The world’s wireless systems are getting huge upgrades this year and next: 5G cellular is beginning its rollout, with the promise of much faster speeds; and WiFi is getting a big upgrade too, with the release of WiFi 6 devices that will give us not just better speed, but better battery life and reliability. There’s one thing that WiFi really needs, though, so we can take the best advantage of its new promise. More radio-frequency spectrum.
In 2020, we will finally get it: A big chunk of new wireless spectrum in the 6 Gigahertz (GHz) band – potentially from 5.925 GHz up to 7.125 GHz.
When WiFi was first developed, it used spectrum in the 2.4 GHz range. From the start, the air was crowded. 2.4 GHz was, and is, used by many other device types, including cordless phones, Bluetooth devices, and some IoT protocols.
In 1997, parts of the 5 GHz spectrum opened up, which the newer standards like 802.11n (now called WiFi 4) can use, and which 802.11ac (WiFi 5) must use. Access to 5 GHz spectrum was last expanded in 2003, with a new subset of the band that can only be used by devices that dynamically avoid previous allocations for 5 GHz radar.
Since then, the use of WiFi has grown dramatically, taking on more of the global data traffic (which is also growing). All that traffic has had to crowd into those frequency bands. There’s not enough capacity in them for future needs.
Please note: In this story, we discuss 5 GHz and 6 GHz, which are frequency bands, as well as the wireless standards 5G and WiFi 6. The frequency ranges may sound like they are related to the wireless standards, but the terminology similarity is a coincidence.
By 2022, WiFi and mobile devices will account for 79 percent of Internet traffic. (Cisco VNI)
In 2020, for the first time in 17 years, we expect that WiFi will get additional airspace. While we don’t know all the conditions that regulators will require for use of the 6 GHz band, we do expect access to a broad swath of spectrum. More importantly, that spectrum will, at least at first, be uncrowded by legacy devices, and will contain more contiguous, uninterrupted ranges of spectrum than any of the existing WiFi bands.
Here’s why that matters.
A Closed Course
I’ve written previously about the benefits coming to us in WiFi 6 (WiFi 6 Powers Real-World Wireless Enterprise Applications). The new version of WiFi gets us better performance and improved battery life, for starters. But the full advantages of WiFi 6 can only be realized when WiFi 6 equipment isn’t trying to work around other radio standards. When a WiFi 6 radio is sharing spectrum with WiFi 5 (or other) radios, it may find it has to compete with those transmissions for spectrum. In particular, it can’t take full advantage of the protocols for scheduled transmitting and receiving, which could impact performance and battery life.
When no other radio types are sharing the air, WiFi 6 devices can negotiate more aggressively with each other on how they use the spectrum millisecond-by-millisecond over time (not just splitting up the frequencies, which WiFi 5 already offers); the cooperation is one of the reasons WiFi 6 can offer such improved performance.
When a WiFi 6 radio is sharing spectrum with WiFi 5 (or other) radios, it may find it has to compete with nearby transmissions for spectrum, lowering performance and efficiency. In WiFi 6, an access point (AP) can schedule how the devices it’s communicating with can use the spectrum millisecond-by-millisecond. The AP can also schedule multiple devices at the same time by aggregating devices into different frequencies. Such scheduling and aggregation is one of the reasons WiFi 6 can offer such improved performance.
Furthermore, legacy WiFi 4 and WiFi 5 devices will be not be allowed in the 6 GHz band, so that WiFi 6 radios on this frequency will not have to compensate for other WiFi radios barging into their transmissions. The 6 GHz band will allow WiFi 6 to meet the potential designed into it.
Wide Lanes
WiFi spectrum, in all frequency ranges, is broken up into channels. When a radio uses WiFi, it picks a channel to transmit on, and the energy it puts into adjacent channels is limited by design so it doesn’t bleed into neighboring channels. Current channels in the 2.4 and 5 GHz range are mostly 20 MHz or 40 MHz wide, with a very few that use 80 MHz or even 160 MHz. The wider the channels (literally, the bandwidth), the faster the data throughput can be. There aren’t enough wide-band channels on the 2.4 and 5 GHz frequencies to support wireless network growth.
WiFi 6 gets more channels that are 160 GHz wide, which will allow many more simultaneous users to transmit and receive at the highest possible speed.
The 5G Imperative
The new 6 GHz spectrum is valuable not just to WiFi, so we hope that the cellular and local wireless communities can cooperate on ways to share these frequencies. But in the shorter term, when 6 GHz frequencies become available to WiFi, this expansion will also serve the cellular business. In fact, 5G cellular will need WiFi to have this new capacity.
As more users take up 5G cellular and become accustomed to even higher speeds when they are mobile and outdoors, they will expect that experience to seamlessly transfer to their indoor spaces. The current 5 GHz WiFi spectrum will strain to carry that load. Cellular carriers need solid solutions to take care of their customers when they move into spaces not well-covered by their outdoor networks.
With WiFi getting additional capacity, the likelihood of building seamless hand-off experiences goes up. This will improve satisfaction and productivity for all wireless users no matter what networks they use.
We also expect that the cellular carriers will want to take full advantage of OpenRoaming to make the wireless experience as seamless as possible.
Bonus: Location Accuracy
WiFi can be used for more than data transfer. It can also geolocate devices using it – an important capability since satellite-based GPS doesn’t generally work well in the in-building domain of WiFi.
The 6 GHz band will allow for greater location accuracy than other WiFi bands, because location accuracy is proportional to channel width, and as we discussed above, almost all the 6 GHz channels are wider than channel widths now used in 2.4 and 5 GHz.
Improved and reliable location accuracy can lead to entirely new solutions and business benefits.
When, Not If
While we don’t know precisely which parts of the 6 GHz spectrum will be opened up to WiFi 6, nor exactly when, we are highly confident that sometime in 2020 we’ll know how much of that frequency will become available. The proposal on the table as I write this is for one half of the 6 GHz band to be freed up in the US, with more to come a year following; and for about 500 megahertz of the range to open up in Europe.
We are gratified to see the various standard-setting and regulatory agencies we work with moving in a direction that will serve the needs of business and users, and keep expanding the scope of what we can achieve with wireless networking.
Anand Oswal
Published with permission from blogs.cisco.com.