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Millimeter waves, low-band and mid-band explained



  A Hand Holding an iPhone with a Hologram Marked
Marko Aliaksandr / Shutterstock

You've probably heard that 5G uses the millimeter-wave spectrum to reach 1

0 Gbps. But it also uses the low and mid band spectra, just like 4G. Without all three spectra 5G would not be reliable.

So what is the difference between these spectra? Why do they transfer data at different speeds and why are they all critical to the success of 5G?

How do electromagnetic frequencies transmit data?

Before we dig deep into the low, mid, and millimeter waves, we need to understand how wireless data transmission works. Otherwise, we will have problems closing the differences between these three spectra.

Radio waves and microwaves are invisible to the naked eye, but they are literally shaped like waves. As the frequency of a wave increases, the distance between the waves (the wavelength) becomes shorter. Your phone measures the wavelength to identify frequencies and "hear" the data trying to transmit a frequency.

  Visual example of a modulating wave. As the frequency increases, the wavelength (the distance between the waves) decreases.
Wikipedia

However, a stable, unchanging frequency can not "talk" to your phone. It must be modulated by subtly increasing and decreasing the frequency rate. Your phone watches these tiny modulations by measuring wavelength changes and then translating them into data.

If this helps, imagine this as a combined binary and Morse code. If you try to use Morse code with a flashlight, you can not just leave the flashlight on. You have to "modulate" it so that it can be interpreted as language.

CONNECTION: What is 5G and how fast is it?

5G works best with all three spectra [19659006] Wireless data transmission is severely restricted: the frequency is tied to bandwidth too much.

Low frequency waves have long wavelengths, so modulations occur at a snail's pace. In other words, they "talk" slowly, resulting in low bandwidth (slow internet).

As you would expect, waves that operate at a high frequency "speak" very fast. But they are prone to distortions. If something gets in the way (walls, atmosphere, rain), your phone may lose track of wavelength changes, which is like missing a part of the Morse code or binary file. For this reason, an unreliable connection to a high frequency band can sometimes be slower than a good connection to a low frequency band.

In the past, carriers avoided the high-frequency millimeter-wave spectrum in favor of mid-band spectra that "talk" at medium speed. But we need 5G to be faster and more stable than 4G. Therefore, 5G devices use so-called adaptive beam switching to quickly switch between frequency bands.

Adaptive beam switching makes 5G a reliable replacement for 4G. Essentially, a 5G phone continuously monitors signal quality when connected to a high-frequency band (millimeter-wave) and pays attention to other reliable signals. When the phone detects that signal quality is becoming unreliable, it seamlessly switches to a new frequency band until a faster and more reliable connection becomes available. This prevents hiccups when watching videos, downloading apps or making video calls – and makes 5G more reliable than 4G without sacrificing speed.

Millimeter Wave: Fast, New and Short Range

5G is the first wireless standard to use the millimeter-wave spectrum. The millimeter-wave spectrum works over the 24 GHz band and is expected to be excellent for super-fast data transmission. However, as mentioned earlier, the millimeter wave spectrum is susceptible to distortion.

Imagine the millimeter-wave spectrum as a laser beam: it is precise and dense, but can only cover a small area. Besides, it does not bother much. Even a small obstacle like the roof of your car or a rain cloud can hinder the transmission of millimeter waves.

  Man
alphaspirit / Shutterstock

Again, adaptive beam switching is so important. In a perfect world, your 5G-enabled phone is always connected to a millimeter-wave spectrum. But this ideal world would need a ton of millimeter wave towers to compensate for the millimeter wave's poor coverage. Carriers may never spend the money installing millimeter wave towers on every street corner. So adaptive beam switching ensures your phone does not hiccup every time it switches from a millimeter-wave connection to a mid-band connection.

Currently, only the 24 and 28 GHz bands are licensed for use with 5G. However, the FCC expects the 37, 39 and 47GHz bands to be auctioned for 5GHz by the end of 2019 (these three bands are higher in spectrum and therefore offer faster connections). Once high frequency millimeter waves are licensed for 5G, the technology becomes much more ubiquitous.

Center Band (Sub-6): Decent Speed ​​and Range

Center Band (also called Sub-6) is the most practical range for wireless data transmission. It works between the frequencies 1 and 6 GHz (2.5, 3.5 and 3.7-4.2 GHz). If the millimeter wave spectrum is like a laser, then the midrange spectrum is like a flashlight. It is able to cover a reasonable amount of storage with reasonable Internet speeds. In addition, it can move through most walls and obstacles.

Most of the midrange spectrum is already licensed for wireless data transmission, and of course 5G uses these bands. 5G will also use the 2.5GHz band that was previously reserved for educational programs.

The 2.5GHz band is at the lower end of the midrange spectrum, which means it has wider coverage (and slower speeds) than the mid-range bands we already use for 4G. This does not sound intuitive, but the industry wants the 2.5GHz band to make remote areas aware of upgrading to 5G, and extremely high-traffic areas not end up with extremely slow low-band spectra.

Band: Slower Spectrum for Remote Areas

Since the launch of 2G in 1991, we have been using the low-band spectrum for data transmission. These are low-frequency radio waves operating below the 1 GHz threshold (ie 600, 800) and 900 MHz bands).

  A man's hands hold a tray with a
Tero Vesalainen / Shutterstock

Because the low-frequency spectrum consists of low-frequency waves, it is virtually impermeable to large-range distortions and can move through walls. However, as mentioned earlier, slow frequencies result in slow data transfer rates.

Ideally, your phone will never have a low-band connection. However, there are some connected devices, such. B. Smart Bulbs, which do not require gigabit data transmission . If a manufacturer manufactures 5G bulbs (useful if your Wi-Fi fails), there is a good chance that they will work in the low-band spectrum.

Sources: FCC, RCR Wireless News, SIGNIANT


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