With 5G still in its early stages of implementation and not yet available in every country, you might be hearing about the 5G bandwidth spectrum, spectrum auctions, mmWave 5G, etc. Don’t worry if this is confusing. All you really need to know about 5G frequency bands is that different companies use different parts of the spectrum to transmit data. Using one part of the spectrum over another impacts both the speed of the connection and the distance it can cover. Lots more on this below.
Defining the 5G Spectrum
Radio wave frequencies range anywhere from 3 kilohertz (kHz) up to 300 gigahertz (GHz). Every portion of the spectrum has a range of frequencies, called a band, that go by a specific name. Some examples of radio spectrum bands include extremely low frequency (ELF), ultra low frequency (ULF), low frequency (LF), medium frequency (MF), ultra high frequency (UHF), and extremely high frequency (EHF). One part of the radio spectrum has a high frequency range between 30 GHz and 300 GHz (part of the EHF band), and is often called the millimeter band (because its wavelengths range from 1-10 mm). Wavelengths in and around this band are therefore called millimeter waves (mmWaves). mmWaves are a popular choice for 5G but also has application in areas like radio astronomy, telecommunications, and radar guns. Another part of the radio spectrum that’s being used for 5G, is UHF, which is lower on the spectrum than EHF. The UHF band has a frequency range of 300 MHz to 3 GHz, and is used for everything from TV broadcasting and GPS to Wi-Fi, cordless phones, and Bluetooth.
Frequency Determines 5G Speed & Power
All radio waves travel at the speed of light, but not all waves react with the environment in the same way or behave the same as other waves. It’s the wavelength of a particular frequency used by a 5G tower that directly impacts the speed and distance of its transmissions. Wavelength is inversely proportional to frequency (i.e., high frequencies have shorter wavelengths). For example, 30 Hz (low frequency) has a wavelength of 10,000 km (over 6,000 miles) while 300 GHz (high frequency) is just 1 mm. When a wavelength is really short (such as the frequencies at the higher end of the spectrum), the waveform is so tiny that it can become easily distorted. This is why really high frequencies can’t travel as far as lower ones. Speed is another factor. Bandwidth is measured by the difference between the highest and lowest frequency of the signal. When you move up on the radio spectrum to reach higher bands, the range of frequencies is higher, and therefore throughput increases (i.e., you get faster download speeds).
Why the 5G Spectrum Matters
Since the frequency used by a 5G cell dictates the speed and distance, it’s important for a service provider (like Verizon or AT&T) to use a part of the spectrum that includes frequencies that benefit the job at hand. For example, millimeter waves, which are in the high-band spectrum, have the advantage of being able to carry lots of data. However, radio waves in higher bands are also absorbed more easily by gases in the air, trees, and nearby buildings. mmWaves are therefore useful in densely packed networks, but not so helpful for carrying data long distances (due to the attenuation). For these reasons, there isn’t really a black and white “5G spectrum”—different parts of the spectrum can be used. A 5G provider wants to maximize distance, minimize problems, and get as much throughput as possible. One way to get around the limitations of millimeter waves is to diversify and use lower bands. A frequency of 600 MHz, for example, has lower bandwidth, but because it’s not affected as easily by things like moisture in the air, it doesn’t lose power as quickly and is able to reach 5G phones and other 5G devices further away, as well as better penetrate walls to provide indoor reception. A service provider might use higher 5G frequencies in areas that demand more data, like in a popular city where there are lots of devices in use. However, low-band frequencies are useful for providing 5G access to more devices from a single tower and to areas that don’t have direct line-of-sight to a 5G cell, such as rural communities. Here are some other 5G frequency ranges (called multi-layer spectrum):
C-band: 2–6 GHz for coverage and capacity.Super Data Layer: Over 6 GHz (e.g., 24–29 GHz and 37–43 GHz) for high bandwidth areas.Coverage Area: Below 2 GHz (like 700 MHz) for indoor and broader coverage areas.
5G Spectrum Usage by Carrier
Not all service providers use the same frequency band for 5G. Like we mentioned above, there are advantages and disadvantages to using any part of the 5G spectrum.
T-Mobile: Uses use low-band spectrum (600 MHz) as well as 2.5 GHz spectrum. Sprint has been merged with T-Mobile and claimed to have more spectrum than any other carrier in the US, with three spectrum bands: 800 MHz, 1.9 GHz and 2.5 GHz. Verizon: Their 5G Ultra Wideband network uses millimeter waves, specifically 28 GHz and 39 GHz. AT&T: Uses millimeter wave spectrum for dense areas and mid and low-spectrum for rural and suburban locations.
