Blind estimation of primary signal in cognitive satellite communication systems

The cognitive radio (CR) have been proposed to improve spectral efficiency and to meet growing demands for higher data rates in mobile communications and satellite communications. In this paper, we propose a blind estimation algorithm for a secondary user to estimate transmission parameters of the primary signal in an OFDM overlay system, using only the available fast Fourier transform (FFT) component of the secondary user. The algorithm does not require any a priori knowledge of the primary signal or the environmental noise. Simulation results show that our proposed algorithm outperforms existing blind estimation methods especially in low signal-to-noise ratio (SNR) regions.