Go.
So let's go back because you mentioned a whole bunch of terms there.
So let's start right at the beginning.
In wi fi, we have these things called channels.
So as an analogy, are you is that kind of like a radio channel where I'm like in my car driving and
then I go to a certain frequency and then I get a radio station?
Is that is that what is that what you're talking about?
That is exactly it.
Right.
A channel in WiFi terms is really a range of frequencies.
So in 2.4 gigahertz, there's 14 channels in the US.
But we only use we like to use three channels because they're what we call non overlapping.
And I don't know if you guys recall ever being in the car listening to radio and then you hear two radio
stations at the same time, right?
That's that's similar to having channel access points operating on the same channel in the same area.
And so it's hard to understand what's going on when you have access points on the same channel, providing
service in the same area for a bunch of devices.
And think of wi fi as a, as a standard radio, like a two way radio where you have to speak, you have
to wait for the other person to respond.
But if you guys try to talk at the same time, nothing happens because no one understood each other
or that transmission failed because you can't speak at the same time.
That's how that's how WiFi works.
It's really like one user or one device transmitting at a time, but it happens very quickly.
Yes.
I mean, this is that going back to the analogies.
I just want to give people, you know, the the foundation and then we can come back to this if DMAA.
Is that right?
Yeah, that's correct.
And and mu-mimo mimo thingamajig.
So we still need to get to that.
But let's start with the basics.
Okay.
So we've got a channel which is kind of like 20 megahertz as the size of a party starting at 20 megahertz.
Yeah.
Okay.
So then you so that's like a radio station broadcasting on a specific channel.
In Ethernet, we have carrier sends multiple access collision detection.
And I think what you've just explained is this carrier sends multiple axis collision avoidance, SMS
slash CIA, is that right?
That's correct.
Now, I've heard some hype that.
Why Fi and I'm going to not mention names, but wi fi used to be like a hub.
But now in this new version, it's like a switch type thing.
And I've read that actually in some technical books because it sounds like what you've said is in this
new version of wi fi rather than like a 2020 gig megahertz or is megahertz, is that right?
20 megahertz channel.
And only one person being able to speak on that channel, like with your your two way radio analogy.
Now that channel is split up into sub channels where traffic from multiple, multiple people can be
can be sent at the same time.
Is that correct?
It is correct.
And I still think using the term switch is still incorrect in a way.
And I think the reason why vendors like to use the word switch or switch like is because of the the
theoretical speeds that you can get out of WiFi six and even in, in WiFi five.
Getting over a gig.
Right.
Yeah.
They always mention over a gig, so they're saying it's switch like because in a switch we're used to
one gig ports.
I think it's getting closer to being like a switch, but it's still technically not.
It's still half duplex, wi fi is still a half duplex medium.
So yeah, we're dealing with collision avoidance and whenever there is a collision, you know, in wi
fi, you have to back off with a what's termed as OC.
I sense a collision because I did not get an acknowledgement of my frame from recipient.
So I'm going to wait because I think there's, there's something going on and it's a random timer.
And that's what actually slows down your throughput is if you have a lot of collisions, the wait time
starts to increase, that window starts increasing as you have more collisions.
But I still think switch like is an improper term.
Sorry I interrupted you.
So are you saying it's still.
It's still acts like a hub, even in wifi six?
Yep.
It's it's because we're subdividing the channels.
And when you subdivide those channels, it's still a very specific frequency.
So a device will lock on to that specific frequency, and only that device should be using that frequency.
And that's why I say fi six will be better when all the devices are using wi fi are all wi fi six.
So when you mentioned about channels and I'm sorry to hop on this, I just want to try and get through
some of these terms and then we can like take it to Wi-Fi six.
We had.
A single channel.
And then you mentioned in AC, I think that they do this thing called channel bonding or something.
Can you explain that?
Yeah.
So channel bonding is is very common in the five gigahertz frequency.
And so in five gigahertz, you have multiple channels, 20 megahertz channels, I think about 24 or
25.
And so the most common the first one is Channel 36, and then your next channel is Channel 40.
If you bond those two together, Channel 36 and 40, put them together, you now have a 40 megahertz
wide channel and you have a channel bigger, big enough to hold more data.
So your throughput goes goes higher.
So is that the analogy?
Like, I had a single lane and I've got two lanes on a highway or something.
Yeah, that's correct.
Yeah.
You doubled your lanes.
Right.
So if you look at traffic as an example, single lane, all that traffic behind in that single lane,
it's slow.
But if you open up a lane, you ever notice how some cars just start going to the second lane and now
you can now it speeds up.
There's more cars going down the road.
That's a that's a good analogy.
Yeah.
So I mean, the AC didn't actually increase the speed of like a single channel or did it do that in
addition to, you know, increasing the speed by giving us more channels?
Yeah, it gave us the 160 megahertz channel with which I personally don't use anywhere.
And there's a number of reasons why which we can dig into.
Yeah.
So I mean the, the way just trying to understand this, the way that the speed increased is because
we got more lanes and then we can bond that and send more data by using multiple lanes from the from
the access point down to a client.
Yeah, that's correct.
So can you explain MIMO or how do you pronounce a MIMO?
And, you know, I believe there was a difference between AC and AX.
Now that's quite a big change.
Yeah.
So there's MIMO was introduced, I think back in 802 11, and that's a multiple input, multiple output.
And that's just meant to the best way to explain this is to speed up the the medium by using multiple
radios on your access point or your devices and being able to transmit, again, more data.
That's we're just trying to transmit more data as fast as we can with without breaking the law of physics.
Yeah.
So I saw you had an interview and you were talking about this issue about the law of physics.
And it seems like this is a major issue for a lot of wireless deployments, is this you can't bend physics
and you have to you know, you'd love to go faster, but physics doesn't allow you type thing things
that.
Right, right.
And a lot of it is also because of the unlicensed frequency that we use.
If you have a license frequency, which our devices can't use that because it has to be tuned to that
frequency, then, I mean, that frequency is all yours.
It's a lot cleaner.
You can do potentially like full duplex wireless technologies and that's that's actually capable that's
out there.
And but we see that a lot with point to point transmissions explain this thing about the the the the
multiple antennas because I see like Netgear and some of these vendors have like a whole bunch of antennas
on their AP.
So how does it work with these antennas?
You know, why does how does it work practically to send more data?
Do the antennas work on different frequencies or how does it work?
Yeah.
So the there's a set of radios that will work on 2.4 gigahertz and a set of radios that will work on
five gigahertz.
And then you'll have multiple what's called radio chains, right?
You'll see like two by two, three by three, four by four.
All that really means is you got to, to transmit and to receive three, transmit, three, receive.
And so what that means is you can use that number of radios to transmit data.
And the reason why more antennas is usually good is because you can now use like antenna diversity.
So maybe one antenna can hear a transmission better than another radio.
And so there's these algorithms that that these vendors use to try to take advantage of that through
one antenna.
And then there's a lot of what we call reflections because signal bounces around everywhere.
Yeah.
And maybe another antenna can hear some of that transmission.
And so what it'll try to do is combine those signals internally and try to basically boost that receive
signal so it can what's called modulate that signal, take that that signal in the air and make it digital
and make it understandable.
I think that's really important.
Sorry, I interrupt you.
You carry on.
And I'm saying that's that's basically why we have more antennas on access points is that also helps
increase your your your speed, your throughput on your wireless network.
You can send more data that way.
And the signal is more resilient with with multiple antennas because now you've got more ears listening
and, and more mouths talking.
I mean, I think it's a really important point that you raised.
I mean, the whole idea here is we're taking a digital stream of zeros and ones and then we modulating
it into waves on the air and then somehow trying to modulate that on the other side back into zeros
and ones.
So, I mean, I like your analogy of the radio stations, because if there's a lot of noise from other
devices communicating, it becomes difficult to modulate that.
So pushing you on this now.
So when if I've got I mean, you call it radio chaining.
If I've got like two by two type thing where I've got two transmitting and two receiving, they still
use in the traditional sense.
Only one channel, is that right?
Or do they split channels, use multiple channels?
How does it work?
Yeah, it's it's based on whatever channel you've configured your access point to use.
That's what those, those radio chains will use the operating channel that's configured.
So whether that's 20 megahertz wide or 40, it's going to use whatever channel you've configured to
to use it for.
So I know in WiFi six they suddenly have increased this.
So can you just talk around that?
And I don't want to try and mention the values because I'll get it wrong, but I know in a sea it went
higher and then actually went higher again.
About the channels.
Yeah.
So all the radio chaining is at eight by eight by eight or something.
Yeah.
So they've increased that in WiFi 6 to 8 by eight which there aren't many access points right now that
are that are eight by eight.
And that's just a lot more radio chains because of how complex wi fi is.
Now with WiFi six and all the sub channels you have, you're going to want a lot of antennas to to be
able to grab that signal and also to be able to send that signal.
And also a lot of that depends on another term, mu-mimo, which we can get into also.
Yeah, let's talk about that.
I mean, so firstly, I mean, what you're saying is eight by eight means eight transmit eight receive
top setup.
Yeah.
Right, right.
That's correct.
And and that's greater than a a C, which is four by four.
Is that right.
Yeah.
So I mean they've basically allowed you to add more radios to get better throughput based on like what
you said.
More ears and more mouths I suppose is the analogy.
Yeah.
And it's not just for the access points, it's for the devices to the limiting factor.
For that, though, is the reason why you don't see an eight by eight phone is because that would probably
drain your battery, you know, within minutes because of how many electronics have to be powered up
in order to have an eight by eight.
Right.
Most of our mobile devices are two by two to transmit to receive.
And so maybe the question is, well, why?
Why should I have an eight by eight or even a four by four if my devices are two by two?
Yeah, well, when, when you talk about things like mu-mimo, you could use different antennas to send
data to like a beam beamforming like send a signal out a specific antenna towards a specific direction
passively because the antennas aren't an active antenna.
It's not, it's not changing its internals to like send data, but it's going to try to form a signal
towards a general area of where maybe that device would be.
So I could send a device to a transmission to you.
David But then somebody else could be sitting on this side and I could send a transmission there using
different antennas.
And the thing is, for me, with mu-mimo or multi user, multi user, multiple input, multiple output
is that it's very hard to to really see if that works well.
It's hard for me to see if that works with the technology I have access to.
Right.
There isn't say like a command line where I can go, how well is Mu-mimo working?
And so and also Mu-mimo depends on the spatial diversity of the clients.
So if you have ten clients all clustered together, it's kind of hard to beam form to one of those ten
clients because they're all in the same general direction.
And that's where you'll hear a lot of people saying like, maybe Mu-mimo doesn't work.
But for me, it's I don't know how to check if it actually works.
You mean?
It's very interesting what you said.
So just so that I understand, because once again, I'm going to be the guy that he's the slowest student
in the room.
Beamforming is, as you explain it, so you can push a beam this way and a beam that way to try and
get better throughput.
And then just on this mu-mimo, what there's a difference now, a big difference that I read between
this and AC or wi fi five.
Isn't there something to do with the receiving and transmitting?
Yeah, it allows.
So in AC or wifi five, it was what they call downlink.
So from the AP to the client, you could do mu-mimo with 11 ax.
You can do mu-mimo in both directions.
You could do it downstream and also from the client back to the AP.
So does that mean that getting back to like your your example, it's not switch, it's not a switch,
but it's switch getting closer to switch like so that means that the AP can send to multiple clients
at the same time, but the multiple clients can send back at the same time.
Is that right?
Yeah, it's getting to where it seems like a switch, but it's still half duplex.
Yeah, but the idea is, is like, if you.
Sorry, go on.
No, no, no, go ahead.
Now I'm just going to say my apologies to everyone.
Rules in California, I'm in the UK.
There's quite a bit of delay on the link.
So forgive us, you know, for, you know, speaking one another.
This is the problem.
We're doing wireless here, dude.
It's like it's not full duplex but sorry you carry on the.
I already lost my train of thought there but now so I was going to say, you know, it's not like a
switch you it's kind of getting to switch like with where the app can send at the same time sorry,
the app can send to multiple clients at the same time and the clients can send back at the same time.
So did you want to say something about that or.
I'm going to push you now.
Yeah.
So the caveat there is we always have to remember with WiFi six is we're taking one channel and say
that's channel 36 and we're dividing that channel into sub channels, which are very small frequencies.
So that's what the devices tuned to.
They tuned to that small frequency which which Wi-Fi six, it's called resource unit.
And so the resource unit is a small channel.
And when I say channel, a channel in wi fi is also a frequency.
So it's a very small frequency that a device will tune to and transmit or receive on that frequency.
And that's how you can get the multiple devices being able to receive or transmit because then the app
with its, you know, chips and the math can determine, Kate, that client is on this sub channel of
channel 36 and that clients on this sub channel, it coordinates all that and the resource units, it's
it could expand into different combinations, right.
So with resource units, if you if a device took up the full channel, that's one resource unit.
But the full channel, technically that's 242 resource units and that device can use it all.
You can further subdivide that channel into smaller resource units.
I'm not going to bore everyone with all the numbers, but let's say there's two devices.
You can split that channel into two channel to sub channels and they can transmit and receive at the
same time.
So that's kind of the logic.
It goes further down and you could have up to like eight sub channels.
Yes.
I mean, this is quite a change, isn't it?
Because in the past we had like a channel 20 megahertz and only I could speak on that or you could speak
on that.
But now they breaking it up into these.
Did you call it resource units or sub channel type thing.
Yeah.
In the in the in the draft, it's called resource units.
But really I like to say call it sub channels because we speak in channels anyways.
So that's what it really is.
Yeah.
So basically you're taking 20 megahertz and you splitting it in two.
So you and I both get ten megahertz so we can both send at the same time because rather than using the
full channel we're using one of these sub channels.
Right.
Yeah.
But I still see a sma slash a you see sma slash.
It's still a collision avoidance because there's still possibility of collisions that can happen.
Right.
And then one thing I didn't mention before is we still have this transition from WiFi five to WiFi six.
So you're going to have a mix of devices.
And the if anything, that's not Wi-Fi six is not going to be able to take advantage of those WiFi six
capabilities because you have to be a Wi-Fi six device.
Yeah.
So all the previous versions of wi fi, they use the full channel, is that correct?
Yeah.
So if you wanted to transmit and I wanted to transmit, I'd have to wait for you.
But with I, I'd have to wait for you to transmit first and then I can transmit.
And then with wi fi six, the AP can just subdivide the channel and we can both transmit at the same
time.
So it's like, it's like going to a fast food drive through, you know, single lane drive through.
Yeah.
You had to wait for the guy in front of you to order, but then they came out with two lane drive thrus.
So now you can, you can place two orders at the same time.
Like they try to make that efficient, that line more efficient and make you go through the line faster.
It's it's very similar to that.
I mean, that's great.
I mean, I can understand the analogy of using a switch because it kind of sounds like that, but not
entirely because it's still Kerry avoidance within that channel.
And if you have a an old device broadcasting like crazy in that channel, that's going to affect you.
Exactly.
No saying exactly when.
This is what Wi-Fi six is trying to solve is that density problem.
Because what I like to tell people about wi fi is you have this pie on the table, right?
This delicious looking pie.
If you were the only one there at that table, you can have that pie all to yourself.
But as soon as somebody else comes, now, you got to split that pie.
Maybe in half, right?
Depends how hungry you guys are for for data.
And then the more people come that's smaller.
You get a smaller slice of that pie.
That's kind of like that's kind of how wi fi is, is the more people there are, the a small sliver
of airtime you're going to get because this this is the first time I mentioned airtime because wi fi,
it travels through the air.
What we're trying to do is get people to communicate and get off the air faster.
Right.
Transmit your data, get off the air so somebody else can can transmit.
And so that's what we're trying to make more efficient is that air time utilization, that air time
efficiency is what they what they call it.
Yeah.
I mean, I'm glad you've used that analogy of the pie because I mean, the problem I think with wi fi
is we've only got a certain number of channels, haven't we?
So I mean, you mentioned like they're trying to extend the channels, is that right?
In Wi-Fi six, give more channels four.
They're not trying to extend the channels.
There's a separate project where they're in.
I know in the U.S., I'm not sure about other countries.
They're trying to expand the number of another frequency, like the six gigahertz frequency for wi fi.
And if they did that, we would have a lot more frequency to use and distribute users across different
frequencies.
So that way everyone can get access to different pies.
There's more pies available, and that way there's less what's called this?
The first time I'm going to say this contention, because if you think in terms of a switch, right,
you you have a single port, a switch, switch port and whatever is connected there, that's a single
collision domain.
Right.
I'm sure your your audience will understand that with a hub.
Hopefully you guys know what a hub is.
Yeah, the audience is a level.
I think most people know what a hub is.
Yeah, it's just I haven't seen a hub in so long except for wireless.
I can go and get you one.
I've got one upstairs, but a hub is a single collision domain.
Yeah, that's what wi fi is.
It's like.
It's like a hub.
It's a single collision domain.
And so when we have different channels, we're trying to create different collision domains, because
if you have Channel one and Channel six, those are two collision domains.
But if you have an API on Channel one, let's say here's a room, here's an app and an app right here,
both on channel one that is effectively a single collision domain because they're on the same channel.
So what we're trying to do is create multiple collision domains so that we don't run into what's called
like co channel contention, where a lot of channels, a lot of devices are contending to use airtime
because they're all they're all communicating on the same channel.