基于复数FastICA的双极化干扰对消算法研究

Study on Dual⁃Polarization Interference Cancellation Algorithm Based on Complex FastICA

为解决卫星通信中极化复用导致的交叉极化干扰问题,提出了一种基于复数快速独立成分分析方法,根据传输信道的对称性对算法作了简化处理,减少了计算量。该算法依据发送端的两个线极化信号的不相关性,在无源信号及混合矩阵的先验信息情况下,构造负熵函数并使其最大化来分离出独立成分,进而实现交叉极化信号对消。仿真实验以正交相移键控调制信号为例,从误差向量幅度、信干噪比、交叉极化隔离度、性能指数这几个指标上进行仿真,仿真结果显示基于复数快速独立成分分析方法对解决交叉极化干扰问题具有良好的性能。

To solve the cross⁃polarization interference problem caused by polarization multiplexing in satellite communications,a fast independent component analysis(FastICA)method based on complex numbers is proposed.The algorithm is simplified according to the symmetry of the transmission channel to reduce the computational effort.The al⁃gorithm constructs and maximizes the negative entropy function to separate the independent components based on the uncorrelationofthetwo⁃linepolarization signals at the transmitter,and then achieves the elimination of the cross⁃polariza⁃tion signal without a priori information of the source signal and the mixing matrix.Taking quadrature phase shift key(QPSK)as an example,the simulation experiments are performed in terms of error vector amplitude(EVM),signal to interference plus noise ratio(SINR),cross⁃polarization discrimination(XPD)and performance index(PI).The simula⁃tion results show that the complex FastICA⁃based method has a good performance in solving the cross⁃polarization inter⁃ference problem.