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WiFi Standards: IEEE 802.11

WiFi Standards: IEEE 802.11


As Wi-Fi is used by for so many different purposes and Wi-Fi capabilities are incorporated into a huge number of devices made by different manufacturers, it is of great importance that it has internationally agreed standards and specifications.

By having standards that define the exact operation of the technology, it is possible to ensure that equipment made by different manufacturers will communicate satisfactorily.

It is important for any system that can be manufactured by different manufacturers, that there are common standards that can be used as it enables reliable interoperation, and this enables the technology to be more widely accepted and used.

Wi-Fi, IEEE 802.11 is a prime example of how an accessible standard has enabled multiple manufacturers to make equipment for it, and together ensure that the whole Wi-Fi technology is considerably more widely used.

IEEE Wi-Fi standards authority

The Wi-Fi standards are written and maintained by the IEEE, the Institute of Electrical and Electronic Engineers which has its corporate office in New York City and its operations centre in Piscataway, New Jersey.

The IEEE develops and maintains a large number of standards associated with the electrical and electronics industries - not only do these include the Wi-Fi 802.11 series of standards, but also many others including those for Ethernet, IEEE 802.3.

In total, the IEEE has over 1100 active standards, and around 600 more under development. One of the more notable are the IEEE 802 LAN/MAN group of standards, of which IEEE 802.11 is one of the more well known.

IEEE 802.11 Standards

All the Wi-Fi standards come under the IEEE 802 umbrella for local area and metropolitan area networking, LAN / MAN. The Wi-Fi standards come under the IEEE 802.11 series.

When the first Wi-Fi standard was released in 1997, no suffix letter was added. However as further variants were released, a suffix letter was added to denote the actual variation. This letter was lower case.

The various standards under the IEEE 802.11 umbrella cover everything from the bearers to elements of the system required for interworking, e.g. security, hotspots, quality of service, roaming and the like.

The main IEEE 802.11 standards are listed below:

  • 802.11a: This was the first Wi-FI standard in the 802.11 series. Released in 1999 it defined a wireless network bearer operating in the 5 GHz ISM band using orthogonal frequency division multiplexing with data rate up to 54 Mbps.

    Although 802.11a was used, it was as widely used as the 802.11b version. Although the 5 GHz band was much wider and accommodated many more channels, the technology was more expensive at the time and this reduced its use considerably.


  • 802.11b: The 802.11b standard was far more widely used than 11a. Although the maximum raw data rates were much lower at 11 Mbps, the standard used the 2.4 GHz ISM band and technology for this at the time was much cheaper. Also the usage of Wi-Fi was much less and interference was not the issue it would be today.

  • 802.11e: One of the key areas of sending data over any medium is what is termed the quality of service or QoS and the prioritisation of data. IEEE 802.11e addresses this topic so that a defined approach can be taken.
  • 802.11f: IEEE 802.11f is a recommendation that describes an optional extension to IEEE 802.11 to enable wireless access point communications among multivendor systems. IEEE 802.11F was issues for a trialling its use, but it was not taken up across the industry and therefore it was withdrawn in 2006.
  • 802.11g: The 802.11b standard came as a result of the demand for faster Wi-Fi using the 2.4GHz band. 802.11g utilises OFDM technology and enabled 54 Mbps raw data transfer rates.

    It was also backward compatible allowing communication with DSSS but at the lower rate of 802.11b. Backwards compatibility was a requirement in view of the number of older access points and computers that might only have the older standard available., a requirement that is always of importance.


  • 802.11h: The IEEE 802.11h-2003, specification defines the power control required for Wi-Fi. It governs Spectrum and Transmit Power Management Extensions and addresses issues including the possible interference with satellites and radar that also use the 5 GHz ISM band. The standard originally provided for Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) to the 802.11a PHY, but it has also been integrated into the full IEEE 802.11-2007 standard.
  • 802.11i: Security is a major issue for Wi-FI as many Wi-Fi hotspots are in public areas and open to the possibility of hackings gaining unwanted access to the devices of people using the hotspot. The IEEE 802.11i standard is used to facilitate secure end-to-end communication for wireless local area networks. The IEEE 80211i standard improves mechanisms for wireless authentication, encryption, key management and detailed security.

  • 802.11j: IEEE 802.11j-2004 is an amendment to the basic standard that extends wireless communication and signalling for 4.9 GHz and 5 GHz band operations in Japan.
  • 802.11k: The IEEE 802.11 standard extends Radio Resource Measurement (RRM) mechanisms for wireless local area networks. It provides some recommendations about optimising the WLAN performance.
  • 802.11n: 802.11n, or more fully, IEEE 802.11n-2009 is a Wi-Fi standard that operates in the 2.4 and 5 GHz ISM bands with data rates up to 600 Mbps. It uses MIMO technology along with frame aggregation, and it also provides security improvements over previous wireless bearer standards. Wi-Fi Alliance have also labelled the technology for the standard as Wi-Fi 4.
  • 802.11s: This IEEE 802.11 standard amendment addresses the topic of mesh networking. It details how Wi-Fi devices can interconnect to create a WLAN mesh network, which may be used for relatively fixed - non-mobile topologies and wireless ad hoc networks.
  • 802.11u: IEEE 802.11u-2011 is an amendment to the IEEE 802.11-2007 standard. It adds features that are used for interworking with external networks. It is used for roaming and also it is used for the Hotspot2.0 initiative.

  • 802.11ac: IEEE 802.11ac gave a major leap in terms of performance when it was introduced. The standard was released in 2013, but even though many companies had sight of the standard as it was released it took a short while after its release before products were seen and it became widely used. The standard defines a Wi-Fi "wireless network bearer" that operates below 6GHz and provides data rates of at least 1Gbps per second for multi-station operation and 500 Mbps on a single link.The standard has been labelled as Wi-Fi 5 by Wi-Fi Alliance in view of its features and performance.

  • 802.11ad: 802.11ad also known as WiGi or Gigabit Wifi and it is designed to provide extremely high throughput data and uses millimetre wave bands where there are large amounts of bandwidth to achieve this. It is defined as a Multiple Gigabit Wireless System (MGWS) standard and it operates at frequencies up to 60 GHz frequency - it is a networking standard for WiGig networks.

    In view of the very high frequencies used, ranges are very limited - often jsut a few metres and it is severely attenuated by objects like walls, etc that would allow signals from lower frequencies through.


  • 802.11af: There is often a lot of what is termed White Space in the regions where television transmitters require guard regions so that transmitters using the same frequency do not interfere. In these regions where there is the white space, low power signals can be used for a variety of other services as their power level means they will not travel to far and cause interference to the primary users. One use for this white space is Wi-Fi and IEEE 802.11af has been defined to operate in these regions. In view of its application and method of frequency use, it is often called White-Fi.

  • 802.11ah: Although the 2.4 and 5GHz bands are the most widely used for Wi-Fi, there are also some ISM allocations below 1 GHz. IEEE 802.11ah seeks to use the unlicensed spectrum below 1 GHz. One advantage is that it will be able to provide long range communications and hence give support for the Internet of Everything. The drawback of these bands is that they are relatively narrow and this can limit the data speed.

  • 802.11ax: 802.11ax is seen as the future successor to 802.11ac. Using technologies including OFDMA, MU-MIMO and others its aim is to increase spectral efficiency and hence the overall usability.

  • In addition to the standards seen above, the IEEE and its working groups are working towards developing new Wi-Fi standards. These will ensure that the technology moves forwards in line with the requirements of the industry and IEEE 802.11 Wi-Fi is able to meet the needs of the future.

    Although the network bearer standards like IEEE 802.11g, 802.11n, IEEE 802.11ac, etc.are possibly the most widely known, they are all linked by the common basic technology behind 802.11. As can be seen by the list above, there are many 802.11 standards that address topic common to all Wi-Fi systems. Security, quality of service, authentication and the like are all important and are required to build a strong environment for the development and use of Wi-Fi technology.

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    Watch the video: IEEE Wi-Fi Frame Format (September 2021).