GSM-R is the railway digital radio system in Europe used for voice and data applications. It is also one of the main components of the ERTMS system. In almost all European countries GSM-R is operational: more than 60,000 km of railway lines are covered and more than 40,000 radios in train cabs, 2,000 ETCS data radios and over 120,000 handheld terminals are in use.
GSM-R is fully interoperable, so it is obvious that border crossing and usage of standardised GSM-R functionality in other countries via the so called roaming services is part of daily operation. In order to facilitate this, all GSM-R networks have to be interconnected to a European wide so called GSM-R Overlay Network.
The UIC Working Groups GSM-R Network Management (NMG) and European Network Integration of Railways (ENIR) are doing intensive work on harmonising GSM-R border crossing and Roaming Operations, and constantly supporting new network interconnection updates.
As seen on the appended map, in Europe 12 GSM-R networks are interconnected, with 25 interconnection lines in operation. The European GSM-R Network Operators are cooperating according to the principles agreed in the GSM-R Transit Routing Agreements – instigated by UIC at European level, and the GSM-R International Roaming Agreements.
The GSM-R implementation in Europe is continuously expanding – new GSM-R networks are to be put into operation, and upgraded at national level – like the introduction of geographical redundant network core nodes, all this with the natural upgrade of the consequent interconnections links. This results in the above-mentioned European interconnection overlay network continuously needing to be updated. The UIC ENIR group is responsible in this context for the definition of the integral design and implementation of the so called Routing Data Sets (RDS) – which establishes the main and backup international calling routes via the European GSM-R Networks Interconnection. The RDS databases are analysed, produced and distributed by DB Netz AG.
An annual step in this update process is a very challenging operation, since the concept is to implement a unique RDS database in all GSM-R Networks in Europe, at the same moment! Such an operation has to be synchronised, because it has to take place in every network at exactly the same moment, in order to prevent loss of roaming facilities and network routing conflicts.
The GSM-R Implementers (Austria, Belgium, Switzerland, Czech Republic, Denmark, Germany, Spain, France, Italy, the Netherlands, Norway and Sweden) agreed that there was a strong need that all of them accept this concept, and apply the update at same moment: operation named the “GSM-R Big Bang”.
This year the operation was scheduled on 22 September. In close cooperation, conducted by ProRail NL, the complete schedule of routine checks was done, followed by the most difficult step, the concerted installation of the RDS upgrade. This challenging operation took place from 0.00 to 05:00 a.m., and was a big success, with just some minor issues, which were solved within a couple of hours afterwards. Lessons learnt from earlier implementations have contributed to this excellent result.
Further integration of new GSM-R networks is planned in 2014 as well as the re-organisation from a flat (non-hierarchical) network structure to a layered network structure (hierarchical). With this new, less complex RDS architecture the reliability will increase again. Also important is that there is more flexibility to add new GSM-R network nodes. To be continued….