5G vs. Wi-Fi: Expectation and Reality

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Lately, more often than not, the question of the future of Wi-Fi networks in connection with the anticipated mass construction of the fifth-generation cellular networks is up for debate. In point of fact, why do we need Wi-Fi in a world where cellular networks provide billions of people with high-speed Internet access? Will the progress of the family of Wi-Fi standards come to a halt with the advent of 5G? Will the technology leave the market, having completed its «historic mission»? This article is dedicated to those of you who answered these questions in the affirmative. Hopefully it will also appeal to all the rest who are familiar with the network technologies.

Spoiler Alert

We decided to illustrate the text about the «battle» between the two technologies with the scenes from the immortal Matrix trilogy, where the war between the machines and the people ended in coexistence.

Despite their seeming importance and logic, questions about the rivalry between Wi-Fi and 5G are built on the hyped up juxtaposition of kindred in spirit, but different in the technology application models. Most of the allegations concerning the impermanent nature of Wi-Fi originate from the cell phone operators, and at the end of the article we will tell you why.

Until then, together we will try to dispel two myths — «5G is way faster than Wi-Fi» and «Wi-Fi will die out before much longer». For starters, let’s go back in time and figure out what 5G and Wi-Fi stand for.

Frequency Hunger

By 5G we mean a new generation of cellular communication standards, which will reportedly revolutionise telecommunications. However, in truth, a similar take on 4G back in the day was more than justified. Compared to 3G, 4G substantially increased the data transfer speed, the technology received a brand new air interface, a new backbone network architecture and a ton of new opportunities for providers (and, consequently, for subscribers). In case of 5G, there is also a fair amount of changes and improvements, and some of them are pretty radical. But there is one important fact that is not mentioned often enough: based on the 5G standards, the mobile networks that fall into three different categories will be created. We’re referring to the 5G networks for traditional mobile network usage scenarios in the 1-6 GHz range, networks’ complete territory coverage and the Internet of Things (IoT) at frequencies below 1 GHz and millimeter-wave networks. And only the first of these three 5G types will be widely available for regular mobile subscribers in the foreseeable future. The other two types will have special usage patterns, which we will also talk about.

But first let’s talk about the hot-button issue of the day — the «supersonic speeds» for the subscribers. The 5G networks operating in more or less familiar frequency ranges from 1 to 6 GHz are designed with the purpose of mass servicing regular subscribers. At higher frequencies, it is virtually impossible to provide continuous coverage with a limited number of high-power cell towers (macrocells). Unfortunately, there are few free frequencies below 6 GHz, and that is a worldwide problem. With 3G and 4G, we have already endured and continue to suffer through the conversion of spectral regions, the transfer of various kinds of consumers to other frequency ranges, and the refarming of frequencies from the older standards to the newer ones in the years to come. It stands to reason that there is no new magical source of free frequencies for 5G in the usual ranges. Strictly speaking, a large group of new solutions when it comes to 5G is specifically focused on alleviating the frequency scarcity problem. The goal of the new ideas and technologies in mobile communications is always to increase network capacity and speed without significantly increasing its cost. What exactly can you think of to accomplish this goal? And what does 5G have to offer in this respect?

Wi-Fi Races to the Rescue

In order to increase the network’s capacity and speed, one might obtain new frequencies. As was already mentioned, for all intents and purposes there is nowhere to get them from, and for that reason cellular communication is trying to infringe on the ranges occupied by the other technologies. In 5G, the methods of using Wi-Fi frequencies by the cellular networks have gained momentum, after having found a number of applications in 4G. Fairly large areas of the spectrum (hundreds of megahertz) in the 1-6 GHz range have been allocated to Wi-Fi, and cell phone operators have long been «hunting» for them.

But you can’t simply take these frequencies away from the public networks, that’s why a family of technologies is being developed that will allow to simultaneously use these frequencies for both Wi-Fi and cellular communication, and without a significant harm to the Wi-Fi quality. This is an intriguing trend. From the simple re-use of the common band in the LTE-U technology (poorly coordinated and harmful to Wi-Fi), the development went first in the direction of the LAA technology (supported by 3GPP Release 13) that uses Listen Before Talk Principle (LBT), and then to the LWA and eLAA standards. They go beyond defining the method of sharing frequencies, but also describe the direct coordination technique (through integration and data exchange) used by Wi-Fi and cellular radio subsystems (supported by Release 13 and 14 respectively). Here, the most important trend is the coordination and cooperation of cellular networks and Wi-Fi. Let’s keep that in mind. Will these technologies influence the anticipated speed and capacity of the cellular networks? Of course, with the help of this trend it is possible to ensure a certain growth of these parameters, however, one should not expect a revolution here.

Hormones of 5G Growth

If these frequencies are not enough, it is necessary to increase the spectral efficiency — transmit more data in one channel in the same frequency range. In this case, 5G is better than 4G thanks to the updates in signal modulation and signal coding schemes, but radical progress is not to be expected. Modern modulation systems are already close to physical limits and the practically achievable spectral efficiency of the cellular networks in a single channel can’t be increased dramatically. By the way, during the transition from 3G to 4G, the growth of spectral efficiency of a single channel was more substantial than expected when switching to 5G. Nevertheless, there is still significant potential for increasing the efficiency of using the frequency range for the provision of services, but it is realized by the more complex means. We are talking about the frequency resource distribution between the network services, more efficient resource allocation between the uplink and downlink data channels, network self-organization, resource recombination and cell coordination, increases support of multi-frequency (carrier aggregation), and etc. All this will be actively used in 5G and will have a positive effect, but most of these approaches are already present and in use in the fourth generation.

If one can’t radically improve the efficiency of using a single channel, it is logical to try to organize simultaneous exchange of different data streams between the network and the subscriber or subscribers in the same frequency range. In other words, it is necessary to increase the re-use level of the frequency resource. For that purpose, data channels operating in the same frequency must be isolated from each other in order to avoid interference. There are several approaches to solving this problem that have been used extensively by the existing cellular networks and that have been gaining traction in 5G lately.

The growth of the cellular networks’ capacity has always been guaranteed by a combination of the three factors listed above: expansion of the spectrum being used, increase in spectral efficiency and increase in the level of re-use frequency. In the past two decades, the emphasis has been on the re-use techniques and the way they have contributed towards the capacity increase. By various estimates, over the course of the cellular network existence its capacity has grown by 3-4 times on account of the frequency resource, by 5-6 times — due to increase in spectral efficiency, and by 40-60 times due to improvement in the frequency usage.

A New Technology is not yet a Business

The most well-known example of re-using frequencies is installation of a large number of cells: the more cells, the more times one can use the same spectrum. The main limitation of this approach is crosstalk (interference) at the coverage areas’ boundaries. The greater the cell number is, the less area they cover and the greater is their proportion of areas with high interference. To combat this, a ton of various methods have been employed — from strategies for re-using frequency bands, depending on the mutual disposition of the base stations to complex algorithms for coordinating signals by power and phase at the boundaries of the coverage areas. As the number of cells increases, so does the complexity, and, of course, the cost of solutions that allow them to be shared.

In 5G, provisions have been made for improving the efficiency of using a large number of cells, but nevertheless this improvement is only evolutionary in nature. It would seem that the 5G ideology is oriented towards freedom from macro-architecture, but the same was said about 4G. At a time of the mass construction of 4G networks, the market anticipated that the small cells would take over the role of the main provider of communication services in the context of dense urban development, and the explosive growth of their production and consumption.

This is not to say that a lot of microcellular architectures and 3GPP-supported solutions, for which high-quality equipment is available on the market, haven’t been in high demand; it certainly hasn’t turned into the main method of establishing network coverage. Coverage outdoors continues to be established primarily by the macrocell sectors, while small cells are used for the most part as an additional tool that makes it possible to plug «holes» in the coverage and improve the network quality. A commonly-occurring model of using small cells today involves installing them in close proximity to the macrocells. At the same time, the network is parameterized in such a way that the subscribers near the macrocell (located in close to ideal conditions of radio signal propagation and able to connect at a very high speed) more often than not would be serviced by its «entourage» of small cells, whereby subscribers located at a distance, would receive more cell resources and improved communication quality and speed.

The main reason for the small cells maintaining the auxiliary role and the relatively slow growth in the number of cells is not in fact technical, but economic. The growth of the cellular traffic (for all the mobile operators may say about this) has occurred in the last decade, albeit very intensively, but more slowly than the market anticipated in the face of inflated expectations following the period of initial investment in 4G. And, more importantly, mobile operators haven’t learned how to profit off of this traffic. As early as the moment of the 3G’s debut, the cellular market was well aware of the threat of the mobile operators transforming into a «data pipe» with the rapidly plummeting cost of traffic transmission. If you look at the speeches of telecommunication company executives at industry conferences of those times, they unanimously proclaimed that in a few years mobile operators will be selling not just the basic services to the subscribers («voice», messages and data transfer), but the content and a multitude of useful services (media, communication, related to control, management and security, gaming, etc.). Experts predicted that this will become the main source of revenue for telecom operators.

Of course, even though the mobile operators offer lots of useful services these days, they still extract the lion’s share of their revenues from the same good old data, the «voice» and the messages. Only now the data has moved to the first place. Revenues from additional services and content remained just a pleasant addition. Hence the very conservative recently adopted approach to investments, which inevitably affects the cellular networks architecture. A large-scale implementation of small cells in the cities turned out to be economically unsound and it is not yet clear how 5G will be able to factor into this troubling trend.

Smartphones and MIMO

Another way to increase capacity and speed through re-using the frequency resource is a multi-channel reception and data transmission from one cell to one or more subscribers. This is a family of technologies, commonly referred to as MIMO (Multiple Input Multiple Output) and built on the principle of spatial multiplexing of the radio channels. In 5G, the so-called, Massive MIMO (M-MIMO) and the beamforming technology associated with it (in fact, these are the versions of the general approach that is based on the use of multi-element antennas), in theory allowing a tenfold increase of the total radio network bandwidth. This additional bandwidth can be used either to increase the number of simultaneously serviced subscribers in the coverage area, or to increase the data transfer rate for specific subscribers or groups of subscribers. Beamforming additionally increases the efficiency of using the network’s frequency resource, taking advantage of the fact that not all subscribers in the coverage area simultaneously need a full speed access. The principle of its operation lies in the dynamic redistribution of the signal’s power (by forming directed beams) in favor of those subscribers who currently need large amounts of data.

M-MIMO is a complex technology that requires the creation of phased antenna arrays with hundreds of elements at a reasonable price and in form factors that can be used in the cities (outside the city limits these systems are simply not needed). There is no doubt that M-MIMO will eventually be put to good use in the base stations. But it is very important to emphasize that on the part of the subscribers, the use of MIMO is limited by price, size, energy parameters and the permitted radiation power of portable devices. The practically achievable number of independent data transfer channels available in the smartphone is very limited, and the quality of their work depends heavily on the conditions of use and the distance to the base station. Therefore, if 5G network’s capacity can indeed be significantly increased by means of the M-MIMO, the data exchange rate between the network and the individual subscriber will grow much more slowly, limited by the capabilities of the subscriber devices, and will depend heavily on the conditions of use.

Look on the Bright Side: All You Need is a Substantial Investment

All the above mentioned can generate a substantial increase in the capacity of cellular 5G networks operating in standard frequency ranges, as opposed to 4G, but they can’t guarantee any kind of ground-breaking growth of the communication speed accessible to an individual subscriber. The concepts of capacity and data transfer speed in a cellular network are closely connected, but not equivalent. An increase in the number of subscribers that the network can service without losing quality does not mean that the network will work much faster for each individual subscriber in real-life conditions.

It should be emphasized that in order to achieve a significant effect from the innovations described above, it is necessary to install more base stations, connect them to packet data transfer networks with increased bandwidth, use much more complex and expensive antenna systems and obtain more spectrum. No magic, you just need a very substantial investment. And investors usually go where there’s business. As far as mobile operators are concerned, it is not yet clear why they would be willing to invest huge amounts in the mass segment of 5G networks with continuous coverage and high capacity.

Network for IoT and Improved 4G

Let’s briefly dwell on the other types of 5G networks. The most important of them are networks of inter-machine communication or IoT (Internet of Things). Here, 5G has great advantages over the previous generations of mobile networks. This is, first of all, a low level of delay (a great deal lower than in 4G) and the ability to service a huge number of subscribers in the coverage area of one cell. The 5G standards include LPWA (Low Power Wide Area) communication protocols that are designed for low-speed low-intensity communication of a very large number of subscribers with very low power consumption by the modems. Thanks to the 5G architecture and parameters, it is possible to build not only sensor networks (that combine different sensors and actuators, like for example, urban systems), but also highly reliable control systems for vehicles (cars and drones) and various robots and robotic complexes. IoT 5G networks will mainly be built at frequencies below 1 GHz, where the area covered by the signal of one cell is larger than at the higher frequencies. At the same time, high-speed communication at these frequencies in 5G is unlikely to be available for regular subscribers, due to lack of spectrum and also because Massive MIMO at frequencies below 1 GHz is difficult to use due to the large antenna sizes.

The third type of 5G networks is designed to provide subscribers with extremely high speed communication. Here we are talking about the peak speeds of up to tens of gigabits per second. These are the networks in high-frequency ranges with wavelengths of less than one centimeter (millimeter ranges), which have never been used before in cellular communication. The reason for the decision to include these ranges in the 5G standard is that they have very large unoccupied spectral regions (hundreds of megahertz).

Many people who talk about a significant increase in the speed of communication in 5G do not fully realize that ultra-high speeds will only be available in the networks with millimeter ranges. The signals of these frequencies propagate in such a way that in order for the communication to go through, a direct visibility between the antennas of the transmitter and the receiver is almost always required (i.e., the signal is physically incapable of going around the obstacles), and the permitted (and technically available) radiation power is very small. This means that, in the city conditions in order to build a field of continuous coverage in the millimeter range, it is necessary to install a huge number of small cells.

Many people who talk about a significant increase in the speed of communication in 5G do not fully realize that ultra-high speeds will only be available in the networks with millimeter ranges. The signals of these frequencies propagate in such a way that in order for the communication to go through, a direct visibility between the antennas of the transmitter and the receiver is almost always required (i.e., the signal is physically incapable of going around the obstacles), and the permitted (and technically available) radiation power is very small. This means that, in the city conditions in order to build a field of continuous coverage in the millimeter range, it is necessary to install a huge number of small cells.

These are not all the 5G characteristics, but you now have all the pertinent information necessary to formulate an intermediate conclusion. In the short term (we would estimate it to be 5-7 years, but this is a subjective assessment), no revolutionary effect will be obtained from the construction of 5G networks. With the advent of smartphones and coverage areas that support 5G, the user experience will improve due to higher and more stable network quality and the higher available data transfer speed. During this period, 5G networks will be perceived by the subscribers as an improved 4G. The data transfer speed with 5G coverage and the device that supports it (we are not talking about the pace of 5G devices’ market appearance) will, as a rule, be higher, but will remain in the price range. If now, in ideal conditions, it is possible to see peak speeds of above 100-150 Mbps in commercial LTE networks, and the average value is located in the range between 10-40 Mbps, then 5G networks are expected to peak at about 200-300 Mbps or higher, while the average speed will be between 30-80 Mbps.

5G Indoors

Above we considered the cellular networks outside the buildings. The situation indoors has a number of special features. It is there that most of the traffic is consumed, including the mobile one. Therefore, it is important for cellular operators to provide high-quality coverage and high network capacity in urban buildings. Since the most probable spectral regions available for 5G communication will be located in the vicinity of 3-4 GHz, macrocells located on the streets will not be able to establish quality coverage inside the city buildings due to strong absorption of the radio signal at these frequencies by the walls. Consequently, the 5G signal will have to come from the antennas located directly in the buildings. The use of high-quality MIMO indoors is generally not technically and economically viable, so indoor 5G will use small cells and antenna systems similar to those used today for 4G indoor networks. For this reason, the data transfer speed that will be available for the 5G subscribers indoors at frequencies below 6 GHz will be of the same order as the ones that can be obtained today in indoor 4G networks.

Currently, most of the traffic consumed by smartphone and tablet users is generated not in cellular networks, but in Wi-Fi networks. And this traffic is mainly consumed indoors. In order for the situation to change, not only should the cellular networks provide a higher data transfer speed than Wi-Fi (which is often the case now), but this speed should also become available to the subscribers in public places, in homes and apartments. Solving this problem for 5G will require huge investments in the construction of indoor networks, including the residential buildings.

Wi-Fi is at Least as Good as 5G, and Here’s Why

Now, after teaching you the nuts and bolts of 5G, it’s time to consider the main question. How is Wi-Fi different from 4/5G and what it stands for exactly, is it worse or better than cellular communication? The notion of Wi-Fi as a technology is largely shaped by the experience of using existing public networks, arranged very primitively. Meanwhile, modern Wi-Fi is capable of almost everything in the field of data transfer, same as the cellular networks. Wi-Fi fully supports mobility, allowing you to establish continuous coverage areas and service moving subscribers, service classes, automatic network authorization, advanced data protection, and automatic roaming between the Wi-Fi networks of different operators. Moreover, from 3GPP cellular standards and from the Wi-Fi IEEE standards, there are many tools designed for sharing and coordinating the operation of Wi-Fi and 4/5G. These are the previously mentioned technologies of the LAA/LWA family, and Wi-Fi Calling, and roaming between cellular networks and Wi-Fi networks with automatic network selection. From the point of view of the Wi-Fi data transfer method, both 4G and 5G are very close, since the standards of the 802.11 family use the OFDM modulation method, and in modern versions — OFDMA, virtually analogous to the one used in 4/5G cellular networks. There are many special features and differences, but fundamentally the methods and the available levels of Wi-Fi and 4/5G modulation and coding are close (much closer than 3G and 4G among themselves), which means that spectral efficiency in a single channel is also similar.

It should be emphasized that although Wi-Fi is developing simultaneously with the cellular networks, it always outruns the cellular communication standards of the supported data transfer speeds at short distances. Over the past 10 years, as was the case with the cellular communication, one big change of generations of Wi-Fi standards has occurred. Modern 802.11ac practically ousted 802.11n (adopted in September 2009) from the product lines of equipment manufacturers. But if in the mobile networks the replacement of standards is accompanied by significant and expensive infrastructure transformations associated with limited or absent backwards compatibility between communication generations, Wi-Fi is developing much more smoothly. 802.11ac has full backwards compatibility with 802.11n and for its use in existing networks no serious conversions are required. Since 802.11ac is de facto standard of the day, it is logical to compare its parameters with the currently available 4G network parameters. IEEE uses an approach of implementing standards in «waves» (like 3GPP) and 802.11ac has already passed the first wave stage (Wave 1) and is now at the stage of Wave 2. The standard accounts for the use of Multi User MIMO (which wasn’t previously available in Wi-Fi), and the peak speed of the physical channel (PHY rate) available at this stage is 2.34 Gbps when using three spatial streams and a bandwidth of 160 MHz (in theory, four streams can also be used). The realistically achievable peak data transfer speed at this channel speed can be about 1.5 Gbps. 802.11ac Wave 1 offered channel/actual speeds of up to 1.3/0.8 Gbps with the «old man» 802.11n in the range of 40 MHz offered up to 450/300 Mbps with three streams. The anticipated all-around implementation of the IEEE 802.11ac specification will allow using up to eight spatial streams, obtaining a physical channel of up to 6.77 Gbps and realistically achievable peak data speeds of up to 4.5 Gbps. In existing high-quality Wi-Fi networks (they do exist), you can observe peak speeds of 100-150 Mbps when using mobile devices and upwards of 200 Mbps when using modern laptops, even the ones with the latest versions of outdated 802.11n standard hardware. The new 802.11ax standard (the first approved version is expected in 2019) will add another 40% of spectral efficiency in a single channel and a fourfold increase in the overall efficiency of using the available bandwidth. There is also the 802.11ad standard, which, like the millimeter 5G «component», is designed for high-speed communications at ultra-high frequencies (in this case, it’s 60 GHz). This standard puts the channel’s peak bandwidth at 7 Gbps and supports beamforming. Unlike the 5G millimeter part, 802.11ad already has a number of commercially available chipsets for creating subscriber devices. It is now being replaced with a new 802.11ay standard, with a theoretical peak PHY rate of up to 44 Gbps in a single stream, which will add a millimeter Wi-Fi Multi User MIMO with four streams support (i.e., theoretical bandwidth with four streams and full bandwidth frequencies will reach 176 Gbps), aggregation of channels, and a significant increase in the working distances between the client device and the access point (up to hundreds of meters). Finally, for the sake of the 5G analogy completeness, we will discuss one more new 802.11ah standard (whose official name is Wi-Fi HaLow, which for some reason is pronounced as «HayLow»), which describes the IoT connection in the 900 MHz range. And in this standard, same as in 5G, everything is in good shape in terms of delays and power consumption. It is clear that the IEEE standard ideology development is close to 3GPP and the three network types of networks described above are also formed in the world of Wi-Fi.

Looking at these numbers, it’s only logical to ask the question — Since when is 5G considered to be «faster»? Theoretically achievable maximum data transfer speeds in 5G and Wi-Fi networks are quite comparable. From a technical point of view, 5G will not be faster than Wi-Fi (in fact, in the new Wi-Fi standards at 5 GHz, peak speeds can be higher than in 5G standard ranges, depending on the available frequency resource, and in millimeter ranges they will be even higher). But the truth is, it’s not that important. The main difference between the mobile networks and Wi-Fi is not the data transmission speed, but the usage models. Now we are ready to sum it up more accurately.

Why-Fi?

Mobile networks are designed to service a huge number of subscribers, provided that they still carry the inherited burden of those most basic services. Cellular operators are forced to build their infrastructures in such a way so as to provide the most uniform user experience, support of all standards and, if possible, all frequency ranges wherever network coverage is available, in any conditions, whether it’s an open field or a dense urban area, in buildings and out in the open. 5G, by the way, for the first time ever is trying to systematically move away from this ideology, to reinterpret it architecturally, offering to build this type of networks (remember the three types) exactly where they are needed the most.

Right from the start and to this day — Wi-Fi has been a technology built around only one basic service — data transmission — and focused almost exclusively on areas where there are many relatively inactive users that are present mainly indoors. At the same time, a set of additional Wi-Fi services is drastically different from the cellular networks, largely due to the absence of the need for a contract and the availability of a SIM card. Many of them are only available in these networks: adware popping up when getting connected, hyperlocal advertising and analytics, short-term paid access for tourists with instant activation. In addition, due to Wi-Fi neutrality towards the mobile networks, traffic offloading, Wi-Fi Calling and international roaming for subscribers of all cell phone operators and any Wi-Fi operators is a strong possibility.

Standard mass-oriented Wi-Fi equipment that meets the appropriate standards has significant limitations in terms of radiation power and is designed to service subscribers who are a short distance away. It’s easy to see that Wi-Fi is by nature a niche technology. Because of this, Wi-Fi is much simpler in terms of architecture than the cellular networks. The most notable simplification is the absence of any single centralized core network in the Wi-Fi ideology, which in the case of cellular communication is not only necessarily present, but also very complex. Each Wi-Fi segment can be built independently, using the solutions for processing and routing traffic «in place» and at the same time managed centrally by one operator. As a communication medium that ensures the network unity of such a system, the Internet fits the bill perfectly. Another difference is that the Wi-Fi ranges either do not require licenses and permits, or they have an essentially simplified licensing procedure and a lower frequency resource cost, in comparison with the cellular communication frequencies. Because of that, Wi-Fi network unit is much cheaper in the coverage area. Whatever changes the cellular communication technology may go through; its fundamental difference with Wi-Fi lies in the specific cost of the infrastructure, which makes it possible to serve a certain number of subscribers in a given area with a given level of service. Wi-Fi will always be cheaper.

On the other hand, if we start using Wi-Fi to build a solution for creating continuous coverage, servicing a large number of subscribers outdoors with a single service level and centralized subscriber base management, the result will be worse than when turning to the cellular networks, whose cost-effectiveness and quality are much more superior outside. It should also be noted that the Wi-Fi frequencies are less protected than the cellular communication frequencies, and the probability of interference is much higher. This is not that important indoors where the situation is usually under the owner’s control, but which creates huge problems outside the buildings.

Peace as an Alternative to War

Cellular operators are concerned about the availability of public Wi-Fi networks, not because of their quality level, hassle-free use and lower security, but because they are free. Since mobile operators have not learned to profit off of anything other than traffic, the availability of a free, albeit less qualitative alternative to their networks is unacceptable to them. The market has long offered an alternative to the enmity between the cellular and the Wi-Fi networks, which consist of unloading the subscriber’s cellular traffic in the Wi-Fi Offload network using automatic, user-friendly mode. The subscriber may not even be aware of the type of network his traffic is going through at the moment, since all services (including voice communication, data transmission and all types of messaging services) operate without any differences. There are many types and technologies of Wi-Fi Offload (for example, actively developing Wi-Fi Calling, should be classified as Offload), as well as advanced methods of cooperation and coordination of cellular and Wi-Fi networks (some of them mentioned above) that are used around the world by the ever-growing cellular and Wi-Fi operators. With the emergence of modern high-quality segments of Wi-Fi networks, they are turning into a natural alternative to building or expanding their own infrastructure with traffic growth, changing the network generation, or limiting investments by creating smaller-capacity cellular networks.

The process of establishing cooperation between the cellular networks and Wi-Fi is ill-designed. In my opinion, the reason for this is the practical lack of actual high-quality, standards-compliant and well-maintained Wi-Fi networks in our country. We are now faced with the chicken and eggs dilemma. To build a high-quality Wi-Fi network with many subscribers, it is necessary to invest substantial amounts (which, are much lower than the corresponding costs of the mobile operators, but nevertheless quite sizable). To make an investment, you need to have a business case. You need to be able to earn money using this network. But nobody can profit off of free public Wi-Fi. As a result, public Wi-Fi networks are mostly built with a direct customer in mind and external financing for solving any problems (convenience for visitors, security, etc.), except for the commercial ones. Which means, that such networks are designed to minimise all costs, while maintaining the minimally acceptable quality, without taking into account the needs of cellular operators. Accumulated over time, the experience of using such «cheap» networks led to the formation of a stereotype about the poor quality of Wi-Fi as a technology. In fact, with proper use and quality design, construction and operation, Wi-Fi can provide a user experience no worse than 4G or 5G, but for less money and only where it is feasible to use.

Last but not Least: About the Subway

The discussion around Wi-Fi networks in subway systems highlights key considerations about the future of connectivity, especially with the potential introduction of 5G. Currently, the operator of subway Wi-Fi networks manages around 1.5 million unique subscribers daily, raising questions about how cellular networks, especially in the 5G standard, could impact these subscribers and whether it could lead to a significant shift toward mobile networks.

When examining 5G, its main benefits come from technologies like MIMO (Multiple Input Multiple Output). However, due to the physical constraints of subway tunnels, advanced MIMO and beamforming technologies that define 5G performance may not function optimally. As a result, the speed and capacity of 5G in subway tunnels may not differ significantly from 4G or even 3G. The determining factor for performance will largely be the available frequency spectrum, rather than the generation of the communication standard. Therefore, the operator does not expect a notable impact on its subscriber base from the introduction of 5G in subway tunnels.

The discussion also extends to the differences between cellular networks and public Wi-Fi. Public Wi-Fi, like the one provided by the operator, requires user identification as per legal regulations, which some believe to be a barrier. However, the operator’s experience suggests that most subscribers do not find this process to be a hindrance. Instead, the primary complaint from users is the presence of advertising upon network connection.

The operator funds its network infrastructure, including the Wi-Fi service, without financial support from the subway system, relying instead on advertising revenue. This revenue model allows the service to remain free, though the advertising can be a trade-off for users. The operator’s infrastructure is costly, particularly the Track Side Network (TSN), which enables communication between moving trains and base stations, forming the core of their service.

Looking ahead, the operator anticipates that a reliable cellular network in subway tunnels could attract a small segment of subscribers, particularly those seeking faster, more seamless access. However, the operator remains confident that its Wi-Fi network will continue to offer superior quality in terms of speed, stability, and availability at a lower cost than what mobile operators can provide, even with 5G. Thus, the presence or absence of 5G in subway tunnels is unlikely to significantly affect the competitive advantage of the Wi-Fi network.

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