Primary user signal detection in cognitive radio networks using cyclostationary feature analysis

The improper utilization of frequency spectrum can be overcome by oppurtunistically using the bands allocated to the licensed primary users. Cognitive radio networks can be considered as the next generation network that can be used for the same. In this paper, a 16-QAM/OFDM primary user signal is detected by utilizing the periodicities generated by the pilot subcarriers of the OFDM symbols. The Spectral Correlation Function (SCF) of the signal received from the spectrum is used to make a decision regarding the presence of the Primary User signal in a cyclostationary detector. For improving the ease of identification of the pilots from the SCF, the data subcarriers are given an amplitude scaling. The performance of the detector is evaluated under different SNR conditions.