变换域窄带干扰抑制技术的研究与仿真

提出了一种在变换域中抑制窄带干扰 (NBJ: Narrowband Jamming) 的方法.该方法首先对所接收的直接序列扩频 (DSSS: Direct Sequence Spread Spectrum) 信号进行小波包变换 (WPT: Wavelet Packet Transform) ,然后利用DSSS信号的功率谱密度 (PSD: Power Spectrum Density) 分布特点和能量聚集度 (ECM: Energy Compaction Measure) 准则,有效、快速地跟踪输入信号频谱的变化,从而对DSSS信号中的干扰进行快速定位.对强、弱NBJ的分别抑制是通过自适应改变权系数的方法来实现的.多径莱斯 (Ricean) 衰落信道中的仿真结果表明,这种变换域中的自适应干扰抑制法既可以有效地清除快速时变的强NBJ,又可在处理其它类型干扰时,避免或减小有用信息的损失,从而大大提高DSSS系统在复杂干扰情况下的抗干扰性能.

Narrowband Jamming Suppression Method and Simulation in Transform-Domain

A Narrowband Jamming (NBJ) suppression method in the transform domain was analyzed. By Wavelet Packet Transform (WPT), the received Direct Sequence Spread Spectrum (DSSS) signal and using distribution characteristics of Power Spectrum Density (PSD) of DSSS signal and Energy Compaction Measure (ECM) rule, this method can track the change of the frequency spectrum of the input signal and identify interference to DSSS signal effectively and quickly. The strong and weak NBJ are suppressed respectively by changing the tap weight adaptively. The simulation result in the Multipath Ricean fading channel shows that the adaptive interference suppression method in the transformed domain can effectively eliminate strong NBJ with fast time-variation and avoid or reduce the information loss during the process when the other interferences exist. In this way, the anti-Jamming performance of the DSSS system can be improved significantly under the condition of complex interferences are existed.