GSM-R
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Contents |
[edit] Introduction
GSM-R (GSM-Railway) is a wireless communications platform developed specifically for railway communication and applications.
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 analog radio networks for railways. Over 35 different such systems are reported to exist in Europe alone.
GSM-R is a secure platform for voice and data communication between the operational staff of the railway companies 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 signaling 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 European Union, and countries in Asia, Eurasia and northern Africa.
GSM-R are typically implemented using dedicated base station towers close to the railway. The distance between the base stations are 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 center 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
The GSM-R market is made by different groups:
- The railway operators
- DB, SBB, SNCF, Trenitalia etc.
- The network operators
- The companies Nortel and Siemens are the main suppliers of the GSM-R infrastructure.
- Dispatch and Control Centre Solutions
- Frequentis
- The terminal manufacturers
- Handset manufacturer
- Cab radio manufacturer
[edit] GSM-R Technology
[edit] Frequency band
In Europe GSM-R systems have a dedicated frequency band 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 imitate the analogs PMR (Private Mobile Radio) group call with the PTT key (Push-to-Talk).
- Three kinds of users are defined, the talker, the listner and the dispatcher. The talker can become a listner by releasing the PTT key and a listner becomes a talker when pushing 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 listners 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 gives priority to some users above others.
[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 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) has been proposed in Eirene however it has never been in application since it was based on analog radio.
- Sagem claims to have developped a direct mode based on GSM technology but it is not yet in the GSM-R specification and nobody has used it mainly because there is no frequency allocation for it.
