussion in that room, it would
be pretty impossible just by our
unamplified unamplified of talking
here.
So what an actual receiver
is trying to understand are those parts
that are non overlapping.
And what he forwards to the upper
layers, basically just the stuff that he
could decode, and
that is sort of the.
The fundamental thing that, uh,
that I want to sort of point out
that there that the whole
channel out the
receiver or the upper layers to don't
don't see the actual
utilization of the channel,
so.
There is a sort of loss of information
that happens there all the time because
our equipment is currently working
like it works, you only get what
you could understand and you get some
signal strength information and annotator
to it.
And this is sort of the philosophical
part here. That is some media
theories, if you like.
Keyword is Marshall McLuhan here.
They say all the technologies we develop
are extensions of our
human capabilities.
And if you think about it, wireless
communication is a little bit could be
said as an extension of our ears
and of our mouth.
And this behavior here is
equivalent to the situation where
we are all having sort of
electromagnetically.
So we have we have ears in the in the two
point four and five gigahertz
spectrum. And when we go into a noisy
room, we basically hear nothing.
We just hear the stuff that someone is
speaking to us, really standing
directly and shouting in our ears.
That's what we can hear. But we don't
hear that there is activity in the room.
We don't look for another room,
for example, because we cannot even
perceive the noise here.
And that's a very long
message saying that we now
made a pitch for open W.T..
That when you go for
real time graphs so that he has this real
time graph, you before you even connect
to anything, before you even see any
other, before you do any any
kind of association or attachment.
You see now our third graph.
Uh, additional to the two that were there
before and this aircraft just shows you
on the current channel that you're
listening to, this is the level of
activity like nine percent over
time.
I thought about doing a demo here, but I
think it takes too much time, so I'm just
showing you some screenshots here.
We call it cubists lord,
that I will explain later,
but what you actually can do now is we
see.
The actual channel utilization
we see, what are the resources left
that we can use to communicate with?
And this has many
useful I mean, applications
just because it's observable right now
and we thought, well,
isn't it even better
if we can tell about
the situations,
if we can inform
know the actual reasoning
was now we can
observe it at our local node, but
it's still difficult to communicate this
some way, for example, to clients that
want to talk to
us. So it's we we looked for ways
to distribute this this measurement
data somehow in order to
create a global view of what are the
resources in this room currently
available.
And we thought that we should broadcast
these observations using beacons.
And it turns out if you look into the
standard documents, there is already
defined a way to
do this.
Broadcasting of channel measurements
and this thing, they call it the cupie
is slowed and there's already
a standardized format, how you can
annotate this load in
every beacon that you sent so you'll
get seven bytes of
additional information
to every beacon.
Beacon is normal management information
that is transmitted by
points in infrastructure mode or
I take notes themselves.
So all we did is basically.
Try to implement this
in the software stack on open
at.
We we were aware at that point
in time that some access
points, for example, the
sort of enterprise carrier enterprise
grade Cisco gear is already
doing that.
The reasoning behind is it enables
Voice-Over-IP applications
to have to offer a better
quality of service because the handover
decisions are better.
And so we went forward and
tried to put this into an open
software stack.
The patch itself that does sort of the
main important things is really, really
short.
The problem is that.
I have a background in electrical
engineering, so I'm
really lousy at kind of hacking,
but I have a colleague who
sort of has a computer science degree,
but he's also completely new to
Colonel Space things.
So we pretty much screwed up everything
that we can screw up there
and made all the memory allocation and
all the looking's the wrong way,
but we still were adventurous enough.
So basically, this is this is my
colleague here.
He deserves all the credit for the
coding. I'm just the guy who sort of
suggested it and also
managed to get some some some funding for
it by this new
project called CONFINE.
So we were naive enough to do
our first trial at the at the wireless
Palmach.
In August this year in Maribor
and.
I will never forget the face of Attia
when we had to
sort of quickly find out that our patch
totally Colonel panic's
in a situation as in
the battle.
So I
felt really sorry for them for suggesting
that in any
anyway, we will we
are currently in the face of
sort of polishing it really to make it
sort of to convince subsystem
developers to to let this in.
Because it's a it's a it's a rather nasty
thing that we are updating
fields in a beacon over
time. So this is not not not a usual
thing, but we think it's relevant.
So we want to go for it.
And what it, for example, allows this
rebroadcasting is something like that.
So this is a few that you can
get when you use, uh,
a very nice tool called Horst.
Highly optimized video scanning tool is
one way.
So Bruno wrote it or is maintaining
it. And it's it's pretty useful
when you're doing, uh, debugging of,
uh, Metrolink's
and now we made a little patch to it.
So this the part on the right side is new
in the pattern, right. That just says you
OK, this and these Mac addresses now
see from their point of view, these and
these loads, if it
if if you look, they are
all operating on the same channel,
they are all within communication range.
So this is this is an output
you see just with your normal Wipha
receiver. So I could
I could demonstrate it right here with a
normal with with a normal wife radio.
I see access points around here
broadcasting the channel Load Fuze,
and I see that they're different.
So this.
This is a perfect demonstration of it's
a distributed phenomenon, everybody has a
different perception of noise.
Why is this all
so relevant?
I mean, it's relevant for.
The cases that were mentioned in the
intro, for example, but there is another
thing that I'm
there's another reason why I wanted to
sort of.
Make this point here, and there is,
um, currently
there is a lot of activity
around the five, so there
are lots of things happening because of
it, because of technology operating
in this.
They call it, uh, you and
I and the uni
bands and this activity,
uh.
One part of it is due to
the cellular industry
looking at it from,
uh.
So they are they are looking at ways now
very concretely to use these.
Unlicenced bands.
The terms are LTU or
license assisted exis.
And.
I mean, it's a matter of regulation
whether this will actually be,
uh.
Put in place.
But it's expected
that there I mean, the whole point of
doing this is in order to
have more control.
So cellular industry is looking for ways
to expand their domain of
control into the into the unlicensed
bands. And the problem is, if this
happens, since our Wi-Fi
radios cannot understand those
differently formatted signals,
we will hear basically nothing if this
activity in the neighborhood starts to
appear.
So.
These are put
these are some some some early,
uh, measurements that people did
that show clearly, that the presence of
such in this case is an LTU
base station will greatly diminish
all the performance that we can out of
the five gigahertz bands using Wi-Fi.
Again, it's a matter of regulation,
the regulation, how how how
strict you will be in this
equal access and coexistence if
they really take it, if you really take
coexistence and equal access seriously,
there is no point in doing LTU
or license assisted access
simply because if you want to have an
equal equal access,
you basically have to use the same medium
access protocol, listen before talk
the same rights to every note and then
the whole point practically vanishes
because the channel
is not such
different between those two standards.
And I think that it's.
Partly because of this, that
now this this this discussion has
started because.
No, wait, let me skip this.
Uh.
The FCC and the European Commission
have just or the FCC
is about to join the European Commission
already has put new law
into place that now seems to
try to.
Uh, make it
I would say if you look at
the new law, it says that they want to
make it impossible that people change
the settings on their routers
and they're especially worried about the
uni bands again.
And the official
reason it always is about the weather out
there, but I don't I don't think it's a
coincidence that they are now that
there is now a law being put into place
that restricts the behavior
of or restricts the freedoms that we
have.
And at the same time, there's a there's
another secondary user
sort of to say the primary uses is to
the radars here in the secondary use of
what all this wi fi.
And now it appears that another secondary
user wants all
Wi-Fi users to be as restrictive as
possible. That that that's how I
interpret the whole thing.
Yo, this 10 little patch
will allow us.
If that's the big if
if we are still allowed to run open
software on these things, this channel
will at least allow us to detect
that there are
nearby licenses that exist or else to
base stations that may be the cause of
problems there.
I think I should come I have
a little comment to make, but I
think I'll skip it. And basically
the message I'm trying to make here is.
We should treat these spectrum resources
as our comments, so.
Sort of it's.
It's about the right for free
speech in
in an electromagnetic way.
These are the same sort of
the force of the freedoms that Stallmann
talks about.
We need them also, and we have
to ensure that we still retain
the freedom to express
electromagnetically sort of.
That's my point of.
Christians.
OK,
so we have some more time for questions.
If you want to ask a question and you are
listening on the stream, please go
in the IOC.
We have an angel listening there and
reading the questions out loud.
If you have a question in the room,
please come to one of the six
microphones and I see we already have
the first one on microphone number two.
I'm just a small question regarding
to yours truly where you
made a pitch, where you see on the right
side the cube says,
I didn't fully understand because
you just said that this curious
is broadcasted on the beacon's.
But you could clearly see that normal
stations were also shown their
point of view of
how much interference they see how
this system.
Because if it's only the access point,
sending it in the pictures, how can you
see the station if you
know it's not a station for you?
It's a basically what I'm what I wanted
to say is that you see several access
points there and
sort of all of the all of those give
their individual views.
But that gives you all access
points all on the same page.
OK, yeah.
Second question, because you said that
some vendors implement this
already in the standards.
Yeah.
If somebody is using the patch.
Are these interoperability comparable?
So if I have a group of workstation Cisco
workstation. Yeah.
It's OK. Yeah.
Thanks.
OK, next question from microphone
number four, hello, thank
you for the talk.
Just a quick question. You had a child,
were you short holiday before performance
grades? If base station is Nehama,
yeah. Do you think anybody
will go for it? Because everybody uses
for the public outcry?
I can't imagine that can ever be reality.
Right.
I mean, my would stop working
will see.
I mean, I also I'm yeah.
I'm having the same view. I'm just
puzzled. Thank you.
OK, I see we have a question
up there at microphone number five.
All right, I
have a short question
regarding
measurements. Have you looked at
the
how this behaves
with throughput from access points?
So if you can actually
detect before even you can
before you transmit data how the
throughput will be?
No, but that's an excellent idea.
I mean, building an estimated
four expectable throughput
would be now possible with that.
That was. Yeah.
Excellent, thanks.
Good microphone number four.
Hello, what data do you get
from the hardware and is it similar
from all the devices?
Yeah, the chips, the data.
We get our cycle counters,
they are called cycle counters.
And we for this, we're using the business
cycle counters or to receive cycle,
whatever we like.
And these are registers that are being
sort of in most drivers
they are being copied in.
So they are available via the net link
interface.
And you dispatch
just reads them out in this place.
And it's a very simple thing, actually.
And most most current hardware
or most current drivers are
exporting this feature, so.
So microphone number one.
Do you have an idea how we can keep this
spectrum in the comments?
So I said, I think question,
I think the only way we have is to make
make it visible, what would we do with
it? So this is if you
take this further, we can see, OK, my
neighborhood is full of stuff
and 90 percent of it is El
Tube station. So I will certainly
try to do something about it.
Right. But if you cannot see it, you
cannot act.
So now we
push in very shortly a question from the
Internet.
Do these chipsets matter
all interfaces or just use
it as a Wi-Fi?
Sorry, can you say it again to these
chips that measure all interfaces
or just user usage of other
wildfire's?
Was no.
I don't know if the
chips use only
the user interface.
All in all interfaces or just
the user interface, especially interfaces
not just by wi fi
trust Wi-Fi.
And so that's what I would
say.
I don't get it.
So just Wi-Fi.
OK,
microphone number four.
Yeah. Um, so have you taken a
look at a pair of Qualcomm's
spectrum analysis mode for this?
And does it actually qualify
to supplement your data?
Sure. It's a nice feature.
The the when we
played with it, we just had the
impression that only sparsity samples.
So it's not only about every
half a second or something.
Yeah. It's for for estimating channel
load. It's not really that use of new.
But also to get a look at
how you can classify what kind of
interferer that is, that should
also be put into visualization,
because there's no I know that
IBM has options for that on their
checks, but there's no real option on
open WRP now
to do it.
And it's really not that easy
to do it by hand.
So, yeah, would be great to have an
option for that.
If someone is interested, please come.
Let's talk.
OK, we have time for one last
question.
Microphone number four, please.
Yeah.
Yeah, I just.
Did you have experience with five years
and is there is
a possibility to get the information from
the client also about
inter activities
in there from the.
Which client would you refer to,
if you like your mobile phone or
you mean that if a client is typically
not sending Bekins?
Is that what you mean? Yeah.
Yeah, that's right.
Yeah, yeah. I mean that we
can take it to other management
firms like the pro-Brexit.
Still send out all the time.
Mm. It would be a seven bytes addition
which is pretty small.
OK, let's just OK
for everybody who still has a question,
Paul will be in the foyer afterwards
so you can meet him there and ask your
leftover questions.
Thank you very much.
It was really nice talk.
So the last round of applause for.