Autocorrelation based detection of DSSS signal for cognitive radio system

The direct-sequence spread-spectrum(DSSS) signals are usually transmitted at very low signal to noise ratio(SNR) in Cognitive Radio(CR) system, and the classic energy detection method is not effective enough to do the detection. In this paper, we proposed an autocorrelation estimation based detection method. The method firstly searches the autocorrelation peaks that may appear at integer times of the pseudo noise sequence period, and then do the judgment by the cumulative peak-to- average criteria. Computer simulation results show that the method proposed has good performance, and it is suitable for the real-time detection of DSSS signals at low SNR in CR system.