Until very recently, the different types of WiFi protocols that have been used had quite arcane and esoteric names (802.11b, 802.11g, 802.11ac...), how could it be otherwise.
These names were put by an organization called IEEEE (read iecubo), a troop of engineers very clever, but with certain difficulties to find an appointment on a Saturday night. If a layman wanted to know if the router that was to be purchased and that had 802.11n was better or worse than another 802.11b/g, he had to ask his computer the informant.I'm going to practice when talking about the WiFi that will come, the best WiFi, WiFi 6.
When in 2018 the first equipment with the new 802.11ax protocol was going to be launched, someone in the WiFi Alliance, an organization much closer to the business world that is responsible for certifying the WiFi devices to ensure that they work with each other (and that it owns the WiFi logo that we all know), realized that this way of calling the different types of WiFi was a carajal and so there was no way to sell routers or anything. espabilao , with his colleagues in a room and said:
-Uncles,-unfortunately, there are usually no women in this world.-I had a phenomenal idea: we will change the name of all the WiFi protocols and we will call them by means of a new algorithmic nomenclature that has occurred to me and that is going to petar.
-Well-they said the rest-.Tell us...
-Well look: the first WiFi protocol that was invented (802.11a) we will call WiFi 1, the second (802.11b) we will call WiFi 2, the third (802.11g) we will call...-
-Wait, don't tell me-jump one-WiFi 3
-Male, catch them on the fly...
If you are good at the numerical series, you will already have deduced that the following protocols: 802.11n and 802.11ac were called WiFi 4 and WiFi 5 respectively, and therefore this new 802.11ax protocol was called WiFi 6.
Actually, joking aside, the thing makes sense: Everyone knows that an iPhone 8 is better than an iPhone 7 and much better than an iPhone 6 , and that's why almost every manufacturer mobile devices have successively numbered their new models.It is something simple and easy to understand: the higher the number, the better.
The new 802.11ax standard that IEEE defined changes a bit the way in which the WiFi equipment has to communicate with each other to try to solve one of the biggest problems that exist today with the WiFi and of which we speak already in another article: the saturation of the spectrum and the slowness to when accessing the network, which this saturation causes.
If you remember (and if not, read the article) the main problem we have with WiFi is that it is a shared medium, so the teams have to agree to transmit, and when one does, the rest They must remain silent.For this, it is necessary, before transmitting, to listen in case someone is already doing it and in that case it is time to wait (this is called contention).Each team waits a random time to try again.This works more or less well when there are not many devices, but as as the number of devices grows, the chances of getting a free space for your data are greatly reduced , which results in delays, latencies and get angry, especially when you are throwing your game online at Clash Royal and tear you apart for not leaving your card on time.
The first thing we have to say is that, unlike the previous WiFi 5 (802.11ac) protocol that only worked at 5GHz, in the case of WiFi 6 can operate in both 2.4GHz and 5GHz bands (and in the future it will also do it in the 6GHz), which is a great advantage because it is precisely the 2.4GHz band that, today, has greater saturation problems.
Divide and conquer
As you should know, the 2 bands used in WiFi (2.4GHz and 5GHz) were divided into channels that were like the lanes of a highway.In reality, the channel is a piece of radioelectric spectrum in which they transmit a series of equipment in turns.This way of transmitting, called OFDM ( orthogonal frequency division multiplexing ), has been used in WiFi networks since 2003, year in that said technology was adapted for use in the 2.4GHz band.
Grace, moreover, is that the assigned spectrum bits do not have to be all the same or fixed, but are dynamically assigned based on the transmission needs of each device. For example, in WiFi 6 a 20MHz channel contains 256 subcarriers and is grouped into resource units (RUs) that can be 26, 52, 106 or 242 subcarriers .
quality assurance
In the following graphs you can better appreciate this concept.In OFDM, in a slot of a certain time, only one device could transmit, occupying all the subcarriers of the channel.In OFDMA, these RUs are assigned to each device in that slot so that they can transmit at the same time.For example, in the first slots we have divided the channel into 2 groups of 106 subcarriers to transmit devices 1 and 2.In the 5th and 6th slot we divide into 4 groups of 52 subcarriers so that the 4 devices can transmit at the same time.
When it is the router that transmits to the different equipment in this way, it is called Downlink OFDMA and is simpler to implement than the Uplink OFDMA since putting according to all the devices on the network so that they transmit on their piece of channel is not a simple task.Although 802.11ax specifies both types as mandatory, the Uplink will not be able to see it possibly work in the first devices with WiFi 6.
the future that comes to us is called wifi 6
For the future that comes to us, full of little gadgets connected ( Internet of Things or IoT) this way of transmitting makes a lot of sense because it allows to have a large number of them transmitting very little without affecting the bandwidth of other equipment with much more demand.But perhaps the most revolutionary thing about this technology is that will allow to offer for the first time an SLA ( Service Level Agreement ) or "quality contract" in WiFi .By being able to assign different bandwidths to different devices.
Let's see a concrete example of this concept: suppose we have 3 computers connected to our router:
- A phone that is basically consulting a website and the whatsApp.
- A PC in which I am watching a 4K movie in streaming from that platform of movies and series that you talk to me about and that has a high demand for bandwidth.
- Three connected devices ( IoTs ), e.g.a thermostat, an intelligent plug and a light bulb, which practically do not send anything (a few kbps) and very occasionally.
Well, at a given time what we could do is assign, for example, 70% of that channel to the PC, to the smartphone we assign 24% and to the devices connected only 2% of that spectrum to each one.Those percentages would have to be translated into groups of subcarriers (Rus) per time slot, as we have seen above.
New 1024 QAM modulation
Another feature that improves this new standard is the modulation of the signal, which translates into the number of bits of information that I can transmit for each bit of assigned spectrum.The acronym QAM stands for Quadrature Amplitude Modulation and consists in which to send our data 2 sinusoidal waves displaced 90º in their phase are sent on the same frequency.The different combinations of amplitude and phase of these waves can be translated into information.Each unit of information transmitted at a given time is called symbol .
In order not to get bored with explanations that are too technical, let's say that in WiFi 5 we could transmit at most 8 bits of information per symbol (256-QAM) and in WiFi 6 we can transmit 10 (1024-QAM) so we gain approximately 25% over the previous protocol.
So for example an 802.11ac router (WiFi 5) that emits 4 streams (4 × 4) could reach 433Mbps x 4=1.7Gbps with 80Mhz of channel width (typical) or 3.5Gbps if we used 160MHz In WiFi 6 with the same number of flows (4) we put in 1200Mbps x 4=4.8Gbps in the 5GHz band, although several 802.11ax chipsets are already showing up that will allow 8 × 8 configurations with 160Mhz of channel width so we can double that speed, taking us (though, always theoretically) at speeds close to 10Gbps (9600Mbps).
Damn SpeedTest
We are going to make a paragraph here to talk about speed, because there is still a lot of confusion in what to expect when you hire an internet connection to an operator and only use WiFi connections, most common today in day.
If we talk about WiFi, we always talk about "theoretical" speeds because what we will then get in our homes effectively is always well below those speeds that appear on the routers' labels.First, because we are not alone transmitting on the air and we have to share, but we must also take into account the losses due to attenuation (distance to the router), interference, etc.Although perhaps the most important of all: we will not have equipment that is capable of synchronizing with the router at that maximum speed.
And this is an important message and we will never tire of repeating: Today the bottleneck in the WiFi is almost never in the routers .Any operator today provides routers with WiFi 5 with its Fiber offers capable of reaching speeds close to the real 1Gbps.The bottleneck is usually on the individual computers that connect to that router.
A high-end smartphone of last generation (of those that usually already exceed one thousand euros) has WiFi 5 and two antennas/flows (2 × 2) so we can reach real speeds of about 500-600Mbps.But of course, that is the best case, n or everyone has a smartphone of last generation and the most common is to find phones 1 × 1 WiFi 4 or WiFi 5 that with luck will get speeds of about 100-150Mbps real. If the device is already a couple of years old, it may not even support the 5GHz band and in that case it will be difficult to get more than 50-60Mbps.
connect more devices
In any case, as we mentioned in the previous article, when you hire a fiber of 300 or 500 Megas the objective is not, or should not be, to be doing tests speed all day from a mobile phone, tablet or PC to see if the speed that we have hired arrives (I already tell you that almost certainly it will not come from a single computer) but it is to be able to connect many more devices at the same time and that all go fast.
These speedtest tools are an invention of the devil and what they usually lead to is frustration. When we had 50-100Mbps internet connections this type of tests had some reliability, but from connections of more than 300Mbps giving the test button is something like playing roulette , even if we do it connected by cable to the router (which is how these speed tests should always be done).
The results depend on many factors, such as which server is being used, where the traffic must pass until it reaches it, how many tests are currently being done on that server, and the most Important: that our team from which we are doing the test has sufficient capacity to manage that speed, something that does not usually happen if your PC is already a few years old or you have the Windows full of crap.
MU-MIMO improved
The second version of WiFi 5 (called Wave 2) brought us a very interesting functionality called MU-MIMO (Multiple User-MIMO), which consisted of taking advantage of The routers have several antennas (and therefore flows or streams ) to be able to transmit to several devices at the same time, using beamforming , which basically consists of emitting directionally towards where is the device we want to reach.In the case of more or less static equipment (such as a desktop PC, for example) this technique works very well.
The bad thing is that in the case of moving equipment, the thing changes because the router does not have time to optimize the signal emitted to the correct address and the gain is no longer obvious.
WiFi 5 marked a maximum of 4 devices to which we could transmit at the same time, for which logically we needed the router to be at least 4 flows (4 × 4) in 5GHz. WiFi 6 expands the capacity MU-MIMO up to 8 devices , in addition to allowing MU-MIMO on upload (from the device to the router) which did not allow WiFi 5 where you could only do this in the direction of download (from the router to the devices).
Everything is colored
Another feature that makes WiFi 6 much better is the Color BSS . The idea behind this is to assign each WiFi Network a "color" (actually a number from 0 to 7) so that adjacent networks that transmit on the same WiFi channel always have different colors.What they get is to optimize the content that we talked about before: when a team was going to transmit it had to listen before if there was already another transmitting.
Well, now what we do is to see if that packet that is transmitting the other equipment is the same color or not as that of my Network.If it is the same color it means that it is a team of mine that the content is respected and not transmitted.If it is of another color it means that it is from another WiFi network.
In that case, if the signal with which the package is received is not very strong I send mine anyway since the signal/noise ratio will allow my package to arrive correctly at the destination equipment with a high probability. Obviously this significantly increases the ability to transmit equipment and therefore the flow of traffic in the air, which translates into a greater effective bandwidth.
The problem is that this color only works if the equipment that we have around transmitting is also compatible with WiFi 6 since otherwise the equipment will send the packets over the air without coloring.If a WiFi device 6 detects a package without coloring You will have no choice but to respect the content and shut up to allow compatibility with older adjacent WiFi networks.Unfortunately it will still be many years until all the devices support this new standard so the effects of this improvement will be noticeable long term.
Let's look at the previous image where 9 routers (also called points of WiFi access or nearby APs) share a WiFi environment.Automatic channel selection algorithms will have, at best, ordered the channels so that nearby routers are not on the same channel, but even so, APs 1, 2 and 3 are on the same channel 1.This means that any equipment on the AP1 network may be listening to packets emitted by AP2 or AP3 Network equipment so it will have to shut up until there is no one of those networks transmitting.
On the right side we can see the case in which BSS is used colored: here, when the AP1 or a team of that network detects a packet emitted by equipment of the AP2 or AP3 network, by carrying different color than its own network, it can transmit without content.Content would still be necessary in the event that AP2 and AP3 equipment are close enough so that their networks can listen to each other by carrying the same color, but this already it will be much more difficult to happen unless there is a large concentration of APs in very little space.
Wake up you go out, wifi 6
As if all the above was not enough, WiFi 6 will allow to increase the battery life in our mobile devices. You will be thinking: yes, of course...the times that I will have heard me that and in the end they last less and less...
Well, to be honest, what we can say is that at least the use of Wi-Fi dedicated battery would benefit considerably, although obviously there are many other factors that drain the battery, mainly the screen.
The way that WiFi 6 has to help us in energy consumption is by telling the devices when they have to wake up their WiFi to be able to transmit. Even if you don't believe it, most of the time the device has its WiFi turned off, or, rather, in an inactive state, and they only wake it up periodically to, so to speak, see "what's mine".Until now, the devices used a fixed period (we're talking here of a few hundred milliseconds) to wake up, but if there was no need to transmit or receive anything at that time it is a waste of a beautiful dream since the WiFi of the equipment could have remained so richly saved saving battery.
The novelty that WiFi 6 provides is that, now, the access point can negotiate with the devices when it will be the next time they wake up. If we return to the case of IoT type devices, which needed transmit very little and only quite spaced from time to time, this method is a great advantage because you can negotiate a longer wake up time with them, so, apart from saving battery, vital thing is This equipment, we will be reducing the contention time needed in the most active equipment.This technology is called Target Wake Time (TWT).
They are already here
Since the fall of 2018 the most important router manufacturers in the retail market, that is, those that manufacture routers to sell in computer stores and large stores, such as ASUS or TP-LINK have been launching to the market models that incorporate 802.11ax chipsets.
However, it has taken several months to find a device compatible with this technology on the market.The first has been Samsung with its Galaxy S10, although we will possibly see others like Huawei or Xiaomi join the party soon (like we will see now, the "party" is not a way of speaking).
Something to keep in mind is that neither the routers launched since 2018 nor the devices that are launched during the first half of this year will be certified by the WiFi Alliance and are not expected to start "official" certification processes until the end of summer.This is because the WiFi 6 standard has not been fully ratified, but for the moment there is a draft (the third one) that was approved in July 2018 and now work is being done in the room, to introduce something new like the possibility of using the 6GHz band.
wifi 6 in «first dates»
Does that mean that if I buy a WiFi 6 device now, it won't work well? Quiet, work, work, although possibly not with all the potential or with all the functionalities and improvements that we have seen above at full capacity.
And here comes the party, because, just to make sure that the equipment works with each other, from time to time some saraos are organized between chipset providers and WiFi devices, where each one take their little pots to see if they get along with each other (that is, they have no interoperability problems) and do what they have to do according to the last draft of the standard. They are a kind of "First Dates" of WiFi technology to those who call PlugFests, (imagine the concept of "party" that manages this troop).
I don't tell you more.
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