Crafting New Realities with the 6 GHz Spectrum

December 14, 2023

You may not have noticed, but a major change may be afoot in the world of Wi-Fi. In late-2023, U.S. telecommunications regulators opened the 6 GHz band for ultra-low power use. The move could make wearables lighter and faster, and facilitate a better experience in smart home devices. The big winner, however, is extended reality, or XR, an umbrella term for technologies like virtual reality and augmented reality.

Why is 6 GHz Important?

There are a lot of devices out there, and when they use Wi-Fi, they generally use one of two spectrum bands, either 2.4 GHz or 5 GHz. But those spectrum bands are getting crowded.

More spectrum equals more capacity. To alleviate network congestion, the FCC first opened the 6 GHz band to Wi-Fi in 2020 under certain conditions. A detailed discussion of that decision was covered by the IEEE Communications Society blog.

That move greatly expanded the available spectrum for Wi-Fi, which is significant for technology companies looking to develop faster, more reliable wireless services, said IEEE Senior member David Witkowski.

“It will alleviate Wi-Fi channel crowding in urban areas, and will allow wireless ISPs to build higher-performance data networks with wider channels and less interference.

“One of the significant challenges in 5 GHz is that portions of the band are prioritized for weather radar use, so the number of usable channels is much lower than the number of allocated channels,” Witkowski said.

The 2.4 GHz band, meanwhile, is subject to interference from microwaves and cordless phones.

What are the Interference Challenges with 6 GHz?

One problem with opening the 6 GHz spectrum band is that other services were already using it, raising concerns over interference.

This band has been traditionally used for services like fixed satellite service and for microwave services such as wireless backhaul, utilities and public safety applications also relied on it.

So when the FCC originally allowed devices to access the 6 GHz band, it did so with some caveats. Low power devices (which are different from the very low power devices) could be used indoors under the assumption that a building’s walls would prevent interference. A second set of devices that did run the risk of interference need to get permission from a national database that knows the location of existing, licensed users.

The latest move involving very low power devices is seen as running less of a risk of interference because, even if the devices are used outdoors, the signal will not travel more than a few meters because of the low amounts of power involved. To get a more detailed look at the intricacies of that decision, check out this article from IEEE Spectrum.

Why is XR the Big Winner?

Most XR headsets need to be connected to the internet. Most use Wi-Fi to connect to the local router, and they work better when they have a strong Wi-Fi connection. However, turning data into images, known as processing or rendering, is fairly computationally intense. It needs powerful processors and lots of battery power.

“An alternative would be for headsets to stream video from a nearby computer which would do all the rendering,” said IEEE Fellow William Webb, a former director at Ofcom, the UK’s telecommunications regulator. “This reduces headset power consumption but requires wireless connectivity to the nearby computer, and the connectivity needs a high bandwidth. Low-power 6 GHz regulation is ideal for this. It only works over a few meters, but it can deliver high-bandwidth connectivity.

“Hence, it could result in lighter and cheaper XR headsets. These might then be able to last a full day on one battery charge.”

How Is the 6 GHz Spectrum Viewed Around the World?

Regulators across the planet have approached the issue of the 6 GHz spectrum band from different perspectives.

“Most countries have allowed the bottom half of the 6 GHz band to be used for Wi-Fi but are still debating whether the top half should be Wi-Fi or cellular,” Webb said. “Key is whether the upper 6 GHz band will be used for cellular in some countries which prevents its use for Wi-Fi (although I have shown that cellular and Wi-Fi could share well). The band is also used in some countries by other applications, which may prevent Wi-Fi being used close by, but this is fairly minor.”

These regulatory challenges do have implications for consumer products.

“Different global regions have varying regulations regarding the use of the 6 GHz band, which can pose challenges for global technology companies in terms of compliance and product design,” Witkowski said. “If 6 GHz is not adopted by all or most regulatory agencies, equipment vendors will not be able to leverage economies of scale to bring down costs.”