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Maximum wifi speed 802.11n. Mobile standards

WiFi 802.11 standards are developed by the IEEE (Institute of Electrical and Electronic Engineers)

IEEE 802.11 is a basic standard for Wi-Fi networks that defines a set of protocols for the lowest transfer rates.

IEEE 802.11 b- describes b O higher transfer rates and introduces more technology restrictions. This standard was widely promoted by WECA ( Wireless Ethernet Compatibility Alliance ) and was originally called Wi-Fi .
Frequency channels in the 2.4GHz spectrum are used ().
Ratified 1999.
RF technology used: DSSS.
Coding: Barker 11 and CCK.
Modulations: DBPSK and DQPSK,
Maximum data transfer rates (transfer) in the channel: 1, 2, 5.5, 11 Mbps,

IEEE 802.11 a- describes significantly higher transfer rates than 802.11b.
Frequency channels are used in the 5GHz frequency spectrum. ProtocolNot compatible with 802.11 b.
Ratified 1999.
RF technology used: OFDM.
Coding: Convoltion Coding.
Modulations: BPSK, QPSK, 16-QAM, 64-QAM.
Maximum data transfer rates in the channel: 6, 9, 12, 18, 24, 36, 48, 54 Mbps.

IEEE 802.11 g - describes data rates equivalent to 802.11a.
Frequency channels in the 2.4GHz spectrum are used. The protocol is compatible with 802.11b.
Ratified 2003.
RF technologies used: DSSS and OFDM.
Coding: Barker 11 and CCK.
Modulations: DBPSK and DQPSK,
Maximum data transfer rates (transfer) in the channel:
- 1, 2, 5.5, 11 Mbps on DSSS and
- 6, 9, 12, 18, 24, 36, 48, 54 Mbps on OFDM.

IEEE 802.11n is the most advanced commercial WiFi standard available on this moment, officially approved for import and use on the territory of the Russian Federation (802.11ac is still in the process of being developed by the regulator). 802.11n uses frequency channels in the WiFi 2.4GHz and 5GHz frequency spectra. Compatible with 11b / 11 a / 11 g ... Although it is recommended to build networks with a focus only on 802.11n, since requires configuration of special protection modes if necessary backward compatibility with outdated standards. This leads to a large increase in signaling information andsignificant decrease in available useful productivity radio interface. Actually, even one WiFi 802.11g or 802.11b client will require special configuration of the entire network and its immediate significant degradation in terms of aggregated performance.
Myself WiFi standard 802.11n was released on September 11, 2009.
Frequency supported WiFi channels width 20MHz and 40MHz (2x20MHz).
RF technology used: OFDM.
Uses OFDM MIMO (Multiple Input Multiple Output) technology up to 4x4 (4xTransmitter and 4xReceiver). In this case, at least 2xTransmitters per Access Point and 1xTransmitter per user device.
Examples of possible MCS (Modulation & Coding Scheme) for 802.11n, as well as the maximum theoretical data transfer rates (transfers) in the radio channel are presented in the following table:

Here SGI is the guard interval between frames.
Spatial Streams is the number of spatial streams.
Type is the type of modulation.
Data Rate is the maximum theoretical data transfer rate in the radio channel in Mbps.

It is important to emphasize that the indicated rates correspond to the concept of channel rate and are the limit value using this set technologies within the described standard (in fact, these values, as you probably noticed, are also written by manufacturers on the boxes of home WiFi devices in stores). But in real life, these values are not achievable due to the specifics of the WiFi 802.11 technology itself. For example, "political correctness" in terms of providing CSMA / CA is strongly influenced here (WiFi devices constantly listen to the air and cannot transmit if the transmission medium is busy), the need to confirm each unicast frame, the half-duplex nature of all WiFi standards and only 802.11ac / Wave-2 can this is to start bypassing with, etc. Therefore, the practical efficiency of the outdated 802.11 b / g / a standards never exceeds 50% in ideal conditions (for example, for 802.11g the maximum speed per subscriber is usually not higher than 22 Mb / s), and for 802.11n efficiency can be up to 60%. If the network operates in a protected mode, which often fails due to the mixed presence of various WiFi chips on various devices ah in the network, then even the indicated relative efficiency can drop by a factor of 2-3. This applies, for example, a mix of Wi-Fi devices with 802.11b, 802.11g chips in a network with WiFi 802.11g access points or WiFi 802.11g / 802.11b devices in a network with WiFi 802.11n access points, etc. More about ...

In addition to the main WiFi 802.11a, b, g, n standards, there are additional standards and are used to implement various service functions:

. 802.11d... To adapt various WiFi devices to the specific conditions of the country. Within the regulatory field of each state, the ranges are often different and can be different even depending on the geographic location. The WiFi IEEE 802.11d standard allows you to adjust the frequency bands in devices from different manufacturers using special options introduced in media access control protocols.

. 802.11e... Describes the QoS quality classes for the transfer of various media files and, in general, various media content. Adaptation of the MAC layer for 802.11e, determines the quality, for example, of the simultaneous transmission of sound and image.

. 802.11f... It is aimed at unifying the parameters of the Access Points of the Wi-Fi standard from various manufacturers. The standard allows the user to work with different networks when moving between the coverage areas of separate networks.

. 802.11h... Used to prevent meteorological and military radars from creating problems by dynamically reducing the radiation Wi-Fi power equipment or a dynamic transition to another frequency channel when a trigger signal is detected (in most European countries, ground stations for tracking meteorological and communication satellites, as well as military radars operate in bands close to 5 MHz). This standard is a necessary ETSI requirement for equipment approved for use in the territory of the European Union.

. 802.11i... The first versions of the WiFi 802.11 standards used the WEP algorithm to secure Wi-Fi networks. It was assumed that this method can ensure the confidentiality and protection of the transmitted data of authorized users. wireless network from eavesdropping. Now this protection can be cracked in just a few minutes. Therefore, in the 802.11i standard, new methods of protecting Wi-Fi networks have been developed, implemented both at the physical and software levels. Currently, it is recommended to use Wi-Fi Protected Access (WPA) algorithms to organize a security system in Wi-Fi 802.11 networks. They also provide interoperability between wireless devices of various standards and modifications. WPA protocols use the enhanced RC4 encryption scheme and a mandatory authentication method using EAP. Stability and safety modern networks Wi-Fi is defined by privacy check protocols and data encryption (RSNA, TKIP, CCMP, AES). The most recommended approach is to use WPA2 with AES encryption (and don't forget about 802.1x with highly desirable tunneling mechanisms like EAP-TLS, TTLS, etc.). ...

. 802.11k... This standard is actually aimed at implementing load balancing in the radio subsystem of a Wi-Fi network. Typically, in a wireless LAN, the subscriber unit usually connects to the access point that provides the strongest signal. This often leads to network congestion at one point, when many users connect to one Access Point at once. To control such situations in the 802.11k standard, a mechanism is proposed that limits the number of subscribers connected to one Access Point, and makes it possible to create conditions under which new users will join another AP even though the signal from it is weaker. In this case, the aggregated network bandwidth is increased due to the more efficient use of resources.

. 802.11m... Corrections and corrections for the entire 802.11 group of standards are combined and summarized in a separate document collectively called 802.11m. The first release of 802.11m was in 2007, then in 2011, and so on.

. 802.11p... Defines the interaction of Wi-Fi equipment moving at speeds up to 200 km / h past fixed Points WiFi access, remote at a distance of up to 1 km. Part of the Wireless Access in Vehicular Environment (WAVE) standard. The WAVE standards define an architecture and an additional set of service functions and interfaces that provide a secure radio communication mechanism between moving vehicles. These standards are developed for applications such as, for example, traffic management, traffic safety control, automated payment collection, vehicle navigation and routing, etc.

. 802.11s... A standard for the implementation of mesh networks (), where any device can serve as both a router and an access point. If the nearest access point is congested, data is redirected to the nearest unloaded node. In this case, a packet of data is transferred (packet transfer) from one node to another until it reaches its final destination. This standard introduces new protocols at the MAC and PHY layers that support broadcast and multicast transmission (transfer), as well as unicast delivery over a self-configuring Wi-Fi access point system. For this purpose, the standard introduces a four-address frame format. Implementation examples WiFi networks Mesh:,.

. 802.11t... The standard was created to institutionalize the testing process of IEEE 802.11 standard solutions. Testing methods, methods of measurement and treatment of results (treatment), requirements for test equipment are described.

. 802.11u... Defines the procedures for the interaction of Wi-Fi networks with external networks. The standard should define access protocols, priority protocols and prohibitions on working with external networks. At the moment around of this standard a large movement has been formed both in terms of developing solutions - Hotspot 2.0, and in terms of organizing inter-network roaming - a group of interested operators has been created and is growing, which jointly solve roaming issues for their Wi-Fi networks in dialogue (WBA Alliance). Read more about Hotspot 2.0 in our articles: , .

. 802.11v... The standard should be developed amendments aimed at improving the network management systems of the IEEE 802.11 standard. Modernization at the MAC and PHY levels should allow centralizing and streamlining the configuration of client devices connected to the network.

. 802.11y... An additional communication standard for the 3.65-3.70 GHz frequency range. Designed for the latest generation devices operating with external antennas at speeds up to 54 Mbit / s at a distance of up to 5 km in open space. The standard is not fully completed.

802.11w... Defines methods and procedures for improving the protection and security of the Media Access Control (MAC) layer. The protocols of the standard structure a system for controlling the integrity of data, the authenticity of their source, the prohibition of unauthorized reproduction and copying, data confidentiality and other means of protection. The standard introduces management frame protection (MFP: Management Frame Protection), and additional security measures allow you to neutralize external attacks, such as, for example, DoS. A little more on MFP here:,. In addition, these measures will provide security for the most sensitive network information that will be transmitted over networks with support for IEEE 802.11r, k, y.

802.11ac. A new WiFi standard that only works in the 5GHz frequency band and provides significantly O Higher speeds for both an individual WiFi client and a WiFi Hotspot. For more details, see our article.

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Hello everyone! Let's talk again today about routers, wireless networks, technologies ...

I decided to prepare an article in which to tell about what kind of incomprehensible letters b / g / n are that can be found when setting up a Wi-Fi router, or when buying a device (Wi-Fi characteristics e.g. 802.11 b / g)... And what is the difference between these standards.

Now we will try to figure out what these settings are and how to change them in the router settings and, in fact, why change the operating mode of the wireless network.

Means b / g / n Is the wireless network operating mode (Mode).

802.11n devices can operate in one of two ranges 2.4 or 5.0 GHz.

At the physical layer (PHY), improved signal processing and modulation have been implemented, the ability to simultaneously transmit a signal through four antennas has been added.

The network layer (MAC) makes more efficient use of the available bandwidth. Together, these enhancements allow the theoretical data transfer rate to be increased up to 600 Mbps- an increase of more than ten times, compared to 54 Mbps of the 802.11a / g standard (these devices are now considered obsolete).

In reality, the performance of a WLAN depends on many factors, such as transmission medium, radio frequency, device placement and configuration. When using 802.11n devices, it is imperative to understand exactly what improvements have been made to the standard, what they affect, and how they fit and coexist with legacy 802.11a / b / g wireless networks. It is important to understand what additional features of the 802.11n standard are implemented and supported in new wireless devices.

One of the highlights of the 802.11n standard is support for the technology MIMO(Multiple Input Multiple Output)
Using MIMO technology, the ability to simultaneously receive / transmit multiple data streams through multiple antennas, instead of one, is realized.

Standard 802.11n defines various "МхN" antenna configurations, starting with "1x1" before "4х4"(The most widespread today are the" 3x3 "or" 2x3 "configurations). The first number (M) determines the number of transmitting antennas, and the second number (N) determines the number receiving antennas... For example, an access point with two transmit and three receive antennas is "2x3" MIMO-device. I will describe this standard in more detail later.

The popularity of Wi-Fi connections is growing every day, as the demand for this type of network is increasing at a tremendous pace. Smartphones, tablets, laptops, all-in-ones, TVs, computers - all our equipment supports a wireless Internet connection, without which it is already impossible to imagine the life of a modern person.

Data transmission technologies are developing along with the release of new equipment

In order to find a network suitable for your needs, you need to learn about all the Wi-Fi standards that exist today. The Wi-Fi Alliance has developed over twenty connectivity technologies, four of which are most in demand today: 802.11b, 802.11a, 802.11g, and 802.11n. The most recent discovery of the manufacturer was the 802.11ac modification, the performance of which is several times higher than the characteristics of modern adapters.

Is the senior certified technology wireless connection and differs in general availability. The device has very modest parameters:

Information transfer rate - 11 Mbit / s;
Frequency range - 2.4 GHz;
The radius of action (in the absence of volumetric partitions) is up to 50 meters.

It should be noted that this standard has poor noise immunity and low bandwidth. Therefore, despite the attractive price of this Wi-Fi connection, its technical component lags far behind more modern models.

802.11a standard

This technology is an improved version of the previous standard. The developers focused on the device's bandwidth and clock frequency. Thanks to these changes, this modification does not affect the quality of the network signal from other devices.

Frequency range - 5 GHz;
The radius of action is up to 30 meters.

However, all the advantages of the 802.11a standard are compensated equally by its disadvantages: a reduced range of connections and a high (compared to 802.11b) price.

802.11g standard

The updated modification takes the lead in today's wireless networking standards, since it supports the widespread 802.11b technology and, unlike it, has a fairly high connection speed.

Information transfer rate - 54 Mbit / s;
Frequency range - 2.4 GHz;
The radius of action is up to 50 meters.

As you can see, the clock speed has dropped to 2.4 GHz, but the network coverage has returned to the previous levels of 802.11b. In addition, the price of the adapter has become more affordable, which is a significant advantage when choosing equipment.

802.11n standard

Despite the fact that this modification has long appeared on the market and has impressive parameters, manufacturers are still working on improving it. Due to the fact that it is incompatible with previous standards, its popularity is low.

The information transfer speed is theoretically up to 480 Mbit / s, but in practice it turns out to be half as much;
Frequency range - 2.4 or 5 GHz;
The radius of action is up to 100 meters.

As this standard is still evolving, it has a quirk that it can conflict with 802.11n hardware just because the device manufacturers are different.

Other standards

In addition to popular technologies, the Wi-Fi Alliance manufacturer has developed other standards for more specialized applications. Among such modifications performing service functions, relate:

802.11d- makes wireless devices of different manufacturers compatible, adapts them to the peculiarities of data transmission at the level of the entire country;
802.11e- determines the quality of the sent media files;
802.11f- manages a variety of access points from different manufacturers, allows you to work in the same way in different networks;

802.11h- Prevents loss of signal quality due to the influence of meteorological equipment and military radars;
802.11i- an improved version of the protection of personal information of users;
802.11k- monitors the load of a certain network and redistributes users to other access points;
802.11m- contains all the fixes of the 802.11 standards;
802.11p- determines the nature of Wi-Fi devices located in the range of 1 km and moving at speeds up to 200 km / h;
802.11r- automatically finds a wireless network in roaming and connects mobile devices to it;
802.11s- organizes a fully connected connection, where each smartphone or tablet can be a router or a connection point;
802.11t- this network tests the entire 802.11 standard as a whole, gives out test methods and their results, puts forward requirements for equipment operation;
802.11u- this modification is known to everyone from the Hotspot 2.0 developments. It provides interoperability between wireless and external networks;
802.11v- in this technology solutions are created to improve modifications of 802.11;
802.11y- unfinished technology linking the frequencies 3.65-3.70 GHz;
802.11w- the standard finds ways to strengthen the protection of access to the transfer of information.

The latest and most technologically advanced 802.11ac standard

802.11ac modification devices provide users with a completely new quality of Internet experience. Among the advantages of this standard are the following:

High speed. When transmitting data over the 802.11ac network, wider channels and higher frequencies are used, which increases the theoretical speed to 1.3 Gbps. In practice, the throughput is up to 600 Mbps. In addition, an 802.11ac device transmits more data per clock cycle.

Increased number of frequencies. The 802.11ac modification is equipped with a whole range of 5 GHz frequencies. Latest technology has a stronger signal. The high range adapter covers up to 380 MHz frequency band.
802.11ac network coverage area. This standard provides a wider network range. In addition, the Wi-Fi connection works even through concrete and plasterboard walls. Interference arising from the operation of home appliances and neighboring Internet does not affect the operation of your connection in any way.
Updated technologies. 802.11ac is equipped with the MU-MIMO extension, which ensures uninterrupted operation of multiple devices on the network. Beamforming technology detects the client's device and sends it several streams of information at once.

Having got acquainted with all the modifications of the Wi-Fi connection that exist today, you can easily choose the network that suits your needs. It should be remembered that most devices include a standard 802.11b adapter, which is also supported by 802.11g technology. If you are looking for an 802.11ac wireless network, the number of devices equipped with it is small today. However, this is a very urgent problem and soon all modern equipment will switch to the 802.11ac standard. Do not forget to take care of the security of Internet access by installing a complex code on your Wi-Fi connection and antivirus to protect your computer from virus software.

Data transmission standards

Ethernet

Ethernet is a standard for building a LAN with a data transfer rate of 10, 100 or 1000 Mbps.

Ethernet is the most widely used LAN standard today. Depending on the type of physical transmission medium, the Ethernet standard has many different modifications. The first versions used a bus topology and worked on coaxial cable(50 Ohm) - 10Base5 (up to 500 m) and 10Base-2 (up to 185 m). All subsequent versions Ethernet networks have a star topology and operate over twisted pairs (100 ohms) or optical fibers. The 10Base-T (10 Mbps) and 100Base-T4 versions use Category 3 cables (2 and 4 pairs, respectively), while the 100BASE-TX (100 Mbps) version uses two Category 5 pairs. 1000Base-T (1 Gbps), which uses four pairs of enhanced Category 5, Category 6 and higher.

ATM - universal transport network for voice, data and video transmission. It has transfer rates of 25, 155, 622 and 2400 Mbps.

The first two types can operate on two twisted pairs of category 5, equipment for 155, 622 and 2400 Mbit / s uses an optical cable as a transmission medium.

FDDI standard

FDDI is a Fiber Optic Shared Data Interface. It uses a token transfer scheme, just like Token Ring. Note that in FDDI, the token is sent immediately after the packet is transmitted to the network, while in Token Ring, the token is generated only after returning to workstation the message sent to her. In addition, FDDI uses two independent rings with opposite orientation for data transmission (one of them is redundant). Compared to Token Ring, the token holding time is limited. Only fiber optic cable can be used as the physical medium in FDDI. The maximum data transfer rate over the FDDI network is 100 Mbps. Equipment for FDDI networks is mainly produced by DEC, Cisco, 3COM.

Token Ring Standard

In a token-passing LAN, messages are transmitted sequentially from one node to another, regardless of whether the network topology is ring or star. Each node in the network receives a packet from a neighboring node. If this node is not the destination, then it sends the same packet to the next node. The transmitted packet can contain either data sent from one node to another, or a token. A token is a short message indicating that the network is not busy. When a workstation needs to send a message, its network adapter waits for the token to arrive, and then generates a packet containing data and transmits this packet to the network. The package spreads over the LAN from one network adapter to another until it reaches the destination computer, which will perform standard changes... These changes are confirmation that the data has reached the destination. After that, the packet continues to move on along the LAN until it returns to the node that formed it. The source node verifies the correctness of the packet transmission and returns a token to the network. It is important to note that in a LAN with token transfer, the functioning of the network is organized in such a way that collisions cannot occur. Token Ring data transfer rates are up to 16 Mbps. Token Ring equipment is manufactured by many companies, including IBM, 3COM.

Organizations dealing with standardization in data transmission networks

International Organization for Standardization - founded in 1946 to develop international standards in various fields of technology, production and other activities.

OSI (Open Systems Interconnection) model - interoperability open systems- a seven-level model of data transmission protocols developed by the International Organization for Standardization (see - “ISO”) and CCITT (Consultative Committee for International Telephony and Telegraphy) for interfacing various types of computing and communication equipment from different manufacturers.]

IEEE (Institute of Electrical and Electronic Engineers) - Institute of Electrical and Electronic Engineers (IEEE) is an organization created in the USA in 1963. It is the developer of a number of standards for local computing systems, including software cable system, physical topology and methods of access to the data transmission medium. The most famous is the 802 series of standards (see below), for which the I EEE 802 Committee and (directly) its working groups - subcommittees are responsible.

ITU (International Telecommunications Union) - International Telecommunications Union (a structural unit of the UN), previously - International Advisory Committee on Telephony and Telegraphy - CCITT.

ITU-T - Telecommunications Standardization Committee within the ITU (see earlier), its working body - Telecommunications Standardization Sector - TSS, ITU-TSS (Telecommunications Standardization Sector). ITU-T is tasked with setting telecommunication standards. The members of the committee are the ministries of communications of the UN member states, private companies, scientific organizations and trade associations.

Data transmission channels

The advantages of this approach are the reduction in the number of user specialists in the field, unified management of the network, the optimal service support of the network during its operation and development, and others.

For corporate users, the company provides services for organizing virtual private networks of the second level (VPN Layer 2). If necessary, it is possible to organize point-to-point or point-to-multipoint channels. Frame-Relay or Ethernet 802.1q protocols are used as the link layer protocols.

With such an organization of channels, users have the opportunity to independently organize their corporate IP-network (VPN Layer 3) by imposing it on the provided channels of the second level.

To organize data transmission channels, the company recommends the use of equipment from the manufacturer Cisco Systems (when connecting via the Frame-Relay protocol, the equipment must be equipped with V.35 or G.703 / G.704 interfaces; when connecting via the 802.1q protocol - 10/100/1000 interfaces Base-TX / FX). The company is ready to assist in the selection and purchase of this equipment, followed by its initial setup.

As physical communication lines on the "last mile" can be used optical lines, copper lines using xDSL-protocols, channels of primary networks PDH / SDH.

Organization of data transmission

In a computer, two main methods of organizing data transfer between memory and peripheral devices are used: software-controlled transfer and direct memory access (DMA).

Software-controlled data transmission is carried out with the direct participation and under the control of the processor. For example, when transferring a block of data from a peripheral device to RAM, the processor must perform the following sequence of steps:

form the initial address of the exchange area of the OP;

enter the length of the transmitted data array into one of the internal registers, which will play the role of a counter;

issue a command to read information from the air-blast device; in this case, the address of the air-blast device is issued to the address bus from the MP, the signal for reading data from the air-blast device is sent to the control bus, and the read data is entered into the internal register of the MP;

issue a command to write information to the OP; at the same time, the address of the RAM cell is sent to the address bus from the MP, the data write signal to the OP is sent to the control bus, and the data from the MP register is set to the data bus, into which they were placed when reading from the I / O;

modify the register containing the RAM address;

decrease the array length counter by the length of the transmitted data;

if not all data has been transferred, then repeat steps 3-6, in otherwise finish the exchange.

As you can see, the software-controlled exchange leads to an irrational use of the power of the microprocessor, which is forced to perform a large number of relatively simple operations, suspending the work on the main program. In this case, the actions associated with access to the RAM and to the peripheral device usually require an extended cycle of the microprocessor due to their slower operation compared to the microprocessor, which leads to even more significant losses in computer performance.

An alternative to software-controlled exchange is direct memory access - a way of high-speed connection external device, in which it accesses the RAM without interrupting the processor. This exchange takes place under the control of a separate device - a direct memory access controller (DMA).

Before starting work, the PDP controller must be initialized: enter the initial address of the OP area with which the exchange is carried out, and the length of the transmitted data array. Subsequently, on the basis of a direct access request signal, the controller actually performs all the actions that the microprocessor provided during programmed transmission.

The sequence of actions of the CPD when a request for direct memory access from the I / O device is as follows:

Accept the request for RAP (DRQ signal) from the air-blast.

Generate a request to the MP to capture tires (HRQ signal).

Receive a signal from the MP (HLDA), confirming the fact that the microprocessor has transferred its buses to the third state.

Generate a signal to inform the I / O device that it has started direct memory access (DACK) cycles.

Form on the computer address bus the address of the memory cell intended for exchange.

Generate signals that provide exchange control (IOR, MW for transferring data from the air-blast to the operational memory and IOW, MR for transferring data from the random-access memory to the air-blast).

Decrease the value in the data counter by the length of the transmitted data.

Check the condition of the end of the direct access session (resetting the data counter or removing the request signal for the RAP). If the end condition is not met, then change the address in the current address register to the length of the transmitted data and repeat steps 5-8.

^ Direct memory access allows parallel execution of the program by the processor and the exchange of data between peripheral device and RAM.

Usually, software-controlled exchange is used in a computer for input-output operations of individual bytes (words), which are performed faster than with DPS, since time losses for initializing the DPS controller are eliminated, and DPS is used as the main method for carrying out input-output operations. For example, in the standard configuration of a personal computer, the exchange between drives on magnetic disks and random access memory.

Tele-access protocols.

The specificity of telecommunications is manifested primarily in application protocols. Among these, the best known are the Internet-related protocols and the ISO-IP (ISO 8473) protocols, which belong to the seven-layer open systems model. To applied Internet protocols include the following:

Telnet is a terminal emulation protocol, or, in other words, an implementation protocol remote control used to connect a client to a server when they are hosted on different computers, the user through his terminal has access to the server computer;

FTP is a file exchange protocol (the remote node mode is implemented), the client can request and receive files from the server, the address of which is specified in the request;

HTTP (Hypertext Transmission Protocol) - a protocol for communication between WWW servers and WWW clients;

NFS is a network file system that provides access to files of all UNIX machines on the local network, i.e. file systems nodes look like a single file system to the user;

SMTP, IMAP, POP3 - e-mail protocols.

These protocols are implemented using the appropriate software. For Telnet, FTP, SMTP on the server side, fixed protocol port numbers are allocated.

The seven-tier ISO model uses similar protocols. So, the VT protocol corresponds to the Telnet protocol, FTAM - FTP, MOTIS - SMTP, CMIP - SNMP, the RDA (Remote Database Access) protocol is designed to access remote bases data.

14.15.16.17.18. Tabulation of a function is the calculation of the values of a function when the argument changes from some initial value to some final value with a specific step. This is how tables of function values are compiled, hence the name - tabulation. The need for tabulation arises when solving a fairly wide range of problems. For example, when numerically solving nonlinear equations f (x) = 0, tabulation can be used to separate (localize) the roots of the equation, i.e. find such segments, at the ends of which, the function has different signs. Using tabulation, you can (albeit very roughly) find the minimum or maximum of a function. Sometimes it happens that a function does not have an analytical representation, and its values are obtained as a result of calculations, which often happens in computer modeling different processes... If such a function is to be used in subsequent calculations (for example, it must be integrated or differentiated, etc.), then they often proceed as follows: the values of the function are calculated in the required interval of the argument, i.e. make up a table (tabulate), and then use this table to construct in some way another function specified by an analytical expression (formula). The need for tabulation also arises when graphing a function on a computer screen.

Extremum (Latin extremum - extreme) in mathematics - the maximum or minimum value of a function on a given set. The point at which the extremum is reached is called the extremum point. Accordingly, if the minimum is reached, the extremum point is called the minimum point, and if the maximum is the maximum point. In mathematical analysis, the concept of local extremum (respectively, minimum or maximum) is also distinguished.

Wireless data transmission

author

Lipatnikov Alexander

Name

Wireless data transmission

annotation

This article discusses the various types of wireless data transmission technologies.

Short description

Information networks create a real opportunity for quick and convenient user access to all information accumulated by mankind throughout its history. Email and newsgroups, search for information in The world wide web and in file archives, interactive communication, online games, listening to music, shopping in online stores have become a daily practice for many computer users in developed countries.

Cellular Standards: 1G to 5G

Wireless technologies are now more reliable and, in some situations, are cheaper to deploy than cable networks. There are many wireless technologies, most commonly known to users by their marketing names such as Wi-Fi, WiMAX, Bluetooth. Each technology has certain characteristics that determine its field of application. Wireless technologies are used to transfer information over a distance between two or more points, without requiring them to be connected by wires. To transmit information, infrared radiation, radio waves, optical or laser radiation can be used.

Objective:

Meet to wireless standards data transmission, study the classification and scope of wireless networks

Classification:

By range

Wireless personal networks WPAN (Wireless Personal Area Networks). These networks include Bluetooth.
Wireless local area networks WLAN (Wireless Local Area Networks). These networks include Wi-Fi networks.
Wireless metropolitan area networks WMAN (Wireless Metropolitan Area Networks). Examples of technologies are WiMAX.
Wireless global networks WWAN - (Wireless Wide Area Network). Examples of technologies - CSD, GPRS, EDGE, EV-DO, HSPA.

By application

Corporate wireless networks - created by companies for their own needs.
Operator wireless networks - created by telecom operators for the provision of paid communication services.

By topology

Differences between wired and wireless data transmission technologies

Conclusion

While researching the topic, I came to the conclusion that wireless networks are an excellent way of transferring information between different devices, which does not require direct connection of these devices with wires, and provides constant access to the Internet in the largest possible radius of movement.

Useful Resources

Wi-Fi for Beginners: Standards

The ability to create a local area network without the use of cables looks very tempting and the benefits of this approach are obvious. Take a standard apartment, for example. When creating a local network, the first question that arises before a computer owner is how to hide all the cables so that they do not get tangled underfoot?

Comparison of the main standards for digital data transmission.

To do this, you either have to purchase special boxes that are mounted on the ceiling or walls, or use other methods, including the most obvious ones, for example, hide the cables under the carpet.

However, few people will want to spend time, money and effort on laying the cable so that it is not conspicuous. In addition, there is always a risk of kinking a certain segment of the cable, as a result of which the network for an individual computer or all computers will be inoperable.

The solution to this problem is wireless networks (WLAN). The main technology used to create wireless networks based on radio waves is Wi-Fi technology. This technology is rapidly gaining popularity, and many home LANs are already built on its basis. There are currently three main Wi-Fi standards, each with specific characteristics - 802.11b, 802.11a, and 802.11g. These are the most popular standards, since in reality there are many more, and some of them are still undergoing the standardization process. For example, 802.11n equipment is already on the market, but the standard is still evolving.

The structure of a conventional wireless network is practically the same as the structure of a wired network. All computers on the network are equipped with a wireless adapter that has an antenna and plugs into the computer's PCI slot (internal adapter) or USB connector (external adapter). For laptops can be used as external USB adapters and adapters for the PCMCIA connector, in addition, many laptops are initially equipped with a Wi-Fi adapter. The interaction of computers and portable systems equipped with Wi-Fi adapters is provided by an access point, which can be considered an analogue of a switch in a wired network.

There are currently three main wireless networking standards:

801.11b;
802.11a;
802.11g.

Let's consider these standards in more detail.

802.11 standardb was the first certified Wi-Fi standard. All devices compatible with 801.11b must have a corresponding Wi-Fi sticker. The main characteristics of the 801.11b are as follows:

data transfer rate up to 11 Mbit / s;
range of up to 50 m;
2.4 GHz frequency (matches the frequency of some cordless phones and microwave ovens);
802.11b devices have the lowest price point compared to other Wi-Fi devices.

The main benefit of the 801.11b is universal availability and low price... There are also significant disadvantages, such as low speed data transmission (almost 9 times less than the speed in a 100BASE-TX network) and the use of a radio frequency that coincides with the frequency of radio emission of some household devices.

802.11 standarda was designed to address the low bandwidth problem of 801.11b networks. The characteristics of the 801.11a are presented below:

radius of action up to 30 m;
frequency 5 GHz;
incompatibility with 802.11b;
higher price of devices compared to 802.11b.

The advantages are obvious - data transfer rates up to 54 Mbps and an operating frequency not used in household appliances however, this is achieved at the expense of a lower range and lack of compatibility with the popular 802.11b standard.

Third standard, 802.11g, has gradually gained popularity due to its data transfer speed and compatibility with 802.11b. The characteristics of this standard are as follows:

data transfer rate up to 54 Mbit / s;
range of up to 50 m;
frequency 2.4 GHz;
full compatibility with 802.11b;
the price almost equals the price of 802.11b devices.

802.11g devices can be recommended for creating a wireless home network. A data transfer rate of 54 Mbps and a range of up to 50 m from the access point will be sufficient for any apartment, however, for a larger room, the use of this standard wireless communication may be unacceptable.

Let's say about the 802.11n standard, which will soon replace three other standards.

data transfer rate up to 200 Mbit / s (and in theory, up to 480 Mbit / s);
range of up to 100 meters;
frequency 2.4 or 5 GHz;
compatibility with 802.11b / g and 802.11a;
the price is falling rapidly.

Of course, 802.11n is the coolest and most promising standard. The range is longer and the transmission rate is many times higher than that of the other three standards. However, don't rush to the store. 802.11n has several disadvantages to be aware of.

ASUS WL-500w one of the best 802.11n routers.

Most importantly, to enjoy the full benefits of 802.11n, all devices on your wireless network must support this standard.

If one of the devices works in the standard, say, 802.11g, then the 802.11n router will be put into compatibility mode, and its advantages in speed and range will simply disappear. So if you want an 802.11n network, you need all the devices that will be on the wireless network to support this standard.

Moreover, it is desirable that the 802.11n devices are from the same company. Since the standard is still being developed, different companies implement its capabilities in their own way, and there are often incidents when an Asus 802.11n wireless device does not want to work properly with Linksys, etc.

So before you implement 802.11n in your home, consider whether you have taken these factors into account. Well, read, of course, what people write on forums where this topic is actively discussed.

If the apartment has several rooms with reinforced concrete walls, the transmission speed at a distance of already 20-30 m will be lower than the maximum. The data transfer rate from the access point to the device will decrease in proportion to the distance to this device, since the speed will automatically decrease to maintain a stable signal.

It is advisable not to place the access point near household or office devices such as microwave ovens, cordless telephones, fax machines, printers, etc..

When deciding to implement a wireless network, you should choose the appropriate equipment, which includes, as mentioned earlier, two key components - the access point and wireless adapters. This is discussed in the article “ Wi-Fi for Beginners: Equipment “.

04.06. Section Wireless network

Wi-Fi technology - principles of operation, advantages and disadvantages

The origin of the already familiar abbreviation Wi-Fi in some sources it was originally conducted from the English phrase Wireless Fidelity, which can be translated - “ high accuracy wireless data transmission ". It is a kind of play on words to attract consumers by consonance with another well-known abbreviation Hi-fi(High Fidelity - high accuracy). To date, this formulation has been abandoned and the term "Wi-Fi" has no official decryption. The abbreviation Wi-Fi is used to mean brand Wi-Fi Alliance and denotes the technology of wireless networks built using the standard IEEE 802.11... A whole set of standards for the transmission of digital data over radio communication channels is being developed under this designation. To comply with the IEEE 802.11 standard, equipment must be tested by the Wi-Fi Alliance and certified to use the Wi-Fi logo.

Principle Wi-Fi actions

The principle of operation of a wireless network is based on the use of radio waves, and the data exchange itself is in many ways reminiscent of negotiations using radio communication:

A wireless adapter converts information into a radio signal and transmits it over the air via an antenna.
The wireless router receives and reverses the signal conversion. Then the information is sent to the Internet via cable.
The reception of information is carried out in a similar way. After receiving information from the Internet, the router converts it into a radio signal and sends it through the antenna to the wireless adapter of the device.

Applied in networks Wi-Fi receivers and the transmitters resemble the devices used in cell phones and duplex handheld radios. They transmit and receive radio waves and convert digital signals into radio waves and vice versa. The difference between Wi-Fi devices and similar devices is that they use frequencies of 2.4 GHz or 5 GHz, which are significantly higher, which allows you to transfer more data.

Ethernet data transmission standard

Wi-Fi networks use several modifications of the 802.11 standard:

Standard 802.11a provides for data transmission at a frequency of 5 GHz at a speed of up to 54 Mbit / s. Orthogonal frequency-division multiplexing (OFDM) and a more efficient coding algorithm are used, which splits the original signal into several sub-signals on the transmitter side, which reduces the effect of interference.
Standard 802.11b- the slowest, but has the lowest cost, thanks to which it became widespread for some time. Now, as the cost decreases, it is being replaced by standards with a higher speed. 802.11b uses the 2.4 GHz frequency band, and the data transfer rate is no more than 11 Mbps when using complementary code keying (CCK).
Standard 802.11g operates in the 2.4 GHz band and provides a significantly higher data transfer rate - up to 54 megabits per second. Due to network congestion, the real speed, as a rule, does not exceed 24 megabits per second. The increase in speed is made possible by using the same OFDM coding principle used in 802.11a.
The most widespread standard is 802.11n, in which the information exchange rate is significantly increased (140 megabits per second) and the frequency range is expanded. The standard was approved by the Institute of Electrical and Electronics Engineers (IEEE) relatively recently - September 11, 2009.

Other standards in the 802.11 family are designed for specialized wireless networking applications. Particularly for use in regional networks WAN(wide area network), as well as internal networks of vehicles or technologies that provide switching from one wireless network to another.

Wi-Fi transceivers are designed to operate in one of three frequency bands, and fast switching from one band to another is possible. By using this method, it is possible to reduce the effect of interference and simultaneously use wireless communication with several devices. Since all such devices are equipped with wireless adapters, a single router can be used to connect multiple devices to the Internet. Such organization of communication is very convenient, practically invisible and quite reliable, however, in the event of a router failure or a simultaneous attempt a large number network users take advantage of the broadband connection, there may be mutual interference or even unexpected disconnection.

A traditional Wi-Fi network layout contains at least one access point and one client. Possible switching of two subscribers in point-to-point mode (Ad-hoc). In this case, there is no access point, and clients connect directly through network adapters. To transmit its identification number in the SSID, every 100 ms, the access point sends special signal packets at a data transfer rate of 0.1 Mbps, which is the minimum for Wi-Fi networks. Having learned the SSID, the client determines the ability to connect to this access point. If the receiver is in the coverage area of 2 access points with the same SSID, it has the right to select one of them according to the signal strength. Wi-Fi technology gives the customer the freedom to define the criteria for the connection.

Benefits of Wi-Fi

Wireless data transmission technology has certain advantages:

The ability to deploy a network without using a cable, which reduces the cost of organizing and / or further expanding the network. This is especially important in places where there is no possibility of laying cables.
Providing access to the network for mobile devices.
Widespread adoption of Wi-Fi devices in the market, as well as their guaranteed compatibility due to mandatory certification of Wi-Fi Alliance equipment.
Customer mobility and the ability to use the Internet in any environment.
The ability to connect to the network in the Wi-Fi coverage area of several users from various devices - phones, computers, laptops, etc.
Low level of radiation from Wi-Fi devices at the time of data transfer (10 times less than that of a mobile phone).

Disadvantages of Wi-Fi

Among the disadvantages of the technology, it should be noted:

The 2.4 GHz frequency band is used by many other Bluetooth-enabled devices and microwave ovens and may cause some interference.
Equipment manufacturers indicate the speed at L1, however, the actual transfer rate on L2 in a Wi-Fi network depends on the presence of physical obstacles between devices, the presence of interference from other electronic devices, the relative position of devices and is always lower than stated, which gives the impression that the speed is overestimated by the manufacturer.
V different countries frequency ranges and operating limits are different.
So, in some European countries, the use of two additional channels is allowed, while in the USA they are prohibited.

In Japan, another channel is used in the upper end of the range. In some countries (for example, Russia, Belarus, Italy), registration of all external Wi-Fi networks or registration of a Wi-Fi operator is mandatory.
Points are also subject to mandatory registration in Russia wireless access and Wi-Fi adapters with radiation power exceeding 100 mW.
Even with the correct configuration, the WEP encryption algorithm can be cracked relatively easily. Therefore, the new devices are compatible with the more advanced data encryption protocol WPA and WPA2, which was facilitated by the adoption in June 2004 of the IEEE 802.11i (WPA2) standard. Both protocols require a stronger password. Many organizations use additional encryption (such as VPN) to protect against intrusion.
In ad-hoc mode, only 11 Mbit / s (802.11b) and an easily cracked WEP encryption algorithm are available.

The real connection speed used in Wi-Fi technology.

Question:
Where is the promised speed of 300 Mbps (or 150 Mbps) when connecting wireless devices on the 802.11n standard to the router?

Answer:
300 Mbps is the maximum speed of work at the physical layer according to the IEEE 802.11n standard when connected with adapters that use two spatial streams and a 40 MHz channel for receiving and transmitting. The actual data transfer rate in a wireless network depends on the characteristics and settings of the client equipment, the number of clients on the network, obstacles in the signal path, and the presence of other wireless networks and radio interference in the same range.

150 Mbps is the maximum speed of work at the physical layer according to the IEEE 802.11n standard when connected to adapters using one spatial stream and a 40 MHz channel for receiving and transmitting.

Let's start with the fact that many users incorrectly focus on the connection speed in megabits per second (Mbps), which is displayed in the Speed line on the General tab of the Status window. wireless connection in the operating room Windows system.

Users mistakenly think that this value represents the actual bandwidth of a particular network connection. This figure is displayed by the wireless adapter driver and shows what connection speed at the physical layer is currently used within the selected standard, that is, the operating system only reports the current (instant) physical connection speed of 300 Mbit / s (it is also called channel speed), however, the actual bandwidth of a data connection can be significantly lower, depending on the settings of the 802.11n access point, the number of wireless client adapters connected to it at the same time, and other factors.
The difference between the connection speed shown in Windows and the real performance is primarily due to the large amount of overhead, network packet loss in the wireless environment and the cost of retransmission.

To get a more or less reliable value of the actual data transfer rate in a wireless network, you can use one of the following methods:

Run in Windows copy large file and then calculate the speed at which this file was transferred using the file size and transfer time (Windows 7 long copy to additional information window calculates a fairly reliable speed).

Please note the following:
The technical specifications of the devices indicate the connection speed in Megabits per second (Mbps), and in custom programs(Internet browsers, download managers, p2p clients) the data transfer rate when downloading files (download speed) is displayed in Kilobytes or Megabytes per second (KB / s, KB / s or MB / s, MB / s). These values are often confused.
To convert Megabytes to Megabits, multiply the value in Megabytes by 8. For example, if the Internet browser shows the download speed of 4 MB / s, then to convert to Megabits, you need to multiply this value by 8: 4 MB / s * 8 = 32 Mbps.
To convert from Megabits to Megabytes, divide the value in Megabits by 8.

But back to the speed of the Wi-Fi connection.

V real conditions Wireless bandwidth and coverage will vary depending on interference from other devices, obstacles, and other factors. We recommend that you read the article “What affects the operation of wireless Wi-Fi networks? What could be the source of interference and what are their possible causes? "

As we wrote above, in the Windows operating system, as well as in the utilities supplied with the wireless adapter, when connected, it is not the real data transfer rate that is displayed, but the theoretical speed. The actual data transfer rate turns out to be about 2-3 times lower than that indicated in the specifications for the device.
The fact is that at any given time, an access point (a router with an active access point) works with only one client Wi-Fi adapter from the entire Wi-Fi network. Data transmission occurs in half-duplex mode, i.e. in turn - from the access point to the client adapter, then vice versa, and so on. Simultaneous, parallel data transmission process (duplex) in Wi-Fi technologies impossible.
If there are two clients in the Wi-Fi network, then the access point will need to switch twice as often as if there was only one client, because Wi-Fi technology uses half-duplex data transmission. Accordingly, the real speed of data transfer between two adapters will be two times lower than the maximum real speed for one client (we are talking about transferring data from one computer to another through an access point over a Wi-Fi connection).

Depending on the distance of the Wi-Fi network client from the access point or on the presence of various interference and obstacles, the theoretical and, as a result, the real data transfer rate will change.

Mobile standards

Together with wireless adapters, the access point changes the signal parameters depending on the conditions in the radio air (distance, the presence of obstacles and interference, radio noise, and other factors).

Let's give an example. The transfer rate between two laptops directly connected via Wi-Fi is ~ 10 Mb / s (one of the adapters operates in the access point mode, and the other in the client mode), and the data transfer rate between the same laptops, but connected via a router, is ~ 4 MB / s. It should be so. The speed between two devices connected via an access point via Wi-Fi will always be at least 2 times lower than the speed between the same devices connected to each other directly, because the frequency band is one and the adapters will be able to communicate with the access point only one by one.

Consider another example, when a wireless Wi-Fi network is created in a router that supports the IEEE 802.11n standard with a possible theoretical maximum speed of up to 150 Mbps. A laptop with a Wi-Fi adapter of the IEEE 802.11n standard (300 Mbps) is connected to the router and stationary computer with Wi-Fi adapter of the IEEE 802.11g standard (54 Mbps).
In this example, the entire network has a maximum theoretical speed of 150 Mbps, since it is built on a router with an IEEE 802.11n 150 Mbps access point. Maximum real Wi-Fi speed will not exceed 50 Mbps. Since all Wi-Fi standards operating on the same frequency range are backward compatible with each other, you can connect to such a network using a Wi-Fi adapter of the IEEE 802.11g standard, 54 Mbps. At the same time, the maximum real speed will not exceed 20 Mbit / s.

How to increase the speed of the Internet over WiFi on a router

What to do if you are not satisfied with the low speed of the Internet through the Wi-Fi network of the router? How to increase it and speed up the router?

First, connect your laptop to it via a cable and test the speed. It is possible that your router is not to blame for anything and the reason for the brakes is on the provider's side.
But if everything is fine through the cable, but it slows down according to Wi-Fi, then you should try to "tweak" it a little in terms of parameters and thereby speed up the wireless network.

We use the fastest WiFi standard

The first thing to look out for is using only high-speed Wi-Fi standards... For the usual 2.4 GHz band, this is 802.11N, and for 5 GHz - 802.11AC.

This is usually configured in the basic parameters of the Wi-Fi module on the router, the item is called Wireless mode... The only caveat is that I think you should understand that your wireless adapter on a computer, laptop or phone, too, must support the exposed fast standard.

Router channel width

The second parameter that allows you to increase the speed of WiFi on the router is the width of the radio channel. To make the Internet work faster, set the value to 40 MHz for the 2.4 GHz band:

For the 5 GHz band, either 40 MHz(for 802.11N), or 80 MHz(for 802.11AC).

Usually after that, the speed gain becomes noticeable.

Comment: You can set the maximum value of the router's channel width only if you have excellent signal quality. Otherwise, you can get the opposite effect - an unstable connection and a drop in channel bandwidth.

Non-overlapping WiFi channels

In the typical 2.4 GHz band, the radio channel number in use can have a significant impact. Non-overlapping channels in the 2.4 GHz range are 1, 6 and 11, which means that the Wi-Fi network speed of the router will be higher when using them.

At 5.0 GHz, 24 non-overlapping channels are available, so this range is preferred. These are the features of the work of radio transmitters and there is nothing you can do about it.

Turn on WMM mode

Wireless networks have their own technology for ensuring quality of service, or, as it is more correctly called, traffic prioritization. It is called Wireless multimedia or abbreviated WMM.

Its use is mandatory if you want to squeeze out the maximum Wi-Fi speed on your router when using the 802.11N standard. This option is enabled in the advanced or additional parameters of the radio module.

Router WiFi Signal Strength

The transmitter power of a router or access point can also have a significant impact on the speed of the Internet over Wi-Fi. Again, wireless technology is such that the highest speed is achieved at the highest density. And the higher the transmitter power of the router, the lower the density, which means that the speed also decreases. It is because of this that users are not advised to approach the access point closer than 1.5 meters. Otherwise, the quality of the network, on the contrary, decreases and the data transfer begins to slow down.

Introduction to data networks

Therefore, if you are unhappy with the speed of your router, try lowering the transmitter power to 75%, or even to 50%.

Use fast and secure protection

The use of outdated wireless encryption standards in modern conditions is not only a security hole, but also the cause of the problem with the Wi-Fi speed.

The point is that standards WEP and WPA hopelessly out of date. In addition to being hacked in a few minutes by ordinary schoolchildren, they also have data transfer restrictions. So, using simple WPA, you will not be able to overclock above 54 megabits per second even on powerful modern equipment. That is why be sure to only use WPA2 with encryption AES then your Wi-Fi will not slow down.

Flashing Wi-Fi router

Well, another factor that allows in some cases to speed up the Internet via Wi-Fi several times is the flashing of the router. The firmware that comes on the device from the factory very often turns out to be raw and with errors. And sometimes there were cases when the software was generally unworkable. Only flashing the router will help. For example, on ASUS routers, I have repeatedly met with the fact that the exchange rate of the radio module with wired interfaces (this parameter is called switching speed) on new firmwares is much higher than on old ones.

There are also cases when it is possible to really increase the speed of the Internet via WiFi on a router only with the help of alternative firmware.

Factory software at the same time, the problem with the brakes of the device cannot be solved.

Re-flashing a router is a relatively simple matter. On many modern models there is already an option for automatic software update. In order to perform a manual flashing, you first need to download the firmware file from the manufacturer's website. Then, in the settings menu of the device, go to the system tools and in the "Software update" section, specify the path to the firmware file.

Hello everyone! Let's talk again today about routers, wireless networks, technologies ...

I decided to prepare an article in which to tell about what kind of incomprehensible letters b / g / n are that can be found when setting up a Wi-Fi router, or when buying a device (Wi-Fi characteristics such as 802.11 b / g)... And what is the difference between these standards.

Now we will try to figure out what these settings are and how to change them in the router settings and, in fact, why change the operating mode of the wireless network.

Means b / g / n Is the wireless network operating mode (Mode).

There are three (main) modes of operation for Wi-Fi 802.11. This is b / g / n. What is the difference? They differ in the maximum data transfer rate (I heard that there is still a difference in the wireless coverage area, but I don't know how true this is).

Let's take a closer look:

b Is the slowest mode. Up to 11 Mbps.

g- maximum data transfer rate 54 Mbps

n- new and high-speed mode. Up to 600 Mbps

So, then we figured out the modes. But we still need to figure out why to change them and how to do it.

Why change the wireless network mode?

Everything is very simple here, let's take an example. Here we have an iPhone 3GS, it can work on the Internet via Wi-Fi only in b / g modes (if the characteristics do not lie)... That is, in a new, high-speed mode n he cannot work, he simply does not support him.

And if you have on a router, the operating mode of the wireless network will be n, without mixed, then you will not be able to connect this phone to Wi-Fi, here at least beat your head against the wall :).

But it doesn't have to be a phone, much less an iPhone. Such incompatibility with the new standard can be observed on laptops, tablets, etc.

Already several times I noticed that with a variety of problems with connecting phones or tablets to Wi-Fi, changing the Wi-Fi operating mode helps.

If you want to see what modes your device supports, then look in the specifications for it. The commonly supported modes are listed next to the “Wi-Fi 802.11” mark.

On the package (or on the internet), you can also see what modes your router can operate in.

For example, here are the supported standards that are indicated on the adapter box:

How can I change the b / g / n mode in the Wi-Fi router settings?

I will show you how to do this using the example of two routers, from ASUS and TP-Link... But if you have a different router, then look for changing the settings of the wireless network mode (Mode) on the Wi-Fi settings tab, where you set the name for the network, etc.

On a TP-Link router

We go into the settings of the router. How to enter them? I'm already tired of writing about this in almost every article :) ..

After getting into the settings, on the left go to the tab Wireless – Wireless Settings.

And opposite point Mode You can select the standard for the wireless network. There are many options out there. I advise you to install 11bgn mixed... This item allows you to connect devices that operate in at least one of the three modes.

But if you still have problems connecting certain devices then try the mode 11bg mixed, or 11g only... And to achieve a good baud rate, you can set 11n only... Just see that all devices support the standard n.

Using the ASUS router as an example

Everything is the same here. Go to the settings and go to the tab "Wireless network".

Opposite point "Wireless network mode" you can choose one of the standards. Or install Mixed, or Auto (which I advise to do)... For more details on standards, see a little higher. By the way, in ASUS on the right you can see the help, where you can read useful and interesting information on these settings.

Press the button to save. "Apply".

That's all, friends. I look forward to your questions, advice and wishes in the comments. Bye everyone!