Study on feasibility of SATCOM for railway communication

Final Report
Inmarsat 5 (Global Xpress)
Criterion ID Criterion Evaluation Justification
CRT-TECH-6
Network registration delay for the proposed satcom system
shall be Normal (with similar values of current GSM-R system).
NC
Assuming a good network dimensioning according to the estimated throughput,
the registration process of the GEO/Ka-band system based on DVB-S2 / DVB-
RCS2 communication standards can take a "normal" time similar to current GSM-
R performance.
But for the Inmarsat 5 system, and assuming a previous GPS synchronisation
required just like the Inmarsat 4 system, the network registration delay could take
too long.
CRT-TECH-7
The call establishment delay for the proposed satcom system
shall be Low.
Note: as a first reference, GSM-R establishment delays can be
considered.
C
Assuring the correct dimensioning of the network resources according to
throughput requirements, Inmarsat 5 (or a GEO/Ka-band "open" system), which is
based on IP and DAMA access scheme, can assure a low establishment delay.
CRT-TECH-8
The proposed satcom system shall allow (at least) the
estimated number of European FRMCS users by 2030
registered simultaneously.
C
The use of the Ka-band (with lots of spectrum available), along with the TDM/MF-
TDMA (DAMA) implementation based on DVB-S2/RCS communications
standards, assure the service for the number of users estimated by 2030. In
addition, the use of the Ka-band offers the possibility to support extra performance
and/or business applications (in addition to the critical ones).
GX is able to provide service to more than 500,000 users per satellite.
CRT-TECH-9
The proposed satcom system shall provide priority and preemption
mechanisms.
C
Since GX is based on DVB-S2/RCS communications standards, they offer priority
mechanisms at level 2, providing for example differentiated queues for different
types of traffic (real time, critical data, best effort...).
CRT-TECH-10
The proposed satcom system shall support Data and Voice
services.
C
Inmarsat 5 is a Packet Switched system supporting voice and data IP services.
Doc.Nº: SRAIL-FNR-010-IND
Edit./Rev.: 1/1
Date: 16/02/2017
Page 279 of 285