基于相减式信号抵消的带内隐藏干扰检测

Detection of In-band Hidden Interference Based on Subtractive Signal Cancellation

为实现对通信信号的实时监测,提出一种带内隐藏干扰检测方法。该方法先利用解调结果重构期望信号,然后通过时延估计及自适应滤波使其与接收信号中的有用信号在时间、幅度和相位上尽量保持一致,最后利用相减式信号抵消技术将其从接收信号中消除,能够在不中断通信业务的前提下检测出信号带宽内隐藏的干扰。仿真结果表明,当信干比不低于6 dB、信噪比不低于3 dB时,期望信号、干扰信号与各自原信号的相似系数均能达到0.9以上,提取的干扰信号非常准确。将利用文中方法估计出的干扰抵消后,信号的星座图也得到了显著的收敛。

An in-band hidden interference detection technology is proposed for on-line monitoring of communication signals. The desired signal is reconstructed with demodulated data and it is kept correlated with the received signal in time, amplitude and phase through delay estimation and adaptive filtering. Finally, the estimated signal is re- moved from the received signal to get the in-band signal based on subtractive signal cancellation. The method can de- tect the hidden interference and noise without interruption of the desired carrier. Simulation results show that the similarity coefficient between the expected signal and its original one and that between the detected interference and its original one are both higher than 0.9 when the signal to interference ratio is no less than 6 dB and the signal to noise ratio is no less than 3 dB. As a result, the inference is accurately extracted. Meanwhile, the constellation dia- gram of the mixed signal converges obviously when the detected interference is removed.