Abstract: A cooperated narrow-band jamming suppression scheme is proposed based on Quasi-Cyclic Low Density Parity Check codes（QC-LDPC） and chaotic direct sequence spread spectrum for improving the data transmitting in the low SNR with the different jamming. The QC-LDPC encodes are designed through the Moore-Penrose inverse and the full rank decomposition based on the parity check matrix. The inverse transform for identity matrix and direct product are used for constructing the parity check matrix. The performance of chaotic spread spectrum sequences, produced from improved Logistic MAP, is analyzed and verified by simulations. Simulation results demonstrate that the scheme can bring 8.2 dB SNR gain comparing to current standard when the jamming-to-signal ratio is 20 dB.

Key words: Quasi-Cyclic Low Density Parity Check codes（QC-LDPC）, Direct Sequence Spread Spectrum（DSSS）, Moore-Penrose inverse, improved Logistic MAP, Common Data Link（CDL）

摘要： 为改善低信噪比窄带干扰条件下的信息传输性能，在现阶段宽带数据链的基础上，提出了一种结合QC-LDPC和混沌DSSS的协同窄带干扰抑制方案。该方案在提出单位阵取反变换的直积构造方法来生成校验矩阵的基础上，采用Moore-Penrose逆——满秩分解方法完成了QC-LDPC的编码；针对直序扩频系统，在分析了改进型Logistic映射序列性能的基础上，使用混沌扩频序列提高抗干扰能力。仿真验证了该方案的有效性，结果表明：在JSR为20 dB时，与现阶段传输标准相比，该方案可以获得8.2 dB的信噪比增益。

关键词: 准循环低密度奇偶校验码（QC-LDPC）, 直接序列扩频（DSSS）, Moore-Penrose逆, 改进型Logistic映射, 通用数据链