Performance evaluation of nonlinear satellite link by computer simulation

The performance of a nonlinear satellite channel using QPSK (Quaternary Phase Shift Keying) and MSK (Minimum Shift Keying) has been studied by computer simulation. In the simulation, the pseudo randomly generated input data stream modulates the carrier and this modulated carrier passes through the typical satellite communication link, that consists of a transmit earth station, a satellite transponder, and a receiving earth station. All the signals used in the simulation procedure are real-valued and are transformed back and forth between time and frequency domains depending on the necessity by the Fast Fourier Transform (FFT) or Inverse Discrete Fourier Transform (IDFT). The simulation result represented as average Bit Error Rate (BER) gives the basis for comparison of the performance in various link conditions such as linearity, nonlinearity, band-limited and noisy channels which are expected to be encountered in practical situations.