Next-gen Wi-Fi to trade ludicrous speed for the boring art of actually working

Wi-Fi 8 is coming, but it looks set to focus on greater reliability rather than on pushing the bandwidth ever higher, as the most recent updates to the venerable wireless local network technology have done.

It feels like we have had multiple wireless LAN updates in recent years, with Wi-Fi 6 only being officially adopted in 2021, followed swiftly by Wi-Fi 6E and then Wi-Fi 7. The latter has yet to be ratified, and support for it was only added to Windows 11 this year.

Wi-Fi 7 has not yet been broadly adopted, especially as anyone wanting to take advantage of the higher speed and extra frequency bands on offer will have to upgrade both their devices and access points to hardware that supports the new standard.

According to the Wi-Fi Alliance, 233 million devices were expected to enter the market in 2024, a figure forecast to expand to 2.1 billion devices by 2028.

So why are we seeing talk of yet another update, when Wi-Fi 7 is still getting established and devices such as laptops that support older standards often have plenty of life left in them?

It seems we may have to wait a few years as Wi-Fi 8 is in the conceptual stages and the technical details behind it are being hammered out.

"Dell'Oro is predicting that the first Wi-Fi 8 enterprise-class access points will be sold in the second half of 2028," said Siân Morgan, research director at industry watcher Dell'Oro Group.

Wi-Fi 8, or 802.11bn as it is classed by the Institute of Electrical and Electronics Engineers (IEEE), began life in 2022 as the Ultra High Reliability (UHR) study group. It followed a period of several years that saw rapid advances in data transfer speed, but wireless network users have often found the headline speeds unattainable in practice. This is due to various factors, including interference with other nearby networks and signals being attenuated by walls and other obstructions.

"Since Wi-Fi 4, the theoretical throughput of a Wi-Fi AP has grown about 40 times. So it's not surprising that the focus for Wi-Fi 8 has been on reliability, manageability, and the power efficiency of Wi-Fi communications," Morgan told The Register.

"With a stronger control of jitter and latency, there is potential for Wi-Fi to take a bigger role in mission-critical applications, for instance in a manufacturing context."

Wi-Fi 7 ushered in a number of enhancements, including doubling the channel bandwidth to 320 MHz compared with Wi-Fi 6 and a shift to 4K QAM encoding to deliver a theoretical top speed of more than 40 Gbps. It also supports the use of frequencies in the 6 GHz band in addition to the traditional 2.4 GHz and 5 GHz bands, although this capability was tacked on to some Wi-Fi 6 devices as Wi-Fi 6E.

The attraction of 6 GHz frequency support is the relatively uncrowded territory compared with other bands – until everyone else has compatible hardware, of course.

Wi-Fi 7 also introduced multi-link operation (MLO), which allows for aggregation of channels in different frequency bands, allowing connections using 2.4, 5, or 6 GHz radios simultaneously.

While Wi-Fi 8 is still being developed, a white paper published by wireless chip firm MediaTek indicates that the above specifications are likely to remain pretty much the same, but with additional capabilities to improve the reliability of connections and thus boost the effective throughput that users experience in real life.

In other words, Wi-Fi 8 is focused on implementing features to make the speed gains promised by Wi-Fi 7 more of a reality.

One of those enhancements is Coordinated Spatial Reuse (Co-SR), which is aimed at networks with multiple access points (APs) where their signals overlap, such as mesh networks. The idea is that the APs can coordinate to adjust their signal strengths to avoid clashes. This builds on a capability called spatial reuse (SR) implemented back in Wi-Fi 6 that allows for channel reuse by letting devices adjust their channel sense thresholds.

A related feature is Coordinated Beamforming (Co-BF), which extends spatial nulling in multi-user MIMO (MU-MIMO) environments to allow a device to direct its signal toward the intended receiver while minimizing interference with other devices by creating "nulls" in the signal in the direction of those devices.

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Dynamic Sub-channel Operation (DSO) allows an access point to assign devices to individual sub-channels, as the name suggests, to boost utilization of the spectrum. Improvements in throughput of over 20 percent are possible, according to MediaTek, while in heavy traffic conditions it suggests the improvement could be as much as 80 percent.

Also proposed for Wi-Fi 8 are new Modulation and Coding Schemes (MCS) intended to allow device hardware to better match the data transmission rate to the prevailing signal-to-noise ratio, especially if the endpoint moves away from the AP. Some of the options being considered are 16-QAM with a 2/3 coding rate, 256-QAM with a 2/3 coding rate, and 16-QAM with a 5/6 coding rate.

While these features individually might not make much of a difference, taken together they are expected to help ensure that Wi-Fi 8 actually delivers on the promises of better performance made by earlier releases.

"Wi-Fi 8 focuses on better reliability, but it still targets speed improvements over Wi-Fi 7, which could make it a worthwhile upgrade in a Wi-Fi roadmap, especially for environments where consistent connectivity is crucial, such as industrial and IoT applications," said Gartner senior director analyst Sylvain Fabre.

But as with previous technology transitions, end users will not see the full benefits until they have upgraded both their access points and endpoint devices to the new standard, and this will take an extended time unless users are really keen for the upgrade.

"To take advantage of the Ultra High Reliability of Wi-Fi 8, the mobile and PC vendors will need to include the new features in their latest devices, and the penetration of consumer devices supporting Wi-Fi 8 will influence the broad adoption of the technology," said Morgan.

Fabre noted that Wi-Fi 7 is still in the process of being ratified and has only recently started seeing support in some operating systems, so Wi-Fi 8 is likely several years away from mainstream adoption.

"Typically, there is a gap of several years between the ratification of a new Wi-Fi standard and its widespread adoption. Therefore, Wi-Fi 8 might not hit mainstream adoption until the late 2020s, depending on the pace of development and industry uptake, and by that time, we may also see early uses of 6G," he said, but that's another story.

"Most of the mainstream device vendors now support Wi-Fi 7, and we expect adoption of enterprise-class Wi-Fi 7 access points to accelerate in 2024," commented Morgan. "Given that we still have a few more years to wait for Wi-Fi 8, we should stop to enjoy the impressive speeds enabled by Wi-Fi 7." ®