What is the frequency of 802.11 b g n. The fastest wifi mode. Wi-Fi standards and their differences from each other

The shelves are full of new devices based on 802.11ac that have already gone on sale, and very soon every user will be faced with the question, is it worth paying extra for a new version of Wi-Fi? I will try to cover the answers to questions regarding the new technology in this article.

802.11ac - background

The latest officially approved version of the standard (802.11n) was in development from 2002 to 2009, but its so-called black a new version(draft) was adopted back in 2007, and as many probably remember, routers supporting 802.11n draft could be found on sale almost immediately after this event.

Developers of routers and others Wi-Fi devices acted then absolutely correctly, without waiting for the approval of the final version of the protocol. This allowed them to release devices providing data transfer rates of up to 300 Mb/s 2 years earlier, and when the standard was finally put on paper and the first 100% standardized routers appeared, the old modules did not lose compatibility by following the draft version of the standard, ensuring compatibility at the hardware level (minor differences could be resolved with a firmware update).

With 802.11ac, almost the same story is now repeating itself as with 802.11n. The timing of the adoption of the new standard is not yet known exactly (presumably no earlier than the end of 2013), but the already adopted draft specification most likely guarantees that all devices currently released in the future will work without problems with certified wireless networks.

Until recently, each new version added a new letter to the end of the 802.11 standard (for example, 802.11g), and they increased in alphabetical order. However, in 2011, this tradition was slightly broken and they jumped from the 802.11n version directly to 802.11ac.

Draft 802.11ac was adopted last October, but the first commercial devices based on it appeared literally over the past few months. For example, Cisco released its first 802.11ac router at the end of June 2012.

802.11ac improvements

We can definitely say that even 802.11n has not yet had time to reveal itself in some practical tasks, but this does not mean that progress should stand still. In addition to higher data transfer speeds, which may take a few years to become operational, each Wi-Fi improvement brings other benefits: increased signal stability, increased coverage range, and reduced power consumption. All of the above is also true for 802.11ac, so below we will dwell on each point in more detail.

802.11ac belongs to the fifth generation of wireless networks, and in common parlance it may be called 5G WiFi, although this is officially incorrect. When developing this standard, one of the main goals was to achieve gigabit data transfer speeds. While the use of additional, usually not yet used channels, allows even 802.11n to be overclocked to an impressive 600 Mb/s (for this, 4 channels will be used, each of which operates at a speed of 150 Mb/s), the gigabit bar is not suitable for it and will not be destined to take it, and this role will go to his successor.

It was decided to take the specified speed (one gigabit) not at any cost, but while maintaining compatibility with earlier versions of the standard. This means that in mixed networks, all devices will work regardless of which version of 802.11 they support.

To achieve this goal, 802.11ac will continue to operate at up to 6 GHz. But if in 802.11n two frequencies were used for this (2.4 and 5 GHz), and in earlier revisions only 2.4 GHz, then in AC the low frequency is crossed out and only 5 GHz is left, since it is more efficient for data transmission.

The last remark may seem somewhat contradictory, since at a frequency of 2.4 GHz the signal travels better over long distances, avoiding obstacles more efficiently. However, this range is already occupied by a huge number of “household” waves (from Bluetooth devices to microwave ovens and other home electronics), and in practice its use only worsens the result.

Another reason for abandoning 2.4 GHz was that there was not enough spectrum in this range to accommodate a sufficient number of channels with a width of 80-160 MHz each.

It should be emphasized that, despite the different operating frequencies (2.4 and 5 GHz), IEEE guarantees the compatibility of the AC revision with earlier versions of the standard. How this is achieved is not explained in detail, but most likely the new chips will use 5 GHz as a base frequency, but will be able to switch to lower frequencies when working with older devices that do not support this range.

Speed

A noticeable increase in speed in 802.11ac will be achieved due to several changes at once. First of all, due to doubling the channel width. If in 802.11n it has already been increased from 20 to 40 MHz, then in 802.11ac it will be as much as 80 MHz (by default), and in some cases even 160 MHz.

IN earlier versions 802.11 (up to N specification) all data was transmitted in only one stream. In N their number can be 4, although until now only 2 channels are most often used. In practice, this means that the total maximum speed is calculated as the product of the maximum speed of each channel times their number. For 802.11n we get 150 x 4 = 600 Mb/s.

We went further with 802.11ac. Now the number of channels has been increased to 8, and the maximum possible transmission speed in each specific case can be found depending on their width. At 160 MHz, the result is 866 Mb/s, and multiplying this figure by 8 gives the maximum theoretical speed that the standard can provide, that is, almost 7 Gb/s, which is 23 times faster than 802.11n.

At first, not all chips will be able to provide gigabit, and even more so 7-gigabit data transfer speeds. The first models of routers and other Wi-Fi devices will operate at more modest speeds.

For example, the already mentioned first 802.11ac Cisco router, although superior to the capabilities of 802.11n, nevertheless also did not get out of the “pre-gigabit” range, demonstrating only 866 Mb/s. In this case, we are talking about the older of the two available models, and the younger one provides only 600 MB/s.

However, speeds will not drop noticeably below these indicators even in the most entry-level devices, since the minimum possible data transfer speed, according to the specifications, is 450 Mb/s for AC.

Economical energy consumption
Economical use of energy will become one of the most strengths AC. Chips based on this technology are already being predicted for all mobile devices, claiming that this will increase autonomy not only at the same, but also at a higher data transfer rate.

Unfortunately, it is unlikely that more accurate figures will be obtained before the first devices are released, and when the new models are in hand, it will be possible to compare the increased autonomy only approximately, due to the fact that there are unlikely to be two identical smartphones on the market, differing only in the wireless module. It is expected that such devices will begin to appear on sale en masse towards the end of 2012, although the first signs are already visible on the horizon, for example, Asus laptop G75VW, introduced in early summer.

Broadcom says the new devices are up to 6 times more energy efficient than their 802.11n counterparts. Most likely, the network equipment manufacturer is referring to some exotic testing conditions, and the average savings figure will be much lower than this, but should still be noticeable in the form of additional minutes, and possibly hours of work mobile devices.

Increased autonomy, as often happens, is not a marketing ploy in this case, since it directly follows from the peculiarities of the technology. For example, the fact that data will be transmitted at higher speeds already causes a reduction in energy consumption. Since the same amount of data can be received in less time, the wireless module will be turned off earlier and therefore stop accessing the battery.

Beamforming
This signal conditioning technique could have been used back in 802.11n, but at that time it was not standardized, and when using network equipment from different manufacturers, it usually did not work correctly. In 802.11ac, all aspects of beamforming are unified, so it will be used in practice much more often, although it still remains optional.

This technique solves the problem of a drop in signal power caused by its reflection from various objects and surfaces. Upon reaching the receiver, all these signals arrive with a phase shift, and thus reduce the total amplitude.

Beamforming solves this problem in the following way. The transmitter approximately determines the location of the receiver and, guided by this information, generates a signal in a non-standard way. In normal operation, the signal from the receiver diverges evenly in all directions, but during beamforming it is directed in a strictly defined direction, which is achieved using several antennas.

Beamforming not only improves signal propagation in an open area, but also helps to “break through” walls. If previously the router did not
“reached” into the next room or provided an extremely unstable connection at a low speed, then with AC the quality of reception at the same point will be much better.

802.11ad

802.11ad, like 802.11ac, has a second, easier to remember, but unofficial name - WiGig.

Despite the name, this specification will not follow 802.11ac. Both technologies began to be developed simultaneously, and they have the same main goal (overcoming the gigabit barrier). Only the approaches are different. While AC strives to maintain compatibility with previous designs, AD starts with a blank sheet of paper, which greatly simplifies its implementation.

The main difference between competing technologies will be the operating frequency, from which all other features follow. For AD it is an order of magnitude higher compared to AC and is 60 GHz instead of 5 GHz.

In this regard, the operating range (the area covered by the signal) will also decrease, but there will be much less interference in it, since 60 GHz is used less frequently compared to operating frequency 802.11ac, not to mention 2.4 GHz.

At what exact distances 802.11ad devices will see each other is difficult to say. Without specifying the numbers, official sources talk about “relatively small distances within the same room.” The absence of walls and other serious obstacles in the signal path is also a mandatory and necessary condition for work. Obviously, we are talking about several meters, and it is symbolic that the limit would be the same limitation as for Bluetooth (10 meters).

The small transmission radius will ensure that AC and AD technologies do not conflict with each other. If the first is aimed at wireless networks for homes and offices, then the second will be used for other purposes. Which ones exactly are still an open question, but there are already rumors that AD will finally replace Bluetooth, which cannot cope with its responsibilities due to the extremely low data transfer speed by today’s standards.

The standard is also positioned to “replace wire connections“- it is quite possible that in the near future it will become known as “wireless USB” and will be used to connect printers, hard drives, possibly monitors and other peripherals.

The current Draft version of AD is already ahead of its original target (1 Gb/s), and its maximum data transfer rate is 7 Gb/s. At the same time, the technology used allows us to improve these indicators while remaining within the standard.

What 802.11ac means for ordinary users

It is unlikely that by the time the technology is standardized, Internet providers will already begin to offer tariff plans, which require the power of 802.11ac to unlock. Consequently, real applications for faster Wi-Fi at first can only be found in home networks: fast file transfer between devices, watching HD movies while simultaneously loading the network with other tasks, backing up data to external hard disks connected directly to the router.

802.11ac solves more than just the speed problem. A large number of devices connected to the router can already create problems, even if the bandwidth wireless network not used to the maximum. Considering that the number of such devices in each family will only grow, we need to think about the problem now, and AC is its solution, allowing one network to work with a large number of wireless devices.

AC will spread most quickly in the mobile device environment. If the new chip provides at least a 10% increase in autonomy, its use will be fully justified even with a slight increase in the price of the device. The first smartphones and tablets based on AC technology should most likely be expected closer to the end of the year. As already mentioned, a laptop with 802.11ac has already been released, however, as far as we know, this is the only model on the market so far.

As expected, the cost of the first AC routers turned out to be quite high, and a sharp drop in prices in the coming months is unlikely to be expected, especially if you remember how the situation developed with 802.11n. However, at the beginning of next year, routers will cost less than the $150-200 that manufacturers are asking for their first models right now.

According to information leaking out in small doses, Apple will once again be among the first adopters of the new technology. Wi-Fi has always been a key interface for all the company's devices, for example, 802.11n has found its way into Apple technology immediately after the approval of the Draft specification in 2007, it is therefore not surprising that 802.11ac is also preparing to debut soon as part of many Apple devices: laptops, Apple TV, AirPort, Time Capsule and possibly iPhone/iPad.

In conclusion, it is worth recalling that all speeds mentioned are the maximum theoretically achievable. And just as 802.11n actually runs slower than 300Mbps, actual speed limits for AC will also be lower than what's advertised on the device.

Performance in each case will greatly depend on the equipment used, the presence of other wireless devices, and room configuration, but approximately, a router labeled 1.3 Gb/s will be able to transfer information no faster than 800 Mb/s (which is still noticeably higher than the theoretical maximum of 802.11n) .

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, monoblocks, TVs, computers - all our equipment supports a wireless Internet connection, without which it is no longer possible to imagine the life of a modern person.

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

In order to choose 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 more than twenty connection technologies, four of which are most in demand today: 802.11b, 802.11a, 802.11g and 802.11n. The most latest discovery The manufacturer has become an 802.11ac modification, the performance of which is several times higher than the characteristics of modern adapters.

Is a senior certified technology wireless connection and is characterized by general accessibility. The device has very modest parameters:

• Information transfer speed - 11 Mbit/s;
• Frequency range - 2.4 GHz;
• The range 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 throughput. Therefore, despite the attractive price of this Wi-Fi connection, its technical component lags significantly behind more modern models.

802.11a standard

This technology is an improved version of the previous standard. The developers focused on the device’s throughput and clock speed. Thanks to such changes, this modification eliminates the influence of other devices on the quality of the network signal.

• Frequency range - 5 GHz;
• The range is up to 30 meters.

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

802.11g standard

The updated modification becomes a leader in today's wireless network standards, since it supports work with the widespread 802.11b technology and, unlike it, has a fairly high connection speed.

• Information transfer speed - 54 Mbit/s;
• Frequency range - 2.4 GHz;
• Range of action - up to 50 meters.

As you may have noticed, the clock frequency has dropped to 2.4 GHz, but the network coverage has returned to its previous levels typical for 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 been on the market for a long time 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.

• Information transfer speed is theoretically up to 480 Mbit/s, but in practice it turns out to be half that;
• Frequency range - 2.4 or 5 GHz;
• Range of action - up to 100 meters.

Since this standard is still evolving, it has characteristics: It may conflict with equipment that supports 802.11n just because the device manufacturers are different.

Other standards

In addition to popular technologies, Wi-Fi manufacturer The Alliance has developed other standards for more specialized applications. Such modifications that perform service functions include:

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

• 802.11h- prevents loss of signal quality due to the influence of meteorological equipment and military radars;
• 802.11i- improved version of protecting users’ personal information;
• 802.11k- monitors the load on a particular network and redistributes users to other access points;
• 802.11m- contains all corrections to 802.11 standards;
• 802.11p- determines the nature of Wi-Fi devices located within a range of 1 km and moving at speeds of up to 200 km/h;
• 802.11r- automatically finds a wireless network while roaming and connects mobile devices to it;
• 802.11s- organizes a full mesh connection, where each smartphone or tablet can be a router or connection point;
• 802.11t- this network tests the entire 802.11 standard, provides testing methods and their results, and sets requirements for the operation of the equipment;
• 802.11u- this modification is known to everyone from the development of Hotspot 2.0. It ensures the interaction of wireless and external networks;
• 802.11v- this technology creates solutions to improve 802.11 modifications;
• 802.11y- unfinished technology linking frequencies 3.65–3.70 GHz;
• 802.11w- the standard finds ways to strengthen the protection of access to information transmission.

The latest and most technologically advanced standard 802.11ac

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

1. High speed. When transmitting data via the 802.11ac network, wider channels are used and increased frequency, which increases the theoretical speed to 1.3 Gbps. In practice, throughput is up to 600 Mbit/s. In addition, an 802.11ac-based device transmits more data per clock cycle.

1. 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 a frequency band up to 380 MHz.
2. 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 that occurs during the operation of home appliances and the neighbor’s Internet does not in any way affect the operation of your connection.
3. Updated technologies. 802.11ac is equipped with the MU-MIMO extension, which ensures smooth operation of multiple devices on the network. Beamforming technology identifies the client's device and sends several streams of information to it at once.

Having become more familiar with all the Wi-Fi connection modifications that exist today, you can easily choose the network that suits your needs. Please remember that most devices contain 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 today is small. However, this is a very pressing problem and soon all modern equipment will switch to the 802.11ac standard. Don’t forget to take care of the security of your Internet access by installing a complex code on your Wi-Fi connection and an antivirus to protect your computer from virus software.

The IEEE (Institute of Electrical and Electronic Engineers) is developing WiFi 802.11 standards.

IEEE 802.11 is a basic standard for Wi-Fi networks that defines a set of protocols for the most low speeds data transfer (transfer).

IEEE 802.11b- describes b O higher transmission speeds and introduces more technological restrictions. This standard was widely promoted by WECA ( Wireless Ethernet Compatibility Alliance ) and was originally called WiFi .
Frequency channels in the 2.4GHz spectrum are used ().
Ratified in 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 802.11a- describes significantly higher transfer rates than 802.11b.
Frequency channels in the 5GHz frequency spectrum are used. ProtocolNot compatible with 802.11 b.
Ratified in 1999.
RF technology used: OFDM.
Coding: Conversion 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 802.11g - describes data transfer rates equivalent to 802.11a.
Frequency channels in the 2.4GHz spectrum are used. The protocol is compatible with 802.11b.
Ratified in 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- the most advanced commercial WiFi standard, on this moment, officially approved for import and use on the territory of the Russian Federation (802.11ac is still under development by the regulator). 802.11n uses frequency channels in the 2.4GHz and 5GHz WiFi frequency spectrums. Compatible with 11b/11 a/11g . Although it is recommended to build networks targeting only 802.11n, because... requires configuration of special protective modes if backward compatibility with legacy standards is required. This leads to a large increase in signal information anda significant reduction in the available useful performance of the air 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.
The WiFi 802.11n standard itself was released on September 11, 2009.
WiFi frequency channels with a width of 20MHz and 40MHz (2x20MHz) are supported.
RF technology used: OFDM.
OFDM MIMO (Multiple Input) technology is used Multiple Output) up to the 4x4 level (4xTransmitter and 4xReceiver). In this case, a minimum of 2xTransmitter per Access Point and 1xTransmitter per user device.
Examples of possible MCS (Modulation & Coding Scheme) for 802.11n, as well as the maximum theoretical transfer rates in the radio channel are presented in the following table:

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

It is important to emphasize that the indicated speeds correspond to the concept of channel rate and are the limiting value using this set technologies within the framework of the described standard (in fact, these values, as you probably noticed, are 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 standard technology itself. For example, “political correctness” in terms of ensuring 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 will be able to start bypassing this, etc. Therefore, the practical efficiency of legacy 802.11 b/g/a standards never exceeds 50% under ideal conditions (for example, for 802.11g the maximum speed per subscriber is usually no higher than 22Mb/s), and for 802.11n efficiency can be up to 60%. If the network operates in protected mode, which often happens due to the mixed presence of different WiFi chips on various devices ah in the network, then even the indicated relative efficiency can drop by 2-3 times. This applies, for example, to a mix of Wi-Fi devices with 802.11b, 802.11g chips on a network with WiFi 802.11g access points, or a WiFi 802.11g/802.11b device on a network with WiFi 802.11n access points, etc. Read more about .

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

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

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

. 802.11f. Aimed at unifying the parameters of Wi-Fi access points from different manufacturers. The standard allows the user to work with different networks when moving between coverage areas of individual networks.

. 802.11h. Used to prevent problems with weather and military radars by dynamically reducing the emitted power of Wi-Fi equipment or dynamically switching to another frequency channel when a trigger signal is detected (in most European countries, ground stations tracking weather and communications satellites, as well as military radars operate in ranges close to 5 MHz). This standard is a necessary ETSI requirement for equipment approved for use in the European Union.

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

. 802.11k. This standard is actually aimed at implementing load balancing in the radio subsystem Wi-Fi networks. Usually wireless local network The subscriber device 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, the 802.11k standard proposes a mechanism 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 despite a weaker signal from it. In this case, the aggregated network throughput increases due to more efficient use of resources.

. 802.11m. Amendments and corrections for the entire group of 802.11 standards are combined and summarized in a separate document under the general name 802.11m. The first release of 802.11m was in 2007, then in 2011, etc.

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

. 802.11s. A standard for implementing mesh networks (), where any device can serve as both a router and an access point. If the nearest access point is overloaded, data is redirected to the nearest unloaded node. In this case, a data packet 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 levels that support broadcast and multicast transmission (transfer), as well as unicast delivery over a self-configuring point system Wi-Fi access. For this purpose, the standard introduced a four-address frame format. Implementation examples WiFi networks Mesh: , .

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

. 802.11u. Defines procedures for interaction of Wi-Fi standard networks with external networks. The standard must define access protocols, priority protocols and prohibition protocols for working with external networks. Currently around of this standard a large movement has 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, who jointly resolve 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 include amendments aimed at improving the network management systems of the IEEE 802.11 standard. Modernization at the MAC and PHY levels should allow the configuration of client devices connected to the network to be centralized and streamlined.

. 802.11y. Additional standard communications for the frequency range 3.65-3.70 GHz. Designed for the latest generation devices working 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 standard protocols structure a system for monitoring data integrity, the authenticity of their source, the prohibition of unauthorized reproduction and copying, data confidentiality and other protection measures. The standard introduces management frame protection (MFP: Management Frame Protection), and additional security measures help neutralize external attacks, such as DoS. A little more on MFP here:. In addition, these measures will ensure security for the most sensitive network information that will be transmitted over networks that support IEEE 802.11r, k, y.

802.11ac. A new WiFi standard that operates only in the 5GHz frequency band and provides significantly faster O higher speeds both for an individual WiFi client and for a WiFi Access Point. See our article for more details.

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The basic IEEE 802.11 standard was developed in 1997 to organize wireless communications over a radio channel at speeds of up to 1 Mbit/s. in the 2.4 GHz frequency range. Optionally, that is, if special equipment was available on both sides, the speed could be increased to 2 Mbit/s.
Following this, in 1999, the 802.11a specification was released for the 5 GHz band with a maximum achievable speed of 54 Mbit/s.
After this, WiFi standards were divided into two bands used:

2.4 GHz band:

The radio frequency band used is 2400-2483.5 MHz. divided into 14 channels:

802.11b- the first modification of the basic Wi-Fi standard with speeds of 5.5 Mbit/s. and 11 Mbit/s. It uses DBPSK and DQPSK modulations, DSSS technology, Barker 11 and CCK encoding.
802.11g- a further stage of development of the previous specification with a maximum data transfer speed of up to 54 Mbit/s (the real one is 22-25 Mbit/s). Has backward compatibility with 802.11b and wider coverage area. Used: DSSS and ODFM technologies, DBPSK and DQPSK modulations, arker 11 and CCK encoding.
802.11n- currently the most modern and fastest WiFi standard, which has a maximum coverage area in the 2.4 GHz range, and is also used in the 5 GHz spectrum. Backwards compatible with 802.11a/b/g. Supports channel widths of 20 and 40 MHz. The technologies used are ODFM and ODFM MIMO (multichannel input-output Multiple Input Multiple Output). The maximum data transfer speed is 600 Mbit/s (while the actual efficiency is on average no more than 50% of the declared one).

5 GHz band:

The radio frequency band used is 4800-5905 MHz. divided into 38 channels.

802.11a- the first modification of the basic IEEE 802.11 specification for the 5GHz radio frequency range. Supported speed is up to 54 Mbit/s. The technology used is OFDM, BPSK, QPSK, 16-QAM modulations. 64-QAM. The coding used is Convoltion Coding.

802.11n- Universal WiFi standard supporting both frequency range. Can use both 20 and 40 MHz channel widths. The maximum achievable speed limit is 600 Mbit/s.

802.11ac- this specification is now actively used on dual-band WiFi routers. Compared to its predecessor, it has a better coverage area and is much more economical in terms of power supply. Data transfer speed is up to 6.77 Gbit/s, provided that the router has 8 antennas.
802.11ad- the most modern Wi-Fi standard today, which has additional 60 GHz band.. Has a second name - WiGig (Wireless Gigabit). The theoretically achievable data transfer rate is up to 7 Gbit/s.

If you're looking for the fastest WiFi, you need 802.11ac, it's as simple as that. Essentially, 802.11ac is an accelerated version of 802.11n (the current WiFi standard used on your smartphone or laptop), offering link speeds ranging from 433 megabits per second (Mbps), up to several gigabits per second. To achieve speeds that are tens of times faster than 802.11n, 802.11ac operates exclusively in the 5GHz band, uses huge bandwidth (80-160MHz), works with 1-8 spatial streams (MIMO), and uses a peculiar technology called "beamforming" (beamforming). Learn more about what 802.11ac is and how it will eventually replace wired Gigabit Ethernet in your home and home. work network, we'll talk further.

How 802.11ac works.

A few years ago, 802.11n introduced some interesting technology, which significantly increased speed compared to 802.11b and g. 802.11ac works almost the same as 802.11n. For example, while the 802.11n standard supported up to 4 spatial streams, and a channel width of up to 40 MHz, 802.11ac can use 8 channels, and a width of up to 80 MHz, and combining them can generally produce 160 MHz. Even if everything else remained the same (and it won't), this means that 802.11ac handles 8x160MHz spatial streams, compared to 4x40MHz. A huge difference that will allow you to squeeze huge amounts of information out of radio waves.

To improve throughput even further, 802.11ac also introduced 256-QAM modulation (compared to 802.11n's 64-QAM), which literally compresses 256 different signals of the same frequency, shifting and interweaving each one into a different phase. Theoretically, this increases the spectral efficiency of 802.11ac by 4 times compared to 802.11n. Spectral efficiency is a measure of how well wireless protocol or the multiplexing method uses the bandwidth available to it. In the 5GHz band, where the channels are quite wide (20MHz+), spectral efficiency is not so important. In cellular bands, however, channels are most often 5 MHz wide, making spectral efficiency extremely important.

802.11ac also introduces standardized beamforming (802.11n had it but was not standardized, making interoperability an issue). Beamforming essentially transmits radio signals in such a way that they are aimed at specific device. This can improve overall throughput and make it more consistent, as well as reduce power consumption. Beam shaping can be done by using a smart antenna that physically moves in search of the device, or by modulating the amplitude and phase of the signals so that they destructively interfere with each other, leaving a narrow, non-interfering beam. 802.11n uses the second method, which can be used by both routers and mobile devices. Finally, 802.11ac, like previous versions 802.11 is fully backward compatible with 802.11n and 802.11g, so you can buy an 802.11ac router today and it will work great with your older WiFi devices.

802.11ac range

Theoretically, at a frequency of 5 MHz, and using beamforming, 802.11ac should have the same as 802.11n, or more best range(white radiation). The 5 MHz band, due to its lower penetrating power, does not have the same range as 2.4 GHz (802.11b/g). But that's a trade-off we're forced to make: we simply don't have enough spectral bandwidth in the heavily used 2.4GHz band to allow 802.11ac's peak gigabit-level speeds. As long as your router is in the perfect location, or you have several of them, there is no need to worry. As always, the more important factor is the power transmission of your devices, and the quality of the antenna.

How fast is 802.11ac?

And finally, the question everyone wants to know: how fast is 802.11ac WiFi? As always, there are two answers: the speed theoretically achievable in the lab, and the practical speed limit you'll likely be content with in a real-world home environment surrounded by a bunch of signal-jamming obstacles.

The theoretical maximum speed of 802.11ac is 8 channels of 160MHz 256-QAM, each capable of 866.7Mbps, giving us 6.933Mbps, or a modest 7Gbps. Transfer speed of 900 megabytes per second is faster than transfer to a SATA 3 drive. In the real world, due to channel clogging, you most likely will not get more than 2-3 160 MHz channels, so the maximum speed will stop somewhere at 1.7-2.5 Gbit/s. Compared to 802.11n's theoretical maximum speed of 600Mbps.

Apple Airport Extreme at 802.11ac, disassembled by iFixit today's most powerful router (April 2015), includes D-Link AC3200 Ultra Wi-Fi Router (DIR-890L/R), Linksys Smart Wi-Fi Router AC 1900 (WRT1900AC), and Trendnet AC1750 Dual-Band Wireless Router (TEW-812DRU), as reported by PCMag. With these routers, you can definitely expect impressive speeds from 802.11ac, but don't bite off your Gigabit Ethernet cable just yet.

In Anandtech's 2013 test, they tested a WD MyNet AC1300 802.11ac router (up to three streams) paired with a number of 802.11ac devices that supported 1-2 streams. Fastest transfer speed has been achieved Intel laptop 7260 s wireless adapter 802.11ac, which used two streams to achieve 364Mbps over a distance of just 1.5m. At 6m and through the wall, the same laptop was the fastest, but the maximum speed was 140Mb/s. The fixed speed limit for the Intel 7260 was 867Mb/s (2 streams of 433Mb/s).

In a situation where you don't need maximum performance and the reliability of wired GigE, 802.11ac is truly compelling. Instead of cluttering your living room with an Ethernet cable running to your home theater from your PC under your TV, it makes more sense to use 802.11ac, which has enough bandwidth to wirelessly deliver high-definition content to your HTPC. For all but the most demanding cases, 802.11ac is a very worthy replacement for Ethernet.

The future of 802.11ac

802.11ac will become even faster. As we mentioned earlier, the theoretical maximum speed of 802.11ac is a modest 7Gbps, and until we hit that in the real world, don't be surprised by the 2Gbps mark in the next few years. At 2Gbps, you get 256Mbps transfer speeds, and suddenly Ethernet will be used less and less until it disappears. To achieve such speeds, chipset and device manufacturers will have to figure out how to implement four or more channels for 802.11ac, given how software, and hardware.

We represent Broadcom, Qualcomm, MediaTek, Marvell and Intel has already are making strong strides in providing 4-8 channels for 802.11ac to integrate the latest routers, access points, and mobile devices. But until the 802.11ac specification is finalized, a second wave of chipsets and devices is unlikely to appear. Device and chipset manufacturers will have a lot of work to do to ensure that advanced technologies like beamforming are compliant with the standard and are fully compatible with other 802.11ac devices.