feature
GSM-R
An all embracing railway radio technology
and converts the radio signals into a carried on a person at ground level. to the new Nokia Siemens Networks
64kbit data rate suitable for routing over company (NSN) in line with their public
conventional transmission lines. Other acronyms commonly used in GSM business. A new company – Huawei
BTS (Base Transmitting Station). These GSM-R terminology are: in China – has also started making
provide the transmitter/receiver points at FN – Functional Numbering that makes equipment as GSM-R is being adopted by
the lineside and incorporate the radio it possible for a mobile/portable to be China and elsewhere in the Far East.
station, a secure power supply, a tower or called by a number that corresponds to a To date, NSN has 22 contracts covering
mast and the aerials to give the required function e.g. a train description, rather 43k km (39%) of route and 55% of the
coverage. Typically, BTSs are spaced than the mobile/portable number total value; Nortel has 9 contracts
between 5 and 6 km apart to give a LDA – Location Dependent Addressing covering 60k km (60%) of route and 44%
signal strength of 38.5 dB V/m (– 98 that ensures that calls from a train are of the total value, with Huawei gaining
dBm) required for voice and non safety routed to the control or signalling centre 1% of route km and value since start up.
data. Spacing may have to be closer if appropriate to the train's location Nortel has been successful in winning the
GSM-R supports ETCS when a signal VBS – Voice Broadcast Service which larger contracts covering Germany, France
strength of 44.5 dB V/m (– 92 dBm) is allows a call to be made to all trains (or and the UK, NSN is supplying Switzerland,
mandated. radios) in a predefined group and Spain and most of the Nordic countries. In
Spacing can also depend on height with geographical area short, Nortel and NSN have been
a 30 metre tower giving the optimum VGCS – Voice Group Call Service successful in each getting a fair share of
coverage. Lower heights sometimes have enabling a number of radios defined by the business.
to be used in sensitive areas. Eventually the call initiator to participate in a call The Mobiles and Portables. A number of
in the UK there will be around 3000 BTSs. eMLPP – Enhanced Multi Level suppliers now make GSM-R radios. These
The number of channels at each BTS is Precedence and Pre-emption ensuring include Sagem, Kapsch, Funkwerk Kolleda,
determined by the anticipated load, each that a priority call can be received if an Isolectra, Selex, Hoermann and Siemens.
channel having a capability of 7 emergency situation arises or if the radio The train radio comprises a radio set and
simultaneous radio calls. (train) is in a predetermined group. is usually an integrated unit mounted
Mobiles and Portables. Mobile is the within the driver's control panel in the
generic term for the train borne The GSM-R Supply Base cab. Where space is a constraint, the radio
equipment and portable is the hand held Sufficient suppliers within the public transceiver can be positioned in an
set as used by ground staff. Both are GSM industry have been enticed to equipment cabinet, separate from the
derivations of the public GSM radio sets in develop and make the special GSM-R driver's control panel. It is usual to
common day usage. In a train, the mobile equipment. provide a separate radio for each cab on
is a fixed installation including a power This splits into two constituent parts; the train.
supply and a roof mounted low profile The Radio Infrastructure. Nortel and The Siemens product is developed and
aerial. This will give better radio Siemens were the original main suppliers made by their UK division located at
performance than the portable, which is but Siemens have migrated their element Poole. A host of ancillary suppliers provide
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october 2008 | the rail engineer | 37
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