基于变换域滤波的直扩通信单通道混合信号分离抗干扰方法

针对直扩通信信号和干扰在时/频域严重重叠这一实际情况,提出一种基于变换域滤波的直扩通信单通道混合信号分离抗干扰算法。该方法首先利用直扩信号和干扰的二阶循环平稳差异,基于直扩信号部分调制先验信息,构造基于变换域的单通道混合信号分离模型;然后基于训练序列和最小均方误差准则设计代价函数,使输出信号接近于导频序列并得到此时的分离向量;最后利用该分离向量,从含有强干扰的业务混合信号的频移向量中分离出期望的通信信号,提升了直扩通信在强干扰下的抗干扰能力。仿真结果表明，未分离信号在单音/多音干扰、扫频干扰等强干扰下的误码率接近0.5,而本文算法在此条件下的误码率可低至10^-3以下。

Anti-jamming algorithm for direct sequence spread spectrum communication based on source separation of single channel#br# mixed signal by using transform-domain filter

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.