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Consider the example shown in Table F-6.
Satellite & Transponder
Earth Station 1
Earth Station 2
Data Rate
While the traditional link was based on QPSK, TPC 3/4 and required 3.9 MHz of leased
bandwidth, the Carrier-in-Carrier link was based on QPSK, LDPC 3/4 and QPSK, LDPC 1/2 and
required 2.8 MHz of leased bandwidth.
The savings summary is shown in Table F-7.
Item
Data Rate (kbps)
Modulation
FEC
Occupied BW (MHZ)
Power Eq. BW (MHz)
Leased BW (MHz)
Hub HPA (W)
Remote HPA (W)
If this link was designed using QPSK, LDPC 3/4 in both directions, it would have required:
Occupied BW
Power Eq. BW
Leased BW
Hub HPA
Remote HPA
Appendix F
Table F-6. Asymmetric Data Rate Link Example
Table F-7. Asymmetric Data Rate Link Savings Summary
Original Link
Hub to
Remote to
Remote
Hub
3000
1000
QPSK
QPSK
TPC 3/4
TPC 3/4
2.8
0.9
3.3
0.6
26.0
10.6
Table F-8. QPSK and LDPC ¾ Link Requirements
2.8 MHz
3.0 MHz
7.2% increase in Power Eq. BW
3.0 MHz
7.2% increase in Leased BW
20.3 W
8.3 W
30% increase in Remote power
CDM-425 Advanced Satellite Modem
IS-901 @ 342º W, 22/22 (EH/EH)
Africa – 4.5 m
Africa – 3.0 m
3000 Mbps / 1000 Mbps
With Carrier-in-Carrier and LDPC
Hub to
Total
Remote
3000
QPSK
LDPC 3/4
LDPC 1/2
3.7
2.8
3.9
2.5
3.9
F–14
Revision 0
Savings
Remote
Total
to Hub
1000
QPSK
1.4
2.8
0.3
2.8
2.8
27.5%
20.3
22%
6.4
40%
MN-CDM-425
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