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WLAN (symbolic image): For many people, technology is an important part of their everyday life
Photo: c't
A few years ago, Wi-Fi 6, as the current IEEE standard 802.11ax is commonly called, was still a dream of the future.
In the meantime, however, the new WLAN standard has definitely reached customers: The first devices with Wi-Fi 6 found their way into the c't test laboratory in spring 2019.
And since autumn 2020 at the latest, the technology can be seen as standard equipment for WLAN routers, repeaters and mesh systems.
The cheapest Wi-Fi 6 routers can sometimes be found for less than 40 euros.
A small selection of USB sticks for Wi-Fi 6 for upgrading older computers that work under Windows and Linux are now also available.
The standard brings a few major improvements compared to Wi-Fi 5: a finer level of modulation (1024QAM instead of 256QAM) with further optimizations increases the throughput by almost 40 percent in the best case.
More important are the transmission technologies Orthogonal Frequency Division Multiple Access (OFDMA) and Spatial Reuse with BSS Coloring.
The latter could turn out to be a killer feature for faster data transmission over the next few years as Wi-Fi 6 devices become more widespread.
With OFDMA, a WLAN base station can serve several end devices in different frequency sections of their transmission signal at the same time with different data rates.
This indirectly increases the overall throughput of a Wi-Fi 6 radio cell because the base distributes its data more quickly and thus has to allocate less transmission time.
Based on the BSS Color feature sent early in the WLAN data packet, Wi-Fi 6 stations can identify which radio network has competitors on the same channel.
If it is a foreign network and its signal is comparatively weak, then a station does not have to wait until the radio channel is free again, but can send in parallel.
WLAN users in densely populated areas particularly benefit from BSS Coloring.
Even if half a dozen neighboring networks use the same radio channel, your own WLAN hardware more often recognizes the spectrum as free and can be slowed down less often.
Finally, with its Target Wake Time (TWT) feature, Wi-Fi 6 helps mobile devices stay in power-saving standby for longer.
This extends the battery life.
Overall, Wi-Fi 6 brings enough benefits to make it preferable to outdated Wi-Fi 5 routers, repeaters, and mesh systems.
Wi-Fi 6E as an intermediate step
In the summer of 2021, the Federal Network Agency in Germany released the 6 GHz band between 5.945 and 6.425 gigahertz to the general public.
Wi-Fi 6E-enabled devices are now allowed to use it in addition to the traditional 2.4 and 5 GHz ranges.
WLAN bases therefore need a third radio module so that they can serve clients in all three bands at the same time.
As a result, the power consumption of routers increases slightly in idle mode, contrary to the trend towards saving energy.
WLAN routers or mesh systems with a radio module for 6 GHz are already on the market, for example Asus' GT-AXE11000 and Netgear's Orbi RBK963.
There are also some smartphones and notebooks that can also use WLAN at 6 GHz.
In the first tests, a converted older notebook surprisingly transmitted at 6.4 GHz, even more than 20 meters through walls, hardly slower than in the 5 GHz band, and occasionally even a little faster.
Because the notebook antennas are only designed for up to 5.7 GHz, we had expected that the transmission signal would be weaker due to mismatching and that the throughput at higher frequencies would drop noticeably over longer distances.
Wi-Fi 6E has the potential to offload legacy Wi-Fi bands, especially in mesh Wi-Fi systems that couple multiple bases over a wireless backbone.
However, it was heard from some manufacturers that they are skipping the Wi-Fi 6E intermediate step and are waiting for the next Wi-Fi standard for the 6 GHz band.
WiFi 7 is coming
The first devices that transmit according to the next WLAN standard Wi-Fi 7 aka IEEE 802.11be will probably appear as early as 2023 - five years after the standardization project was given the working title Extremely High Throughput (EHT).
According to the current status of the specification, Wi-Fi 7 should transport a gross 23 gigabits per second with a 320 MHz wide radio signal at 6 gigahertz with 4096QAM coding over eight MIMO streams.
The most important further innovation will be Multi-Link Operation (MLO).
With MLO, a WLAN base station and a client can maintain simultaneous connections over multiple radio bands.
So the client does not have to switch between 2.4 and 5 and 6 GHz.
This either increases throughput or improves reliability (the same data packet is sent in multiple bands).
In general, it should make it easier to change radio cells.
IEEE Group 802.1 Time Sensitive Networking (TSN).
TSN is intended to replace fieldbuses in industrial plants such as Modbus, Profinet or CAN with real-time capable Ethernet.
With r-TWT, only certain data services are allowed to broadcast at certain times.
This allows Wi-Fi 7 to ensure packets from time-sensitive services arrive on time.
This should be of interest to company users who previously had to rely on mobile radio technology in the form of expensive campus networks for real-time applications.
In the vote in July 2022, the 11be draft 2.0 failed to achieve the required 75 percent approval;
the IEEE working group had to do another round.
Nevertheless, according to insiders, the manufacturer association Wi-Fi Alliance (WFA) is already working on a Wi-Fi 7 test program, which will probably be presented at the beginning of 2024 at the CES trade fair.
That's why not much will change until the final standard.
The chip manufacturer Mediatek announced two components for Wi-Fi 7 bases in October 2022.
In mid-November, the device manufacturer TP-Link followed suit and announced 16 models in five categories (WLAN routers, 5G routers, mesh systems, company APs, provider devices) with Wi-Fi 7.
The fattest WLAN router BE900 is said to transmit simultaneously with four Wi-Fi 7 modules in three bands each via four MIMO streams (2.4 and 2 × 5 and 6 GHz).
From the maximum gross rates of the individual blocks of 1376, 2 × 5760 and 11,520 Mbit/s, TP-Link sums up an impressive 24 Gbit/s.
The router brings this WLAN power to the LAN via two 10 Gbit/s ports and four for 2.5 Gbit/s.
The fun doesn't come cheap: the router, which will be released in the USA in the first quarter of 2023, should cost a whopping 700 US dollars.
WiFi 7++
And it goes even further: The Study Group Ultra High Reliability (SG UHR) is to define the standardization framework for the next but one Wi-Fi 8 Wi-Fi standard.
At the first meeting in September, a large number of proposals poured in.
The multi-AP operation - MIMO distributed over several bases - once planned for Wi-Fi 7 Release 2 is considered to be set.
This creates a large virtual base whose antennas transmit to individual clients (beamforming) or separately to several clients at the same time (MU-MIMO).
In order for the method to bring an advantage, there must be a significant transmission gain, which is expensive in terms of hardware.
Furthermore, the idea of allowing Wi-Fi 8 to transmit in the 60 GHz range, which can be used license-free in many countries, is also circulating.
There it could use a signal width doubled again to 640 MHz.
Some see this as an indirect admission that the 60 GHz 802.11ad and 11ay standards - marketed as WiGig by the WFA - are failures with no market relevance, despite Meta's involvement with Terragraph.
Part of the UHR Study Group opposed the excursion into the 60 GHz band because the room radio was simply not able to meet the expectations of the WLAN customers.
Of all the improvements in previous WLAN generations, the only thing that has always brought users noticeably more throughput is the increased signal width, according to the other side.
Whether the 60 GHz super wide gauge will come in Wi-Fi 8 remains open for the time being.
Hidden WiFi
In addition to acceleration, the WLAN future also has further improvements in store for low-friction data transmission.
For a long time, Windows, Android and iOS have been scrambling the MAC address of their WLAN interface (MAC address randomization) so that the devices and their users are not so easy to recognize in different wireless networks.
So far, these are proprietary methods.
But now the IEEE group 802.11bh (Randomized and Changing MAC Addresses) wants to develop an overarching standard.
It should also clarify how disadvantages of the procedure can be avoided.
For example, if a device were to get a new MAC address with every radio cell change, you would have to log in anew each time when roaming in a larger WLAN hotspot with several bases.
Energy Harvest and AI
A new topic interest group (TIG), entitled Ambient Power for IoT (AMP), is investigating how WLAN devices could draw energy from the environment in order to occasionally send data away from power sockets and without batteries.
They could extract energy from the radio field or convert mechanical energy (shaking, vibrations) into electricity.
Another TIG focuses on the hype topic of artificial intelligence and machine learning (AIML).
WLAN systems for companies already rely on artificial intelligence.
Among other things, AI should improve automatic channel selection and find the best combination of signal width and gross data rate.
So far, it has been questionable which aspects should be standardized so that artificial intelligence could exchange information on radio operation.
The controlling 802.11 Working Group will decide whether new standards will emerge from the TIG work when the final reports are available.
Another group has already cleared this hurdle: the upcoming 802.11bf standard is intended to regulate how WLAN base stations use changes in the radio channel to determine changes in the environment (sensing).
A WLAN system could determine how many people are in a room, whether they are sitting or standing, whether a person has fallen or even how many heartbeats and breaths a sleeper takes.
Such Wi-Fi sensing is already provided by products from Celeno, a company taken over by Renesas.
Ensuring that WLAN users can avoid unwanted spying through Wi-Fi Sensing is also one of 11bf's tasks.
Conclusion
Wi-Fi 6 has established itself in the market, but it will only be able to fully exploit its advantages as it becomes more widespread.
If you want to replace an old router or repeater, you should now ignore the outdated Wi-Fi 5.
With Wi-Fi 7, there will not only be more speed from 2023.
The successor to Wi-Fi 6 also comes with clever new functions that ensure more stable WLAN connections and real-time data transmission.
