ND SatCom SKYWAN IDU 7000 Manual page 68

General Carrier Design
TDMA Carrier Design with 'TDMA Calculator'
For the definition of the user data refer to chapter 2.5. The spectral efficiency is represented by
two definitions:
- Efficiency per symbol = user data rate / symbol rate.
- Efficiency per Hz = user data rate / frequency bandwidth.
The difference between these definitions is given by the carrier spacing factor.
64 Network Design and Engineering Guide 2010-10-26