Adaptive Wideband Beamforming With Frequency Invariance Constraints
Adaptive Wideband Beamforming With Frequency Invariance Constraints
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DOI：
10.1109/tap.2011.2110630
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发表时间：
2011-02
影响因子：
5.7
通讯作者：
Yong Zhao;W. Liu;R. Langley
中科院分区：
文献类型：
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作者：
Yong Zhao;W. Liu;R. Langley
引入响应变化（RV）元件来控制自适应宽带波束形成器在感兴趣的频率范围内响应的一致性。通过将 RV 元件合并到线性约束最小方差 (LCMV) 波束形成器中，我们开发了一种新型线性约束波束形成器，与传统公式和基于特征向量的公式相比，由于增加了干扰抑制的自由度，因此具有改进的输出信号与干扰加噪声比 (SINR)。此外，还提出了两种新颖的宽带波束形成器，对视线方向估计误差具有鲁棒性，作为 RV 元件的进一步应用。一种是通过对 RV 元件施加约束，同时将波束形成器的幅度响应限制在参考频率下的预定义角度范围内来设计的；另一种是结合RV元素和最坏情况性能优化方法得到的。两者都以凸形式重新表述为二阶锥（SOC）规划问题，并使用内点法有效求解。与原始的鲁棒方法相比，可以更有效地控制波束形成器在观察方向区域的响应，并提高整体性能。
A response variation (RV) element is introduced to control the consistency of an adaptive wideband beamformer's response over the frequency range of interest. By incorporating the RV element into the linearly constrained minimum variance (LCMV) beamformer, we develop a novel linearly constrained beamformer with an improved output signal-to-interference-plus-noise ratio (SINR), compared to both the traditional formulation and the eigenvector based formulation, due to an increased number of degrees of freedom for interference suppression. In addition, two novel wideband beamformers robust against look direction estimation errors are also proposed as a further application of the RV element. One is designed by imposing a constraint on the RV element and simultaneously limiting the magnitude response of the beamformer within a pre-defined angle range at a reference frequency; the other one is obtained by combining the RV element and the worst-case performance optimization method. Both of them are reformulated in a convex form as the second-order cone (SOC) programming problem and solved efficiently using interior point method. Compared with the original robust methods, a more efficient and effective control over the beamformer's response at the look direction region is achieved with an improved overall performance.