Steffen Ring, M.Sc.E.E.
Mandated by the European Commission, the CEPT/ECC organization is currently elaborating a new spectrum and technology plan, aimed at replacing the current GSM-R system with a new Wide Band system (FRMCS), based on the 5G (NR) platform.
The new system will become harmonized across Europe for the smooth operation of the future rail services operating at very high speeds throughout the 48 countries of the EEA (European Economic Area), which includes the 27 European Union Member States.
With so many nations involved in the development of a single spectrum/technology plan not only a great deal of spectrum engineering is required, but also a smooth political artwork is necessary for agreements to be reached amongst so many sovereign nations.
Based on the results of the work of CEPT/ECC the EU Commission will seek to adopt a new legal measure (a Decision) to be followed by EU Member States and subsequently also applied by other EEA nations.
This article by WWRF members who are participating in the work, represents a quick overview of the status of this techno-political and complicated international task.
It does not cover radio equipment intended for local services such as rail repair and maintenance and train shunting activities, which are of a local/national nature.
The current GSM-R environment and the way ahead
The total length of the current European rail network is around 221.000 Km, out of which 68.000 Km is serviced by the GSM-R radio standard (ETSI EN 301 502 for GSM base stations and EN 301 511 for GSM mobile stations) which delivers voice, messaging and low speed data linking track-to-train and control posts, and operate in the 874.4-880 MHz / 919.4-925 MHz harmonized band.
GSM-R is today more than 20 years old, and the radio suppliers will not guarantee manufacturing to this system after 2030. This sets the timing of the roll out of new radio technologies for RMR, in particular the WB part, the FRMCS.
The big challenge for engineers, regulators and spectrum administrations is to develop a migration strategy, which allow for an interruption free implementation of a new system in parallel to the operation of GSM-R.
To this end, ECC has appointed a dedicated Working Group (WG FM56) chaired by the German administration, tasked to propose and recommend a new spectrum plan, which will allow for a smooth migration to state-of-the-art WB mass-market radio technology, such that CAPEX for the line operators becomes lowest possible, avoiding the development of special, more expensive versions for Rail-only, such as GSM-R, which is a special version, dedicated to Rail applications, of the cellular mass-market GSM. The work is ongoing, and represent yet another well-organized international project by the ECC, which lays forth new opportunities for Europe.
The new European RMR spectrum for WB
On 28 September 2021, the European Commission adopted the IMPLEMENTING DECISION (EU) 2021/1730, which introduced the unpaired frequency band 1 900-1 910MHz for Railway Mobile Radio in conjunction with the harmonized use of the paired frequency bands 874,4-880,0 MHz and 919,4-925,0 MHz.
Figure 1: A full 5G (NR) FDD channel of 2×5 MHz, as an example, may fit in the GSM-R spectrum
In order to ease a smooth migration, the TDD spectrum 1900 MHz – 1920 MHz has been identified and included in the provision of IMPLEMENTING DECISION (EU) 2021/1730 with only the sub-band 1900 MHz – 1910 MHz applied as shown in Fig 2. This spectrum may be made available from 2025 according to national needs.
Figure 2: A full 5G (NR) 10 MHz TDD channel may fit in this band
These examples are developed having in mind the 5G (NR) v 15.
Crossing borders at very high speeds
The 5G (NR) standards include an advanced “color coding” mechanism, which are embedded in the control signaling (named PCI Physical-Layer Cell Identity) and intended for the identification of the country, which operates the currently received signal. Therefore, the handoff/handover at border crossings will automatically and instantaneously indicate, that the train is entering a neighboring country. This well-planned switchover is paramount for an interruption free radio link upon crossing borders.
*) Figure 3: Physical-layer Cell Identity (PCI) coordination for 5G (NR) systems in 1900-1910 MHz TDD band
Especially in Central Europe it takes a complicated radio planning to ensure interference free operation of FRMCS. Note for instance, that Germany has 9 (nine!) different international borders, all serving busy train entries and exits.
For the advanced readers, we kindly refer to the references section, where you will find details relevant for manufacturers and government authorities.
3GPP: See the TR 21 915 here:
Steffen Ring, M.Sc.E.E.
Steffen Ring, M.Sc.E.E., based on his 40 years of experience within telecommunication spectrum, standards and regulation acquired since 1976, founded RING Advocacy ApS in 2015, and was appointed CEO
Ring has served for corporations such as Storno A/S in Copenhagen Denmark, General Electric Inc., Lynchburg, Va., USA, Motorola Inc., Il, USA and Mobile Data International Inc., Vancouver, BC, Canada and throughout liaised close with national and international authorities to agree the technical terms and conditions for bringing foreign Region Radio Frequency equipment onto the market and into operation in a fully compliant manner in the new Region/Country.
In Europe Ring worked close with the European Commission as representing Industry to assist in the inauguration 1988/89 in France of the European Telecommunications Standards Institute (ETSI), and began soon after the standardization work in ETSI on TETRA (at the time called MDTRS) and was appointed chair of the Working Group ETSI EPT WG4.
 This figure is borrowed from the ECC Recommendation: “Cross-border coordination for Railway Mobile Radio (RMR) in the 1900-1910 MHz TDD frequency band”