Suppression of interferences over SATCOM links with transparent transponders

In today's SATCOM systems transparent transponders are widely used. This device is the most vulnerable component of the whole system. Signals which are received accidentally or introduced intentionally into the transponder band will be retransmitted, generating IM products and therefore reducing the available energy to the user signal. It is shown, that the bandwidth spreading of the user signal reduces the vulnerability. Two techniques, frequency hopping (FH) and direct sequence spread spectrum (DS-SS), are considered.