Detection And Recovery Of Direct Sequence Spread Spectrum Signal

Direct sequence spread spectrum communication technology with low probability of intercept, low transmit power spectral density, high anti-fading ability and anti multipath interference, is widely used in civil communication and military communication. Nowadays, with the development of electronic warfare and information warfare technology, the detection and recovery of direct sequence spread spectrum signal(DSSS signal) is increasingly needed under unknown signal circumstance. Therefore the problems of detection and recovery of DSSS signal in non-cooperative mode have gradually become the research focus of the communication field. It is of great significance to study algorithms for detecting and recovering signals in non-cooperative and low SNR manner to fulfill future war needs.For those reasons, low SNR DSSS signal detection and recovery were studied in this paper. Firstly this paper provides an overview of the basic knowledge of DSSS system; then introduces the cyclic spectrum method and power spectrum method to detect the unknown signal; and then solves the parameters information of signal carrier frequency, code rate, code period and so on, finally discusses the recovery of DSSS signal in the conditions of short code DSSS signal and long code DSSS signal respectively. As for signal detection, this paper mainly discusses the cyclic spectrum method and power spectrum method these two kinds of method. In solving the parameter information of carrier frequency, code rate, code period, the paper uses the Monte Carlo simulation method repeatedly to enhance the reliability of simulation results. After getting the correct parameter information, this paper firstly uses eigenvalue decomposition method for short code sequence recovery, and then uses the segmented improved decomposition method for long code sequence recovery. Results show that, both the short code sequence and long code sequence can be correctly recovered in the low SNR case.