The present document defines the minimum set of 3GPP GPRS features to support ETCS application and to guarantee QoS required. Two operational cases are applicable in GSM-R networks:

• GSM-R GPRS packet switched bearer service is only utilized by ETCS PS-mode operation - ETCS only operation.
• GSM-R GPRS packet switched bearer service is utilized by simultaneous ETCS and other packet data oriented applications - Simultaneous operation of ETCS and non-ETCS applications.

Both operational scenarios require basic GPRS features but in case of simultaneous ETCS and non-ETCS operation, ETCS packet data session requires priority over non-ETCS packet data traffic.

The present document is focussing on the relevant references needed for the GSM-R PS-domain. It does not describe the detailed requirements for each of the referred GSM feature.

The minimum requirements on ETSI/3GPP for the use of GSM for application on railway networks are based on the Release 99 version of the Technical Specifications and are described in ETSI EN 301 515 [i.1]. The features serving as the basis for GSM-R PS-domain are described in releases later than Release 99. So the present document is referring to specifications versions later than Release 4 but is not mandating any other functionality than covered by the applicable 3GPP Work Items and referenced in the applicable clauses as listed in clauses 5.1.10 and 5.2.2.