GSM-R
Technology Overview
GSM-R is based on the cellular GSM technology with further enhancements specific to the requirements of railroad operation, such as train control.
In general the GSM-R uses characteristics that are identical or similar to those of the GSM system, such as frequency spacing (200 kHz), modulation (Gaussian minimum shift keying, GMSK) and access type (TDMA, TDD/FDD). The frequencies of GSM-R are extended below the frequencies of the GSM-900 standard.
The general packet radio services (GPRS) for data communications up to 14.4 kbit/s is supported by GSM-R for data transport in the same way as with the regular GSM system. It serves customized applications such as automatic train control (ATC) and electronic train control system (ETCS) for remote or automatic control of train movements and monitoring as well as functional addressing (calling a user by his function rather than by a fixed number) and location-dependent addressing.
Additional railway-specific characteristics include advanced speech call items (ASCI) such as voice group call service (VGCS) and voice broadcast service (VBS) to communicate to a group of handsets simultaneously. GSM-R mobile phones are similar to cellular mobile phones with extended functionality and a different user interface to utilize the additional applications.
Deployment Scenario
The GSM-R standard has been developed to provide a new unified digital radio system for voice and data communications purposes specific to railways. This standard has already been chosen by many railroad operators worldwide.
Key Parameters
| GSM-R | |
|---|---|
| Frequency Range |
Show / Hide
|
| Modulation |
GMSK 8PSK (EDGE only) |
| Multiple Access | TDMA/FDMA |
| Duplex (Uplink/Downlink) | FDD |
| Channel Bandwidth | 200 kHz |
| Peak Data Rate | 14.4 kbit/s
53.6 kbit/s (GPRS) 384 kbit/s (EDGE) |
Standardization
In 1989, the GSM standard was defined by the Groupe Speciale Mobile and became an internationally accepted digital cellular telephony standard. GSM was later transferred to the ETSI technical committee, which continued to define the GSM standards. The GSM-R functionality was later added into the existing GSM specifications. Today, GSM, EDGE and GSM-R are being specified in 3GPP (3rd Generation Partnership Project) and coordinated in TSG GERAN. The following link provides access to TSG GERAN specifications: www.3gpp.org/ftp/specs .
