Study on feasibility of SATCOM for railway communication

Final Report
Forward Link
Return Link
Terrestrial Link
SATELLITE SYSTEM
SPACE
SEGMENT
Traffic
Control
Centre
GROUND
SEGMENT
USER
SEGMENT
Train
Stations
WAN
GES/NCC
GAP FILLERS
RBCs
Figure 1: SATCOM system for the railway environment
SATCOM services can be further broken down into fixed versus mobile services. Fixed SATCOM
services operate from a terminal on the ground at a fixed location, whereas mobile counterparts are
transmitted from a terminal that can be in motion or temporarily stationary at the time of
communication (such as a ship, aircraft or land vehicle). Mobile SATCOM services have traditionally
provided voice and low data rate services up to about 0.5 Mb/s but, more recently, services derived
from fixed satellite systems have become available offering more than 10 Mb/s.
1.2.2 Multi-technology communication architecture description
The coverage of mobile satellite communications (satellite visibility) cannot always be assured
throughout the required area. In the railway domain (for example), tunnels and shadowing zones due
to buildings, trees, etc. provide an obstacle to satellite coverage. To solve this issue, the use of gap
fillers and/or additional (terrestrial) communications systems is required. Therefore, the introduction of
SATCOM within the railway domain also requires the use of terrestrial solutions.
In parallel, the Next Generation Network (NGN) concept separates applications from transport
networks (bearers), and allows the coexistence of different communications systems regardless of
their applications, which will be used according to, for example, the type of terminal and/or availability.
Therefore, this network trend, where several systems of different natures can coexist to provide
service to independent applications, facilitates the introduction of satellite communications within the
railway domain. SATCOM can thus be used as a bearer (main or backup) to cover (for example)
remote areas with small number of users where terrestrial communication system deployment could
be complex and too much expensive.
Figure 2 shows a complete communication architecture combining both satellite and terrestrial
systems in order to provide full coverage in the possible future railway scenarios.
Doc.Nº: SRAIL-FNR-010-IND
Edit./Rev.: 1/1
Date: 16/02/2017
Page 22 of 285