prof. dr. sc. Davor Bonefačić, FER, Zagreb
Mobile communications networks fundamentals
Any mobile communications system is based at a number of base stations. For the proper operation of the mobile communications network, it is extremely important where the base stations are set up. Each base station uses its signal to cover a specific geographical area and to connect with mobile users located in that area. Network planning and location of base stations is a complex task that requires highly educated experts and professional programming tools.
The purpose of base stations is to enable connection of each mobile phone or computer to a wireless communication network, which then transfers data between end users. Therefore, base stations must be where mobile network users are. The higher the density of users, the more base stations must be installed in order to achieve the necessary network capacity and so that all users can always achieve a quality and fast connection. Each base station has limited data transmission capacity. This means that if at some point the number of users in the geographical area covered by the base station becomes too large, some of the users will not be able to use the mobile network, i.e. they will not be able to phone, send messages, view websites, etc. Signal range decreases as frequency increases. Therefore, a higher frequency mobile communications system will require more base stations to cover the same geographical area than a lower frequency system. The high frequency mobile communications system will have several cells, each covering a smaller area and thus a smaller number of users. This is why each user will have at their disposal a greater capacity and speed of data transmission. The range of the base station signal is up to several hundred meters, and in populated areas it is smaller among the buildings. Therefore, it is not possible to achieve a quality coverage of urban areas by means of a signal from base stations that would be located outside of inhabited cities.
The idea of placing base stations outside or on the outskirts of the settlement has another bad effect. If such a configuration of base stations could be achieved, the distance between the user and the base stations would be much greater. This means that both the base station and the user terminal (mobile phone) would have to operate with greater power, so that the user's exposure to electromagnetic fields would be higher, i.e. the opposite effect would be achieved.
5G technology basics - why 5G?
5G technology will enable the connection of other wireless devices to the same mobile network, so in the future it will enable, for example, remote health monitoring and assistance to elderly and disabled persons, connecting wireless networks of sensors for e.g. pollution control, optimizing urban traffic, monitoring of agro-technical systems and crop conditions, fire protection, autonomous driving, etc. One of the main novelties in relation to the existing mobile communication systems that will be provided by 5G technology is direct communication of the machine to machine, without the need for a man as an intermediary. It's the basis for IoT, the Internet of things, where most things in the human environment will be networked. These networked environments create smart home, smart city, energy efficiency, green technologies, climate change mitigation and adaptation and sustainable development of society. 5G technology will be the basis for the development of the economy and new solutions that will improve the quality of life and protect the environment.
Electromagnetic fields of electronic communications networks and impact on human beings and the environment
High-frequency electromagnetic fields on which mobile communication systems are founded are not something new and in itself wrong for human. From its very beginnings, human has been exposed to electromagnetic radiation. It is the radiation of natural sources (e.g. solar radiation or cosmic radiation). Each body situated at a temperature higher than absolute zero (0 Kelvin; -273,15 degrees Celsius) radiates electromagnetic energy. The electromagnetic spectrum is infinite, and a human can feel only one small part of it with his senses, such as visible light or warmth. During evolution, human's organism mostly adapted to the levels of natural radiation sources. Most harmful electromagnetic radiation coming from the universe (including from the Sun) is absorbed in the atmosphere, in the ozone layer.
Human started producing electromagnetic waves with the development of engineering and technology. From the moment Hertz, Tesla and Marconi made their inventions, we have also been exposed to that additional radiation. Such radiation is added to natural radiation and can be considered a kind of pollution. In the consciousness of the average human, electromagnetic radiation is associated with radio communication systems. The mention of the word “radiation” usually causes negative associations, as if radiation is always harmful. In electromagnetic waves we distinguish ionizing and nonionizing radiation. The energy quantum of ionizing radiation have enough energy to ionize atoms and molecules in the human organism. This energy is sufficient to damage cells and hereditary information contained in chromosomes. Such radiation is, for example, gamma-rays produced in the decay of atoms and in a nuclear explosion or X-rays used, for example, in medical diagnostics. Of course, not all the electromagnetic radiation is that dangerous. At the frequencies used in personal communication devices (cell phones), energy quantum are more than a million times lower than those in ionizing radiation, so they can't cause cell damage. This radiation is therefore called non-ionizing.
In non-ionizing radiation, at the frequencies where mobile communication devices operate, the only proven effect is tissue heating. However, regulations on protection from electromagnetic fields have determined very strict limits and such heating cannot be felt in the normal usage of mobile devices. Basic limits in the range of mobile communications frequencies for occupational exposure were determined as the levels of absorbed power that are 10 times lower than those where tissue temperature rises by 1 degree of Celsius during exposure of 30 minutes. For the population, this level is even 5 times lower, i.e. 50 times lower than the mentioned power which causes 1 degree Celsius increase in tissue temperature.
With an increase in the frequency of electromagnetic waves, the depth of penetration into the human organism is decreasing, so in fact the most exposed organ is the skin, and for example, the brain is already very little exposed at mobile communications frequencies. This fact is particularly important for 5G technology which will, in the further stages of development, use frequencies of dozens of gigahertz (e.g. 27 GHz, 38 GHz). It is evident from public reactions that these high frequencies are considered a special threat, however, their penetration into the body and therefore the effect on tissues and internal organs will be minimal due to the very small depth of penetration.
Bluetooth, WiFi, and 3G, 4G and 5G mobile communication systems are wireless communication systems operating in the frequency range from several hundred MHz (megahertz) to several GHz (gigahertz), i.e. in the mentioned area of non-ionizing electromagnetic fields. They differ in terms of maximum permitted radiation power, range, type of modulation, data transmission speed, etc.
Bluetooth and WiFi work in the so-called free frequency band, so the device owner does not need to obtain individual license to operate such a transmitter. The usage is allowed for everyone, but users are not protected from any interference. Due to the free usage and avoidance of interference, the allowed output of such devices is significantly lower than for “mobile telephony” systems, i.e. 3G, 4G and 5G.
3G, 4G and 5G systems operate in the licensed spectrum for which the operator pays fees to the state. In return, each operator has been assigned a precisely defined frequency band and protection against interference is guaranteed. This makes the operation of these mobile networks much more reliable. The allowed radiated power is higher, but for each base station it is necessary to obtain an appropriate permit and perform first and periodic measurements of the level of electromagnetic fields in order to protect people from electromagnetic radiation.
Exposure to high-frequency electromagnetic fields is described by radiated power density. 5G technology is no more dangerous than the existing wireless communication technologies, so we don't need any new and special protection or precautionary measures. The radiation density decreases with a square distance from the source, so if we increase the distance from the body from 1 cm to 1 m, we reduce our exposure by 10,000 times. The basic principle of self-protection against excessive exposure to electromagnetic fields of mobile communications is distance. A smartphone deposited on a distance of extended hand instead of in a trouser pocket and a tablet or laptop leaning on a cushion or pad instead of directly onto the lap will repeatedly reduce our exposure to electromagnetic fields. Due to distances, power density caused by the operation of base stations is hundreds or thousands of times lower than the one created by our mobile devices.
Mobile phone radiates the maximum power when making a call, before we hear the sound of calling in the headphones when we call, that is, before the phone rings when we receive the call. When we make a call, it's enough to keep the phone in your hand, away from your head or body, until we see on the screen that the call was made and then press it on your ear. At that time, the radiated power of the mobile device has already been reduced to the minimum necessary level for achieving a quality connection. An additional beneficial effect of moving the cell phone away from the body is that less radiation power is lost in the body, so the cell emits less power due to more favorable operating conditions, which additionally reduces exposure and can prolong battery life. When we receive a call, we will not always be able to avoid the phone ringing near our body, but then we can carry it in our outer pocket or in our purse. When we are in the workplace or at home, we can put the mobile phone on the table or shelf that is within our reach. Thus, we are reducing our exposure to the electromagnetic field in the establishment of the received call. With longer conversations, it is better if we can use a speaker or headphones, as this reduces the exposure to the electromagnetic field during the whole conversation.
In addition to increasing distances, we can reduce our exposure to electromagnetic fields by shortening the time of use of wireless communication devices, whether mobile phones, computers or tablets that are wirelessly connected to the Internet, because here too the general rule applies: anything that is excessive can be dangerous.
This particularly applies to children who increasingly become intensive users of wireless technologies every day.
Studies on the harmfulness and impact of 5G mobile communications networks
Many studies have been conducted to learn about the influence of electromagnetic fields depending on the frequency, strength and time of exposure on cells, tissues and living organisms. Based on these studies, the ICNIRP (International Commission on Non-Ionizing Radiation Protection) made recommendations to limit human exposure to electromagnetic fields. These recommendations are based on the thermal effects of high-frequency electromagnetic fields, as none of the non-thermal effects that had been studied has been scientifically confirmed. Of course, the studies are not concluded by that. They are still conducted in the whole world and the new results and cognitions are used to amend the protection measures. Definition and eventual changes in allowed level of exposure to electromagnetic fields must be based on medical and biomedical studies that must determine sufficient level of correlation between the cause, ie. specific level of electromagnetic field, and a consequence, ie. a certain biological effect.
5G and COVID -19
Direct occurrence and transmission of the disease by electromagnetic waves is not possible. Electromagnetic waves cannot produce, transmit or create any biological creation, including the virus or bacteria. The transition of computer viruses to humans takes place only in fantastic movies.
Suspicions that exposure to electromagnetic fields of mobile communications has any impact on human immune system, which would facilitate the spread of coronavirus infection are not based on current scientific findings. According to my knowledge, no study or scientific research in the field of medicine or biomedicine has found that exposure to high frequency electromagnetic fields has a direct negative impact on the human immune system.
The ban of 5G networks and impact on technological development
Since 5G technology envisages the deployment of new mobile communication frequency bands, it is particularly important to respect the limit levels for total exposure at all frequencies, which has so far been an obligation under the positive regulations.
Possible suspicions of increased exposure to electromagnetic fields resulting from the wider use of the MIMO systems with multiple antennas on the mobile device and at the base station, from the rotation of the base station beam towards the user, can be taken into account when calculating using appropriate modelling and taking into account the so-called “worst case”. Verification of the exposure model is carried out by measurements, and in order for the measurements to be carried out, conditions are necessary as close as possible to the actual ones, i.e. the 5G operating network with a sufficient number of base stations and users. Therefore, in this case the ban would not contribute to the resolution of this issue.
The deployment of any new technology requires time, investment of financial resources and expert staff. A possible delay or ban on the deployment of 5G technology would certainly cause a technological lag, financial investments in infrastructure and knowledge would be missing, and skilled employees would either stagnate or go to other countries in need of such knowledge. The departure of experts would only increase further technological delays and it would be difficult to get out of such spirals.
If you want to conduct measurements of electromagnetic fields at your premises, authorized companies exist for this. Authorized companies have calibrated instruments and qualified calibrators, and measurement procedures are harmonized with the Croatian and European standards. Each authorized metrology company must possess a certificate issued by the Ministry of Health and a certificate issued by the Croatian Accreditation Agency. Both documents are issued for a limited period of time and need to be renewed. Professional authorized measurers will gladly show you both documents, and many of them already have them posted on their web pages. The list of authorized companies is available on the website of the Ministry of Health.
Individuals or companies that carry out measurements of electromagnetic fields, and do not possess appropriate authorizations, deceive citizens for the purpose of illegally obtaining material gain. Electromagnetic field measurements are not carried out using plumbline, dowsing rod or “instruments” that periodically write, light and display some figures, and can be obtained online for a couple of hundred HRK. The implementation of such “measurements” and the procurement of such “instruments” are a waste of money. Various amulets, stickers and pendants sold as protection against electromagnetic fields are also a fraud and do not provide any protection. Don't believe the so-called “experts” on social networks.
- Why do we need base stations?
- Why are base stations set up in populated areas?
- Is it possible to plan mobile communications networks in such a way that base stations are deployed outside inhabited places and what would be the consequences of such planning?
Any mobile communications system is based at a number of base stations. For the proper operation of the mobile communications network, it is extremely important where the base stations are set up. Each base station uses its signal to cover a specific geographical area and to connect with mobile users located in that area. Network planning and location of base stations is a complex task that requires highly educated experts and professional programming tools.
The purpose of base stations is to enable connection of each mobile phone or computer to a wireless communication network, which then transfers data between end users. Therefore, base stations must be where mobile network users are. The higher the density of users, the more base stations must be installed in order to achieve the necessary network capacity and so that all users can always achieve a quality and fast connection. Each base station has limited data transmission capacity. This means that if at some point the number of users in the geographical area covered by the base station becomes too large, some of the users will not be able to use the mobile network, i.e. they will not be able to phone, send messages, view websites, etc. Signal range decreases as frequency increases. Therefore, a higher frequency mobile communications system will require more base stations to cover the same geographical area than a lower frequency system. The high frequency mobile communications system will have several cells, each covering a smaller area and thus a smaller number of users. This is why each user will have at their disposal a greater capacity and speed of data transmission. The range of the base station signal is up to several hundred meters, and in populated areas it is smaller among the buildings. Therefore, it is not possible to achieve a quality coverage of urban areas by means of a signal from base stations that would be located outside of inhabited cities.
The idea of placing base stations outside or on the outskirts of the settlement has another bad effect. If such a configuration of base stations could be achieved, the distance between the user and the base stations would be much greater. This means that both the base station and the user terminal (mobile phone) would have to operate with greater power, so that the user's exposure to electromagnetic fields would be higher, i.e. the opposite effect would be achieved.
5G technology basics - why 5G?
- What makes 5G different from the existing technologies in mobile communications networks (e.g. 4G, 3G, 2G) and is there a need to introduce it?
- What frequencies do 5G networks use?
5G technology will enable the connection of other wireless devices to the same mobile network, so in the future it will enable, for example, remote health monitoring and assistance to elderly and disabled persons, connecting wireless networks of sensors for e.g. pollution control, optimizing urban traffic, monitoring of agro-technical systems and crop conditions, fire protection, autonomous driving, etc. One of the main novelties in relation to the existing mobile communication systems that will be provided by 5G technology is direct communication of the machine to machine, without the need for a man as an intermediary. It's the basis for IoT, the Internet of things, where most things in the human environment will be networked. These networked environments create smart home, smart city, energy efficiency, green technologies, climate change mitigation and adaptation and sustainable development of society. 5G technology will be the basis for the development of the economy and new solutions that will improve the quality of life and protect the environment.
Electromagnetic fields of electronic communications networks and impact on human beings and the environment
- What types of electromagnetic radiation do we distinguish and can you briefly explain them?
- What kind of electromagnetic radiation transmits a network of mobile communications?
- Does EM radiation of 5G mobile communications networks differ from those of previous generations (e.g. 4G, 3G, 2G) and what is their impact on the human organism and the environment?
- What are the differences in the operation and EM radiation of modern wireless communications (e.g. Wi-Fi, Bluetooth, mobile communications)?
- Are there certain precautions and how to apply them?
High-frequency electromagnetic fields on which mobile communication systems are founded are not something new and in itself wrong for human. From its very beginnings, human has been exposed to electromagnetic radiation. It is the radiation of natural sources (e.g. solar radiation or cosmic radiation). Each body situated at a temperature higher than absolute zero (0 Kelvin; -273,15 degrees Celsius) radiates electromagnetic energy. The electromagnetic spectrum is infinite, and a human can feel only one small part of it with his senses, such as visible light or warmth. During evolution, human's organism mostly adapted to the levels of natural radiation sources. Most harmful electromagnetic radiation coming from the universe (including from the Sun) is absorbed in the atmosphere, in the ozone layer.
Human started producing electromagnetic waves with the development of engineering and technology. From the moment Hertz, Tesla and Marconi made their inventions, we have also been exposed to that additional radiation. Such radiation is added to natural radiation and can be considered a kind of pollution. In the consciousness of the average human, electromagnetic radiation is associated with radio communication systems. The mention of the word “radiation” usually causes negative associations, as if radiation is always harmful. In electromagnetic waves we distinguish ionizing and nonionizing radiation. The energy quantum of ionizing radiation have enough energy to ionize atoms and molecules in the human organism. This energy is sufficient to damage cells and hereditary information contained in chromosomes. Such radiation is, for example, gamma-rays produced in the decay of atoms and in a nuclear explosion or X-rays used, for example, in medical diagnostics. Of course, not all the electromagnetic radiation is that dangerous. At the frequencies used in personal communication devices (cell phones), energy quantum are more than a million times lower than those in ionizing radiation, so they can't cause cell damage. This radiation is therefore called non-ionizing.
In non-ionizing radiation, at the frequencies where mobile communication devices operate, the only proven effect is tissue heating. However, regulations on protection from electromagnetic fields have determined very strict limits and such heating cannot be felt in the normal usage of mobile devices. Basic limits in the range of mobile communications frequencies for occupational exposure were determined as the levels of absorbed power that are 10 times lower than those where tissue temperature rises by 1 degree of Celsius during exposure of 30 minutes. For the population, this level is even 5 times lower, i.e. 50 times lower than the mentioned power which causes 1 degree Celsius increase in tissue temperature.
With an increase in the frequency of electromagnetic waves, the depth of penetration into the human organism is decreasing, so in fact the most exposed organ is the skin, and for example, the brain is already very little exposed at mobile communications frequencies. This fact is particularly important for 5G technology which will, in the further stages of development, use frequencies of dozens of gigahertz (e.g. 27 GHz, 38 GHz). It is evident from public reactions that these high frequencies are considered a special threat, however, their penetration into the body and therefore the effect on tissues and internal organs will be minimal due to the very small depth of penetration.
Bluetooth, WiFi, and 3G, 4G and 5G mobile communication systems are wireless communication systems operating in the frequency range from several hundred MHz (megahertz) to several GHz (gigahertz), i.e. in the mentioned area of non-ionizing electromagnetic fields. They differ in terms of maximum permitted radiation power, range, type of modulation, data transmission speed, etc.
Bluetooth and WiFi work in the so-called free frequency band, so the device owner does not need to obtain individual license to operate such a transmitter. The usage is allowed for everyone, but users are not protected from any interference. Due to the free usage and avoidance of interference, the allowed output of such devices is significantly lower than for “mobile telephony” systems, i.e. 3G, 4G and 5G.
3G, 4G and 5G systems operate in the licensed spectrum for which the operator pays fees to the state. In return, each operator has been assigned a precisely defined frequency band and protection against interference is guaranteed. This makes the operation of these mobile networks much more reliable. The allowed radiated power is higher, but for each base station it is necessary to obtain an appropriate permit and perform first and periodic measurements of the level of electromagnetic fields in order to protect people from electromagnetic radiation.
Exposure to high-frequency electromagnetic fields is described by radiated power density. 5G technology is no more dangerous than the existing wireless communication technologies, so we don't need any new and special protection or precautionary measures. The radiation density decreases with a square distance from the source, so if we increase the distance from the body from 1 cm to 1 m, we reduce our exposure by 10,000 times. The basic principle of self-protection against excessive exposure to electromagnetic fields of mobile communications is distance. A smartphone deposited on a distance of extended hand instead of in a trouser pocket and a tablet or laptop leaning on a cushion or pad instead of directly onto the lap will repeatedly reduce our exposure to electromagnetic fields. Due to distances, power density caused by the operation of base stations is hundreds or thousands of times lower than the one created by our mobile devices.
Mobile phone radiates the maximum power when making a call, before we hear the sound of calling in the headphones when we call, that is, before the phone rings when we receive the call. When we make a call, it's enough to keep the phone in your hand, away from your head or body, until we see on the screen that the call was made and then press it on your ear. At that time, the radiated power of the mobile device has already been reduced to the minimum necessary level for achieving a quality connection. An additional beneficial effect of moving the cell phone away from the body is that less radiation power is lost in the body, so the cell emits less power due to more favorable operating conditions, which additionally reduces exposure and can prolong battery life. When we receive a call, we will not always be able to avoid the phone ringing near our body, but then we can carry it in our outer pocket or in our purse. When we are in the workplace or at home, we can put the mobile phone on the table or shelf that is within our reach. Thus, we are reducing our exposure to the electromagnetic field in the establishment of the received call. With longer conversations, it is better if we can use a speaker or headphones, as this reduces the exposure to the electromagnetic field during the whole conversation.
In addition to increasing distances, we can reduce our exposure to electromagnetic fields by shortening the time of use of wireless communication devices, whether mobile phones, computers or tablets that are wirelessly connected to the Internet, because here too the general rule applies: anything that is excessive can be dangerous.
This particularly applies to children who increasingly become intensive users of wireless technologies every day.
Studies on the harmfulness and impact of 5G mobile communications networks
- What are the studies on the effect of mobile communications networks’ radiation on the human organism so far?
- Are there studies on the impact of 5G networks on human organisms and their harmfulness?
- What makes the study professionally and scientifically relevant?
Many studies have been conducted to learn about the influence of electromagnetic fields depending on the frequency, strength and time of exposure on cells, tissues and living organisms. Based on these studies, the ICNIRP (International Commission on Non-Ionizing Radiation Protection) made recommendations to limit human exposure to electromagnetic fields. These recommendations are based on the thermal effects of high-frequency electromagnetic fields, as none of the non-thermal effects that had been studied has been scientifically confirmed. Of course, the studies are not concluded by that. They are still conducted in the whole world and the new results and cognitions are used to amend the protection measures. Definition and eventual changes in allowed level of exposure to electromagnetic fields must be based on medical and biomedical studies that must determine sufficient level of correlation between the cause, ie. specific level of electromagnetic field, and a consequence, ie. a certain biological effect.
5G and COVID -19
- According to your knowledge, is there any connection between the use of 5G technology and the outbreak of COVID-19?
Direct occurrence and transmission of the disease by electromagnetic waves is not possible. Electromagnetic waves cannot produce, transmit or create any biological creation, including the virus or bacteria. The transition of computer viruses to humans takes place only in fantastic movies.
Suspicions that exposure to electromagnetic fields of mobile communications has any impact on human immune system, which would facilitate the spread of coronavirus infection are not based on current scientific findings. According to my knowledge, no study or scientific research in the field of medicine or biomedicine has found that exposure to high frequency electromagnetic fields has a direct negative impact on the human immune system.
The ban of 5G networks and impact on technological development
- Do you think 5G technology should be banned and what are the possible consequences of such a ban?
Since 5G technology envisages the deployment of new mobile communication frequency bands, it is particularly important to respect the limit levels for total exposure at all frequencies, which has so far been an obligation under the positive regulations.
Possible suspicions of increased exposure to electromagnetic fields resulting from the wider use of the MIMO systems with multiple antennas on the mobile device and at the base station, from the rotation of the base station beam towards the user, can be taken into account when calculating using appropriate modelling and taking into account the so-called “worst case”. Verification of the exposure model is carried out by measurements, and in order for the measurements to be carried out, conditions are necessary as close as possible to the actual ones, i.e. the 5G operating network with a sufficient number of base stations and users. Therefore, in this case the ban would not contribute to the resolution of this issue.
The deployment of any new technology requires time, investment of financial resources and expert staff. A possible delay or ban on the deployment of 5G technology would certainly cause a technological lag, financial investments in infrastructure and knowledge would be missing, and skilled employees would either stagnate or go to other countries in need of such knowledge. The departure of experts would only increase further technological delays and it would be difficult to get out of such spirals.
- ADDITIONAL QUESTION: From the window I can see one or more antennas, I'm afraid, who can I call to measure electromagnetic fields?
If you want to conduct measurements of electromagnetic fields at your premises, authorized companies exist for this. Authorized companies have calibrated instruments and qualified calibrators, and measurement procedures are harmonized with the Croatian and European standards. Each authorized metrology company must possess a certificate issued by the Ministry of Health and a certificate issued by the Croatian Accreditation Agency. Both documents are issued for a limited period of time and need to be renewed. Professional authorized measurers will gladly show you both documents, and many of them already have them posted on their web pages. The list of authorized companies is available on the website of the Ministry of Health.
Individuals or companies that carry out measurements of electromagnetic fields, and do not possess appropriate authorizations, deceive citizens for the purpose of illegally obtaining material gain. Electromagnetic field measurements are not carried out using plumbline, dowsing rod or “instruments” that periodically write, light and display some figures, and can be obtained online for a couple of hundred HRK. The implementation of such “measurements” and the procurement of such “instruments” are a waste of money. Various amulets, stickers and pendants sold as protection against electromagnetic fields are also a fraud and do not provide any protection. Don't believe the so-called “experts” on social networks.