ND SatCom SKYWAN IDU 7000, Manual

Page: 96 / 154

92 Network Design and Engineering Guide 2010-10-26
Outdoor Unit and Satellite Link Design
SkyWAN
®
Link Budget Calculation Tool
3.5.5 Summary Worksheet
Input
Figure 3-18 Link Budget Tool - Summary Worksheet Input
The input section of the summary sheet allows the definition of the carrier parameters for all
Sky WAN
®
carriers used in the network.
Step (1) Define the following carrier parameters:
- ’Carrier Modulation’
- ’FEC Rate’
- ’Modem Data Rate’ (as calculated by the
Sky WAN
®
TDMA Calculator)
- ’Gross Container Size’ (as calculated by the Sky WAN
®
TDMA Calculator)
From the carrier input parameters the tool derives an estimated carrier symbol rate which is
displayed at the bottom of the carrier parameter box. Note that this is only an estimated value;
the precise values for the symbol rate have to be taken from the TDMA Calculator. Additionally
the following link quality parameters must be defined:
- ’Maximum Bit Error Rate’
- ’Two Way Rain Availability’
Step (2) For each carrier the network topology may be selected from a pull-down menu:
’Mesh’ (mandatory for carrier 1) or ’Star’.
- ’Star’ topology: for all stations which use a ’Star Carrier’ as their home channel
only links to the hub stations (the first two columns in the station sheet) are cal-
culated.
- ’Mesh’ topology: For stations on a meshed carrier links to all other stations in the
network are calculated.
Step (3) The carrier parameters may be copied to the Stations sheet using a copy button
located on this sheet. Another copy button on the Stations sheet allows the loading
of stored carrier parameters for a specific network into the Summary sheet. The
carrier parameters here will be used to calculate the links.
Step (4) Optionally define an additional back-off for TWTA amplifiers in the marked field of