Estimation-Based Blind Detection in Low SNR on Direct-Sequence Spread Spectrum Signal

In nowadays, the Direct-Sequence Spread Spectrum (DSSS) technology has been widely used. It´s necessary to research blind detection algorithms on DSSS signal. Many studies before successfully detect the parameters of the signal, like carrier frequency, code rate, code period etc. The current main problem is that signal-noise ratio (SNR) required is much higher than which DSSS signal working at. Therefore these algorithms are difficult to carry out practical applications. The proposed algorithm can effectively suppresses the noise through estimating data and code information, thus achieving a low SNR threshold of the blind detection of DSSS signals. For DSSS signal using 15 bits spreading code, algorithm proposed can easily complete the detection in the SNR lower than -8 dB. The threshold could be even lower if spreading code is longer or there are more signal samples. Algorithm in this paper can also demodulate data blindly with good BER performance.