Technologies wireless communication do not stand still and more and more routers appear on the market that can distribute WiFi at frequencies 2.4GHz And 5 GHz. Frequency 5 GHz has a number of advantages, among which, first of all, it is necessary to note less network congestion, support 23 channels versus three in 2.4GHz and higher throughput. Lack of frequency workers 5 GHz- smaller coverage area than networks 2.4 GHz.

Alas, not all computers and mobile devices can see such a network. Let's assume you have a router that supports 5 GHz, but your Windows 10 laptop does not detect the WiFi. Can something be done? Unfortunately, your device's wireless adapter does not support networks on the frequency 5 GHz is the main condition for working with them. However, there is a possibility that the adapter still supports the frequency 5 GHz, but the settings are incorrect.

How to know if the adapter supports 5 GHz

The first option is to go to the website of the adapter manufacturer and familiarize yourself with it. technical specifications. But there is an easier option. Open as administrator command line and run the following command:

netsh wlan show drivers

Among the list of parameters we find and see what standards the adapter supports.

802.11b And 802.11g 2.4GHz.
802.11ac- support for networks with range only 5 GHz.
802.11a, 802.11n, 802.11j And 802.11n- can operate at a frequency as 2.4GHz, so on 5 GHz.

Note: a distinction must be made between adapters with a standard 802.11n Dual Band 2009 years and adapters 802.11n 2006 of the year, working only in one range.

If support is declared, but WiFi- the network is not visible in the device manager in the properties of the driver wireless adapter you need to check the selected range. For example, in the case of an adapter Marvell AVASTAR Wireless-AC Network Controller tab "Additionally" property must be selected Band and set a value for it "Automatically" or "Only 5 GHz".

It is also worth considering the case when a networked 5 GHz the computer stops seeing it after upgrading to Windows 10. The main reason for this is the replacement of the adapter driver with a standard driver from Microsoft.

This problem is usually solved by downloading and installing latest version "native" wireless adapter drivers from the official website of the manufacturer. Automatic update Windows drivers at the same time, it is better to disable it so that the driver is not replaced again during the next update. If the adapter no longer supports high frequency but work online 5 GHz I still want to, you can buy an external one USB WiFi-adapter with appropriate characteristics.

I think I won’t be mistaken if most of us have an Internet connection like this: there is some fairly high-speed wired channel to the apartment (now gigabit is not uncommon), and in the apartment it is met by a router that distributes this Internet to clients, giving them "black" ip and performing address translation.

Quite often, a strange situation is observed: with a high-speed wire, a very narrow wifi channel is heard from the router, which does not load even half of the wire. At the same time, although formally Wi-Fi, especially in its ac version, supports some huge speeds, when checking it turns out that either Wi-Fi connects at a lower speed, or connects, but does not give out speed in practice, or loses packets, or all together.

At some point, I also encountered a similar problem, and decided to set up my Wi-Fi in a human way. Surprisingly, it took about 40 times longer than I expected. In addition, it somehow happened that all the instructions for Wi-Fi setup, which I found, converged to one of two types: in the first it was proposed to put the router higher and straighten the antenna, to read the second, I lacked an honest understanding of spatial multiplexing algorithms.

Actually, this note is an attempt to fill a gap in the instructions. I will say right away that the task has not been fully resolved, despite decent progress, the connection stability could still be better, so I would be glad to hear the comments of my colleagues on the topic described.

Chapter 1:

So the problem statement

The Wifi router offered by the provider has ceased to cope with its duties: there are long (30 seconds or more) periods when the ping to the access point does not pass, very long (about an hour) periods are observed when the ping to the access point reaches 3500 ms, there are long periods when the connection speed with the access point does not exceed 200 kbps.

Scanning the range using the inSSIDer windows utility produces the picture presented at the beginning of the article. There are 44 Wifi SSIDs in the 2.4 GHz band and one network in the 5.2 GHz band in the district.

Solution Tools

Celeron 430 self-assembly computer, 2b Ram, SSD, fanless, two wireless network cards on a Ralink rt2800pci chip, Slackware Linux 14.2, Hostapd from Git as of September 2016.

Assembling the router is beyond the scope of this post, although I note that the Celeron 430 performs well in fanless mode. I note that the current configuration is the latest, but not final. Perhaps there are still improvements to be made.

Solution

In fact, the solution would, for good, be to run hostapd with minimal configuration changes. However, experience so well confirmed the truth of the saying "it was smooth on paper, but forgot about the ravines" that it took the writing of this article to systematize knowledge about all the non-obvious details. Also, I initially would like to avoid low-level details for the sake of harmony of presentation, but it turned out that this is impossible.

Chapter 2

A bit of theory

Frequencies

Wi-Fi is a standard for wireless networks. From an OSI L2 point of view, the access point implements a switch type hub, but most often it is also combined with an OSI L3 switch of the "router" type, which leads to a fair amount of confusion.

We will be most interested OSI layer L1, that is, in fact, the environment in which the packets go.

Wi-Fi is a radio system. As you know, a radio system consists of a receiver and a transmitter. IN wifi hotspot access and the client device perform both roles in turn.

The Wi-Fi transmitter operates on a certain frequency. These frequencies are numbered, and each number corresponds to a certain frequency. Important: despite the fact that for any integer there is a theoretical correspondence to this number of a certain frequency, Wi-Fi can only work in limited frequency bands (there are three of them, 2.4 GHz, 5.2 GHz, 5.7 GHz), and only on some of the numbers.

Full list You can see the correspondences in Wikipedia, but it is important for us that when setting up an access point, you need to specify which channel the carrier frequency of our signal will be on.

An obscure detail: not all Wi-Fi standards support all frequencies.

There are two Wi-Fi standards: a and b. "a" is older and operates in the 5GHz band, "b" is newer and operates in the 2.4GHz band. At the same time, b is slower (11 mbit instead of 54 mbit, that is, 1.2 megabytes per second instead of 7 megabytes per second), and the 2.4 GHz band already accommodates fewer stations. Why this is so is a mystery. It is doubly a mystery why there are practically no standard access points in nature.

(Image borrowed from Wikipedia.)

(Actually, I'm being a little disingenuous, because a also supports the 3.7 GHz frequency band. However, I haven't seen a single device that knows anything about this band.)

Wait, you ask, but there are also 802.11g, n, ac - standards, and they seem to just beat the unfortunate a and b in speed.

But no, I will answer you. The g standard is a belated attempt to bring speed b to speed a, in the 2.4 GHz band. But why, you answer me, did you even remember about b? The answer is because even though the ranges of both b and g are called 2.4, they are actually slightly different, and the range of b is one channel longer.

The standards n and ac have nothing to do with ranges at all - they regulate the speed, and nothing more. Standard point n can be either "in the base" a (and operate at 5 GHz), or "in the base" b and operate at 2.4 GHz. I don’t know about the ac standard point, because I haven’t seen it.

That is, when you buy an access point n, you need to look very carefully at what ranges this n works in.

It is important that at one moment in time one wifi chip can only work in one range. If your access point claims that it can work in two at the same time, as, for example, free routers from popular providers Virgin or British Telecom do, then it actually has two chips.

Channel Width

Actually, I have to apologize because I said earlier that one range is longer than another without explaining what "longer" is. Generally speaking, not only the carrier frequency is important for signal transmission, but also the width of the coded stream. Width - this is what frequencies above and below the carrier the existing signal can climb. Usually (and fortunately in Wi-Fi), the channels are symmetrical, centered on the carrier.

So in Wi-Fi there can be channels with a width of 10, 20, 22, 40, 80 and 160 MHz. At the same time, I have never seen access points with a channel width of 10 MHz.

So, one of the most amazing properties of Wi-Fi is that despite the fact that the channels are numbered, they intersect. And not only with neighbors, but even with channels through 3 from yourself. In other words, in the 2.4 GHz band, only access points operating on channels 1, 6, and 11 do not intersect with 20 MHz wide streams. In other words, only three access points can work side by side so as not to interfere with each other.

What is an access point with a channel width of 40 MHz? The answer is - and this is an access point that occupies two channels (non-overlapping).

Question: and how many channels with a width of 80 and 160 MHz fit in the 2.4 GHz band?

Answer: No one.

The question is, what affects the width of the channel? I do not know the exact answer to this question, I could not check it.

I know that if the network intersects with other networks, the connection stability will be worse. Channel width of 40 MHz gives more crossovers and worse connection. According to the standard, if there are other working access points around the point, the 40 MHz mode should not be enabled.

Is it true that twice large width channel twice gives more bandwidth?
It seems to be, but it is impossible to verify.

Question: If my access point has three antennas, is it true that it can create three spatial streams and triple the connection speed?

Answer: unknown. It may turn out that out of the three antennas, two can only send, but not receive packets. And the signal speed will be asymmetrical.

Question: So how many megabits does one antenna give?

Answer: You can see here en.wikipedia.org/wiki/IEEE_802.11n-2009#Data_rates
The list is strange and non-linear.

Obviously, the most important parameter is the MCS index, which determines the speed.

Question: Where do these strange speeds come from?

Answer: There is such a thing as HT Capabilities. These are optional chips that can slightly correct the signal. Chips are very useful: SHORT-GI adds a little speed, about 20 Mbps, LDPC, RX STBC, TX STBC add stability (that is, they should reduce ping and packet loss). However, your hardware may simply not support them and still be quite “honest” 802.11n.

Signal strength

The easiest way to deal with bad connection is to fry more power into the transmitter. Wi-Fi has a transmission power of up to 30 dBm.

Chapter 3

The solution of the problem

From all of the above vinaigrette, it would seem that the following conclusion can be drawn: Wi-Fi can implement two “modes” of functioning. “Improving speed” and “Improving quality”.

The first, it would seem, should say: take the most unoccupied channel, channel width 40 MHz, more antennas (preferably 4), and add more Capabilities.

Second - remove everything except the basic n-mode, turn on more power, and turn on those Capabilities that add stability.

Recalling once again the proverb about ravines, we will describe what kind of uneven terrain awaits us when trying to implement plans 1 and 2.

Ravine zero

Although Ralink rt2x00 family chipsets are the most popular chipsets supporting the n standard and are found both in high-end (Cisco) and low-end (TRENDNET) cards, and moreover, they look exactly the same in lspci, they can have radically different functionality, in particular, support only the 2.4 band, only the 5GHz band, or support incomprehensibly limited parts of both bands. What is the difference is a mystery. It's also a mystery why a card with three antennas only supports Rx STBC in two streams. And why don't they both support LDPC.

First ravine

There are only three non-overlapping channels in the 2.4 band. We have already spoken on this topic and I will not repeat myself.

Second ravine

Not all channels allow you to increase the channel width to 40 MHz, moreover, what channel width the card agrees to depends on the card chipset, card manufacturer, processor load and weather on Mars.

The third and largest ravine

Regulatory domain

If you were missing the fact that the Wi-Fi standards themselves are a noble vinaigrette for happiness, then rejoice that every country in the world is striving for all sorts of different ways Wi-Fi to infringe and limit. In the UK, things are still not so bad, unlike, say, the USA, where the Wi-Fi spectrum is regulated to the point of impossibility.

So, the regulatory domain may require restrictions on the power of the transmitter, on the ability to launch an access point on the channel, on acceptable modulation technologies on the channel, and also require some “spectrum pacification” technologies, such as DFS (dynamic selection frequencies), radar detection (which each regdomain has its own, say, in the Americas almost everywhere offered by the FCC, in Europe it’s different, ETSI), or auto-bw (I don’t know what it is). At the same time, with many of them, the access point does not start.

Many regulatory domains simply ban certain frequencies altogether.

You can set the regulatory domain with the command:

Iw reg set NAME
The regulatory domain can be omitted, but then the system will be guided by the union of all restrictions, that is, the worst possible option.

Fortunately, firstly, data on regulatory domains are available in open access on the kernel site:

And you can search for them. In principle, it is probably possible to patch the kernel so that it ignores the regulatory domain, but this would require rebuilding the kernel, or at least the crda regulatory daemon.

Fortunately, the iw phy info command displays all the capabilities of our device, taking into account (!) the regulatory domain.

So, how do we fix the state of our Wi-Fi?

First, let's find a country in which Channel 13 is not banned. A path of at least half the frequency will be empty. Well, there are quite a few such countries, although some, without prohibiting it in principle, however, prohibit either the high speed mode n on it, or the creation of an access point in general.

But one channel 13 is not enough for us - because we want a larger signal-to-noise ratio, which means we want to launch a point with a signal strength of 30. We are looking for-looking in CRDA, (2402 - 2482 @ 40), (30) 13 channel, width 40 MHz, signal strength 30. There is a country New Zealand.

But what is it, at 5 GHz, DFS is required. In general, this is theoretically a supported configuration, but for some reason it does not work.

An optional task that can be completed by people with advanced social skills:

Gather signatures / movement in support of accelerated relicensing of Wi-Fi bands in the ITU (well, or at least in your country) in general towards expansion. This is quite real, some deputies (and candidates for deputies), thirsting for political points, will be happy to help you.

This is ravine number 4

The access point may not start with DFS, without explanation. So, which regulatory domain should we choose?

There is one! The freest country in the world, Venezuela. Its regulatory domain is VE.

A full 13 channels of the 2.4 band, with a power of 30 dBm, and a relatively relaxed 5 GHz band.

Asterisk challenge. If you have a complete disaster in your apartment, even worse than mine, there is a separate, bonus level for you.

Regulatory domain "JP", Japan, allows you to do a unique thing: run an access point on the mythical channel 14. True, only in mode b. (Remember, I said that there are still small differences between b and g?) So if everything is really bad for you, then channel 14 can be a salvation. But then again, it is physically supported by a few client devices and access points. Yes, and the maximum speed of 11 Mbps is somewhat discouraging.

Copy /etc/hostapd/hostapd.conf into two files, hostapd.conf.trendnet24 and hostapd.conf.cisco57

We trivially edit /etc/rc.d/rc.hostapd to run two copies of hostapd.

In the first one, we indicate channel 13. However, we indicate the signal width as 20 MHz (capability 40-INTOLERANT), because, firstly, this way we will be theoretically more stable, and secondly, “law-abiding” access points simply will not start at 40 MHz from -because of the clogged range. Set capability TX-STBC, RX-STBC12. We cry that capabilities LDPC, RX-STBC123 are not supported, and SHORT-GI-40 and SHORT-GI-20, although they are supported and slightly improve speed, but also slightly reduce stability, which means we remove them.

True, for amateurs, you can patch hostapd so that the force_ht40 option appears, but in my case it makes no sense.

If you are in a strange situation when access points turn on and off, then for special gourmets you can rebuild hostapd with the ACS_SURVEY option, and then the point itself will first scan the range and select the least “noisy” channel. Moreover, in theory, it should even be able to move at will from one channel to another. However, this option did not help me, alas :-(.

So, our two points in one case are ready, we start the service:

/etc/rc.d/rc.hostapd start
The points are starting successfully, but ...

But the one that works on the 5.7 range is not visible from the tablet. What the hell is this?

Ravine number 5

The damned regulatory domain works not only on the access point, but also on the receiving device.

In particular, my Microsoft Surface Pro 3, although made for the European market, does not support the 5.7 band in principle. I had to switch to 5.2, but then at least the 40 MHz mode started up.

Ravine number 6

Everything started up. The points started, 2.4 shows a speed of 130 Mbps (would be SHORT-GI, it would be 144.4). Why a card with three antennas only supports 2 spatial streams is a mystery.

Ravine number 7

It started up, and sometimes the ping jumps up to 200, and that's it.

And the secret is not at all hidden in the access point. The point is that by Microsoft rules, Wi-Fi card drivers themselves must contain software for finding networks and connecting to them. Everything is like in the good old days, when a 56k modem had to have a dialer with it (which we all changed to Shiva, because the dialer that came with the standard delivery Internet Explorer 3.0 was too terrible) or the ADSL modem had to have a PPPoE client.

But even those who do not have a standard utility (that is, everyone in the world!), Microsoft took care of it by making the so-called “Wi-Fi auto-configuration”. This auto-configuration cheerfully spits on the fact that we are already connected to the network, and scans the range every X seconds. Windows 10 doesn't even have a "refresh networks" button. Works fine as long as there are two or three networks around. And when there are 44 of them, the system freezes and gives out a few seconds of 400 ping.

"Autoconfiguration" can be disabled with the command:

Netsh wlan set autoconfig enabled=no interface="???????????? ????" pause
Personally, I even made myself two batch files on the desktop “enable autoscan” and “disable autoscan”.

Yes, please note that if you have Russian Windows, then most likely the network interface will have a name in Russian in the IBM CP866 encoding.

Summery

I've rolled out a rather long sheet of text, and I should have ended it with a brief summary of the most important things:

1. The access point can only work in one range: 2.4 or 5.2 or 5.7. Choose carefully.
2. The best regulatory domain is VE.
3. The commands iw phy info, iw reg get will show you what you can do.
4. Channel 13 is usually empty.
5. ACS_SURVEY, 20MHz channel width, TX-STBC, RX-STBC123 will improve signal quality.
6. 40 MHz more antennas, SHORT-GI will increase the speed.
7. hostapd -dddtK allows you to run hostapd in debug mode.
8. For amateurs, you can rebuild the core and CRDA, increasing the signal strength and removing the restrictions of the regulatory domain.
9. Auto-discovery of Wi-Fi in Windows is disabled with the command netsh wlan set autoconfig enabled=no interface="???????????? ????"
10 . Microsoft Surface Pro 3 does not support the 5.7 GHz band.

Afterword

I am most of the materials used in writing this manual, found either in google or in mana to iw, hostapd, hostapd_cli.

In fact, the problem IS NOT SOLVED. At times, the ping still jumps to 400 and stays at that level, even for the “empty” 5.2 GHz band. Therefore:

I am looking for a Wi-Fi range spectrum analyzer in Moscow, equipped with an operator, with whom I could check what the problem is, and whether it is that there is a very important and secret military institution nearby that no one knows about.

P.S

Wi-Fi operates at frequencies from 2 GHz to 60 GHz (less common formats). This gives us a wavelength of 150mm to 5mm. (Why do we even measure radio in frequencies and not in wavelengths? It’s also more convenient!) I, in general, have an idea, buy wallpaper from a quarter wavelength metal mesh (1 mm is enough) and make a Faraday cage to guarantee isolate yourself from neighboring Wi-Fi, and at the same time from all other radio equipment, such as DECT phones, microwaves and traffic radars (24 GHz). One problem - it will block GSM / UMTS / LTE phones, but you can allocate a stationary charging point for them by the window.

I will be glad to answer your questions in the comments.

Not all phones, even modern ones, are equipped with 802.11ac Wi-Fi modules, which provide operation at a frequency of 5 GHz and data transfer rates up to 1.3 Gbps. It is fully compatible with other Wi-Fi 802.11a/b/g/n standards. High speed allows for the transmission of surround video signals high definition. Below - best smartphones Wi-Fi 5 GHz support.

1st place - Honor 10

The new flagship from Huawei - Honor 10 - appeared recently and managed to collect positive reviews. It is equipped with 802.11ac Wi-Fi module.

Options:

1. Screen with a diagonal of 5.84 inches and a resolution of 2280 × 1080.
2. Camera with 2 modules 16/24 MP, aperture f/1.8 and support artificial intelligence. She herself determines the plot sets the shooting settings.
3. Front camera with a resolution of 24 megapixels.
4. Processor: HiSilicon Kirin 970 with Mali-G72 MP12 video processor.
5. 4 GB RAM and 128 GB storage.
6. 3400 mAh battery.

The device, in addition to supporting the Wi-Fi 802.11ac standard, is a cool modern device with high performance and a cool camera, large memory and high autonomy.

2nd place - Apple iPhone X

A controversial phone that did not receive unequivocal positive reviews, but is a modern technological device that includes the best modules.

Options:

1. AMOLED display with a diagonal of 5.8 inches and a resolution of 2436 × 1125.
2. Camera with 12 and 12 megapixel resolutions, optical stabilization and f/1.8 aperture. At one time it was recognized as the best in the world, but by the middle of 2018 it was not the best.
3. Wi-Fi 802.11ac (5 GHz).
4. Processor: Apple A11 Bionic, 3 GB RAM and 64 GB storage.

The advantages include proprietary iOS, a cool camera and revolutionary 3D scanning technology, although there are complaints about the accuracy of its work.

3rd place - Xiaomi Mi Note 3

A new smartphone on the market, which, with flagship characteristics, received a low price. So far, it is difficult to find it on sale, but you can order it in China.

1. Full HD screen with a diagonal of 5.5 inches.
2. Dual camera 12 and 12 MP, optical stabilization, aperture f/1.8.
3. Wi-Fi 802.11ac (5 GHz).
4. Qualcomm Snapdragon 660 processor with Adreno 512.
5. 4 GB RAM and 64 GB storage.
6. 3500 mAh battery with Qualcomm Quick Charge 3.0 technology.

The advantages of the phone are not only fast Wi-Fi, but also a good camera, display, NFC chip, autonomy - 1.5 days it works without any complaints. With its low cost, a phone with cool characteristics and excellent assembly is recommended.

4th place - Huawei P20 Lite

The “younger version” of the cool Huawei P20 camera phone received weaker hardware and cut functionality, but the price has also dropped significantly. For only 20 thousand rubles, you can take an excellent flagship with high-quality shooting.

Options:

1. HiSilicon Kirin 659 with Mali-T830 MP2 video processor.
2. Camera with resolutions of 16 and 2 megapixels, f/2.2 aperture.
3. Front camera 16 MP.
4. Wi-Fi 802.11ac, NFC, face recognition (although it's not 3D scanning).
5. 3000 mAh battery.

5th place - Nokia 7 Plus

The device is somewhere between flagships and state employees, differs in performance, cameras and autonomy.

Options:

1. 6-inch IPS display with 2K resolution.
2. Dual camera 12 and 13 megapixels with f/1.75 aperture; front - with a resolution of 16 megapixels.
3. New mid-range Snapdragon 660 processor with Adreno 512 video accelerator.
4. 4 GB RAM and 64 GB storage.
5. 3800 mAh battery.
6. Cool design, fast Wi-Fi that supports 5 GHz, the presence of a full-fledged NFC chip, and most importantly, “bare” Android without a shell that works fine, does not create unnecessary loads and is constantly updated. Judging by the reviews, the phone is cool - our recommendations. This also includes Nokia 7 Plus, Nokia 8.

6-10 places

There are others cool phones with Wi-Fi 5 GHz. Let's list them below:

1. ASUS ZenFone 5 ZE620KL (28000 rubles)
2. OnePlus 6 (42-43 thousand rubles)
3. Samsung Galaxy S9+ (67,000 rubles)
4. Sony Xperia XZ1 (45,000 rubles)
5. LG V30+ (35,000 rubles)

Please rate this article:

Until now, many users are connected to the Internet via an Ethernet cable, but now laptops, tablets and smartphones, which simply need Wi-Fi wireless technology, have gained momentum. Earlier speed wireless connection left much to be desired, and reliability "limped". On this moment all modern Wi-Fi adapters comply with the IEEE 802.11n standard, which allows you to transmit over wireless network HD content, although the transfer of this type of data is not always comfortable on devices of this standard.

In theory, we have the following device throughput:

• up to 150 Mbps when using 1 antenna
• up to 600 Mbps with 4 antennas

In practice, the real speed is 1.5 - 2 times lower than the declared one.

When choosing a router, first of all, rely on the support of the 802.11n Wi-Fi standard, as it is the most modern and is compatible with equipment of previous generations: 802.11 a, 802.11 b and 802.11 g. The next standard to replace 802.11n will be - 802.11ac or 5G wifi.

Currently available for purchase Wi-Fi 802.11ac-enabled network equipment, which manufacturers release on the market marked "draft". You will not experience any problems with device compatibility, especially since there was a similar story with the 802.11 n standard. The Wi-Fi 802.11n standard is now the most popular. Plus, he has not exhausted his potential. The transfer rate is sufficient for most users.

Benefits of a Wi-Fi 802.11ac Router

• high throughput
• long range
• reduced power consumption

One of the reasons for the appearance WiFi technology 802.11ac - Achieving 1Gbps throughput. Importantly, compatibility with previous generations of network equipment has been preserved. Wi-Fi 802.11 ac has been upgraded to 5 GHz to improve data transfer speeds. As you know, 802.11n devices operate at 2.4GHz. In order to combine technologies, 802.11ac Wi-Fi equipment is capable of switching to 2.4 GHz. Many have already seen for sale, and some are currently using dual frequency routers.

It is important to consider that radio waves at a frequency of 2.4 GHz better bend around obstacles, thereby propagating over long distances, but this frequency range is subject to interference from various household appliances. In addition, in this frequency range it is not possible to place a sufficient number of channels with a width of 80-160 MHz each. Namely, a twofold increase in the channel width made it possible to increase the throughput of Wi-Fi 802.11ac technology. Based on this, the frequency of 5 GHz becomes a more rational option. Indeed, in addition to the increased width of the channels, their maximum amount- from 4 for the 802.11n Wi-Fi standard to eight for 802.11ac.

If we take into account that the bandwidth of one 160 MHz channel is 866 Mbps, then the peak data transfer rate of the Wi-Fi 802.11ac standard with 8 antennas is about 7 Gbps. For most Wi-Fi 802.11 ac enabled devices, the channel width will be limited to 80 MHz and the number of channels will be limited to three. As a result, we get a throughput of 1.3 Gbps.

What is beamforming?

Directional signal generation technology, so-called beamforming, appeared before the final specifications of Wi-Fi 802.11n were approved, but even with the transition to 802.11 ac, it remains optional. Nevertheless, beamforming itself is already a fully formed technology, which avoids problems with incompatibility. network equipment from different manufacturers. Beamforming is able to minimize signal attenuation after radio waves encounter various obstacles.

How the technology works

The transmitter determines the approximate location of the receiver and sends the signal in a strictly specified direction, which affects the increase in the range of Wi-Fi access points, and the only prerequisite is that the transmitter has several antennas directed in different directions.

Power consumption wi-fi 802.11 ac

Each user of a smartphone or tablet has experienced a rapid discharge of the battery of a mobile device when active use wireless connection. Theoretically, 802.11ac Wi-Fi controllers consume 6 times less power to transfer data at the same speed as 802.11n. In practice, the numbers are much more modest, but the results are noticeable. In addition, the increased bandwidth of 802.11ac Wi-Fi technology allows you to download data from the Internet faster and, when completed, the controller goes to sleep to reduce power consumption. In the near future, mobile devices(smartphones and tablets) will use energy-efficient 802.11ac Wi-Fi controllers with data rates from 433 Mbps to 866 Mbps.

Wi-Fi controllers 802.11ac

Currently released 802.11ac Wi-Fi controllers support 1 to 4 80MHz channels with throughput 433 Mbps each, so their peak data rate is only 1.7 Gbps. Now you can buy wifi router with support for Wi-Fi 802.11ac, but, however, with a speed limited to 1.3 Gb / s from NETGEAR, TP-Link, D-Link, ASUS, Belkin and Buffalo.

Today is one of the popular means of wireless communication? Yes, because this standard is fast and reliable.

For the first time, Wi-Fi devices began to appear in the late 90s, and users could choose one of two, at that time, versions - a And
b. Version b has become more affordable in terms of price, so it has become a mass standard. Thus, almost all devices are made specifically for this standard, which still uses the 2.4 GHz band.

In recent years, the use of the 2.4 GHz frequency band has not been considered a problem, as a large house rarely has more than two or three Wi-Fi devices. Now the situation has changed dramatically - almost every apartment has at least one Wi-Fi device, in particular, it can be laptops, tablets or phones using the 2.4 GHz frequency range. By the way, many household appliances, such as refrigerators, microwaves, wireless mice and keyboards also use this range. And finally, the well-known and popular Bluetooth standard also relies on it.

What could be the problem. And the fact is that the more devices operate at the same frequency, the more they interfere with each other. This phenomenon is called "interference" and greatly degrades the quality of communication, as well as the speed of data transfer.

To solve this problem, the company WiFi Alliance a new frequency range has been introduced - 5GHz. It is part of the protocol version n. Also, now many devices can use both the 2.4 GHz and 5 GHz bands. But with the advent of the new standard - ac, all new devices must support only the 5 GHz frequency range.

Why you need to use the 5 GHz frequency band

Since this range appeared relatively recently, there are not very many devices that use it now. Therefore, even in a densely populated city, you can safely use the device in the 5 GHz band and at the same time there will be no interference and communication disruptions, there will be a speed and stability of the Wi-Fi connection.

Naturally, both Wi-Fi devices (which communicate via Wi-Fi) must support this range. In other words, the 5 GHz band must be supported by both the router and the device that receives the signal.

How to know if the device supports 5 GHz?

If you have a router, then, accordingly, there is an instruction in which you can see if it supports this standard. This can still be said on the packaging for the device. You can also open the router control panel and see the supported frequencies.

Features of using 5 GHz

In order to take full advantage of the 5GHz band, you need to have a dual-band router. Such a router offers the ability to use two bands at once 2.4 GHz and 5 GHz. Thus, if you have an old wifi device, which only supports 2.4 GHz, then the router will be compatible with it. And if the router only supported 5 GHz, then any device with 2.4 GHz would not be able to work with it.

By the way, if the router only supports 5 GHz, but a laptop or tablet does not, then you can purchase a special Wi-Fi adapter that will allow you to use it normally. wifi network. The only downside is that one USB port will be busy, and so everything is fine.