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 Why GSM-R GSM-R Global System for Mobile Communications-Railways ?

During the course of their work in the period 1985 to 1989, the UIC radio frequency group concluded that efforts would have to be undertaken to negotiate, with the European Frequency Committee (CEPT), for the allocation of a certain spectrum of the GSM-band to the railways, due to the permanent increasing needs to secure frequencies to underpin future railway needs. This request was supported by a pre-study on the usability of either GSM or TETRA for the future railway mobile communications. Some studies were undertaken to assess possible frequency needs (Studies to define a traffic model for three representative areas, London, Paris and Munich, were carried out) and in parallel the advantages and disadvantages of the two potential systems ( GSM or TETRA) were discussed.

Finally a decision was taken to adopt GSM, which was, at that time, the only system in commercial operation with products available. This was a very important consideration as one of the main objectives was, to use a system, which was already proven and where off-the-shelf products were available, with the minimum of modifications. However, even at that time it was clear, that GSM could not fulfil all the requirements necessary for an efficient railway service. Therefore it was necessary to identify and specify the above mentioned ASCI features.

The request for frequencies resulted in a recommendation from CEPT, to provide a spectrum of 4 MHz out of the GSM-band and to allocate this for railway use only. This recommendation was later modified into a decision, which required the national frequency authorities to free this spectrum, which was already used (mainly by military services), by 2005 at the latest.

 The way from the idea to GSM-R

Following the decision to adopt GSM, the UIC launched a project in 1992, together with the EC and the railways, called EIRENE (European Integrated Radio Enhanced Network). The aim of this project was, to specify the functional and technical requirements for mobile networks which would both fulfil the needs of railways and ensure interoperability across borders. That involved the description of mandatory requirements for operational communication services, in and between networks of neighbouring railways, with the goal to allow, in the future, uninterrupted train-services, when crossing borders.

Two leading working-groups were established within this project, a functional group and a project team. The functional group had the task to prepare a Functional Requirement Specification (FRS FRS Functional Requirements Specifications ), which would mainly describe the mandatory features necessary for interoperability . In addition, a description of some optional features were envisaged to also take account of national requirements.

The project team had the task to develop the System Requirement Specification (SRS), based on the functional requirements. This document also set out to define the technical specialities related to railway operation and the specification of the additional ASCI features. As these ASCI features were based on the GSM standardisation it was necessary to work together with specialised ETSI working groups to find the right definitions for these features and to incorporate them into the standards.

A first draft of these EIRENE specifications was finalised by 1995.

To validate, that these specifications could be transferred into technical implementations, a further project was launched in 1995 with the involvement of the UIC, three major railways, the EC and a limited number of GSM suppliers, who were willing to support GSM-R. This project was named MORANE (Mobile oriented Radio Network), supported by the railways in France, Italy and Germany and set up in Paris. Three pilot-lines were planned and realised :

  • Florence – Arezzo
  • Stuttgart – Mannheim
  • Paris (suburban area)

With the help of the manufacturers, three small networks were set up and the relevant components for networks and mobile equipment provided. The three systems were independent and not interconnected. Nevertheless, it was possible to prove, during the lifetime of this project, that all the mandatory functions could be implemented and tested. One issue that remained was the testing of inter-working and thus interoperability.

In 1997, the UIC prepared a Memorandum of Understanding (MoU MoU Memorandum of Understanding ), committing the railways, who signed this MoU, to no longer investing in analogue radio systems, and only investing in the implementation of GSM-R. It also included the major statements, that early implementers would help the other railways starting an implementation, through the exchange of knowledge and experience.

This MoU was signed at that time by 32 railways all over Europe. As of to-day, the number of signatories has increased to 37, including railways outside of Europe. In addition to the declaration of willingness set out in the MoU, the UIC also instigated an Agreement of Implementation (AoI), where the signing railways committed themselves to start their implementation of the national GSM-R system in 2003 at the latest. This AoI was signed by 17 railways.

The two Projects EIRENE and MORANE were finally concluded at the end of 2000 with the delivery of the FRS and SRS versions 4 and 12, respectively, the delivery of the MORANE FFFIS and FFFS documents and a final report incorporating the result of the measurement campaigns from all three trial sites.

To complement the work carried out in EIRENE and MORANE the UIC started a new project, called ERTMS ERTMS European Rail Transport Management System /GSM-R to take account that ERTMS is a system, formed by three elements ::

  • GSM-R as a radio telecommunication system and bearer system for ETCS ETCS European Train Control System
  • ETCS as the future European train control system
  • The future Traffic Management Layer, which was conceived during the EU project Optirails and has since been developed into a working system in the Europtirails project.

The new ERTMS/GSM-R project combined experiences from the trial-sites and knowledge from early implementing railways. This common development has continued up to to-day. Within this project there are three permanent working groups and a number of Ad Hoc groups integrated. These groups are:

ERIG forms the assembly of railways having signed the MoU and the AoI.

The main goal of this group is to exchange information about ongoing implementations based on results already achieved and discussion about gaps in the specifications or implementation reports related to national or international functions Information is also given on the work of the different permanent and Ad Hoc-groups and the presentation of actual Change requests together with their status. This group is mainly a dissemination platform.

Functional Group (FG) The main task of this expert group is to maintain the FRS, to check incoming implementation reports concerning impact to functional requirements and to raise change requests related to the FRS. The FG is also responsible for creating a new version of the FRS. The FG works with OG and the GSM-R industry Group (IG) to find the right solutions and requirements. The FG takes responsibility for the migration of functional requirements towards new and future technologies to ensure consistent railway operation.

Operators ‘Group (OG) The name of this group could more appropriately, be called the Technical Group. The main task of this expert group is to maintain the SRS, to define technical solutions for functional requirements, to liaise with ETSI, the standardization Body for GSM related to railway requirements, to create change requests, based on implementation reports, to liaise with the TIG (technical part of the Industry Group) to find solutions and to ask for technical improvement. The OG is also responsible for creating a new version of the SRS and upgrading of former MORANE documents.

When it is necessary to work on specific subjects, in a more detailed way, the OG forms Ad Hoc Groups with experts from the GSM-R industry and from the railways. These groups prepare the ground for a deeper analysis of specific subjects, which cannot be developed, in detail, in the permanent working groups.

In parallel to this railway oriented working groups the GSM-R suppliers have formed a separated group, called IG ( (GSM-R) Industry Group) which works on two aspects :

  • a marketing part, looking for common approaches to promote GSM-R worldwide
  • a technical part, which forms the interface to the railway groups FG and OG

To protect the specific railway features of GSM and to improve the development of the GSM standard, UIC has created, together with ETSI, an interface group that has the status of a technical committee in ETSI. Based on liaison-statements with the different committees in ETSI this group is in a position to improve the standards and to protect them against commercial encroachment from public suppliers.