The Future Railway Mobile Telecommunications Systems Study is a UIC project to assess and shape the future of railway mobile communications over the next ten years and beyond. Participants in the study have included national railways, the supply industry and other telecommunications experts. One of the key objectives of the study is to identify suitable candidate technologies for railways to use after the obsolescence of GSM-R.
Mobile radio has evolved within the railways from analogue to digital telecommunications systems, offering seamless connectivity and functionalities, thus improving operations. Telecoms have introduced a new level of signalling excellence meeting very strong demands, where a reliable communications layer is essential for the transmission of very precise train movement authorities.
Through nationally integrated communications, information systems are built, from railway station to core management servers. The national railway networks are interconnected, and with the development of transit routes, a Europe-wide network is under construction.
Railways generally use off-the-shelf technologies and add applications to meet specific services and quality demands. In order to obtain the required result of properly functioning modified technology, railways must work together to agree on a set of basic concepts, which can then be introduced as standards, norms or specifications.
GSM-R is a successful example of this process: in 1992, railways selected technology which was readily available on the market (GSM-R is based on the GSM Standard). Today, over 68,000 km of lines are equipped and operate with GSM-R in Europe, and more km are in operation or under implementation abroad. Today GSM-R is the radio digital system, enforced by European law and a significant component of ERTMS.
When using a technology similar to public telecoms operators, it is vital to monitor technological trends and constantly keep up to date avoid a system becoming obsolete and no longer supported.
The mobile telecommunications industry intends to migrate most existing technologies towards the Long Term Evolution (LTE) technology. Strong commitments have already been made by Suppliers and Public Mobile Operators regarding the implementation of LTE and the first set of implementations will take place in 2010/2011.
LTE is seen as the main candidate for the so-called 4G technology. It is considered to be a turning point for telecoms, since it affects all end-to-end components (core, backbone, radio network, terminals) – all components are migrating towards IP and a software defined network elements concept.
An assessment of the impact of new technology on GSM and therefore GSM-R was needed.
UIC made the first step towards this objective by publishing a technical report in September 2009 on the potential for LTE to meet railway needs. It was presented at ERIG, the UIC ERTMS Platform and at the Infrastructure Forum. Since answers to vital questions were needed, a follow up study, “The Future Railways Mobile Telecommunications Systems Study” was started in 2010.
On 30 November 2010 the achievements of the study were presented and discussed.
At the meeting, the GSM-R suppliers from the GSM-R Industry Group made a commitment to continue supporting GSM-R until 2025. The statement was welcomed by the railway community.
The main requirements for a future telecoms system are the fulfilment of railway specific needs – (e.g. meeting the operational requirements), a life cycle that would fulfil the railway’s expectations, and a migration phase that is compatible with the operational and business needs of the European railways. This could lead to a life cycle of around 20-25 years, which is difficult to imagine for a public mobile technology.
When tackling next generation systems, the railways have decided to define the radio mobile needs in a document, taking the existing EIRENE specifications as a starting point, but with a technology-free approach that leaves it open to new services that could improve railway operations. The document – “Railway Mobile Communication System User Requirements Specification”, agreed during the meeting, is intended to be a launch pad for discussion between the railways and suppliers regarding the successor to GSM-R.
The railways intend to use a standard off-the-shelf system, where the specific needs would be defined in the application level (in other words they aim to minimise changes in the core system where practical). Experience of more then 10 years in using GSM-R will make this work easier.
The meeting concluded the following points:
GSM-R is the radio system in Europe, and also abroad. Suppliers have committed to continue supporting GSM-R until 2025.
The public market will evolve towards LTE. Sooner or later this will affect GSM, and when GSM reaches the end of its lifecycle, GSM-R survival will be matter of years (depending also on developments within the railways). LTE’s current level of maturity and its use with voice-based applications (which account for most railway-related needs), mean any decisions taken at present would be premature. The deadline for a decision is not today, but it will not be far away, most likely in just a few years’ time.
Work on this issue will continue within UIC. The next step will be to initiate discussions with suppliers, based on the document described above. Technology surveys and participation in trials will continue. The next meeting is scheduled for March/April 2011.