Real-valued MVDR beamforming using spherical arrays with frequency invariant characteristic

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• 作者：Qinghua Huang ; ^{qinghua@shu.edu.cn" class="auth_mail" title="E-mail the corresponding author}Author Vitae ; Rui HuAuthor Vitae ; Yong FangAuthor Vitae
• 关键词：Spherical arrays ; Spherical harmonic decomposition ; Real-valued minimum variance distortionless response (MVDR) ; Frequency invariant beamforming ; Unitary transform
• 刊名：Digital Signal Processing
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：48
• 期：Complete
• 页码：239-245
• 全文大小：1280 K

文摘

Complex-valued minimum variance distortionless response (MVDR) beamforming for wideband signals has very high computational amount. In this paper, we design a novel real-valued MVDR beamformer for spherical arrays. The dependence of the array steering matrix on source signal directions and frequencies is decoupled using spherical harmonic decomposition. Then a compensation network is designed to solve the frequency dependence of the array response and to get a new array response only determined by the spherical harmonics of the source directions. All frequency bins of wideband signals can be used together instead of being processed independently. By exploiting the property of the conjugate spherical harmonics, a unitary transform can be found to acquire a real-valued frequency invariant steering matrix (FISM). Based on the FISM, real-valued MVDR (RV-MVDR) is developed to obtain good performance with low computational amount. Simulation results demonstrate the performance of our proposed method for beamforming and direction-of-arrival (DOA) estimation by comparing with the complex-valued and real-weighted MVDR methods.