Where are all the Wi-Fi 6E devices?
Get ready for the 6GHz army
In December 2020, the FCC certified the first Wi-Fi 6E device, a low-power indoor transmitter from Broadcom. By the end of this year, well over 300 million Wi-Fi 6E devices are expected to enter the market.
Inevitably, most of the big brands in wireless are already on board, including Broadcom, Qualcomm, Intel, Samsung, and Netgear. The first Wi-Fi 6E smartphone is the new Samsung Galaxy S21 Ultra. The new handset’s Wi-Fi 6E connectivity is powered by technology from none other than Broadcom.
With no fewer than seven Wi-Fi and Bluetooth radios, including support for dual Wi-Fi 6E streams, the Galaxy S21 Ultra is a glimpse into the future of handheld Wi-Fi, capable of around 2Gbps of peak wireless performance along with claimed latency of just a few milliseconds. It can operate across the full Wi-Fi spectrum, including the 2.4Ghz band and all the way from 5.1GHz to 7.125GHz. The Galaxy S21 Ultra also supports all the key Wi-Fi 6E technologies, including superwide 160MHz channels and MU-MIMO.
Meanwhile, at CES several companies including Netgear, TP-Link, Linksys, and Asus announced Wi-Fi 6E hardware, including routers and mesh systems. The fastest of the lot, at least by the claimed numbers, is the Asus ROG Rapture GT-AXE11000, which is said to be good for 11Gbps. While we doubt you’ll see that in the real world, we suspect Wi-Fi 6E kit will get closer to the theoretical maximums than previous wireless kit.
As for device adapters, we haven’t seen any Wi-Fi 6E USB dongles yet. But a number of PCIe add-in boards for desktops are available. Intel’s Wi-Fi 6E AX210 M.2 card will add Wi-Fi 6E to laptops for a piffling $44.
increasing. Imagine all those devices in an apartment building, battling for limited airspace that was defined decades ago.
Maintaining speedy Wi-Fi performance in built-up areas, with noisy airwaves full of devices, is already hard. Without the new spectrum, the anticipated uptick in Wi-Fi-connected devices would make a bad situation worse, which is where Wi-Fi 6E’s huge new airspace will really deliver.
How does it work?
So that’s the broad brush of how Wi-Fi 6E is going to free up capacity, but it’s worth digging one layer deeper into the details of how wireless networking works, to understand the mechanics of just how limited the spectrum has been so far, and why the 6GHz band is such a big deal.
At the core of it all are channels, the portions of spectrum over which wireless devices transmit. The 2.4GHz spectrum has 11 channels, each 20MHz wide. However, only three of those channels do not overlap. The 5GHz band ups that to 24 nonoverlapping 20MHz channels. That’s the basic channel structure. However, multiple channels can also be combined to create a single, wider channel. If you think of channels as physical highways, it’s a bit like adding lanes to increase traffic capacity, or in this case data throughput. Remember those impressive peak speeds quoted by Wi-Fi router makers? They’re typically achieved using wider channels.
Anyway, the 2.4GHz band supports 20MHz and 40MHz channel widths, while the 5GHz band also supports 80MHz and 160MHz channels. We’ll come to the channel structure of Wi-Fi 6E in a moment. So, when a device on a Wi-Fi network wants to transmit, it must wait for the channel on which it is operating to be clear. Only one device can transmit at a time.
There are mitigating technologies designed to enable a certain amount of parallel device transmission on a given channel, such as MU-MIMO, or “multi-user, multiple input, multiple output.” However, where overlapping channels are in use, devices on one channel will transmit regardless of the traffic on the other overlapping channels, causing interference and performance degradation. This is known as “adjacent-channel interference” (ACI).
The other type of interference happens when the coverage area of a wireless access point, known as a cell, overlaps with that of another access point running on the same channel. Known as “co-channel interference” (CCI), this creates a single, larger cell that forces any device in the combined cell to wait in turn for the channel to become clear before transmitting. Imagine an access point in a next-door apartment running on the same channel as yours. In terms of network contention, any devices connected to the neighboring access point may as well be connected to yours.
As for how all this applies to the real world, well, in theory wider channels deliver more bandwidth. If you’re running a single access point and you don’t have any neighbors or other sources of wireless contention, setting your access point to operate over the widest possible channel will give the best performance. Most people, of course, live in built-up areas with numerous nearby wireless networks. In that context, a wide channel is almost guaranteed to overlap with nearby networks and suffer interference. A smaller channel with less overlap and therefore reduced interference can actually deliver better performance.
Now you’ve got your head around all that, how does Wi-Fi 6E fit in? For starters, it has enough spectrum for 59 fully non-overlapping 20MHz channels. So, the odds of suffering significant interference on a 20MHz channel will be very low for most users. At the other end of the scale, there’s space for seven of the highest bandwidth 160MHz channels. Add in existing 2.4GHz and 5GHz channels, and even in a fairly busy urban area Wi-Fi 6E users will have a fighting chance of achieving
something like the claimed maximum performance figures – which until now were really only relevant for marketing purposes. At the very least that will be true for the first few years, before Wi-Fi 6E hardware becomes more commonplace.
A further corollary benefit that flows from the lack of channel overlapping and contention in the 6GHz band is lower latency. Not only does waiting for a given channel to become clear before transmitting hobble throughput, but that waiting time also increases latency. Some early movers in the Wi-Fi 6E hardware market are making spectacular claims of sub 1ms latency.
That’s yet to be proven. But even if sub 1ms isn’t achieved, the simple fact of lower contention and less interference will ensure that Wi-Fi 6E still offers major improvements in latency. Will it be enough for truly lag-free gaming, or good enough for VR applications, which are hyper sensitive to latency? That’s the promise, and we’ll see soon enough. Certainly Wi-Fi 6E will deliver the best wireless VR experience yet.
All that sounds promising, but are there any downsides? One obvious disadvantage of the new 6GHz band is range. Like other Wi-Fi technologies, Wi-Fi 6E transmits in the microwave segment of the electromagnetic spectrum. Microwaves fall between the shorter wavelength infrared spectrum and longer wavelength radio waves.
More generally, higher frequencies imply shorter wavelengths. All other things being equal, shorter wavelengths allow for greater bandwidth, while longer wavelengths enable greater transmission range. That’s because shorter wavelength energy is more easily absorbed by materials and matter of all kinds, from walls right through to air particles. Long story short, then, 2.4GHz has the best range, while 6GHz has the best bandwidth. However, the really clever bit is that Wi-Fi 6E is a superset of Wi-Fi 6. That should make the creation of wireless networks that offer the best of both worlds – range and bandwidth – possible.
For example, a mesh network might use 6GHz to connect the extenders or access points at high speed, while using smart algorithms to connect to client devices at 2.4GHz, 5GHz, and 6GHz, depending on range and any physical obstructions. Scaling back to 2.4GHz and 5GHz outside is particularly likely given one of the other shortcomings of Wi-Fi 6E – the fact that the 6GHz spectrum has some licensed users.
However, because Wi-Fi 6E augments rather than replaces existing Wi-Fi standards, any given wireless network implementation will be able to pick and choose among a much wider array of frequencies, bands, and channel widths to deliver the best-possible performance to users in any given scenario. Whether it’s physical barriers, local interference, or just a huge number of devices nearby, Wi-Fi 6E brings such a huge increase in usable spectrum that it should have the answer to any situation.
Even when Wi-Fi 6E can’t directly improve network performance, it will help free up the airspace for legacy Wi-Fi networks to perform more optimally. The result will be speedier wireless networks for decades to come. It really is that big a step change in wireless technology.