ND SatCom SKYWAN IDU 7000, Manual

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2010-10-26 Network Design and Engineering Guide 95
Outdoor Unit and Satellite Link Design
SkyWAN
®
Link Budget Calculation Tool
Optional Link Filter for Complex Topologies
Normally the link budget tool calculates either meshed networks or star networks with up to two
hub stations. More complex topologies like hybrid or multi-hub star networks may be defined
by the link filter matrix at the bottom of the summary sheet.
Figure 3-22 Link Budget Tool - Summary Worksheet Complex Filter
By default every cell in this link filter matrix has the value 1. If a specific link should not be cal-
culated for the link budget, the cell value must be set to 0. In the example presented in the fig-
ure, for station 4 and 5 only links to stations 1-3 are calculated, station loop links and links to
station 4 and 5 are not considered. This would be an example for a star network with 3 hub
stations (1-3) and two remote terminals (4-5) as described in chapter 3.6.3.
3.5.6 Required Settings for MRB-DUB Networks
A Sky WAN
®
network configured for MRB-DUB mode can be considered to consist of two sub-
networks:
-
Stations belonging to Uplink Population 1 are located in Uplink Area 1 (ULA1).
- Stations belonging to Uplink Population 2 are located in Uplink Area 2 (ULA2).
To serve satellite links between stations located in these areas, carriers on up to four different
transponders may be required:
-
Carrier 1 must be located on a looped transponder for ULA1. This carrier is used by the
master and backup master station to send reference bursts and to receive request bursts
from stations located in ULA1 and for the master synchronization which requires self-re-
ception of the master stations. It is also used for data communication between all stations
in ULA1.
- Carrier 2 is located on a cross-strapped transponder linking ULA2 to ULA1 for transmitting
request bursts from stations in ULA2 to the master station. Also data bursts from ULA2 sta-
tions to the master or potentially other stations in ULA1 use this carrier.
- Carrier 3 is located on a cross-strapped transponder linking ULA1 to ULA2 for transmitting
reference and data bursts from the master stations to stations in ULA2. Potentially other
station in ULA1 could also use this carrier to send data bursts to ULA2 stations.
- The optional carrier 4 is located on a looped transponder for ULA2. This carrier is used by
stations in ULA2 to directly communicate with other stations in that area. Note that for such
stations a second demodulator is needed, because the primary demodulator for these sta-
tions must be used to receive carrier 3. If meshing within ULA2 is not required, this carrier
is not necessary.
Additional carriers may be defined if needed on looped transponders in ULA1 or ULA2.