联合正交投影与盲波束形成的干扰抑制方法

针对L频段数字航空通信系统1(L-band digital aeronautical communications system 1, L-DACS1)以内嵌方式部署在航空无线电导航频段而产生的高强度测距仪脉冲信号干扰正交频分复用(orthogonal frequency division multiplexing, OFDM)接收机的问题,提出联合正交投影与盲波束形成的干扰抑制方法。接收机首先通过将接收信号矢量投影到干扰信号正交补空间的方法消除高强度测距仪脉冲干扰,然后利用OFDM信号循环前缀的对称特性,基于期望信号与参考信号矢量内积度量最大化准则得到波束形成权值,并通过波束形成方法提取OFDM直射径信号。计算机仿真表明:论文提出方法可有效克服测距仪脉冲及OFDM散射径信号的干扰,提高L频段数字航空通信系统1的链路传输的可靠性。

Interference mitigation method based on subspace proj ection and blind adaptive beamforming

To mitigate the deleterious influence of distance measure equipment (DME) impulse interference on the orthogonal frequency division multiplexing (OFDM) receiver of L-band digital aeronautical communications system 1(L-DACS1) operating as an inlay system, a new interference suppression receiver for the L-DACS1 system is proposed based on jointing the subspace projection and the blind adaptive beam forming algorithm. Firstly, the subspace projection algorithm is used to suppress the strong DME interference by projecting the array received signals on the orthogonal complement space of interferences. Then, the blind adaptive beam forming algorithm is proposed to extract the OFDM direct path signals based on inner product maximization criterion between the desired and reference signals. Computer simulation results show that the proposed OFDM receiver can effectively suppress the strong DME impulse interference and OFDM scattering signal and improve the reliability of the L-DACS1 system.