In satellite communication systems, in order to overcome the loss on which the long distance space transmission brings
and provide the reliable and high-quality means of communication to the earth station, the RF carrier power of receiving
signals should be much greater than the noise power, that is to make the satellite link satisfy the carrier noise ratio
As the primary means of making the carrier noise ratio to meet the requirement of system designed, communication link
calculation will be able to identify the carrier noise ratio, earth station required and system capacity, or the earth station
antenna size, receiver noise performance, transmitter power, etc.
The paper introduces a general method of satellite communication link calculation, and then analyzes the impact of
different working conditions such as single-carrier and multi-carrier on communication links calculation process
especially on the result of carrier-to-noise ratio. The calculation methods are proposed in conclusion respective.