It’s hard to find someone these days without the benefits of Wi-Fi. Almost every home has its own Wi-Fi router, and the phone contains at least a couple of other networks from places of regular visit. Wi-Fi standards are evolving at a regular rate, and manufacturers of routers release new devices year after year and lure ordinary people with promises of unprecedented speed and coverage. But not everyone will be able to understand the strange encodings “802.11a / b / g / n / ac / ax” when choosing in a store, so you have to rely on intelligent consultants and all the same advertising articles and “honest reviews” from the manufacturers themselves, written cleanly by marketers without any reference to the real world. What to do when choosing? And is it really worth chasing progress at all, or will you get nothing from the upgrade? Or maybe you can completely “shamanize” the existing equipment and achieve better communication quality? Let’s try to figure it out.
But first, I will answer a potential question: “Who are you and why should I listen to you?” Everything is simple here – I have been designing and troubleshooting corporate Wi-Fi networks since 2014 and have a couple of certificates from Cisco, according to which I, allegedly, am a professional in this area (no, I am not, they all lie). I was motivated to write the article by the desire to explain to others the principles of Wi-Fi and its main points in an accessible language, in order to increase general literacy on the topic and save from creating problems for yourself and, especially, those around you. To which we will proceed.
About home Wi-Fi routers
What we used to call a Wi-Fi router is actually a composite device – a router (or router) with a Wi-Fi access point function. Why know this? Yes, just to separate the warm from the soft and understand that the router itself is responsible for connecting to the provider, issuing IP addresses to your home devices and, in fact, your connection to the Internet. And the Wi-Fi glasses function is limited to linking your smartphone with the router itself. That is, a banal replacement for the same cable from the router to the PC.
Now the question is: what is the speed of your ISP? The one for which you pay a subscription fee? 10 Mbps? fifty? one hundred? Hardly more. And now for an even more interesting question: if your Wi-Fi point will deliver the 6 Gbps promised by marketers (but unattainable), will this increase the speed of your Internet connection? Answer: no, not a drop, because you also continue to pay for your 10 Mbps. In fact, a Wi-Fi hotspot only affects the speed between your smartphone, router, and other devices on your home network. For reference, when connected by wire, you get guaranteed 100 Mbps or 1 Gbps depending on the type of cable and ports on the router and your PC. Therefore, further increase in speed outside the Internet connection will make sense only for communicating with local storage, if there is one.
On the principles of data transmission over the air
Before talking about Wi-Fi standards and speeds, let’s figure out how data transmission over the air works.
To understand the difference between cable and Wi-Fi, you just need to imagine a meeting in a small room, densely packed with pairs of people, where everyone has to report to their boss about the work done during the day. When trying to communicate, everyone will interrupt each other, and it will be extremely difficult to conduct a conversation against the background of the general noise. Therefore, the best option would be to speak in turn, and everyone else will listen, although they absolutely do not give a damn – after all, the information is not intended for them, it will pass away like white noise. Among this crowd, someone is bound to come across someone who is extremely talkative, and his volume of chatter will easily exceed the report of 5 other people. Such an individual will be interrupted from time to time so that he can catch his breath and formulate the next tirade, and during this time someone else will have time to issue: “I have been writing an article all day” and calmly go about their business. The rest will have to look after him sadly and wait for their turn. Congratulations, you just figured out how Wi-Fi works.
If you split all these pairs of people into different rooms, then everyone will be able to report to their boss personally, no one else will hear him, and they will not have to wait for others. This is how cable communication works. Do you feel the difference?
One very simple conclusion can be drawn from this: the speed, quality and security of wired communication will fundamentally always be better than wireless, regardless of how many new standards they still have time to come up with. It turns out that the main and only advantage of Wi-Fi is mobility and lack of wires. And there is also a second, slightly less obvious conclusion, which marketers prefer to keep silent about: the speed of the Wi-Fi network is divided between all participants working on the same channel (that is, hearing each other). So the promised 6 Gbps suddenly turns into a pumpkin, unless you have the only Wi-Fi hotspot in the whole village with only one connected (and very cool) client. And even in this case, with real speed, everything is much more complicated, but it is better to write about this separately.
About radio bands and interference
On this slightly sad note, let’s dive a little deeper into the technical part and look at how Wi-Fi works in terms of the radio signal. First, you need to understand that Wi-Fi exists on one of two unlicensed radio bands. Most often they are referred to as 2.4 GHz and 5 GHz for simplicity. An important point: what does “unlicensed” mean? And the fact that you do not need to obtain a license to broadcast in these frequencies if the transmitter power is below the permissible norm (read: you can put a Wi-Fi point at home), but you have to put up with potential interference from primary devices, a.k.a. ISM (Industrial, Scientific, Medical, which includes weather radars). In practice, this also means that no one will forbid you to develop your own wireless data transmission technology and use it in the 2.4 GHz band. What devices are we talking about? Everyone’s favorite Bluetooth and the whole range of devices available at home: microwaves (yes), cordless phones, video nannies, cameras, wireless keyboards, mice, gamepads, headphones – all this works at 2.4 GHz. Therefore, it interferes with each other and especially for Wi-Fi. At 5 GHz, the situation is much better, but more on that later.
About frequencies and channels
It’s time to go directly to the signal itself. Historically, the first mainstream Wi-Fi devices ran at 2.4 GHz (although, surprisingly, the 5 GHz version was developed earlier). As you already understood, for Wi-Fi this is not the best environment due to the forced proximity to a bunch of other wireless devices, but in those days no one imagined the scale of the potential problem.
From the selected Wi-Fi frequency range, the point selects one of the available channels and works there together with all clients connected to it. In total, 13 Wi-Fi channels are allocated in the 2.4 GHz range (plus 1 more exclusively for Japan), but in fact only 3 of them should be used: 1, 6, and 11. Why? Each channel occupies 22 MHz, and only these three are non-overlapping – that is, the clients of one will not hear the clients of the other two and, accordingly, will not interfere with each other. In other words, only 3 Wi-Fi points can be located in the neighborhood and not slow down the work of others in any way. Add the fourth – and now she is forced to share the channel (and with it the transmission speed) with one of the others. And now the question: how often do you see only 4 Wi-Fi points in the range of your connection? That’s the same.
Now let’s imagine an interesting situation: your neighbor is a homebrew Wi-Fi guru who knows how to achieve excellent signal quality and avoid interference from points on the same channel! Without thinking twice, he changes the channel with the pens, say, to 3. It would seem an excellent solution, because that channel is completely free! In fact, this means that his Wi-Fi point and all clients on it now interfere with both the first channel and the sixth. Congratulations, Sharik, you dunce!
What about 5 GHz? In short, it is much more fun – there is no neighborhood with Bluetooth and others like it, the number of channels is greater, all of them are already removed from each other by default, so there is no way to choose the “wrong” one. Although here there are some nuances with the real number of available channels, which, however, do not need to know. In short, in Russia in the 5 GHz range, up to 23 channels with a width of 20 MHz are available, but from some of them you may be automatically thrown out when a radar signal is detected. And, by the way, this is a limitation of the technology itself, and not legal troubles of a particular country.
About Wi-Fi standards
Finally we got out of the abstract and got to something substantial. So, all Wi-Fi standards are combined into a common 802.11 group and differ in letters in various combinations. Understanding those very letters will help both when choosing a home router and when setting it up. Let’s get started:
- 802.11b is the very first standard to hit the masses. In fact, the letter means operation on the 2.4 GHz band and at speeds up to 11 Mbps. Do not forget that the speed is divided between all devices on the channel, even those connected to neighboring points. It also has a slightly wider channel width, so in modern systems 802.11b is either not supported at all, or it is better to turn it off ourselves in favor of the next item.
- 802.11g is the second standard for 2.4 GHz, providing speeds up to 54 Mbps (which is still divided by the number of devices). It is used to this day in combination with 802.11n, which is described below.
- 802.11a is the first standard for 5 GHz. The same 54 Mbps, just a different range with more channels and no interference from non-Wi-Fi devices.
- 802.11n – in the modern world it is also called Wi-Fi 4. The letter n itself does not imply any range, it only matters in the bundle .11gn or .11an (2.4 GHz and 5 GHz, respectively). It offers a number of improvements, including an increase in speed by merging two adjacent channels to obtain a 40 MHz channel. I would like to dwell on this function separately and warn people against using channel bonding. Having done this in the 2.4 GHz band, you simply clog two of the three available channels at once, for which the neighbors will not thank you. At 5 GHz, the consequences will not be so critical, but the resulting performance gain for home devices will still be disproportionate to the damage done to the radio air, especially in densely populated areas. By the way, it was in this standard that the use of multiple antennas first appeared.
- 802.11ac (aka Wi-Fi 5) is the most popular standard at the moment, operating only at 5 GHz (the letter “a” hints). I won’t dwell on all the advantages, for the sake of simplicity we can say that he developed the ideas of .11n for increasing speed, working with multiple antennas, etc.
- 802.11ax (or Wi-Fi 6) is the latest standard, another development of the technical part of the previous one. Many have dubbed it the “Wi-Fi revolution” with two new features. The first is the ability to mark data and distinguish one’s devices from strangers in order to ignore strangers, and not wait for their turn to transmit (that is, roughly speaking, added the ability for points to shout over each other in the hope that their clients are closer and will still hear). The second is the ability to transmit data from the access point to several clients at the same time, putting several “packages” in one heap so that each device takes its part when receiving a signal. The main goal of this approach is to cope with the rapidly growing number of IoT devices. That’s just …
About skepticism
Advertising you the next newest Wi-Fi router, marketers (whether intentionally or not) prefer to keep silent about one extremely important detail – the standard must be supported not only by the Wi-Fi point, but also by the clients themselves, because communication takes place in both directions. How many Wi-Fi 6 devices do you think are on the market right now? I dare to suggest that much less than 1%. With a quick search, I found about 15 models of smartphones, and all of them were not the most budgetary price category. This means that there is not so little chance that your brand new expensive router will collect dust on the cabinet very nicely and work in compatibility mode with previous standards. Someone very optimistically claims that there is no need to be part of the problem, it is worth investing in infrastructure right now, and the devices will be updated in 2-3 years. From personal experience, I will say that active devices are not completely updated even in 7 years, and still there are a bunch of devices without support for new standards. And if we talk about manufacturers, then many budget smartphones still do not even support 802.11a (which, by the way, is 20 years old) and are forced to work at 2.4 GHz. About the IoT (“Internet of Things”) I’m generally afraid to even guess – they are unlikely to completely climb at least 5 GHz in the foreseeable future, unless the production of components becomes cheaper than 2.4 GHz. What kind of Wi-Fi 6 is there?
Finally
In fact, I wanted to tell much more: about the signal strength, about its range and absorption by walls, about repeaters (avoid them at all costs), about the correct direction of the antennas (just remember, strictly vertically and nothing else), about the “harm from Wi- Fi “. But since the site is non-core, it is easier to put up with the time spent on 4 pages of text than on 8, if suddenly the admins do not want to skip. If there is a response from the community, then maybe I’ll scrape together for a second article.
If you have any questions, I will gladly try to answer them.
