What is 802.11ax and how does WiFi 6 work?

IEEE 802.11ax is a WiFi standard that’s been around since 2019. It uses 5 GHz as well as 2.4 GHz. Thanks to various improvements, the technology is faster and more secure than its predecessors.

What is 802.11ax?

802.11ax or IEEE 802.11ax is a standard for wireless networks, colloquially known as WiFi 6 or HEW (High Efficiency WLAN). Like its predecessor IEEE 802.11ac, 802.11ax was adopted by the prestigious Institute of Electrical and Electronics Engineers (IEEE). Together they belong to the family of WLAN standards IEEE 802.11.

While development of 802.11ax started in 2014, the first devices supporting the standard didn’t make it to market until 2019. The goal of the new technology was higher efficiency, higher throughput, and lower susceptibility to interference. Unlike its direct predecessor, IEEE 802.11ax uses the 2.4 GHz band in addition to 5 GHz.

How does 802.11ax work?

Much like its predecessors, 802.11ax is a WLAN standard. Unlike an ethernet connection, data transmission happens wirelessly. For this purpose, a WLAN router receives data via an internet or telephone connection and forwards it via radio to all connected devices. One of the most important features of 802.11ax is the higher speed of a transmission. In theory, 9,608 megabits per second can be achieved which is four times higher than the maximum speed of 802.11ac. However, the actual transmission rates depend on the number of available antennas, the distance, the frequency ranges, and the channel width, and tend to be below the maximum.

What are the advantages of IEEE 802.11ax?

Even if the maximum speed of over 10 gigabits per second isn’t usually achieved, IEEE 802.11ax has several advantages over its predecessors. Theoretical and practical transmission rates tend to differ for all IEEE standards which means 802.11ax’s transmission rate is still four times higher on average than its predecessor. The use of 5 GHz and 2.4 GHz provides more options. Nevertheless, 802.11ax is backward compatible with its predecessor 802.11ac, and the version before it 802.11a, b, g and n. End devices consume less energy and are less susceptible to interference.

What are the differences between 802.11ax and 802.11ac?

Comparing 802.11ax with its predecessor, several advantageous optimizations emerge. In addition to having a choice between 5 GHz and 2.4 GHz and four times higher data speed, the following aspects are worth mentioning:

Orthogonal Frequency-Division Multiple Access

A significant innovation of 802.11ax is the OFDMA (Orthogonal Frequency-Division Multiple Access) modulation method. The various channels of 20, 40, 80 and 160 MHz can be divided into smaller subchannels. Even hundreds of such subchannels are possible. In combination with MUMIMO (Multi User Multiple Input Multiple Output), data can be sent simultaneously to different clients assigned to different subchannels. This reduces latency and speeds up data transmission.

Bidirectional MUMIMO

In theory, MUMIMO was already possible as of 802.11ac, but it only worked as a downlink, i.e. from the access point to the respective clients. In addition, multiple transmissions could not be carried out simultaneously. With 802.11ax, transmission is now possible in the other direction. Using the uplink method, several clients can send data to the access point at the same time.

Target Wake Time

The aforementioned lower energy consumption is mainly achieved by the TWT (Target Wake Time) technology. In IEEE 802.11ax, this optimizes the individual sleep cycles of various battery-powered devices. These are put into sleep mode and then activated with the help of TWT.

Spatial Frequency Reuse

With Spatial Frequency Reuse, several neighboring WLAN hosts can also transmit on one and the same frequency. In many cases, this would cause an interference during transmission. However, if the signal strength is good enough and there’s sufficient signal-to-noise ratio, transmission is possible with 802.11ax. This makes the best possible use of the wireless network.

Support of 6 GHz

An extension of IEEE 802.11ax enables data transmission in the 6 GHz frequency range. Called WiFi 6E, the technology uses the range from 5.9 GHz to 6.4 GHz in Europe. In the USA, Canada, Brazil and South Korea, up to 7.1 GHz is possible. WiFi 6E is intended for short distances and will probably be primarily used in the professional sector.

Which applications is IEEE 802.11ax intended for?

802.11ax is a real improvement for transferring large amounts of data. This is noticeable when streaming high-resolution videos, for example. For companies relying on high performance and a secure infrastructure IEEE 802.11ax is also an asset. The technology tends to be used during large events or at large venues allowing numerous users to access the network simultaneously. 802.11ax avoids interference and delays as best as possible.


Want to learn more about other networking standards from the Institute of Electrical and Electronics Engineers? Read more about IEEE 802.1X and IEEE 802.3af in our Digital Guides.

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