ND SatCom SKYWAN IDU 7000, Manual

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104 Network Design and Engineering Guide 2010-10-26
Outdoor Unit and Satellite Link Design
Link Budget Examples
Therefore, the modulation and coding on this carrier can be increased, leading to the following
carrier coding and bandwidth:
Table 3-8 Scenario 2 - Carrier Coding and Bandwidth
Table 3-9 Scenario 2 - Summarized Power Requirements
Compare Scenarios
Compared to the meshed network, the star network requires:
-
About 1200 kHz less bandwidth on the satellite transponder.
- On the Berlin earth station a 20 W instead of a 8 W amplifier.
The transponder bandwidth saving should compensate the higher cost of the amplifier at the
Berlin station within a very short time frame, so that the star network should be for a longer op-
eration much more economical. Assumption is that there is really only negligible communica-
tion need between the remote stations.
Optimization
There is still potential room for optimization. Whereas on carrier 2 PEB and carrier bandwidth
is almost equilibrated, on carrier 1 the network still uses only 1/3 of the available transponder
power. The limitation is given by the Casablanca earth station which is located at the edge of
the satellite footprint. To compensate this disadvantage, it makes sense to install a bigger an-
tenna at this site.
Star Network Carrier 1 Carrier 2 Total bandwidth re-
quired ( carrier spac-
ing = 1.2) [KHz]
Modulation 8PSK 8PSK
FEC 2/3 2/3 5900
Estimated Symbol
Rate [ksps] 2713 2203
Star Network; 2.4 m An-
tenna all Madrid Berlin Rome Casablanca Tunis
Home Channel 1 1 2 2 2
Power requirement [W] 17.2 11.9 8.8 23.9 12.1
Amplifier power class [W] 20 20 20 30 20
Power equivalent band-
width [kHz]
with UPC (Home Channel) 1064 983 1004 2047 986
Carrier bandwidth [kHz]
(Home Channel) 3256 3256 2644 2644 2644