Telecommunications have become an important part of any kind of economic activity, and railways are no exception. Telecoms form an important foundation for any type of business.
Based on nationally integrated communications, information systems are built: for railway stations all the way through to core management servers. National railways today interconnect, and through ongoing construction of new lines are gradually forming a European network.
Previously analogue train radios are now part of a telecommunication system which uses digital technology. This provides seamless connectivity and functionalities, contributing to an improvement in operations. In terms of signalling, telecoms have introduced a new level of signalling excellence meeting ever greater demands, to cater for an environment in which reliable communications are essential for the transmission of very precise train movement authorisations .
Railways generally use off the shelf technologies, and add applications to meet specific service quality demands, which is the case of dispatcher systems or mobiles which use standard technology with tailored configurations .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 a standards, norms or specifications.
GSM-R is a successful example of this process: in around 1992-5, railways selected a technology which was readily available on the market. Today, over 60.000 km of line is equipped and operates with this technology.
When using a technology similar to and dependant on that used by a public telecoms operator, it is vital monitor technological trends, and constantly keep up to avoid a system becoming obsolete and no longer supported. .
GSM-R is based on the GSM Standard (GSM 2+, Released in 99), and the GSM life cycle is reaching its end.
The last delivery for GSM 2+ products is expected at the end of 2015/16. This will be followed by GSM R4, with an IP core central switch but using the same radio network.
Of course GSM will continue to be supported for the medium term after the last delivery.
This highlights the fact that most existing technologies in the mobile telecommunications world are migrating towards Long Term Evolution (LTE) technology.
LTE is seen as the main candidate for so called 4G technology. It is a turning point for telecoms, since it affects all end to end components:
• Fixed telecom network
• Radio network
• Mobile stations
All components are migrating towards IP and a software defined network elements concept.
UIC has carried out a technical study on the LTE capacity to meet railway needs.
The study centres on:
• What is LTE?
• How it fits in with Railways needs
• Backward compatibility
• Consequences of introducing the new concept,
• Interferences
• Next steps
• Migration strategy
A possible Roadmap for the development of a new railway mobile communications system, based on LTE is described in detail in chapter 3 – Research and Development.
The report was published in September 2009, and received comments from the two major European network suppliers and from Railways themselves. The final version was to appear October 2009.
The Report was presented at ERIG, the UIC ERTMS Platform and the Infrastructure Forum.
A proposal from UIC for a follow up as part of a dedicated feasibility study was approved.
Based on this, a strategy meeting was held, where paths for follow up were discussed.
Participants from ADIF, B-Holding, BV, DB, CER, ERA, JBV, SNCF, REFER Telecom, RFF, RFI, Network Rail, Prorail, SBB, ZSR, NSN, Nortel, attended.
The meeting comprised two sessions, the first informal, where GSM-R Infrastructure providers Nortel and NSN presented their positions and state of the art, and the second, during which participants expressed their views on this challenging but provocative issue.
The discussion touched on all aspects of railways possibly migrating to a new radio telecommunications system, including key factors to be taken into account (e.g. frequency management, interoperability, technology life cycle, respecting both IM and RU needs, making the best use of investment,…).
The “Logical Chain” – Frequency availability – Meeting Operational needs – Technology to be used remaining as the main issue.
A “Basic Service Concept” must also be defined, and all possible applications inventoried. Migration towards IP is a necessity; R4 would be a first step. Most countries are preparing IP migration strategies. First full IP Railway network in place – Portugal
Analysis has to follow a certain order:
– GSM roadmap
– Operational aspects
– Existing experience for NGN
– For how long will existing GSM-R systems be supported?
– Choice of technology should not be the driving factor
– First step is to discuss Railways needs
– Past mistakes have to be avoided and overcome
The next step after the UIC Technical Report described above is a Future Radio Communication System Feasibility Study, presented in the picture.
The feasibility study is to be started beginning 2010. Call for experts in the UIC related working groups will be made soon.
Next meeting is programmed for 25 March 2010.
