Railway communications of the future – FRMCS
About 30 years ago, GSM-R became the standard for railway communications on the basis of the 2G-technology GSM, and hardly anyone could anticipate how breathtakingly fast the technology would change.
In our days, some of the 2G-functionalities appear to be almost archaic and for several diverse reasons the time has come to adapt railway communications to the changes in realities. One of them is that suppliers intend to cease their support of the 2G-technology by 2030 or in some exceptional cases by 2035. But a quickly progressing digitisation also takes place in the railway world and beyond, boosting the demands on supporting telecommunication technologies, particularly in terms of the required broadband networks. The multitude of modern applications requires reliable, fast and undisturbed communication platforms with great bandwidths and short latencies – or response times – for the transmission of signals, that the 2G technology is unable to supply. Although the supporting systems and applications are being adapted to the current state-of-the-art, they are nevertheless limited by the basic technology that is being used. The Internet with its functionalities has become an everyday companion for users, and particularly so for applications beyond the private use, like social media, email retrieval, route planning et cetera. First and foremost, the industry needs broadband networks in order to handle the data volumes of the technologies that are commonly known as industry 4.0. With regard to railways, more than the current communication of a train driver with the operations centre must be possible. Railway communication technology must be able to reliably process the data volumes that are incurred by interconnected infrastructure assets and trains, the ERTMS/ ETCS signalling system or the automatic operation of trains.
FRMCS: the challenge
Future Railway Mobile Communication System, short FRMCS, was the name of the project that was initiated in 2014 by the International Union of Railways UIC, with the aim of developing a system that meets the challenges of an interconnected world of railways. The GSM network – and therefore also the GSM-R-technology was standardised under the responsibility of the European Telecommunications Standards Institute (ETSI), an institution that was created by the European Union. With the third generation of mobile phone networks UMTS, the standardisation institutes of the USA, Japan, Korea and China joined in, and for this reason, it is also called the Third Generation Partnership Project (3GBPP). Meanwhile, 4G (LTE) and 5G have also been standardised by 3GPP and the GSM specifications have also been transferred to 3GPP. For this reason, standardisation is meanwhile applied around the world. For FRMCS, this means that now many institutions have to cooperate in this project, in order to reach an optimum. While some partners must define the requirements of the railways (UIC), others (ETSI) must describe them in Use Cases and submit them as so-called Change Requests to 3GPP. 3GPP is in charge of verifying if these Use Cases can already be fulfilled with existing standardised functionalities. 3GPP and the connected framework MCX for safety-critical applications is therefore an ideal entry point for FRMCS to enable the use of existing safety-critical services. This means a significant gain in standardisation and provides more flexibility for the future digital applications. If hitherto things seemed complicated to read, they will not become simpler: it must furthermore be exactly defined which transmission technologies and which application layers shall be used. As a special challenge, the railway sector will be facing the coexistence of GSM-R and FRMCS as it is not possible to implement such a fundamental transition from one day to the next. The community will have to solve the special task of developing the best migration path
FRMCS: the future
Last year, the 5G licenses were auctioned. 5G will allow for an ultrahigh- speed and reliable data transmission: the latency of the 5G technology is anticipated to be as short as a mere millisecond (for comparison: 3G-network have a latency of about a hundred milliseconds). This means that data can be transmitted almost in real time. Nevertheless, for the time being it has not been clarified yet which bandwidths and frequency ranges will be available for railways. The decision is expected during this year and national regulation bodies will then be able to implement them. It is only on this basis that the final configuration of FRMCS as the future communications system for the European railways will be possible.