Specifications

2010-10-26 Network Design and Engineering Guide 85
Outdoor Unit and Satellite Link Design
SkyWAN
®
Link Budget Calculation Tool
If it is not feasible to equip every station using a specific carrier for transmission with an outdoor
unit which produces a sufficient large EIRP to reach the maximum IPFD on the satellite, the
satellite transponder will also transmit this carrier with an EIRP which is lower than the satellite
EIRP
max
. In this case the reachable Eb/No will also be smaller and therefore the modulation
and coding of that carrier has to be adjusted accordingly.
3.5 SkyWAN
®
Link Budget Calculation Tool
To simplify link budget calculations for SkyWAN
®
networks, ND Satcom provides a spread-
sheet which contains the necessary formulas to calculate power requirements for earth stations
in SkyWAN
®
networks.
The ND Satcom SkyWAN
®
Link Budget Tool offers the following functionalities:
- Support of C-Band and Ku-Band satellite links.
- Data for up to 23 networks may be entered.
- Data of up to 20 earth stations may be defined per network.
- Support of meshed, star and hybrid network topologies.
- Up to 4 satellite transponder data sets may be used for each network.
Result: Power requirement for every SkyWAN
®
earth station in the network.
The link budget tool is a Microsoft
®
Excel spreadsheet which consists of the following work
sheets:
- Summary: Input: Carrier parameters for up to 8 SkyWAN
®
carriers, required bit error rate
level and rain availability. Output: Earth station power requirements, power equivalent
bandwidth.
- Stations: Earth station data, link to satellite transponder used for the network.
- Link Data: Intermediary results for link budget calculations like e.g. path loss, rain fade etc.
- Local_Ku_Antdata: Antenna data for antennas used in Ku-Band.
- Local_C_Antdata: Antenna data for antennas used in C-Band.
- Ku_Satellites: Satellite transponder data for Ku-Band transponders.
- C_Satellite: Satellite transponder data for C-Band transponders.
- TxAmp: Available amplifier power classes for Ku and C-Band.
In the following pages the various input and output fields of the link budget tool are explained.
Note that the input cells are indicated by a dark grey background. Cells with a different back-
ground color are output fields which should NEVER be overwritten by user input to avoid any
damage to the workbook’s built-in formulas. If an input field requires a numerical input, only the
value but not the unit should be entered.
Example: Saturation EIRP for the satellite transponder: Enter “37” not “37 dBW”.