Earth station capable of effectively using a frequency band of a satellite

In an earth station for carrying out communication in a satellite communication system through a satellite by the use of an up-link frequency band and a down-link frequency band, said earth station comprising a transmission section responsive to first and second input signals for transmitting first and second transmission signals through said up-link frequency band towards said satellite, the improvement in combination with the foregoing wherein:

• each of said up-link and said down-link frequency bands has a plurality of frequency subbands spaced apart from one another with frequency gap bands interposed between said frequency subbands;
• said transmission section comprising:
• modulating means for modulating a carrier by said first input signal to produce a transmission subband signal occupying a selected one of said frequency subbands of the up-link frequency band;
• first transmitting means coupled to said modulating means for transmitting said transmission subband signal as said first transmission signal through said selected one of the frequency subbands;
• spread spectrum processing means for processing said second input signal into a spread spectrum transmission signal having said up-link frequency band;
• and
• second transmitting means coupled to said spread spectrum processing means for transmitting said spread spectrum transmission signal as said second transmission signal through said up-link frequency band.