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5G Network

PhD Gordan Šišul, FER, Zagreb

Basics of mobile communications networks
  • Why do we need base stations?
  • Why are base stations implemented 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?
Mobile communications networks are wireless electronic communications that use the electromagnetic wave as a means of transmitting information. These electromagnetic waves are called signal. In accordance with the needs and forms of information, the “shaping” of signals is made in order to be most suitable for transmission. Besides the shape, we're saying the signal has a level, a transmission frequency, a channel width. The transmission frequency is usually several magnitudes of order larger than the channel width, and the channel width tells us what kind of transmission speed we can achieve. The signals are transmitted from antenna systems connected to base stations. The base station is a transmitter with which cell phone communicates and which transmits the signals to/from the fixed part of the network. An area (space) where there is sufficient signal level for reliable communication is called a cell. So, the antenna system together with the base station supplies the cell with an adequate signal. If we want a bigger cell, we're transmitting a stronger signal. Inside the cell there are users who share the capacity to transmit data supplied by the base station. Capacity is limited by transmission technology and channel width. In the case of N users within a cell who have a connection established simultaneously, each of them may receive the N-th part of the data. This simple consideration can easily conclude that the achievement of high transmission speeds per individual user is more likely if there are fewer users within the cell, and this is the case when the cell covers a smaller area. Coverage of smaller area is realized with lower power of transmission. This is particularly visible in urban areas where population density is high and where it is necessary to use small cells. I repeat, smaller cells mean a smaller number of users within a cell and a greater capacity per user. This is the reason for installing base stations in populated areas, and in practice it is shown as an increased number of antenna systems within a given area.

You can wonder why this is not the case with digital terrestrial television (or radio) when transmitters (base stations) are mostly outside the populated areas. The reason lies in the fact that it is a different form of communication or data transmission. In television we talk about broadcasting, which is a one-way transmission of the same data to all users. In this case, every user (regardless of their number) within a cell can always get the same capacity or quantity of data. Capacity is not shared. So here, for economic reasons, it is convenient to have large cells and transmitters can be located outside the settlement.
 
The grounds of 5G technology -- why 5G?
  • What makes 5G different from the existing technologies in mobile communications networks (e.g. 4G, 3G, 2G) and is there a need for its deployment?
  • What frequencies do 5G networks use?
 
5G represents the fifth generation of public mobile networks. The fifth generation of mobile networks is an upgrade of existing mobile networks, which is enabled by the advancement and development of several technologies. If you had to explain and describe yourself with one term, you would say 5G is a comprehensive network. It represents a single universal integrated network for different types of traffic (service) with the possibility of data transmission almost in real time (latency of ~1 ms). Therefore, it has the ability to connect everything that surrounds us and as such is the key to the realization of Industry 4.0. We know that Industry 4.0 is based on convergence of networking and smart systems. So if we want to be fully connected and have acceptably small delays (in real time), we are forced to use fifth generation mobile network services. 5G network represents a complex and expensive system and will take a long time to be deployed.  It is necessary to have a lot of base stations available, build an expanded fixed access optical network to which base stations will be connected, have access to a lot of frequency spectrum, use artificial intelligence to manage and process large quantities of data. New concepts in network architecture are also needed, such as centralization and virtualization, i.e. Software-Defined Networking (SDN) and Network Function Virtualization, etc. NFV), then use of cloud computing and much more. The aim of all this immense technology is to have the following three main types of services at the same time:
  • Improved mobile broadband access,
  • Mass communication with sensors and simple machines,
  • Ultra-Reliable and Low-latency Communications - URLLC.
In reference to the improved mobile broadband, we can conclude that it represents the natural evolution of the existing 4G network. The aim in this communication mode is primarily to increase network throughput in order to enable the end user speeds greater than 1 Gbit/s. The initial deployment of 5G networks includes only this functionality. Internet of Things is a concept that involves connecting a very large number of different devices (mostly simple sensors) with a small amount of data and low required transmitted speeds. URLLC is a communication branch where the most critical parameters are delay and reliability. Examples of such services are traffic management and control (example communication between vehicles), and various industrial automation processes. In addition to these, it will be possible to define specific user oriented services. The term network is introduced as a service.

Wireless (or radio) interface of 5G network is very similar to 4G network, and signal shapes in 4G and 5G are obtained using the same techniques. In order to meet the set requirements on the network, it will be implemented at different transmission frequencies and with different channel widths. In particular, it will be implemented where there is available spectrum. In the Republic of Croatia 5G will operate at 700 MHz, 3.5 GHz and 26 GHz. The only big news of 5G technology compared to the previous ones will be the “new” field of operation at 26 GHz (where it will be implemented at the latest). Bigger cells and better signal coverage can be achieved at lower frequencies (700 MHz) (signal attenuation is weaker, diffraction is more relevant), but due to available narrower channel widths, the achievable transmission speeds cannot be so high. This area is convenient for covering rural areas and roads because there is no such a need for capacity, and it is also useful for connecting sensors. The 3.5 GHz area provides sufficient capacity and here a significant increase in speed will be seen compared to 4G. Unfortunately, the existing locations of base stations (so-called sites) will not be sufficient for the entire coverage of the desired area, but additional antenna masts (and base stations) will also have to be installed. This is because existing generations of mobile networks work on slightly lower frequencies (800 MHz, 900 MHz, 1800 MHz, 2100 MHz, 2600 MHz). Nevertheless, operators will find this band very interesting (probably the most interesting) for implementation. The 26 GHz band provides opportunities for “extreme” data transmission speeds, but due to the low range (high attenuation, no communication without optical visibility) it will be financially expensive and very difficult to achieve the desired coverage. In the beginning, it is certain that only the so-called hot spots will be installed in urban areas, which will serve to demonstrate the power (speed) of new technology. Only after a longer period of time and large financial investments will it be possible to achieve some “significant” coverage with the 26 GHz signal.

A significant news of 5G networks in relation to previous generations, in the radio part of the network is the usage of more advanced and complex antenna systems that allow the signal to focus towards the user. This technique is emphasized in the 3.5 and 26 GHz bands. There are no significant performance differences between 4G and 5G networks at the 700 MHz frequency band.

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? 
The waves represent the propagation of a disturbance by which energy is transmitted. The energy transmitted by waves can be spread through a medium (mechanical waves) and through a space where there is no matter (electromagnetic waves). In addition to these waves, there are also gravitational waves, matter waves. We'll only stay on the electromagnetic waves because they're used in wireless communications. It is important to emphasize that each body, heated to a temperature, radiates the electromagnetic waves. Electromagnetic waves are named after the fact that they consist of oscillating electrical and magnetic fields. Electromagnetic waves are expanding in free space at the speed of light. They are characterized by wave length, periods, frequencies, amplitudes (levels). The number of crests or troughs of waves, formed in a certain period, is called wave frequency (unit Hz) and it is invert from the time period. Wave length and frequency are connected by wave velocity, i.e. it is equal to their multiplication. So if the wave has a very high frequency, it has a short wave length and vice versa. For example, we can say that the wave has a frequency of 1 GHz or a wave length of 30 cm. The electromagnetic waves are divided into radio waves, infrared radiation, visible light, ultraviolet radiation, X-ray radiation, gamma radiation. All these waves have some specific properties and behave differently, especially in interaction with objects and bodies. Regarding the electromagnetic waves we distinguish ionizing and non-ionizing radiation. The concept of radiation usually has a negative connotation, but in this case it refers to the frequency of the electromagnetic wave. Ionizing radiation (the one at very high frequencies that we do not use for wireless communication) has sufficient energy (quantum energy) to ionize molecules in the human organism and it can cause cell damage and hereditary information contained in chromosomes (that depends on the level of exposure). The examples of ionizing radiation are gamma rays, X-rays (frequencies ≈ 1016 to 1020 Hz). At the frequencies that we use in wireless communications, energy quants are smaller (more than a million times) and there is no ionizing effect. That's why such radiation is called non-ionizing. It is necessary to distinguish between the term quantum energy (depending on frequency; the term from quantum physics that says it is the smallest, indivisible amount of energy that an atomic core, atom or molecule can emit or absorb) and the energy of an electromagnetic wave (depending on the levels of electrical and magnetic field). In communication we are focused on the transmission of electromagnetic wave (signal) energy which is transmitted and received by antennas. It is important to point out that the power of the electromagnetic wave decreases on average with a square of distance. This means that the power decreases by 100 times by moving away from the radiation source from 10 cm to 1 m,
The type of signal in the fifth generation mobile communications systems is similar to the 4G signal format, but it is also similar to the signals used in Wi-Fi (wireless local network), digital terrestrial television and digital terrestrial radio. All these systems operate at different frequencies (or wavelengths), have different powers, different channel widths. (But they're all radio waves). So if we compare the 5G signal impact with that of 4G signals of the same level and close frequency, we can't talk about an increased risk. The 5G technology is no more dangerous than the existing wireless communication technologies with the same exposure level. The 5G network operating mechanisms in the 700 MHz and 3.5 GHz bands do not differ from other wireless technologies, and the news is operation at 26 GHz band. By increasing the frequency, the depth of penetration into the human organism is decreasing, only the skin is exposed to the effect of heating. This effect is not a consequence of technology but of the operating frequency. The public considers high frequencies a special threat, but the penetration of electromagnetic waves (non-ionizing) into the body is smaller, and thus the effect on tissues and internal organs is smaller. Once again, I note that this frequency of 26 GHz also belongs to non-ionizing radiation (this frequency is still more than a million times lower than the frequency of ionizing radiation).
 
Studies on the harmfulness and impact of 5G mobile communications networks
  • What are the studies on the effect of mobile radiation on the human body so far?
  • Are there any studies on the effect of 5G networks on human body and its harmfulness?
  • What makes the study professionally and scientifically relevant?
Questions about the harmfulness and influence of electromagnetic waves on human organisms should primarily be answered by physicians, molecular biologists. Dosimetry (allowed exposure levels) is determined on the basis of their studies. The dosimetry does not have anything to do with a used generation of mobile systems. If we have considered so far (defined by the ordinance and the law) that exposures that are less than defined limits are not harmful, the usage of new technologies (5G), while keeping the same limits, does not change anything.

We should be honest and say that it is very difficult to conduct this type of research (the influence of electromagnetic radiation on the human organism). Experiments on humans cannot be conducted, and the mapping of results obtained from animal studies on humans is not unambiguous. It is a demanding procedure to establish a statistical analysis of the occurrence of diseases in humans related to the influence of electromagnetic radiation. Namely, it is difficult to create a large control group of subjects in which other health impacts (e.g. air and water pollution, food pollution) can be excluded.

There are many studies and many results. The biggest problem is the fact that there is an inability to reproduce research and obtain the same results. We know that every scientific research is based on repeatability. Simply put, the result of the same scientific experiment must always be the same regardless of the number of repetition of experiments.
 
5G and COVID-19
  • According to your knowledge, is there any connection between the usage of 5G technology and the outbreak of COVID-19?
There is no connection between the usage of 5G technology and the outbreak of COVID-19.
 
Banning the 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?
As already mentioned in previous explanations, the 5G technology is only one of a series of wireless technologies used to transmit information (as well as all other generations of mobile networks, Wi-Fi, digital terrestrial television and radio, Bluetooth, LoRa and many other technologies). The effect on the organism does not depend on the name of the technology, but on the strength and frequency of the signal. That's why it makes no sense to ban 5G. It is necessary to continue to take care of the protection against electromagnetic radiation and to follow the latest scientific achievements and positive practices from the most advanced societies.

The new thing that 5G brings is support to realization of 4.0 Industry as well as realization of different types of traffic (services) with the possibility of data transmission almost in real time. Full realization of 5G networks (not only improved broadband access) provides preconditions for further technological advancement of society. Banning 5G would mean denying new advanced services, reducing the profits and competitiveness of companies, income to the individuals, the state and society.
We live in a democracy and it will be the way the majority decides, and it is up to me, with my expertise, to present the facts to the public and facilitate the choice. Unfortunately, rationality sometimes doesn't live in people.