GSM-R

GSM-R, Global System for Mobile Communications - Railway or GSM-Railway is an international wireless communications standard for railway communication and applications. A sub-system of European Rail Traffic Management System (ERTMS), it is used for communication between train and railway regulation control centers. The system is based on GSM and "EIRENE - MORANE" specifications which guarantee performance at speeds up to 500 km/h (310 mph), without any communication loss.

History

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.

The standard is the result of over ten years of collaboration between the various European railway companies, with the goal of 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 European Union-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 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.

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.

In the UK, over 14,000km of GSM-R enabled railway is planned, with 280km currently in operation. [ERIG (European Railways Industry Group) report from meeting #35 2007 ] GSM-R cab radio for use in UK trains is currently being developed by a number of companies undergoing trials in the Strathclyde and Glasgow areas of Scotland.

Upper system

GSM-R is one part of ERTMS (European Rail Traffic Management System) which is composed of:
* ETCS (European Train Control System).
* GSM-R.

Frequency band

In Europe, GSM-R uses a specific frequency band: [http://www.willtek.com/english/technologies/gsmr Willtek, radio measure devices provider]
* 876 MHz — 880 MHz: used for data transmission (uplink)
* 921 MHz — 925 MHz: used for data reception (downlink)Channel spacing is 200 kHz.

The used modulation is GMSK modulation (Gaussian Minimum Shift Keying). GSM-R is a TDMA (“Time Division Multiple Access”) system. Data transmission is made of periodical "TDMA frames" (with a period of 4.615 ms), for each carrier frequency (physical channel). Each "TDMA frame" is divided in 8 time-slots, named logical channels (577 µs long, each time-slot), carrying 148 bits of information.

GSM-R occupied a lower extension of GSM 900 MHz frequencies (890 MHz — 915 MHz range for transmission and 935 MHz — 960 MHz range for reception), as per 3GPP TS 05.05 V8.20.0 (2005-11). In China GSM-R occupied a 4 MHz wide range of the E-GSM band (900 MHz-GSM).

GSM-R uses

GSM-R permit new services and applications for mobile communications in several domains :
* control and protection (Automatic Train Control/ETCS) and ERTMS)
* communication between train driver and regulation center,
* communication of on-board working people
* information sending for ETCS
* communication between train stations, classification yard and railtracks

Main use

It is used to transmit data between trains and railway regulation centres with level 2 and 3 of ETCS. When the train passes over a Eurobalise, it transmits its new position and its speed, then it receives back agreement (or disagreement) to enter the next track and its new maximum speed. In addition, trackside signals become redundant.

Other uses

Like other GSM phone, GSM-R equipment can transmit data and voice.New GSM-R features for mobile communication are based on GSM, and are specified by EIRENE project.Call features are:
* PtP Call: "Point-to-Point Call", the same type of call as a normal GSM call
* VGCS: "Voice Group Call System", quite similar to walky-talky communication
* VBS: "Voice Broadcast System", like a VGCS but only the call initiator can speak (the other are only listeners)
* REC: "Railways Emergency Call", it is a special VGCS with high priority dedicated to emergencies.
* Priority control of all the different calls (PtP, VGCS, VBS and REC calls)There are other additional features:
* "Functional Addressing", alias system to call someone registered on the GSM-R network, only by knowing the temporary function user (engine driver of train such-and-such, …)
* "Shunting" mode, when users work on the tracks.

GSM-R features

ASCI (Advanced Speech Call Items) features

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 calls (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, one timeslot is dedicated to each user.

VBS (Voice Broadcast Service)

:VBS is a broadcast group call: this means that compared to VGCS, only the initiator of the call can speak. The others who join the call can only be listeners. This kind of call is mainly used to broadcast recorded messages or to make advertisements.

REC (Railway Emergency Call)

:"REC" is a group call, or VGCS, dedicated to urgency. It is a higher priority call (REC priority is level 0 — see below : eMLPP)

Multi-Level Precedence and Pre-emption Service (eMLPP)

:This defines the user’s priority. The different priority levels are:

:* A and B: Highest priority levels (reserved to Network messages):* 0: Highest priority levels for ASCI and normal calls (mainly used for REC calls):* 1: Lower priority than level 0:* 2: Lower priority than level 1:* 3: Lower priority than level 2:* 4: Lowest priority level (default priority, assigned to Point-to-Point calls)

:An "Auto-Answering" feature with a timer is also available for calls with priority 0, 1 and 2.

Eirene features

Functional number management

:* Functional numbering:** Allows 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:** Improves the functional numbering:** Allows to call the nearer MS linked to a function: nearer driver, nearer controller, …

End Call Confirmation

:End Call Confirmation feature is only available for highest priority (Priority level 0) group calls (VGCS) and broadcast calls (VBS) (see eMLPP).:It consists of an end call report which sent by all MSs (mobile stations) which joined the high priority call (initiator included). This report informs about::* Call type:* Call duration:* MS Identity:* End call cause Normal, ended by user, MS power off by user, power off due to low battery, …):* …

:If the report can't be sent (MS power off by user or power off due to low battery), the MS will try again (several times if needed) to send the report at the next power on.

Shunting mode

:Shunting mode is the term used to describe the application that will regulate and control user access to shunting communications.:A Link Assurance Signal (LAS) is provided in order to give reassurance to the driver that the radio link is working.

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.

GSM-R market

GSM-R market groups

Different groups make up the GSM-R market:

;The network operators and the railway operators:

::Source : UIC (23 May 2006) [http://gsm-r.uic.asso.fr/implement_map.html UIC, GSM-R Implementation planning and progress map]

;The network operators : The companies Nokia Siemens Networks, Huawei, and Nortel are the main suppliers of the GSM-R infrastructure.;Dispatch and control centre solutions: Siemens Transportation Systems, [http://www.necportugal.pt/ NEC Portugal] , [http://www.frequentis.com/Internet/PublicTransport/GSMR/ Frequentis] and [http://www.wenzel-elektronik.de/ Wenzel Elektronik] ;The terminal manufacturers:; Handset manufacturer:: Sagem (SAFRAN group) is the main GSM-R handset supplier, followed by [http://www.selex-comms.com/en/?cat=98 Selex Communications] , Triorail and Huawei.:; Cab radio manufacturer:: [http://www.selex-comms.com/en/wp-content/uploads/2008/05/GSM-R_CAB_Radio_EN_LR.pdf Selex Communications] , Siemens Transportation Systems, [http://www.necportugal.pt/ NEC Portugal] , Alstom, Center Systems, Nortel and Hoermann Funkwerk Kolleda are the main suppliers. Hoermann Funkwerk Kolleda (formerly Kapsch) and Sagem mainly provide the GSM-R core of these cab radios.

Railways using GSM-R

A fully-functional GSM-R system is being trialed on the North Clyde Line in Scotland from 2007. For some years before these trials commenced however, GSM-R has been in use for voice-only purposes (known as the 'Interim Voice Radio System' (IVRS) ) in some locations where axle counters are used for train detection, for example parts of the West Coast Main Line (WCML) between Crewe and Wembley. Britain’s GSM-R network should be fully operational by 2013 at a cost of £1.2 billion. This cost though does not include the WCML.

In France, the first commercial railway route opened with full GSM-R coverage is the LGV Est européenne linking Paris Gare de l'Est to Strasbourg. It was opened on the 10th of June 2007.
*On Sunday, June 10, 2007 at 0643, the first high speed train run on it was the ICE, the high speed train from the German passenger operator : DB. It linked the "Gare de l'Est" in Paris to Saarbrücken (Germany).
*On the same day, 0715, it was the opportunity of the TGV POS, the last generation high speed train from the French operator, SNCF. It linked Strasbourg to Paris (Gare de l'Est)."(Réf. SNCF - Paris AFP, 10th of June 2007)" [Réf. SNCF - Paris Agence France Presse (AFP), Sunday the 10th of June 2007, 07h13 (am).]

In Norway, the GSM-R network was opened on all lines on 1 January 2007.

References

External links

* [http://www.huawei.com/news/view.do?id=2805&cid=42 Huawei Technologies Co., Ltd. GSM-R]
* [http://www.siemenstransportation.co.uk Siemens Transportation Systems]
* [http://gsm-r.uic.asso.fr/ UIC ERTMS/GSM-R Project]
* [http://www.nokiasiemensnetworks.com/global/SSP/Solutions/PCS/GsmR.htm?languagecode=en Nokia Siemens Networks GSM-R]
* [http://www.nortel.com/gsm-r Nortel GSM-R]
* [http://www.frequentis.com/Internet/PublicTransport/GSMR/ Frequentis Public Site]
* [http://wenzel-elektronik.de/en/v_produkte/en-m2_07.shtml Wenzel Elektronik GSM-R]
* [http://www.sagem.com/index.php?id=116&L=0 Sagem GSM-R]
* [http://www.triorail.com Triorail GSM-R]
* [http://www.era.europa.eu ERA ERTMS]
* [http://www.comtestwireless.eu/ Comtest Wireless]
* [http://www.centersystems.com/index.php?cccpage=project_gsmr&set_language=en Center Systems GSM-R]
* [http://www.eirene.hu EIRENE (Hungarian)]