Study on feasibility of SATCOM for railway communication

Final Report
C.9 SATCOM SOLUTION 9: SMARTLNB
SmartLNB
Criterion ID Criterion Evaluation Justification
CRT-TECH-1
The “link availability” of the proposed satcom system shall be
High.
NC
Since SmartLNB system has not been conceived to provide critical services, the
link availability provided is not meeting this demanding link availability
requirement.
CRT-TECH-2 The “reliability” of the proposed satcom system shall be High. C (High)
Despite the SmartLNB terminals are low cost, the satcom solution is based on a
GEO/Ku-band system. If finally this solution is feasible to provide safety
applications for railways, redundancy at both space and ground segments can
(and shall) be provided, assuring this way the high reliability required. In addition,
more robust and reliable terminals will be required for on-board, in order to comply
with MTBF and MTTR figures than commercial ones.
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
On the forward link, this solution relies on the DVB-S2 standard, which defines
mechanisms to assure a high level of continuity. On return link, although the
transmission is asynchronous with a random access scheme, a special receiver
with a Successive Interference Cancellation (SIC) mechanism is able to decode
messages if the traffic load is under control. Traffic load is managed by means of
congestion control mechanisms.
CRT-TECH-4a
Transfer delay for the proposed satellite system shall be Low.
Note: It refers to the end-to-end (one-way) delay due to the
satellite channel. Therefore, it shall be measured from satellite
transmitter to satellite receiver.
4a: Single-hop required
NC
On return-link, despite the pure random access mechanism requires a nonnegligible
time on reception due to an iterative process, the data rate of 160 kbps
makes the transfer delay is around 255 ms.
Doc.Nº: SRAIL-FNR-010-IND
Edit./Rev.: 1/1
Date: 16/02/2017
Page 265 of 285