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The licensed electromagnetic spectrum is used for tightly controlled activities like cellular service and radio stations. In contrast, portions of unlicensed spectrum, used by Wi-Fi, are free and open to the public.
Key takeaways:
- Various communication channels transmit signals over the electromagnetic spectrum.
- Licensed spectrum refers to bands reserved by the FCC for organizations like radio stations, cellular companies, and television providers.
- Unlicensed spectrum is free and open for anyone to use, and it is where Wi-Fi lives.
- In 2020, the FCC opened up a significant amount of unlicensed spectrum within the 6 GHz band.
A big part of understanding how wireless connections are made and sustained is understanding the electromagnetic spectrum. Government agencies control how the spectrum is used and license certain frequency bands for specific activities. These actions lead to slices of licensed versus unlicensed spectrum.
To better explain how all of this relates to Wi-Fi, it’s helpful to first dig into how Wi-Fi works.
The nuts and bolts of Wi-Fi
Wi-Fi stands for “wireless fidelity," and the term can be conflated with a wireless local area network, or WLAN. The technology allows devices to connect to the internet wirelessly using radio waves, a type of electromagnetic radiation. And the electromagnetic spectrum is divided up into frequency bands.
So, at its core, Wi-Fi is essentially just like radio. When you want to listen to something in your car, you tune into a station via a transmitter and a receiver, which communicate over radio waves via electromagnetic pulses traveling at the speed of light. Wi-Fi works much the same way, with an access point and a client device communicating with one another.
One key difference, however, is that your car radio receives frequencies in kilohertz (kHz) or megahertz (MHz), while Wi-Fi transmits data in gigahertz (GHz).
What is licensed spectrum?
The Federal Communications Commissions (FCC) doesn’t just let anyone broadcast on any frequency. Instead, there are licensed and unlicensed bands of the spectrum. Radio stations pay a lot of money to the FCC to have the right to broadcast their signal over a specific frequency—and no one else can use it, or they are fined.
Cellular companies and television providers also use licensed spectrum and pay the FCC to reserve sections for their explicit use. They have the sole right to employ these frequencies within a particular geographic area and can thus rest assured that their transmissions don’t experience significant interference.
What is unlicensed spectrum?
Wi-Fi uses portions of the unlicensed spectrum, which is, again, available to the public and free—anyone can broadcast signals over it.
However, that means that everyone does use it. Wireless equipment, including access points and rapidly expanding IoT devices, broadcast and received signals within these unlicensed bands. Other unlicensed applications include Bluetooth devices and other wireless equipment such as garage door openers. However, it’s important to note that the FCC still has certain device requirements and certifications, even for using the unlicensed spectrum.
The unlicensed Wi-Fi spectrum has long included just the 2.4 GHz and 5 GHz bands. Think of them like highways and the slices within them— the channels—like lanes. A channel is basically a slice of air in the band. To accommodate more “cars,” you need more lanes on the highway. Thus, to serve more clients with Wi-Fi, you need more channels.
Congestion occurs when too many clients are trying to use the same channel, for example. There are only three usable, or non-overlapping, channels in 2.4 GHz (1, 6, and 11), whereas 24 non-overlapping channels exist in 5 GHz.
With the now billions of connected devices out there, it's easy to see why congestion is becoming a more significant issue for Wi-Fi.
The FCC opened up 6 GHz for more room
In 2020, the FCC announced that it would open up a new unlicensed band of frequency: 6 GHz. It has 59 non-overlapping 20 MHz channels that can be used, which is quite an expansion from the other two unlicensed bands.
This announcement ushered in the next Wi-Fi generation: Wi-Fi 6E. The Wi-Fi Alliance extended the already existing Wi-Fi 6 standard (802.11ax) to include the new 6 GHz band, resulting in the "E" at the end. This is the first expansion of the Wi-Fi spectrum and thus considered the biggest upgrade of the technology in 20 years.
To leverage this expansion, devices must have 6 GHz radios in them. Laptops, access points, and routers all must be upgraded to transmit on the new band.
The US has authorized 1,200 MHz within the 6 GHz band, while regions like the EU only have 500 MHz of spectrum approved. Compare that to the 2.4 GHz and 5 GHz bands, where only 600 MHz of unrestricted spectrum is allotted.
Thus, Wi-Fi 6E is set to address many challenges created by the onslaught of more connected devices. There will be less congestion and the potential for higher speeds and lower latency.
Why wireless network monitoring is crucial for WLAN performance
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