Why are mobile networks tracking us?
Even if at first glance you can find a great conspiracy behind something, with which you can scare people, the real reasons and explanations are offered by simple physics.
There are a lot of conspiracy theories around mobile networks, and perhaps with the advent of 5G, they resonated even more loudly because the advent of the fifth generation of mobile networks came at the same time that the world was affected by the global pandemic of COVID-19. (Already at the beginning of 2020, there were articles published in the spirit of “Coincidence? I don’t think so…”). In general, these conspiracy theories are nothing new, they have appeared here to some extent since the beginning of the 20th century, when the first radio transmitters were installed on our territory.
Mostly, the discussion about the harmfulness of mobile networks revolves around the influence of electromagnetic radiation from transmitters and mobile phones. Today, there are many studies that prove that 30 years of our coexistence with mobile networks has had no major impact on the incidence of head tumors or many other diseases. However, opponents of mobile networks, including from the scientific community, present their studies in which they claim the opposite. Basically, this is somehow good — by constantly challenging what we know so far, if we use appropriate scientific methods and procedures, we advance our knowledge.
With the advent of 5G networks, opponents of “radio waves” got a new reason to argue — because 5G networks use some new frequency bands (for example, so-called millimeter waves, frequencies from 10 GHz and higher). Around this, a new outcry began about how these specific frequencies will change everything we know about mobile networks so far and how they will be harmful. However, an extensive review study on the impact of low-level radiation at frequencies above 6 GHz published in the Journal of Exposure Science & Environmental Epidemiology under the Nature publishing house reassures the reader — authors in the study looked at the results of 107 previous studies on this topic and state that “a review of experimental studies provided no confirmed evidence that low levels of MMW (millimeter waves, author’s note) are associated with biological effects relevant to human health.” The study is publicly available, you can read it here.
New frequencies — new problems
But let’s move on to a more interesting topic — opponents of 5G like to argue that at higher frequencies, signal penetration through obstacles (e.g. walls of buildings) is more problematic, so the number of antennas will grow and we cannot avoid them anywhere. I asked my friends responsible for building networks for mobile carriers and I received information that the deployment of 5G networks in Slovakia in the foreseeable future will have almost no effect on the number of base stations.
At the same time, the more technically proficient opponents point out that new generation mobile networks are increasingly using Massive MIMO technology, which can be simply explained by the fact that where there used to be one, two, or four antennas in a box on the roof of an apartment building, there can now be let’s say 128 antennas (we call such a grouping of antennas an antenna array, it is important for the continuation of the article). There is no need to worry that it would look different on the outside on the roofs. The box where there are 128 antennas can easily be smaller than the ones you see on the roofs of buildings today. Thanks to the Massive MIMO technology, the operator can precisely aim the radio beam in a specific direction — the conspiracy theory fans fear that it is this technology through that secret power organizations will be able to control us, or even kill us remotely. Interestingly, when 3G and 4G networks were coming, the fake news scene didn’t write any clickbait headlines like I found with 5G, but I understand — new frequencies and new type of antennas can be scary. The only thing the conspirators don’t realize is that these technologies are actually not as new as they might seem. By the way, Massive MIMO started to be deployed already with LTE networks (fourth generation) — why the hysteria only came with 5G, I didn’t fully understand.
Why do we need new frequencies? Here the answer is simple — higher frequencies mean wider channels and that means we can transmit a much larger amount of information at the same time. If we want mobile Internet at speeds in gigabits or dozens of gigabits per second, we simply have to go to higher frequencies. Lower frequencies will continue to be used, e.g. in the 700 MHz band, you will not provide users with ten-gigabit speeds, but you will cover a large part of the territory relatively easily with good signal penetration through obstacles.
However, where we have high density of people who want to use a high-quality high-speed data connection with low latency, we need higher frequencies. Since there are many obstacles in the city — buildings, subways, underground garages — we also need more base stations (antennas). Of course, these have their transmission power adapted to the fact that they cover a tiny area of the order of hundreds of meters around them and may not radiate as strongly as transmitters that cover areas of tens of square kilometers.
However, it is still true that we do not want to release radiation into the environment unnecessarily — one one hand, it is really about not exposing people to radiation where it is not necessary, but on the other hand it is also about energy efficiency — why waste resources where no one needs them? And this is where Massive MIMO and the technology known as beamforming get their chance. Let’s look at it a little closer.
How does the antenna work?
If we want to communicate wirelessly using radio waves, we need two basic components — a radio frequency (RF) module, which receives the data we want to transmit wirelessly at the input and takes care of coding, modulation, or transmission power , which we want to use for wireless transmission. If I make it extremely simple, the RF module creates a radio wave from the data intended for transmission. And to radiate it sensibly into the surroundings, we need to connect an antenna to the RF module. The antenna does not create a radio signal, but it has a fundamental influence on how this signal will spread in the surrounding space. When receiving a signal, the process is the same, only in the opposite direction.
For the antenna, we need to define two things — the size (length) of the antenna and the desired gain. In principle, it is simple with length. The antenna (more precisely, a dipole, a specific commonly used type of antenna) should have a length equal to 1/4 of a wavelength. And wavelength is directly related to frequency. If, for example, Bluetooth uses a frequency of 2.4 GHz, the wavelength is approximately 12.5 cm, so the dipole should ideally be around 3 cm long. (I’m simplifying it a bit here, but this is enough for us for now.)
With the antenna gain it is a little more complicated. It is given in decibels (dB), which is a dimensionless unit, in addition on a logarithmic scale. Since more parameters are given in decibels for antennas, when we talk about antenna gain, we use the abbreviation dBi. You might have seen it if you ever bought an antenna for a home Wi-Fi router or some “smart gadget”. The basic value is an antenna with a gain of 0 dBi — it is a so-called isotropic radiator, i.e. an ideal omnidirectional antenna. It would mean that such an antenna radiates the radio signal from the RF module to its surroundings in the shape of an ideal sphere — in all directions exactly the same and evenly. But you may remember from high school that if we call something “ideal” in physics, it usually means that it doesn’t exist in reality. It is the same with antennas. Moreover, we don’t even want an ideal omnidirectional antenna in most cases.
Imagine, for example, that you want to cover your larger garden with a high-quality Wi-Fi signal — if you want your antenna to cover larger distance, you need to supply the antenna with more power from the RF module. If you were to use an isotropic antenna, in addition to the fact that some of this power will actually spread through your garden, you will be radiating a much larger amount of power towards the sky or towards the ground. But we said that the antenna does not create a radio signal, but it has a fundamental influence on how it radiates it into the environment.
The gain of the antenna in dBi, which you will read in the product description when you are looking for a new antenna for your router, tells you how this antenna radiates a signal compared to an ideal antenna with a gain of 0 dBi. Since the power from the RF module is the same no matter how you use the antenna, if the antenna only shines in certain directions, with the same transmit power of the RF module, such an antenna will shine further. For a better idea, the following picture will help you. A higher gain of the antenna is usually reflected in the fact that the antenna will be physically larger. At first glance, one might think that a larger antenna will shine further. And as already mentioned, it is indeed true, but with higher antenna gains, you have to think about the fact that, although it shines further, it only shines in certain directions.
The gain of the antenna and the possibility to influence the direction of the radiated power is a very important knowledge for the world of wireless communications. On one hand, it allows us to shine further with the same power, if a narrow beam is enough for us, and at the same time it allows us not to shine where it is not necessary. However, if we accept the possibility that the device with which we are communicating is moving (which is, in principle, the very essence of mobile networks), if we want to shine as accurately as possible to the given device, we would have to actively tilt the antenna in the direction in which the device is moving (you know this from satellite networks — the parabolic antenna must be pointed in a specific direction, otherwise it is useless). However, such a solution with tilting antennas would not be completely practical in the mobile network environment.
How to shape a beam and move it?
This is where the already mentioned beamforming technology comes into the game. Because if you don’t use just one antenna, but instead, you use an array of antennas (many identical antennas next to each other) and they will all radiate the same, they will affect each other, which affects the resulting beam of signal radiation. Again, we can help ourselves with picture.
If the operator does not place “one antenna” but “an array of antennas” on the roof of an apartment building, while the conspiracy theory fan is afraid, because he has a feeling that 64 times more antennas means 64 times more radiation on the surface of his body, in fact the operator uses this physical property of the array of antennas to avoid radiating electromagnetic waves where they are not needed and to focus the radiated energy towards the device that needs to communicate. The advantage of such a solution compared to the use of one directional (e.g. parabolic) antenna is that it is possible to move such a beam in different directions without physically moving the antenna or array of antennas. Here we start talking about the so-called beamsteering. It is enough to change the phase shift of the radio wave. Without bothering with physics and explaining phase shift here in this article, it is simply something that can be affected electronically in the RF module itself, and the antenna array can be fixed to the mast. Additionally, if the antenna array has a sufficient number of antennas, it is possible to beam several separate beams to several separate devices and still not radiate power where no one needs it.
That’s why today we have the already mentioned Massive MIMO, where the operator has an array of 64x64 antennas on the roof of the apartment building (64 antennas for reception and 64 antennas for transmission). And when the device moves — because mobile networks were created for that, otherwise we would still need just a fixed line — the RF module only moves with a phase shift and the beam changes its direction so that it still follows the device that needs to communicate. The advantage of this solution is that it also works the other way around — as soon as a signal from a mobile phone hits such a field of antennas, the RF module can calculate the so-called Angle of Arrival, so it knows from which direction the device is communicating and in which direction it must send a signal to the device.
A very nice and understandable explanation of beamforming and beamsteering, including the necessary mathematics, can be found, for example, at this link.
This property of antenna arrays again appeals to conspiracy theory fans — first of all, they can use the argument that mobile networks are already physically tracking us, evenmore they are tracking our movements in real time. It is interesting, however, that as long as the GPS sensor in our mobile phones really tracks our location and transmits it to Google or Apple, or to dozens of other applications that we have allowed in our phone settings and that we use daily, this does not fundamentally disturb anyone. Why anyone gets nervous that the mobile network can track a mobile with a beam of radiation remains a mystery to me personally. Especially if I take into account the fact that even today, in critical situations, the operator can technically force the detection of the location of the device from its GPS chip — it is used, for example, when you call the emergency line.
The second argument of the conspirators and opponents of 5G on the topic of beamforming and beamsteering is the waving of physics — they claim that while with omnidirectional antennas we were all irradiated evenly and only a little, now the antennas shine on us completely targeted and much more concentrated. They explain it something like this, see the picture below.
The picture tries to give us the impression that we do not radiate signal in the direction where it is not needed, but we are shining a concentrated beam on active users of mobile networks holding their mobile phones close to their heads. On some “alternative” websites, I even found a fear that this is how a mobile operator can aim a beam at a person on demand and cook his brain with this concentrated energy, that is, kill him on remote command. In addition to the fact that it is nonsense since the very beginning — to cook the brain with beamforming, the RF modules on the roofs of buildings would need to have an order of magnitude higher transmission power than they have. Nevertheless, someone has already managed to deal with this conspiracy theory scientifically.
In a study done at the University of Rome and published in 2021 in the journal IEEE Access, the authors looked at the radiation effect of 5G networks using beamforming compared to using traditional antennas and their conclusions, unsurprisingly, showed that the expected increase in exposure to the electromagnetic field associated with beamforming is not supported by any scientific evidence. The authors further state that “on the contrary, when beamforming integrates data on the location of the device, a significant reduction in exposure (to electromagnetic fields, author’s note) is observed not only over the deployment sites, but also over the entire territory.” This study, with its complex mathematics and physics and description of the experiments, is also publicly available and you can read it here.
Summary
If we asked a provocative question in the title, why mobile networks are tracking us, after reading this text, each reader can tell the answer himself — someone can continue to look for a conspiracy, control of humanity and the possibility of killing at a distance. Perhaps this explanation is tempting because it does not need to be supported by anything, no physics, no mathematics. To popularize this explanation, it is enough to use a natural human characteristic — fear.
However, those who do not need to see a consipracy of reptilians and behind everything of lizards or any other cosmic people of light powers, will find an explanation in physics. And this physics is not new at all — the theory of electromagnetism and the existence of radio waves began to be devoted to the theory of electromagnetism and the existence of radio waves already in the 19th century, and in 1905 Jozef Murgaš, a Slovak-born engineer, successfully transmitted a radio signal over a distance of 32 kilometers in the USA, using radio waves transmitted Morse code.
Since then, the world of wireless communications has gone from radio broadcasting via digital television to today’s high-speed mobile networks, which have changed the way we live in ways people could only imagine in science fiction 100 years ago. Try to imagine what your normal day would look like if you had to function without mobile internet and without a Wi-Fi connection.
And regarding that mobile networks and wireless devices are tracking you today? As long as it’s just tracking at the radio signal level, be happy — it’s to keep the antennas from irradiating you less and not to waste electricity running the wireless networks we have extreme demands on today. If you are concerned about who is tracking you and why, you should go through the list of installed applications on your phone and think about who you are giving information about yourself to and why. Antennas themselves do not care about your private data at all.
The author is an assistant professor at the Faculty of Informatics and Information Technologies of the Slovak Technical University in Bratislava, where he currently works as the head of the Automotive Innovation Lab @ FIIT STU. The laboratory is focused on wireless communication, especially for connected and automated mobility applications. More information about the laboratory can be found here:
https://ail.sk/
