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.