2010-10-26 Network Design and Engineering Guide 95Outdoor Unit and Satellite Link DesignSkyWAN® Link Budget Calculation ToolOptional Link Filter for Complex TopologiesNormally the link budget tool calculates either meshed networks or star networks with up to twohub stations. More complex topologies like hybrid or multi-hub star networks may be definedby the link filter matrix at the bottom of the summary sheet.Figure 3-22 Link Budget Tool - Summary Worksheet Complex FilterBy 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 tostation 4 and 5 are not considered. This would be an example for a star network with 3 hubstations (1-3) and two remote terminals (4-5) as described in chapter 3.6.3.3.5.6 Required Settings for MRB-DUB NetworksA SkyWAN® 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 differenttransponders may be required:- Carrier 1 must be located on a looped transponder for ULA1. This carrier is used by themaster and backup master station to send reference bursts and to receive request burstsfrom 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 stationsin ULA1.- Carrier 2 is located on a cross-strapped transponder linking ULA2 to ULA1 for transmittingrequest 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 transmittingreference and data bursts from the master stations to stations in ULA2. Potentially otherstation 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 bystations in ULA2 to directly communicate with other stations in that area. Note that for suchstations 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 carrieris not necessary.Additional carriers may be defined if needed on looped transponders in ULA1 or ULA2.
