Wavelet transforms detection of spectrum sensing in the space network

Cognitive Radio systems have been proposed to address the shortage of space spectrum resources illusion and the spectrum sensing is a key technology in cognitive radio system. Spread spectrum modulation signal has been applied widely in satellite measurement and control, satellite-ground communications, inter-satellite communications. And the spread spectrum signal detection perception is another difficulty in spectrum sensing. Based on wavelet transform (WT) spectrum sensing technology can be applied to the spread spectrum signal sensing systems. The magnitude characteristic of discrete wavelet transform and the maximum likelihood estimation (MLE) are applied to space network signal receiver, in order to sense inter-satellite link signal. Compared with energy detection, the detector based on discrete wavelet transform has better detection performance at low SNR. The result of research is expected for providing technical information and support for the future space network management and engineering applications.