Study on feasibility of SATCOM for railway communication

Final Report
C.4 SATCOM SOLUTION 4: GEO / L-BAND BASED ON ANTARES CS (IRIS FOC)
GEO / L-band + ANTARES CS (IRIS FOC)
Criterion ID Criterion Evaluation Justification
CRT-TECH-1
The “link availability” of the proposed satcom system shall be
High.
C (Low)
Unlike the Inmarsat 4 system, it is an "open" solution where a high link availability
for safety applications can be considered, since the use of a low frequency band
(L-band) helps to this demanding requirement.
Anyway, it is also worth to mention that being compliant with the high link
availability required may imply the impossibility to provide some types of terminals
(basically handhelds). Regarding this issue, it is true that Inmarsat 4 (also a
GEO/L-band solution) enables the use of handhelds, but not being compliant with
the high link availability criterion.
CRT-TECH-2 The “reliability” of the proposed satcom system shall be High. C (High)
With the aim of increasing reliability and comply with the safety applications
requirements, this future (hypothetical) satcom system can be designed with
redundancy in both ground and space segments.
In addition, railway terminals shall be designed to provide the required MTBF and
MTTR figures.
CRT-TECH-3
The end-to-end error ratio of the proposed satcom system shall
be Low.
Note: Since this criterion only considers the satellite system,
the error ratio shall be measured after the last satellite
communication
C
The end-to-end error ratio depends mainly on the FEC used. Current satcom
systems have implemented powerful FECs based mainly on turbo codes (e.g.
TCC, TPC, LDPC, etc.) that enable the use of low Eb/No to assure the minimum
required BER and/or PER.
ANTARES CS also provides powerful FEC codes, such as TCC and LDPC, and
also ARQ techniques to improve continuity.
Doc.Nº: SRAIL-FNR-010-IND
Edit./Rev.: 1/1
Date: 16/02/2017
Page 239 of 285