The Satellite bandwidth in different frequency bands varies between 0.5 to 3 Ghz. This available bandwidth can be used by several channels coming from different earth stations. Each channel gets a unique frequency slot in the satellite bandwidth. All the channels are transmitted or received simultaneously at a time.
Ths the sharing takes place in the frequency spectrum. So it is Frequency Division Multiplexing (FDMA) technique. If the satellites use digital modulation then time division multiplexing can be used. Each earth station can utilize the full bandwidth of the satellite but for a stipulated time period.
There are basically three multiple access methods used for satellite communication. They are:
- Frequency Division Multiple Access(FDMA).
- Time Division Multiple Access(TDMA).
- Code Division Multiple Access(CDMA).