Study on feasibility of SATCOM for railway communication
SRAIL-FNR-010-IND%20-%20FinalReport_v1.1_20170216
SRAIL-FNR-010-IND%20-%20FinalReport_v1.1_20170216
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Final Report<br />
C.5 <strong>SATCOM</strong> SOLUTION 5: THURAYA<br />
Thuraya<br />
Criteri<strong>on</strong> ID Criteri<strong>on</strong> Evaluati<strong>on</strong> Justificati<strong>on</strong><br />
CRT-TECH-1<br />
The “link availability” <strong>of</strong> the proposed satcom system shall be<br />
High.<br />
NC<br />
Thuraya is a "closed" satcom system mainly oriented to voice communicati<strong>on</strong>s via<br />
CS (Circuit-Switching). It is also a GEO/L-band (like Inmarsat 4 and ANTARES<br />
previously analysed). It enables the use <strong>of</strong> handhelds but not providing the high<br />
link availability required <strong>for</strong> safety applicati<strong>on</strong>s (since this system was not<br />
designed <strong>for</strong> this type <strong>of</strong> services).<br />
CRT-TECH-2 The “reliability” <strong>of</strong> the proposed satcom system shall be High. C (Low)<br />
Thuraya, which terminals are fully compatible with GSM networks, <strong>of</strong>fers GSM as<br />
a backup system, increasing this way the reliability. It is worth to menti<strong>on</strong> that<br />
Thuraya has an agreement with more than 300 GSM partners worldwide in order<br />
to <strong>of</strong>fer GSM roaming services when satellite is not available.<br />
CRT-TECH-3<br />
The end-to-end error ratio <strong>of</strong> the proposed satcom system shall<br />
be Low.<br />
Note: Since this criteri<strong>on</strong> <strong>on</strong>ly c<strong>on</strong>siders the satellite system,<br />
the error ratio shall be measured after the last satellite<br />
communicati<strong>on</strong><br />
C<br />
The end-to-end error ratio depends mainly <strong>on</strong> the FEC used.<br />
Thuraya relies <strong>on</strong> the GMR-1 standard, which provides lots <strong>of</strong> FEC codes, such as<br />
c<strong>on</strong>voluti<strong>on</strong>al, turbo codes, Reed Solom<strong>on</strong>, etc.<br />
CRT-TECH-4a<br />
Transfer delay <strong>for</strong> the proposed satellite system shall be Low.<br />
Note: It refers to the end-to-end (<strong>on</strong>e-way) delay due to the<br />
satellite channel. There<strong>for</strong>e, it shall be measured from satellite<br />
transmitter to satellite receiver.<br />
4a: Single-hop required<br />
C (Low)<br />
The low data rate provided by Thuraya in the return link, al<strong>on</strong>g with the GEO<br />
satellite, increases the transfer delay up to around 300 ms (see delay study<br />
below).<br />
CRT-TECH-4b 4b: Double-hop required<br />
NC<br />
Taking into account the delay estimated <strong>for</strong> the single-hop, the transfer delay <strong>for</strong> a<br />
double-hop scenario exceeds the 500 ms.<br />
Doc.Nº: SRAIL-FNR-010-IND<br />
Edit./Rev.: 1/1<br />
Date: 16/02/2017<br />
Page 244 <strong>of</strong> 285
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