GSM-R

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GSM-R (GSM-Railway) is a wireless communications platform developed specifically for railway communication and applications. It guarantee performance at speeds up to 500km/h.

Contents

[edit] Introduction

GSM-R is built on GSM technology, and benefits from the economies of scale of its GSM technology heritage, aiming at being a cost efficient digital replacement for existing incompatible in-track cable and analogue railway radio networks. Over 35 different such systems are reported to exist in Europe alone.

GSM-R is a secure platform for voice and data communication between railway operational staff, including drivers, dispatchers, shunting team members, train engineers, and station controllers. It delivers features such as group calls (VGCS), voice broadcast (VBS), location-based connections, and call pre-emption in case of an emergency. This will support applications such as cargo tracking, video surveillance in trains and at stations, and passenger information services.

The standard is the result of over ten years of collaboration between the various European railway companies, achieving interoperability using a single communication platform. GSM-R is part of the new European Rail Traffic Management System (ERTMS) standard and carries the signalling information directly to the train driver, enabling higher train speeds and traffic density with a high level of safety.

The specifications were finalized in 2000, based on the EU-funded MORANE (Mobile Radio for Railways Networks in Europe) project. The specification is being maintained by the International Union of Railways project ERTMS.

GSM-R has been selected by 38 countries across the world, including all member states of the European Union, and countries in Asia, Eurasia and northern Africa.

GSM-R is typically implemented using dedicated base station towers close to the railway. The distance between the base stations is 3-4 km. This creates a high degree of redundancy and higher availability and reliability. The train maintains a circuit switched digital modem connection to the train control centre at all times. This modem operates with higher priority than normal users (eMLPP). If the modem connection is lost, the train will automatically stop. In Germany, Italy and France the GSM-R network has between 3000 and 4000 base stations.

[edit] GSM-R Market

Different groups make up the GSM-R market:

The railway operators 
DB, SBB, SNCF, Trenitalia etc.
The network operators 
The companies Huawei, Nortel and Siemens are the main suppliers of the GSM-R infrastructure.
Dispatch and Control Centre Solutions
Siemens Transportation Systems and Frequentis
The terminal manufacturers 
Handset manufacturer
Sagem (SAFRAN group) is the main GSM-R handset supplier, followed by Selex, Triorail and Huawei.
Cab radio manufacturer
Alstom, Siemens, Nortel and Hoermann are the main suppliers. Kapsch and Sagem mainly provide the GSM-R core of these cab radios.

[edit] GSM-R Technology

[edit] Frequency band

In Europe GSM-R systems have dedicated frequency bands of 876-880 MHz (Up Link) and 921-925 MHz (Down link). In China 4 MHz of the E-GSM is used.


[edit] ASCI (Advanced Speech Call Items) features

[edit] VGCS (Voice Group Call Service)

VGCS allows a great number of users to participate in the same call. This feature imitates the analogue PMR (Private Mobile Radio) group call with the PTT key (Push-to-Talk).
Three kinds of users are defined: the Talker, the Listener and the Dispatcher. The talker can become a listener by releasing the PTT key and a listener becomes a talker by pressing the PTT key.
The main advantage of VGCS compared to multi-party call (the GSM conference call feature) is the spectrum efficiency. Indeed, when many users are in the same cell they will use only one frequency for all listeners and two frequencies for the talker (as in point-to-point call). In a multi-party call there are two frequencies by each user.

[edit] VBS (Voice Broadcast Service)

[edit] Multi-Level Precedence and Pre-emption Service (eMLPP)

This defines the user’s priority.

[edit] Eirene Features

[edit] Railway Emergency Call (REC)

Well defined process with three stages

  • Warning
  • Information
  • Terminate railway emergency call

[edit] Functional number management

  • Functional numbering
Allow to call an MS by its function: driver of the train xxx , …
It uses
USSD and Follow Me
UUS1 (for number display)
  • Location dependent addressing
Improve the functional numbering
Allow to call the nearer MS linked to a function: nearer driver, nearer controller, ...

[edit] Shunting mode

Shunting mode is the term used to describe the application that will regulate and control user access shunting communications.
A link assurance signal is provided in order to give reassurance to the driver that the radio link is working.

[edit] Direct mode

Direct mode is the walkie-talkie mode (mobiles station talking to each other without the network) and has been proposed in Eirene, however it has never been in application since being based on analogue radio.
Sagem claims to have developed a GSM direct mode, not currently recognised in the GSM-R specification, and has no frequency allocation.

[edit] External links

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