空时分组码MC-CDMA系统盲干扰抑制
Blind Interference Suppression for a Space-Time Block Coded MC-CDMA System
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摘要: 该文考虑空时分组码多载波码分多址(MC-CDMA)系统的盲干扰抑制。通过研究多径信号频域码空间和数据矢量空间，采用噪声子空间技术进行盲信道估计。使用一种修改的ULV更新算法进行噪声子空间跟踪，该算法不需要相关矩阵的秩估计，直接估计噪声子空间。为了抑制多址干扰(MAI)，提出一种基于投影的辅助矢量(PAV)算法，用前一级滤波矢量的输出重构最大比合并(MRC)滤波矢量，将重构滤波矢量到由基本滤波矢量和前几级辅助矢量张成子空间上的正交投影作为辅助矢量，将前一级滤波矢量和新产生辅助矢量线性合并得到新的滤波矢量。仿真结果验证了该文算法的有效性。Abstract: This paper considers blind interference suppression for a space-time block coded MultiCarrier CDMA (MC-CDMA) system. By investigating the code space in frequency domain and the data vector space of the multipath signals, the noise-subspace-based approach is used to perform blind channel estimation. A modified ULV updating algorithm is applied to performing noise subspace tracking. The algorithm does not require rank estimation of the correlation matrix, and estimate directly the noise subspace. To suppress Multiuser Access Interference (MAI), a Projection-based Auxiliary Vector (PAV) algorithm is proposed. A reconstructed Maximum Ratio Combining (MRC) filtering vector can be evaluated by using the outputs of the last filtering vector. Taking the orthogonal projection of the reconstructed filtering vector onto the space spanned by the basic filtering vector and the previously derived auxiliary vector as an auxiliary vector, a new filtering vector can be formed by linearly combining the last filtering vector and newly generated auxiliary vector. Simulation results show the effectiveness of the proposed algorithms.
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