Abstract:

In order to solve the problem that the communication signal and the jamming overlap seriously in time and frequency domain, an antijamming algorithm for direct sequence spread spectrum (DSSS) communication based on source separation of single channel mixed signal by using transform-domain filter is presented. First of all, the source separation model of single channel mixed signal is constructed in transform-domain based on partial modulation prior information of the DSSS signal by using the second-order cyclostationary difference among the DSSS signal and the jamming. Then, the optimal separation vector of the pilot mixed signal is obtained by iterating of the separation cost function which is designed based on the training sequence and minimum mean square error criterion. Finally, the expected DSSS signal is extracted from the frequency shift vector of the service mixed signal by using the optimal separation vector obtained above, which accordingly promotes the anti-jamming capacity of the DSSS communication. Simulation results show that, in the condition of strong jamming such as singletone/ multi-tone jamming and sweep-spot jamming, the bit error rate (BER) of the un-separated signal is almost constant and fluctuates in the vicinity of 0.5, while the BER of the proposed algorithm can be as below as 10^-3.