FDMA (Frequency Division Multiple Access) http://etechtour.com/2009/03/fdma-frequency-div... It is the oldest and still one of the most common methods for channel allocation. In this scheme, the available satellite channel bandwidth is broken into frequency bands for different earth stations. This means that guard bands are needed to provide separation between the bands.
CDMA (Code Division Multiple Access) http://etechtour.com/2009/03/cdma-code-division... Under this, a central network monitoring system allocates a unique code to each of the VSATs enabling multiple VSATs to transmit simultaneously and share a common frequency band. The data signal is combined with a high bit rate code signal which is independent of the data.
