5G – What is it?

11 Min Read
Cellphone Towers
Cellphone Towers

I was ask this question today from one of my Coffee Readers. They wanted to know what 5G is and why so many people are upset and going as far as burning down cell phone towers over the proposed plan to implement 5G networks.

In order for me to explain all of this in a somewhat comprehensible way, lets start off with some of the basics of radio waves, what they are, what they do and their behavior. Keep in mind that radio waves are effected by many different factors, such as weather, the ionosphere, the troposphere and objects in the way of their path.

A frequency is an event for a duration of time. Think of it this way. When the heel of your foot hits the pavement, start the clock. Then you reach the mid part of your foot and you have completed one-half of a cycle, then your foot reaches your toes and as it starts to lift off the ground, you stop the clock. You have then completed one cycle. A cycle can take one-millionth of a second or one day to complete.

In radio waves, those cycles are called “Hertz,” named after Heinrich Rudolf Hertz. A German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell’s equations of electromagnetism. The unit of frequency or cycle per second was named the “hertz” in his honor. In radio waves, you have Hertz, (HZ – Hundreds) Kilohertz, (KHZ – Thousands) Megahertz, (MHZ – Millions) Gigahertz, (GHZ – Billions) THZ, (Terahertz) and EHZ, (Exahertz). The last two being a whole lot and more than what we want to talk about in this discussion.

Frequency Spectrum
Frequency Spectrum
Frequency Spectrum
Frequency Spectrum

Looking at the two graphics to the above, you can see and get a better perspective of all of these frequencies – also called “Radio Waves” – including the familiar radio and TV broadcast frequencies.

I want to point at that the squiggly line running through the middle of the second graphic is the cycle representation of that frequency, although not very accurate as that squiggly line should be a lot more compressed together as the frequency increases. So much so, that it would just look like one line, but for this writing, it works to give you an idea about cycles per second.

The most current, popular, and most in production cell service here in the US and many other parts of the world is 4G or you might see LTE at the top of your cell phone screen. LTE means “Long Term Evolution”.

The 5G spectrum is a range of radio frequencies in the sub-6 GHz range and the millimeter-wave frequency range that is 24.25 GHz and above. The 5G spectrum refers to the radio frequencies that carry data from user equipment to cellular base stations to the data endpoint. LTE networks use frequencies in the sub-6 GHz range and will be sharing the space with 5G traffic. The lower frequency bands will be used for less-densely populated areas because data can travel further, though slower, on them.

According to the standards body, 3GPP, the radio frequency spectrum used by LTE networks ranges from 700 MHz to 2.7GHz. In theory, LTE peak data rates are 75 Mb/s for the uplink and 300 Mb/s for the downlink when using a multiple-input multiple-output antenna system, also referred to as spatial multiplexing.

The frequency bands for 5G networks come in two sets. Frequency range 1 is from 450 MHz to 6 GHz, which includes the LTE frequency range. Frequency range 2 is from 24.25 GHz to 52.6 GHz. The sub-6 GHz range is the name for frequency range 1 and the millimeter wave spectrum is the name for frequency range 2. In theory, the peak data rates for a fully mature 5G network are 20 Gb/s downlink and a 10 Gb/s uplink, as standardized by the International Telecommunications Union.

5G and LTE networks share LTE’s frequencies because 5G is not wholly and immediately replacing LTE. A network operator can use frequency division duplex and time division duplex technologies to share spectrum. Frequency division duplex is where different bands of frequency are used by users; one for uplink and the other for downlink. Time division duplex is where one frequency band will be used for uplink and downlink, switching between the two from millisecond-to-millisecond. According to an approved United States patent assigned to AT&T, bands can be dynamically allocated between LTE and 5G in tens of milliseconds.

Network operators are able to use certain radio frequencies they have licensed from governments through spectrum auctions. In the US, the Federal Communications Commission is licensing millimeter wave and sub-6 GHz frequencies down to 800 MHz to network operators for use. In 2019, Germany auctioned off 420 megahertz worth of spectrum between the 2 GHz and 3.6 GHz bands for $7.4 billion. Network operators who won certain bids are 1&1 Drillisch, Deutsche Telekom Germany, Vodafone Germany, and Telefonica Deutschland.

Governments auction off frequency licenses to network operators as the bands become available. With lower bands that have been in use, licenses must expire before the frequencies can be auctioned. The millimeter wave frequency bands are available for auction because they are a previously untapped range. The first US 5G spectrum auction began on March 16, 2016. Since then, auctions have taken place periodically and into 2020.

With all of this in mind, one needs to know that the higher the frequency, the cleaner, clearer, better quality the signal will be for the receiver (that being you, the cell phone user). But. There are also limitations. For example, we’ve all heard a radio station in the AM radio band range of 535-1605 kHz, seemingly coming in clear and then it fades, comes back and repeat. Only to find out later that the radio station you were listening to is thousands of miles away. Without getting into a lot of complicated theory and math, the simple answer is that it is a low frequency and that frequency will travel very long distances without much effort, bouncing off water, the ionosphere, etc.

As the frequency increases, the amount of distance that a wave will travel is decreased considerable. For example. The 2 meter Amateur Radio Band that is 144-148 MHZ will travel – on a good day – about 75 to 150 miles, (120.7 to 241.4 Km) as the frequency continues to increase, the distance will decrease a lot and very rapidly. Once you are in the GHZ range of frequencies, the range is decreased to a mere 1/4 mile (1.2 Km).

Frequency Allocation Chart
Frequency Allocation Chart

Looking at the graphic to the right, one can see that the higher frequency ranges are very popular, in high demand by network operators and very, very crowed, starting with the third row from the bottom.

So why is everyone so upset about the coming of 5G? What is it that makes this particular set of frequencies such a hot topic that – as you’ve seen on the news – groups of people have actually gone out of their way to burn-down cell towers in protest of the proposed 5G rollout.

There are number of factors involved and way out of the scope of this writing, so we are going to stick to some of the theories that have circulated around on the internet and what doctors have to say about it.

Theory number one – as typical with all news broadcast – “We’re all gonna die!”. Theory number two “Everyone will get cancer!”. And of course, there are a number of other theories on the internet about how our TV’s will stop working and they will be able to spy on us through the TV; Google’s YouTube will melt into a glob that will become Facebook; satellites will fall from the sky, home WiFi will stop working; GPS’s will stop working and how will we ever find our way to Starbucks. You can fill in the rest of the blanks from here.

What people do not understand is that the radio waves that are emitted from cell tower antenna’s are emitted in a horizontal fashion and aimed at the horizon. Given that the earth is round – sorry flat earthers, the earth really is round – those radio waves that are emitted, will not fall to the ground for you to get more bars on your cell phone. The truth of the matter is that these radio waves will continue for a short distance in a horizontal fashion till they become so weak that they are useless.

Jumping to another part of the radio spectrum is Microwaves, like the little box that sits on your counter that boils your coffee way to fast. These microwave ovens use a electromagnetic wave frequency – or wave length – of 2.45 GHz and the power of that radio wave that is emitted is around one thousand watts. Basically, without getting into to much about how a microwave oven works, there is a tube inside that is blasted with a ton of voltage. That tube then screams into action shooting a ton of waves down a small wave guild (usually a small square tunnel leading to the top of the microwave oven cavity) and into the oven cavity itself where your coffee is now blown all over the inside of the oven, which by-the-way leaks radiation a lot more than people know about, especially around the door. Note to my readers. You really should stand about a foot away from the oven while it’s on.

Bonus trivia question. Why are the little holes on the screen of the microwave door the size they are?

Faraday discovered that a metal mesh worked just as well as solid metal as long as the size of the mesh was much less than the wavelength of the radio waves. Microwave radio has a wavelength of 15cm so the tiny holes in the door of the microwave stop any leakage.

Where are you going with this? I diverted our discussion to microwave ovens for a minute as it is part of what some of the theories are. As in, we are all going to get cooked like turkey’s for the holidays, except nobody would show up for dinner because we all got cooked.

Our current implementation of 4G (LTE) – with the frequencies as noted above – is pumped out of cell tower antenna’s in a three sector, 12 radio setup at an effective radiated power of six thousand watts (about 1,000 to 1,500 watts each). Take into consideration that the term “effective radiated power” is not the actual amount of power that is being pushed out of the antenna (antenna dB gain and a bunch of other math). Also you need to consider that there are three antenna’s, each having four antenna’s inside. Also, cell towers are typically 50 to 200 feet above ground, far away from the person standing below, and remembering that these radio waves are emitted horizontally and not pointed at the ground.

With the 5G implementation, network operators will be allowed by the FCC to have up to 30,000 watts of effective radiated power – same principals apply as with 4G setup’s – per 100 MHZ of bandwidth spectrum. The key notes to take into consideration here is that if you did the math, you are still only going to be pushing out about 1,000 to 1,500 watts for each antenna, again, we are not going to dive into the complicated math involved with all of this and as with 4G, the radio waves emitted with be horizontal.

So why is everyone so excited to burn down cell towers over the implementation of 5G? One, as noted above, all of the theories and two, there have been research studies done to find out the effects of high frequencies injected into the human body, much like the high frequencies that are injected into the coffee cup in the microwave oven that is now a lovely shade of black from the coffee being blown out of it. Some studies have shown that high frequencies will cause cancer and some have shown that it will not cause cancer.

For the average, everyday person like you and I, I am relatively certain and most positive that you will not be sleeping inside of the microwave oven while it is turned on, as much as you will not be sitting up your campsite on top of a cell phone antenna tower to become the lovely turkeys that we all enjoy eating.

And that is why the implementation of 5G networks is nothing to worry about.

Author: David

As a retired traveler, IT systems engineer by trade, Electronics engineer by hobby. I spend my free time writing about subjects giving the reader events in history to ponder, as well as current events.

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