This paper presents a cyclostationary difference-based anti-jamming method by blindly extracting direct sequence spread spectrum signal.Aiming at approximate independence among source signals

an anti-jamming model based on blind source separation is established for direct sequence spread spectrum communication.And then

by using typical extreme points of cyclic autocorrelation function

a characteristic parameter called second-order cyclic difference degree is defined based on cyclostationary difference to distinguish between direct sequence spread spectrum signal and jamming.Finally pattern recognition is used to extract expected signal and suppress jamming by comparing the values of characteristic parameter

so as to achieve the purpose of anti-jamming.Simulation results show that

when the NSNR (Normalized Signal to Noise Ratio) is 9 dB and the SJR (Signal to Jamming Ratio) is -40 dB

the direct de-spreading/demodulation signal achieves the bit error rate (BER) of nearly IE-0.3

while the proposed algorithm achieves the bit error rate of as low as IE-3

which can extract the direct spread signal from the strong jamming effectively.