What is Wi-Fi internet connection. See what "WiFi" is in other Wi fi dictionaries how it works

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

Wi-Fi used to stand for “Wireless Fidelity” wireless fidelity, but now it is believed that Wi-Fi stands for nothing and just looks like a pun on Hi-Fi, that is, high quality.

In order for the manufacturer to be able to name his Wi-Fi equipment, he must submit it for verification to Wi-Fi company alliance. This company checks whether the equipment complies with the requirements of the IEEE 802.11 standard. And the right to use the Wi-Fi trademark is given after the Wi-Fi Alliance makes sure that the equipment is fully compliant with IEEE 802.11.

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

Wi-Fi location in

Wi-Fi, like Ethernet, is at the physical and data link levels, and the data link uses two sub-layers, the MAC media access control sub-layer and the LLC logical channel control sub-layer.

Wi-Fi operating mode

Wi-Fi can work in two modes, the most commonly used infrastructure wifi mode in which there is wireless equipment, the so-called access points that connect to a wired network and then to the Internet. Now 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.

WiFi and Ethernet

WiFi technology is very similar to Ethernet technology, one might say, adapted to a wireless environment. For wifi addressing, as well as in Ethernet, they are used.

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 for Wi-Fi and Ethernet is the same, IEEE 802.2. In practice, this means that if you use wireshark to capture 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 transmitting over a wireless medium 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 rate is more than 6 Gb / s.

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

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, such as a microwave, and this interferes with the transmission of the Wi-Fi signal.

Signal representation

Modern Wi-Fi standards use Orthogonal Frequency Division Multiplexing (OFMD) to transmit data. Data is transmitted in parallel at different frequencies.Although the frequencies are superimposed on each other in the picture, the OFMD method allows you to reliably recognize signals.

Channels in the 2.4 GHz band

Channels in the 2.4 GHz band for data transmission uses 14 channels, 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 in the same place is limited by the number of channels; they cannot be more than 14. If more than 14 networks work in the same area, they will not have enough channels. This situation is known as “wi-fi jungle” and it is quite common, for example, in residential buildings where a Wi-Fi router is installed for Internet access in each apartment.

WiFi channel width

Wi-Fi can use channels of different widths. The channel width is the difference between the maximum and minimum frequency at which data can be transmitted. The wider the channel, the more qualitatively we can transmit data, therefore, the higher the data transfer rate.

In the 802.11n standard, it became possible to use 40 MHz channels and thereby increase the transmission rate. In the latest Wi-Fi standard 802.11ac, you can use the channel width of 80 MHz and 160 MHz. However, support for 160 MHz channels is provided at the discretion of the manufacturer.

Spatial flow

The 802.11n standard introduced the ability to use multiple antennas for transmitting and receiving 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, then the data rate increases. This uses a special signal encoding method 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, so we increase the transmission rate 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 hardware speed is fixed, it will be the same for all devices on the network. Wifi also allows you to change the speed depending on the quality of the signal. If the signal quality is high, then the speed increases, and if it is low, then 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 to be transmitted at different speeds and reliability
It is possible to change the interval of data between characters that are transmitted via Wi-Fi.

A table that shows different speed options for one spatial Wi-Fi stream. The lowest rate of 6.5 Mbps is obtained using a 20 MHz BPSK channel and 800 ns symbol spacing. The highest speed of 866 Mb/s is obtained using quadrature amplitude modulation which has 256 states, a 160 MHz channel and a 400 ns symbol interval.

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 thus increase the transmission rate even more.

At the dawn of the home Internet era, everyone hid arrays of wires as best they could. They were “sewn” into the plinth, fastened along the perimeter of the wall, packed in dust bags. In computer tables, there were even special holes for pulling a network cable. But with the popularization of Wi-Fi wireless technologies, the need to “encrypt” cables disappeared.

A relatively new technology allows you to access the network "over the air", subject to the availability of an access point - a router or other device similar in functionality. For the first time, they started talking about what Wi-Fi was in 1991, when the standards were only being tested, and they gained wide popularity only closer to 2010.

What is WiFi?

Wi-Fi is not the Internet as such, but a modern standard for data exchange between devices equipped with special radio modules. Wi-Fi modules are installed on the lion's share of electronics and equipment produced today. So, initially they were equipped only with wearable computers, mobile phones and handhelds, but recently cameras, printers and even multicookers have the ability to communicate with the global network and other devices.

An access point is a mandatory attribute for accessing the network via Wi-Fi. As usual, this role is played by a router - a device that looks like a compact box with antennas and a set of standard sockets for connecting wired Internet. The “box” itself is connected to the Internet via a twisted-pair wire, and through antennas it “distributes” data received from the network and transmits data transmitted from devices connected “over the air” to the network.

In addition to the router, you can use a laptop, mobile phone or tablet as an access point. All these devices, as well as mobile routers that are gaining popularity, must be connected to the global network through mobile communications(sim card with GPRS, 3G, 4G). The principle of receiving / transmitting data is the same as that of a wired router.

What is Wi-Fi for?

The primary "household" function of wireless access is to visit sites, download files and communicate over the network without the need to be tied by wires to a specific point. Every year, cities are more and more “covered” with access points available to everyone, so that in the near future, if you have a device with a radio module, you can use the network in any city.

Also, radio modules can be used to organize an internal network between devices. Lenovo, for example, has already posted in open access an application for mobile devices that allows you to share any type of files between gadgets via Wi-Fi, but without the need for an Internet connection. The program creates a tunnel through which it transmits some information to the receiving party. When using the application, data exchange is ten times faster than via Bluetooth. In the same way, a smartphone can play the role of a joystick in conjunction with a game console or laptop, or take on the functions of a remote control. remote control TV with Wi-Fi.

How to use WiFi?

To forget about the web of wires at home or in the office, you need to purchase a router. Connect the Internet access wire to the socket highlighted in color (usually yellow or white) and configure it according to the instructions. After that, on all devices that are equipped with a Wi-Fi module, you need to turn on the module, search for a network and connect.

Attention! The speed of Internet access through one access point is the lower, the more devices are connected to it at the same time. The speed is divided proportionally between all devices.

If your computer does not have a radio module, you can purchase one. The external radio module looks like a flash drive, it is also connected via a USB interface. The average cost is within $10.

Internet with mobile device can be "distributed" through the "Access Point" option. Find the option in your phone or tablet settings and follow the step by step network setup.

Attention! When a mobile phone or tablet “distributes” the Internet, being an access point, it is better not to watch videos and listen to podcasts on it. The speed between the distributing and connected device is divided according to the residual principle, and only if the Internet is not actively used on the “access point”, the connected device can download sites at normal speed.

Wi-Fi technology allows you to enter the network without being tied to an Internet cable. Any device equipped with a radio module that supports the transmission standard can be a source of wireless Internet. WiFi data. In this case, the signal propagation radius depends on the power of the access point antenna. Through Wi-Fi, you can not only connect to the Internet, but also transfer files and combine devices into a separate network.

Articles and Lifehacks

Such an interesting and useful thing as WI-FI was invented relatively recently - in 1991 in the Netherlands. At first the name sounded like HI-FI and was deciphered " high accuracy". After a while, the name was rephrased to " wireless precision". Now the decoding of the invention has been abandoned, it is simply used by a short abbreviation. This access point is popular and indispensable in almost every corner of the world.

What is Wi-Fi in a mobile phone? This is a wireless connection to the Internet that is based on radio signals. That is, the Wi-Fi itself goes to other devices using a router (router). The more people connect, the slower the data transfer rate.

Where to find Wi-Fi and how to connect to it

Often, many establishments provide a service such as a wireless network for free. Cafeterias attract busy people who dine and work online without looking up from their phones and laptops. For students, this is also a free salvation: I downloaded the abstract, printed it out - and it is already ready for the seminar.

In such establishments, it is easy to see an icon that lures you with wireless Internet. It is very easy to connect: you need to go to the phone settings, turn on WI-FI (in some it is referred to as " WLAN"). After that, go to " wireless networks”, a list of all devices that your phone sees and can connect to will be displayed. There are password-protected networks. It must be entered, and access will be immediately allowed.

You can connect to various shopping centers, for example, as well as at home, if a router is installed.

Pros and cons of wireless connection

Of the pros:

It does not matter the location - whether the house, office, favorite cafeteria.
The scale of the zone, the possibility of movement.
Low emissivity of the device.
High data transfer, while saving mobile Internet.

Of the minuses:

A password that restricts access to the network.
If the access point exceeds 100 mW, then registration is required.
Experienced hackers can easily break the protection.
Phones that only use Wi-Fi have a short network range.
The quality of the connection is affected by foreign objects (walls, furniture, vehicles).

In the early days after the advent of the Internet, everyone tried to hide a huge amount of wires. PC users built them into skirting boards, packed them in special bags, fixed them to walls, etc. Special holes were even made in the tables for network cables. However, after the advent of Wi-Fi wireless technology, everything has changed dramatically, and you no longer need to think about how to disguise the cords in the room.

general description

Talk about what Wi-Fi means began at the end of the last century, when this technology was going through the testing stage. It began to become widespread around 2010.

Thinking about what the word Wi-Fi means, you should remember the English phrase “Wireless Fidelity?”, Which translates as “wireless accuracy”. It is from this phrase that the abbreviation “Wi-Fi” itself came about.

A Wi-Fi network is not the Internet. This is a special principle of information exchange between devices in which radio modules are built-in. Today, these devices are found in almost all modern models of technology and electronic equipment. T So, at first, modules were built into only a few devices:

smartphones;
portable PCs;
handhelds.

However, now printers, photo and video cameras, and even kitchen multicookers have the possibility of wireless connection. And the tasks for which Wi-Fi is needed are becoming more and more.

A mandatory component of Internet access through the Wi-Fi system is the so-called access point. A router is used for this purpose. This is a compact device with standard connectors and amplifier antennas. The instrument is connected to the network using a twisted-pair cable, and antennas are designed to transmit information to devices connected "over the air".

In addition to the router, access points can create:

These gadgets must have an Internet connection using a mobile network (sim card with 4 G, 3 G or already outdated GPRS). In this case, the principle of transmitting / receiving information will be similar to that of a wired router.

Technology features

The main task of Wi-Fi technology is visiting resources on the Internet, download files and communicate online without being tied to wires. Today, cities have an increasing number of access points that anyone can use. Experts have no doubt that soon the Internet will be available in any locality.

Radio modules are also often used to set up an internal network, for example, in a company. Lenovo specialists, who know what Wi-Fi means, have long developed a special program for mobile devices that allows you to very quickly exchange various files between devices using a Wi-Fi network without an Internet connection.

The application creates a special virtual tunnel that is responsible for data transfer. The advantage of this technology is that with its help information is transmitted several tens of times faster than with the use of outdated Bluetooth. So, a mobile phone can be used as a gaming joystick for a laptop or console. You can also change channels on your Wi-Fi enabled TV.

Application features

To get rid of the array of cables once and for all at home or in the office, you need to get a router in advance. The device has a special socket, which is usually highlighted in white or yellow. You need to connect a network cable to it. Then you have to configure the equipment in accordance with the instructions. After that, on all devices where there is a Wi-Fi module, you need to activate it, find the created network and connect to it.

It should be noted that the speed of Internet access depends on the number of devices connected to one access point. This is due to the fact that the speed will be proportionally divided between them.

If the PC does not have a Wi-Fi module, then it can be purchased separately. By appearance this device resembles an ordinary USB flash drive. The average price of the device is about 10-15 dollars.

You can access the network from your smartphone using the Hotspot function. For this purpose, you need to configure the option in the tablet settings or mobile phone.

Wi-Fi allows you to access the Internet without any cables and wires. The signal source can be any device that has a radio module. The radius of action in this case depends on external obstacles in the form of walls., ceilings and other structures, as well as from the power of the transmitting antenna. With the help of this modern technology, you can not only use the Internet, but also exchange files on different devices, as well as combine all gadgets into a single internal network.