What does Wi-Fi mean? How Wi-Fi works: everything about the operation of a wireless network from WiFiGid! Where is Wi-Fi used?

Introduction

So, Wi-Fi is a wireless method of data transmission that uses radio signals. Literally, wi-fi means wireless quality.

The technology was originally based on the IEEE 802.11 standard, from which various other offshoots of digital signal transmission standards emerged.

The birth date of wi-fi is considered to be 1991, and the technology was being developed for cash register equipment. After some time, the developers saw that the potential of their project was much greater, which was later confirmed.

Nowadays, Wi-Fi wireless data transmission is extremely popular. Not a single large public place in big cities can do without it.

How to hack Wi-Fi in 1 minute? (how to hack wifi)

How wi-fi works or the answer to the question of how to connect to the Internet via wi-fi

It is important to understand that wi-fi is not an Internet connection at all, but simply a wireless method of transmitting information, like bluetooth. In order to access the Internet via Wi-Fi, there must be an exit point to it.

Usually this is a modem (router), which in turn connects to the Internet via a telephone cable, local network, etc. (in public places they are installed in advance by the administration, but at home you will have to buy it, and at the same time enter into an agreement with the provider to provide you with the Internet through it).

So, such a modem (router) must contain a Wi-Fi module (if you need Wi-Fi), to which you can connect via Wi-Fi from your phone, laptop, tablet, etc.

Let's summarize what you need to access the Internet via Wi-Fi:

1. Modem (router) with Wi-Fi module (already present in public places)
2. An agreement with the provider on access to the Internet via this modem (this is for home use)
3. Create a Wi-Fi network on this router (that is, configure it), write down its name and password there
4. Well, the device through which you want to access this Wi-Fi network can be a smartphone, notebook, tablet, etc.

Only if all these steps are followed will you be able to connect to the Internet via wi-fi. Because many users often ask the question: does my smartphone support Wi-Fi and how can I connect to the Internet? Usually, in most cases, only in the order described above.

Pros of wi-fi:

• Transfer of information wirelessly, that is, there is no need to lay wires, which sometimes makes it possible to save money, as well as provide access to worldwide network in places where any technical work is prohibited (pulling cables)
• Ability to access the network from mobile devices
• Freedom of movement, that is, you can access the network from different places along your route
• Simultaneous access by multiple users from different devices
• According to some data, wi-fi radiation is much safer (ten times) than that of mobile phones

Cons:

• Within the most common Wi-Fi operating range (2.4 GHz), many other equipment also operate - bluetooth-based devices, microwaves, etc., which impairs their operating stability
• There are various frequency restrictions in a number of countries, plus recently (Russia, Italy) there are legal restrictions, that is, in these countries registration of Wi-Fi networks and operators is required
• The first methods of protecting Wi-Fi networks are relatively easy to hack, although they are still used to this day.

Development of the 802.11 standard

Let's note some stages. The old 802.11g was replaced by 802.11n, it was approved on September 11, 2009. It gave an actual increase in information transfer speed by 4 times, namely from 54 Mbit/s to 220 Mbit/s (theoretically up to 600 Mbit/s). Plus an important condition Such an increase was the same use on both devices of this particular version.

Also, it is worth noting the release of IEEE 802.22 in the summer of 2011; devices based on this standard allow you to exchange data at a speed of 22 Mbit/s over a distance of up to 100 km, which is very impressive.

This is how we can briefly describe the well-known wireless Internet access wi-fi. This technology It turned out to be very successful, practical and easy to use.

Wi-Fi is modern technology wireless connection of computers, laptops and smartphones into one network and connecting them to the Internet. You can read more about Wi-Fi and how to set it up on your computer in the article.

How Wi-Fi works

Wireless connection of computers to the Internet occurs through the use of radio waves and, according to the principle of operation, does not differ from the operation of radio stations, cell phones and television receivers. The only significant difference with Wi-Fi is the use of higher frequencies than in radio communications and television broadcasts (2.4 GHz or 5 GHz). Operating at such frequencies makes it possible to transmit large amounts of information.

To implement wireless Internet access, you need a router (router) with a built-in module for receiving and transmitting radio signals and a similar module built into a computer or laptop. The router connects to the Internet via network cable through any provider. The cable carries the digital signal from the Internet to the router, where it is converted into radio waves. The router sends a radio signal to the computer's receiving module, which again converts it to digital. Similarly, a digital signal from a laptop is encoded by a transmission module into a radio signal, transmitted “over the air” to the router, converted there into digital and sent to the worldwide network.

How does a Wi-Fi router work?

Routers are capable of transmitting a signal from the Internet to more than one device. This allows one network cable to access the Internet immediately from a desktop computer, laptop, tablet, etc. The coverage area of ​​modern routers is 50-100 meters (if there are no obstacles). This allows a person to move freely around the apartment with mobile device without losing connection with the World Wide Web.

The router's memory contains a routing table that stores paths to all connected devices. The Internet access channel width provided by the provider is also distributed among all mobile and stationary devices. It should be noted that a Wi-Fi connection through a router is convenient for communicating on social networks or via Skype, viewing email, internet surfing. For online viewing of large videos or downloading files, a network connection is more suitable.

How Wi-Fi works on a laptop

Most modern laptops are equipped with a built-in module for receiving and transmitting radio signals that supports a Wi-Fi connection to the Internet. Such devices usually have a sticker with the Wi-Fi logo. Network equipment for wireless connections is produced by many companies, using different technical solutions. However, the presence of the Wi-Fi logo tells consumers that manufacturers use a single communication standard, and devices from different companies will be mutually compatible, that is, they will be able to work with each other on the same network.

Wi-Fi is now the most popular wireless data transmission technology. computer networks. The name is a trademark that belongs to the wi-fi alliance. Technical description technology is contained in the IEEE 802.11 standard.

Previously, Wi-Fi was deciphered as “Wireless Fidelity”, wireless precision, but now it is believed that Wi-Fi is deciphered in no way and is simply similar to a play on words Hi-Fi, that is, high quality.

In order for a manufacturer to call its equipment Wi-Fi, it must submit it for inspection to the Wi-Fi Alliance. This company checks whether the equipment meets the requirements of the IEEE 802.11 standard. And the right to use trademark Wi-Fi is provided after the Wi-Fi Alliance verifies that the equipment fully complies with IEEE 802.11.

For comparison, such a check is not performed for ethernet; a manufacturer can create equipment that operates according to the 802.3 standard and its modifications and call it an Ethernet switch

Wi-Fi location in

Wi-Fi, like Ethernet, is located at the physical and link levels, and at the link level two sublayers are used, the MAC media access control sublayer and the LLC logical link control sublayer.

Wi-Fi operating mode

Wi-Fi can operate in two modes, the infrastructure mode is most often used wifi mode which contains wireless equipment, so-called access points, that connect to wired network and then to the Internet. Nowadays Wi-Fi is most often used to connect to the Internet. Therefore, the infrastructure mode is the most popular.

Another connection option is also possible, a peer-to-peer network, where computers interact without any access points, directly with each other.

Wi-Fi and Ethernet

Wi-Fi technology is very similar to Ethernet technology, one might say, adapted in a wireless environment. For addressing wifi, just like in Ethernet, .

For data transmission, a shared medium is used, as in classic Ethernet. Only in classic Ethernet the signal is transmitted over a cable, and in wifi electromagnetic radiation (radio air) is used.

The frame format at the LLC level is the same for Wi-Fi and Ethernet, IEEE 802.2. In practice, this means that if you use wireshark to intercept packets that go over the network, then regardless of whether your frame came from Ethernet or from Wi-Fi, its format will be the same. Although in the process of wireless transmission at the MAC level, Wi-Fi uses a different frame format.

Wi-Fi Physical Layer Standards

There are several different options for implementing Wi-Fi, they are described in 6 standards. The very first 802.11 standard was adopted in 1997 and had a speed of 1 or 2 Mb/s; Ethernet at that time could transmit information at a speed of 10 Mb/s. The modern wifi standard 802.11ac was adopted in 2014, the maximum transfer speed is more than 6 Gb/s.

Now Wi-Fi is used to transmit data - electromagnetic radiation or radio broadcasts, but in the first version of Wi-Fi, infrared radiation was used, now this method is used in TV remote controls.

But since the second generation of the 802.11b standard, only electromagnetic radiation has been used. Two frequencies are used: 2.4 and 5 GHz. Frequencies in this range can be used without licensing. However, other devices operate in the same range, for example a microwave, and this creates interference with Wi-Fi signal transmission.

Signal representation

In modern wi-fi standards Orthogonal frequency division multiplexing (OFMD) method is used to transmit data. Data is transmitted in parallel at different frequencies.Although the frequencies in the picture overlap each other, the OFMD method allows you to reliably recognize the signals.

Channels in the 2.4 GHz range

Channels in the 2.4 GHz range 14 channels are used for data transmission, their frequencies are listed in the picture. The channels are slightly shifted relative to each other, but still partially overlap.

Thus, the number of Wi-Fi networks that are located in the same place is limited by the number of channels; they cannot be more than 14. If more than 14 networks operate in the same area, they will not have enough channels. This situation is known as “a Wi-Fi jungle” and it occurs quite often, for example in residential buildings where a Wi-Fi router is installed for Internet access in each apartment.

Wi-Fi channel width

Wi-Fi can use channels of different widths. Channel width is the difference between the maximum and minimum frequencies at which data can be transmitted. The wider the channel, the better quality we can transmit data, therefore, the higher the data transfer speed.

The 802.11n standard makes it possible to use 40 MHz channels and thereby increase the transmission speed. In the latest Wi-Fi standard 802.11ac, you can use channel widths of 80 MHz and 160 MHz. However, support for 160 MHz channels is provided if possible and at the request of the manufacturer.

Spatial flow

The 802.11n standard makes it possible to use multiple antennas to transmit and receive data. This feature is also used in the modern standard.

If we have several antennas, then we can use several spatial streams - this is a signal that is transmitted from one antenna to another.

If we transmit several spatial streams in parallel, the data transfer speed increases. In this case, a special signal coding method is used called MIMO - multiple transmission and multiple reception.

Example: we have 3 antennas, at the transmitting station and three at the receiving station. Each antenna at the transmitting station (Tx) sends its own spatial stream, thus we increase the transmission speed by 3 times. At the receiving station, all three antennas receive 3 spatial streams, and using the mimo coding method they are able to separate them and improve the signal quality for each individual spatial stream.

Speed ​​adaptation

In Ethernet, the speed of the equipment is fixed, it will be the same for all devices on the network. WiFi allows you to change the speed depending on the quality of the signal. If the signal quality is high, the speed increases, and if it is low, the speed decreases. In order to increase or decrease the speed, Wi-Fi changes several parameters:

• You can use different channel widths from 20 MHz to 160 MHz.
• Supports various modulations that allow data transmission from at different speeds and reliability
• It is possible to change the data interval between characters that are transmitted via Wi-Fi.

A table that shows different speed options for one spatial Wi-Fi stream. The lowest speed of 6.5 Mb/s is obtained using a 20 MHz BPSK channel and an 800 ns symbol interval. The most high speed 866 Mb/s is obtained if we use quadrature amplitude modulation, which has 256 states, a channel width of 160 MHz and an interval between symbols of 400 ns.

The data is presented for one spatial stream; if your access point and your station have multiple antennas, then you can use multiple spatial streams and thereby increase the transmission speed even more.

One of the most common questions when connecting to global web is: “How to use Wi-Fi?” This is the most used data transmission standard today. It can be found both on desktop computers and on tablets, smartphones, and laptops. Depending on operating system and hardware implementation, the method of connecting to such a network changes significantly. Therefore, it would be more correct to link how to use Wi-Fi to a group of devices. There is one algorithm for laptops and stationary system units, but another for tablets and smartphones.

What is Wi-Fi?

Before using Wi-Fi, let's find out what it is. This term hides the most common data transfer standard. It has a number of advantages. Among them are:

• No wires.
• Maximum mobility within signal range.
• Can be installed in most mobile and desktop computing devices.

Among the disadvantages are:

• There is a possibility of hacking.
• High power consumption.
• A sharp decrease in signal quality in rooms with reinforced concrete slabs.

It has several different modifications, which in most cases are compatible with each other. To date, several
security options, the best of which is WPA2. It is the most difficult to hack.

On a smartphone or tablet

Now let's figure out how to use Wi-Fi on the most popular mobile gadgets: smartphones and tablets. To do this, turn on the device. After downloading it, go to the address: “Applications/Settings/Wireless/Wi-Fi Settings”. At the bottom of the screen there will be a list of available networks. We choose the one we need. If it is protected by a password, a window will appear for you to enter it. Next, the device automatically connects, after which you can launch the browser to surf the Internet. Then you can use the accelerated connection. To do this, you need to open the drop-down menu on the main screen. At the top there will be a characteristic set of buttons, including a Wi-Fi activation button. When you press it, the wireless network will turn off. When you press it again, it will be reactivated and you will be able to visit pages on the World Wide Web. This connection is configured on a tablet in the same way.

On a laptop or desktop PC

On a PC running Windows, the algorithm for how to use Wi-Fi is very similar. On the taskbar in the lower right corner there is an icon for wireless networks. Click on it once with the right button of the manipulator. A list will open in which you need to select the required connection. If the network is protected by a password, a window will appear in which you will need to enter it. Next, a short period of time is required to obtain a network address. After this procedure is completed, you can launch the browser and browse sites on the Internet.

Conclusion

This article examined the wireless technology for transmitting information over a distance - Wi-Fi. How to use it, configure it, visit pages on the Internet? These are the most common questions that arise while working with it. These are the questions that were answered here.

Wi-Fi... oh how much sound there is in this! And how many myths these sounds have created among the people, it’s scary to imagine. Hi all! Today it will be on our portal about wireless technologies central article about Wi-Fi itself. Only without any special wisdom, in simple words, well, you understand) Let's go!

Central problem

After running down the street, when asked what Wi-Fi is, people answer differently. I leave several options below; I give the meanings themselves, and not verbatim statements:

• The Internet - well, in terms of Wi-Fi - is the Internet itself, on which they look at sites, their favorite VKontakte and YouTube
• Router/Router – the device itself.
• Wireless transmission of information – in the meaning of technology.
• Connecting a smartphone/laptop is one of the device functions.

A few people simply “hanged”, apparently considering the answer either stupid, or they were asked it at the wrong time) Well, oh well. Everyone has heard about Wi-Fi. But what is it really? Do you have the correct answer?

By the way, comments are always open for me. If you have a question, ask it below and we’ll figure it out there)

Definition, or what is it?

So the correct answer and the only smart term here is:

Wi-Fi - wireless technology local network with devices based on IEEE 802.11 standards.

The bottom line for dummies is WIRELESS data transmission TECHNOLOGY.

Precisely the technology itself, and precisely without wires. Other well-known technologies in the same vein are Bluetooth, Infrared transmission (TV remote control, IR port on old phones), radio, technology mobile operators. And somewhere among them Wi-Fi appeared, and the features of its technology are precisely described in the standard from the IEEE 802.11 definition. Whoever wants it will look for it himself.

Origin of the word

Another question is the meaning of the term “Wi-Fi” itself. Indeed, from all of the above, this question remains open. So this is short for:

WiFiWirelessFidelity – translated as “wireless accuracy” or “wireless data transmission”.

Pronunciation

There is nothing complicated: we read WiFi as [wifi]- can be quickly in one word, or separated a little.

There is no need to pronounce this word as [wi fi] - it’s completely savage.

Clearing up the confusion

The people's answers above arose from the frequency of use in everyday life. Let's look at them in a little more detail and identify the differences:

• Internet. Wi-Fi as a technology creates a local network to which other devices can be connected. But on the network, all these devices may not have the Internet at all. In this sense, it is more correct to understand that you are connecting to a device that distributes the Internet using Wi-Fi technology. The Internet is global network, to which everyone is trying to connect using various technologies.
• Router/Router. These are just devices, and even nowadays they can be without Wi-Fi, but perform their functions via wires.
• Connecting a smartphone/laptop– and it happens that the laptop is connected via wire, and the smartphone is connected through the operator’s technology. The bottom line is that Wi-Fi is not a feature here, but they do have the feature of using a Wi-Fi connection.

That's it... enough nonsense. All myths and legends were considered. Let's go to more nuances.

How does it work and how to use it?

I will outline how the Internet via Wi-Fi is delivered to your end user - a laptop, smartphone, tablet. Yes, it can be connected via adapters to desktop computer, but usually the latter still clings to the wire.

To connect a PC toWi-Fi you can always buy an adapter - good device you can find no more than $10.

But for mobile equipment at home this is already a standard. So, let's see.

1. You connect to the Internet service from your Internet provider (Rostelecom, or whatever you have).
2. The provider usually already has a cable installed in your home and even your entrance. When connected, the master only leads it from the panel to your apartment.
3. Your apartment now has a cable that connects to the device (the same router).
4. The router's creation function is activated Wi-Fi networks. Through which he distributes the Internet to everyone.
5. All devices connect to it and use the Internet.

Another possible scheme is based on the use of networks of cellular operators and their modems:

1. You buy a SIM card mobile operator with a special Internet tariff.
2. The SIM card is inserted into the modem.
3. The modem creates an Internet connection via a SIM card and distributes Wi-Fi.

Here an external antenna is also connected to the modem to strengthen the signal (not always used)

Total: WI-FI creates special device, operating in “Access Point” mode:

• Via router
• Via modem

In public places, cafes, hotels, everything is usually already done for you - there are usually good powerful routers there. All you have to do is find the correct network on your device, enter the password and enjoy free internet(Sometimes it’s paid, depending on your luck). Another name for public points is hot spots.

These 2 schemes are the most common. There are other methods (access point via laptop, tablet, phone), but for our purposes this is more than enough. If you want to know more, feel free to write in the comments)

Basic functions, or what is Wi-Fi needed for?

In total, devices that distribute Wi-Fi now have two main functions:

• Connect to the Internet and visit your favorite sites and services from there.
• Creating a local network - all devices connected to one access point can see each other and transfer the same files directly.
• Expansion of the previous paragraph - connection wireless devices. A printer, joysticks, a TV remote control, a refrigerator - it’s impossible to imagine everything.

Historical information. The technology was invented in 1991 and was used specifically for cash register equipment.

Advantages and disadvantages of Wi-Fi

• Possible slight delays in the network - ping - may be noticeable in games
• Internet speed may be reduced due to technology speed limits
• Possible loss of signal indoors due to obstacles - you need to place the router at home correctly
• The use of 2.4 GHz frequency technology can also create interference with other devices - remote controls, microwave ovens, etc.
• Weak security of old security protocols.

I note that the advantages and disadvantages here are more technical and depend on the device itself. So everything can be decided, it all depends on the specific situation.

Myths and legends - radiation

The main myth about Wi-Fi is the danger of radiation. Yes, Wi-Fi uses radio frequency. The most common operating frequency is 2.4 GHz. Other known ones also operate at this frequency. household appliances- like a microwave. But in fact, the operating radiation of Wi-Fi is tens of times less than the influence of the same mobile phone. And not to mention how many other radio waves pass through our house...

Transmission range

Another myth is about the data transmission range in a radio channel. I have met from a minimum of 5 meters to hundreds of kilometers. The bottom line is that it all depends on the transmission power. Average transmission rates:

• 45 m – indoor communication
• 90 m – communication in open space

It is worth understanding that reinforced concrete in the walls can greatly dampen the signal, even to the point of its absence in neighboring rooms. So you need to carefully consider the location of the access point.

There are other standards wireless network with an increased range of kilometers (read below).

I will devote a separate article to Wi-Fi standards. We are talking about the letters on the Wi-Fi devices themselves. You may have seen them: a, b, g, n... These are essentially versions of the standards. In this series, the higher the letter, the higher the transmission speed. So, for example, for the 802.11 standard:

• IEEE11 is the base of the standard from where “legs grow”.
• IEEE 11a – up to 54 Mbit/s, operating frequency 5 GHz – therefore not compatible with other versions.
• IEEE11b – up to 11 Mbit/s, frequency – 2.4 GHz – modern devices are compatible with it.
• IEEE11g – up to 54 Mbit/s
• IEEE11n – up to 300 Mbit/s, uses band 2 – 2.4 GHz and 5 GHz

Versions of the standard older than " b" are backward compatible. To maintain speed, you need support for the standard not only on the transmitter, but also on the receiver. For example, a phone with " g" will not be able to receive Internet with a bandwidth higher than 54 Mbit/s from the access point on "n".

Other standards for comparison are presented in the table:

Among the interesting developments, we note the IEEE 802.22 standard (WRAN, regional wireless network, not to be confused with regular Wi-Fi): here the transmission speed becomes lower (22 Mbit/s), but the transmission range increases to 100 km. For an ordinary home Wi-Fi, the normal values ​​will be 10-100 m, depending on the location.

In Russia, the use of these channels does not require additional licensing. But something has recently been developing towards registering households wireless points access - in practice, it is almost impossible to implement this, so for now we live and breathe. Some other countries impose restrictions on the use of such networks - check with your location.

Video about Wi-Fi