General

The present document specifies the FRMCS Transport Stratum for the Future Railway Mobile Communications System 
(FRMCS). In general, the FRMCS Transport Stratum provides data connectivity and the related services. 
The present document covers: 
• 3GPP terrestrial access. 
• Transport stratum interconnection scenarios in all aspects. 
• 3GPP access sharing, mobility within transport stratum. 
• QoS and policy control. 
• Authentication and authorization for the use of the transport stratum. 
• Transport stratum common features. 

The present document defines the Service Stratum for the Future Railway Mobile Communications System (FRMCS). 
In general, the FRMCS Service Stratum provides communication service and corresponding complementary service 
resulting from 3GPP Mission Critical Services (MCX) and 3GPP multimedia system. 
While FRMCS is defined in various FRMCS ETSI Technical Specifications, the present document determines 
necessary components of the FRMCS Service Stratum, encompassing: 
• Building blocks and corresponding reference points of 3GPP MCX/IMS. 
• Reference points between MC systems/IMS for interconnection and unilateral use by MC organizations 
(MC migration). 
• Reference points between the MC system/IMS and external systems. 
• QoS and priority management. 
• User identification, authentication and authorization for the use of the FRMCS service stratum. 
• Communication security aspects. 
• Complementary and auxiliary service, e.g. alternative user addressing schemes. 

The present document specifies the interfaces of the On-Board FRMCS enabling either interaction with On-Board 
applications or with FRMCS entities outside the train. The present document also specifies the On-Board Multipath 
Function and a set of procedures the On-Board FRMCS will need to conform to. 

The present document specifies non-3GPP network functions and interfaces applicable to the FRMCS Trackside 
Infrastructure. 
The present document describes the trackside network architecture and proceeds with specifying the non-3GPP 
trackside network functional entities (such as the FRMCS Trackside Gateway), including functions, interfaces and 
procedures they need to comply to. 
The present document does not consider message sequences within and between 3GPP and non-3GPP building blocks. 
These message sequences will be defined by related 3GPP specifications, ETSI FRMCS transport stratum definition 
and FRMCS service stratum definition documents or UIC FRMCS FIS [i.3] and UIC FRMCS FFFIS [1]. 

The present document specifies the UE capabilities applicable to an On-Board FRMCS Radio Module. 
NOTE: The present document does not specify UE capabilities applicable to FRMCS-capable Handhelds and 
FRMCS-capable Objects.

The present document defines the functional model including reference points as well as the protocol and procedure for 
interworking between GSM-R R4 and FRMCS and covers the following services: 
• Group call. 
• Emergency group call. 
• Point-to-point call. 
• Text messaging Service

The present document addresses the specific RF technical characteristics and methods of measurements required by 
ECC Decision (20)02 [i.1] for base stations, cab radio user equipment and terminals other than cab radio intended to be 
used for the Future Railway Mobile Communications System (FRMCS) and operating in bands as listed in Table 1-1. 
Table 1-1: List of supported 3GPP bands and modes of operation
Band name Uplink Downlink Duplex mode RAT
n100 874,4 - 880 MHz 919,4 - 925 MHz FDD 5G NR 
n101 1 900 - 1 910 MHz 1 900 - 1 910 MHz TDD 5G NR 
The technical characteristics and methods of measurements have been derived from, and are consistent with ECC 
Decision (20)02 [i.1], Commission Implementing Decision (EU) 2021/1730 [i.2], ETSI TS 138 101-1 [1], ETSI 
TS 138 104 [2], ETSI TS 138 141-1 [3], ETSI TS 138 508-1 [4] and ETSI TS 138 521-1 [5]. 
For the clauses not specifically mentioned in the present document, compliance with the above mentioned 3GPP 
Technical Specifications (TS) is also required for BS and UE. Only BS type 1-C characteristics in the previously 
mentioned specifications apply for the base station specifications given in the present document