The development of virtually every layer of telecommunications is a source of challenges. Precise traffic control at the aggregation layer, reliable transport in the backbone network, an open hardware layer, networks protected against eavesdropping by quantum cryptography, space broadband, or fibre optics protected against accidental cutting by a submarine, which, after all, can be bought at any submarine store; and finally, unified network management using the SDN protocol. Each of these topics is a major open technology challenge, requiring R&D projects and promising tangible benefits for telecommunications. However, none of these domains impact everyday life as much as last mile technologies. Anyone who remembers the magic access number 0202122 knows how many last mile revolutions have occurred in recent years. A revolution in modulation protocols over copper lines. FTTH (Fibre To The Home) technologies – in the times of the pandemic, there would be no remote working without broadband. WiFi technology has freed our computers from network cables while allowing constant access to the internet. Mobile broadband through the next generation of cellular protocols including 5G. Without the internet, there would be no smartphone, and without the smartphone, our daily lives would look very different. There is no exaggeration in the slogan “Home Is Where WiFi connects automatically”. We have moved closer to the idea of a global village, which was clearly shown during the pandemic, because during remote work you can walk the dog, make dinner, or set the laundry, which is probably one of the few advantages of the pandemic. Remote work has made its way into the vocabulary of many companies; it is a big change and HR managers hint that it can’t be undone. All of these factors highlight the need for last mile technology development.
On the limits of technology scaling
WiFi is a technology that can be found everywhere. It crosses state, apartment, building, office and floor boundaries. It pays no heed to property rights, internal network integrity, and authorized access. Older phones, from when the technology was young, could have a WiFi list of just a few items, while now in many places there are over twenty of these networks. If there was no scroll bar in the WiFi list, you would not have been able to connect with the appropriate network. There are other problems as well. Sharing bandwidth with the Bluetooth network requires complex synchronization within the chips responsible for managing access in network devices, and this creates a vulnerability to cyber attack. Such coexistence-based attacks were published in 2021. Everyone would like to enjoy Bluetooth connectivity in their immediate vicinity and at the same time be able to access a long-range (compared to Bluetooth) WiFi network. Each of these technologies has its own usage model and safety rules. Each is difficult to do without, and each translates into convenience in everyday life. And our demand for bandwidth continues to grow. A decade ago, many people would have considered watching on-demand movies on a cell phone to be a futuristic vision. Today, there are at least a few people watching movies in every subway or rail car. We are demanding more and more bandwidth and raising the minimums we consider standard. Also, we become increasingly irritated if that minimum is not there – because we depend on it so much.
There are many consumers willing to use the bandwidth of our home or office WiFi, and they are not just the college students in the building across the street or the hacker attacking the office network. The forgotten Spotify stream, the PlayStation console, the growing number of IoT devices, with data oozing from each (Smart technology), Push technology on websites that live their own lives without user interaction. Automatic desktop updates or the growing stream of data in the context of cybersecurity that Windows 10-class systems exchange with security service centers. Data flows that used to be confined within a central processing unit are now going last mile when working with cloud technologies. We have come a long way from single-user systems to distributed systems with a central node, through thick and thin customers to browser-based systems where there is nothing persistent on the customer side except the browser’s stored login information and cookies. From autonomous systems that could operate without a network we come to non-autonomous systems that cannot exist without it. In addition, each of these network tools generates a flow of data that enriches the user context and improves the user experience. Coincidentally, this is the same data that is used to profile you; it communicates information on what mood you are in today and whether you prefer entertainment or insurance policy ads today. The model and volume of local data flow has changed significantly.
Marconi’s legacy
The technological problem lies in the very nature of radio waves; the legacy of Marconi, Hertz or Tesla. Last-mile technologies enabled a change in civilization, and today they are having increasing difficulty consummating their success. Previous generations’ mobile technologies in major cities are largely saturated, and this is a strong growth driver for 5G. End-user data rates are increasing by 50% per year, which has been called Nielsen’s Law, following Moore’s Law (https://www.nngroup.com/articles/law-of-bandwidth/). This raises the bar very quickly. And on the other hand, we are eager to develop cable-free desk technology. No cable connecting with the monitor, network or keyboard. The noble simplicity of design. And just as radio technologies need a transition from 4G to 5G, the same change is needed for WiFi or Bluetooth technology, because the limitations of physical carrier capacity will make itself known, while its expansion would require systemic changes in the allocation of radio bands available for the last mile technology, which is a difficult thing. One must consider both legal (global and national regulation) and technological reasons. Increasingly higher radio frequencies have specific propagation properties, high attenuation, while technological operation is becoming increasingly difficult. We are already getting closer to the range of terahertz radiation that can scan an envelope or undress a passenger at an airport gate and detect scissors hidden under his pants. According to the rules of radio electronics, higher frequencies offer wider bandwidth, e.g. up to 100 Gbps for the terahertz band, and ever-increasing channel information capacity, but unfortunately there is a price for this. Propagation is increasingly capricious, often requiring direct line-of-sight – this technology is an area of intense research. Terahertz sources are poorly available and expensive because they are a combination of several technologies and there are no breakthroughs. From a technical perspective: quantum energy is for terahertz similar to thermal noise in semiconductors. And after all, we cannot lock the source into a refrigerator at helium temperature just to use it as a terahertz antenna in a laptop. It is difficult to talk about a crisis in radio technology, but there are certainly many questions concerning the possibility of scaling the radio band.
Can we overcome this problem?
We should not stop our efforts aiming at overcoming the problems associated with using terahertz technologies, but perhaps there are easier ways to achieve the goal? Note that just beyond the terahertz band is an area the physics of which is well known, radiation sources are ubiquitous and can be bought at any source store, detectors are cheap and propagation is simple. We are, of course, talking about the visible light. And in it some see the key to solving the problems of all previous generations of local wireless telecommunications. Visible light modulated in radio frequencies can carry information. This is no longer the fifth, but the sixth generation – discussions regarding 5G have not yet ceased and we are beginning the era of 6G. And this is the scenario that EXATEL’s latest enterprise fits into, with its RAPID 5G project already paving the way for 5G in Poland in 2014, at a time when it was not yet in fashion. Today we see the need to look further. Therefore, we are already reaching for sixth generation technologies with all the organizational and technological efforts for the introduction of 5G, which we are doing in the name of the broadly understood interest of the State, and the efforts in the development of underlay technologies, such as SDN, which make it possible to fulfil the technological promises. The starting point for EXATEL was the initiative of Prof. Jarosław Turkiewicz from the Faculty of Electronics and Information Technology at the Warsaw University of Technology, which in turn was approached by the German Fraunhoffer Institute – the German equivalent of the Polish Sieć Badawcza Łukasiewicz. The joint search for development opportunities and the building of mutual trust enabled the networking of European entities: between a Polish state-owned company, a Polish university of technology, a German research institute and a German technology startup. It was done in the interest of the European taxpayer, who needs technological autonomy, as it became increasingly evident in the times of the pandemic. Each partner brings its own intellectual contributions develops through participation in the project and at the same time, the synergy brings tangible benefits to all; this is due to the fact that everyone is working at their own level of technology: from building and programming unique sources and protocols based on them to testing the technology.
The solution we are developing is based on using light to provide LAN in small offices or homes. This last mile technology can be used primarily indoors, although outdoor applications are also possible. The scope of EXATEL’s responsibilities is vast, as it includes both defining business requirements which EXATEL sets as a large telecommunications operator, but also contributing to the cyber security aspects of the developed solution, the in-depth knowledge of which is in EXATEL’s DNA.
By benefiting from European integration, we develop the European technological heritage and at the same time act in the interest of the Polish taxpayer, who is our principal. We are proud of both these dimensions of our activity, and at the same time we are glad that our company was able to obtain the opportunity to implement such an interesting project in such a beneficial partnership. Thanks to the high level of communication in the project, Polish and German technical thought can meet on European grounds without prejudice and complexes.
