Study on feasibility of SATCOM for railway communication

Final Report
A. CRITERIA DEFINITION
This section defines the list of applicable criteria for the subsequent assessment of satellite
communication systems and/or related technologies regarding their feasibility to support the critical
railway applications. To reach this goal, each criteria is accompanied of a rationale or justification and
also its traceability to the reference documentation. Table 40 summarizes the information provided for
each criterion.
Criterion
Rationale
Criterion Traceability
Definition of the evaluation rule to be followed during the evaluation
phase.
Justification of the selected criterion.
Documentation (requirement, specification, etc) on which is based the
selected criterion.
Table 40: Definition of traceability matrix fields
Several sources have been considered when identifying and justifying the different criteria. Recent
documentation from the FRMCS project (mainly the URS document) is one of the main inputs, since
the independence of the applications from the bearer are a must for the study of the satcom feasibility
for railway communications.
However, the lack of details of the URS document (it does not include full detailed requirements yet)
has caused (for some specific criterions) the use of current GSM-R documentation in order to has
some first reference values when required or considered of relevance.
Therefore, main sources used and traced for the criteria identification:
FRMCS URS v2.0
EIRENE SRS & FRS
Different Subsets
ITU-T documentation
etc
Some comments and assumptions have been considered while defining main satcom criteria:
- It is worth to mention that current QoS and performance parameters have very demanding criteria
because they refer to high-speed railway lines. Therefore, they could be relaxed in case of
regional or low traffic lines.
- For the criterion identification, it has been considered several guidance 21 defined within the URS
document [AD-01], which indicate that future railway communication system shall keep current
performance and quality of communication provided by GSM-R or public services. Therefore, the
future railway communication system is expected to comply at least with current GSM-R
21
Guidance GN4: “Capacity, reliability, availability, maintainability, quality of service are characteristics to be used to meet the operational
needs of the railways. The “End to End” performance shall be equal-to or better-than legacy radio systems, for example GSM-R”.
Guidance GN5: “The user expects a quality of communication (integrity, clarity, accuracy etc.) which is considered to be normal for the
users by being equal to or better than what can be expected from a public service, and is sufficient to perform the railway operation”.
Doc.Nº: SRAIL-FNR-010-IND
Edit./Rev.: 1/1
Date: 16/02/2017
Page 185 of 285