With the recent FCC announcement to make the 6 GHz band available for unlicensed use, it is important to understand the significance of this event. This decision carves out 1.2 GHz of contiguous spectrum (5.925 – 7.125 GHz) and represents the largest amount of unlicensed spectrum that has been made available in over 20 years.
This sets the stage for wireless technologies (such as Wi-Fi) to be deployed in a relatively pristine area of spectrum, enabling the expansion a variety of next generation capabilities and use cases. Before we dig into some of the impacts of this announcement, let’s sit back, grab some popcorn, and let two weary travelers tell us a story about Wi-Fi user experience in a pre-COVID-19 world…
EXT. A BUSY INTERNATIONAL AIRPORT – DUSK
The camera pans past the exterior of the passenger terminal just as a Boeing 787 lands. Smoke tendrils emerge as the landing gear meets the runway.
CUT TO: Airline waiting lounge. The setting sun casts long shadows through the tall glass windows of the terminal. The airport is bustling with the comings and goings of travelers. Karl Johnson and Alice Hamilton are preparing to board a plane home after a successful meeting with a potential investor.
KARL: Great job today, Alice! That presentation really seemed to wow them.
Karl opens his black messenger bag and removes his laptop.
ALICE: Thanks, Karl. (emits an exhausted sigh of relief) I’ve spent months researching this. It’s great to see that our solution might just save the human race. (slumps an inch into her seat) I’m looking forward to getting home and sleeping in my own bed for a change.
Karl nervously looks at his watch.
KARL: Alice, the flight boards in 5 minutes. The home office should have sent the updates that you requested by now. Aren’t you going to download them?
Alice slowly looks around the terminal. A girl with a red ribbon in her hair walks by, smartphone held out at arm’s length as she chases some invisible digital quarry. Two tourists in matching multi-color satin jackets are huddled together, leaning against the railing of the moving sidewalk, talking two volume levels too high into their tablet with some unseen family member on the other side of the conversation in another part of the world. Across the aisle, a large man wearing a pair of sequined sunglasses shakes with full-body chuckles while looking down at the device he holds in his lap, his earbuds obscuring the hilarious joke from the other travelers. Alice shakes her head.
ALICE: Why bother?
Anyone who has ever tried to use airport Wi-Fi has probably had a similar experience. The user experience in densely populated environments is awful, and our appetite for data consumption is voracious. The problem causing poor Wi-Fi experiences is partly because Wi-Fi has become a victim of its success. Utilizing unlicensed technology, it is simple to deploy, and it has become an expected feature to be built into every mobile product that we purchase today. However, Wi-Fi was not originally designed to be deployed as a high-density, high-capacity network.
Picture a Wi-Fi access point as a single grocery checker in a crowded supermarket, and each mobile device on the network is an impatient shopper looking to make their transaction and move on. The way Wi-Fi has been defined makes it so that each shopper has to wait in one queue to get their turn for their transaction – and it’s not an orderly, single-file line. Over the years, Wi-Fi has improved the speed of the transactions and the size of the grocery carts, but there’s still been that same queue. Until now.
The latest generation of Wi-Fi is built to address the density problem. It is based on the 802.11ax amendment of the IEEE standard, and to help clarify the alphabet soup of this terminology, the Wi-Fi Alliance has branded this as “Wi-Fi 6,” as the 6th generation of Wi-Fi technology. Wi-Fi 6 is also known as “High Efficiency Wi-Fi,” and the data transmission methods used represent a major departure from previous generations. Continuing on our supermarket analogy, Wi-Fi 6 is like adding more supermarket checkers to our fictitious market. Now, our impatient shoppers can make transactions in parallel, and it helps alleviate the traffic jam in the store.
This all sounds great – we users now have an underlying Wi-Fi network technology that is capable of handling densely populated areas. However, the problem with deployment is backward compatibility. One of the essential characteristics of Wi-Fi that has made its adoption ubiquitous is that every new generation of Wi-Fi has been backward compatible with previous generations. A user does not know if they are operating on the 802.11a, 802.11g, 802.11ac, etc. mode. They just know that when they connect to the access point, it works. The deployment challenge with Wi-Fi 6 is that we have an enormous, 20-year installed base of “legacy” Wi-Fi devices operating in both the 2.4 GHz and 5 GHz spectrum.
While Wi-Fi 6 is technically backward compatible with previous generations, in order for a Wi-Fi 6 access point to talk to a legacy Wi-Fi device, it needs to “drop down” into legacy mode, which eliminates all of the benefit of the new transmission methods used in Wi-Fi 6. Essentially, the Wi-Fi 6 access point would act exactly like a legacy access point.
We now turn full circle to why the 6 GHz band is so important to Wi-Fi. Instead of holding new Wi-Fi 6 devices hostage to legacy users, or asking all of the consumers to take their legacy devices and throw them in the garbage, the industry looks to the pristine new 6 GHz spectrum to establish a new set of rules. These new rules continue to allow legacy devices (or Wi-Fi 6 devices) to operate in the 2.4 GHz and 5 GHz bands, but the 6 GHz band is reserved for Wi-Fi 6-capable devices, where the Wi-Fi Alliance has branded Wi-Fi 6 devices operating in the 6 GHz band as “Wi-Fi 6E.” There is now game-changing spectrum availability from 6 GHz to 7 GHz for unlicensed use that will not only unlock the intended capability of Wi-Fi 6, but it will also establish new real estate for Wi-Fi to continue to build on for the next couple of decades.
The 6 GHz unlicensed band additionally makes for an ideal companion for moving into the cellular “5G era.” Whether it is broader indoor coverage for high-throughput carrier offloading, or low latency IoT applications in the next evolution of the Wi-Fi standard, being able to decouple from the binds of legacy Wi-Fi operation opens up new use cases and innovation in unlicensed networks. The release of this new spectrum creates a requirement for new development tools.