Interference cancellation beamforming robust to pointing errors

• Published in: IET signal processing Vol. 7; no. 2; pp. 120 - 127
• Main Authors: Zhuang, Jie, Manikas, Athanassios
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.04.2013; Institution of Engineering and Technology; John Wiley & Sons, Inc
• Subjects: Applied sciences; array beamformer; array signal processing; Arrays; Asymptotic properties; cochannel interference; covariance matrices; desired‐signal‐absent covariance matrix; Detection, estimation, filtering, equalization, prediction; diagonal loading; Exact sciences and technology; Information, signal and communications theory; integral equations; Interference; interference cancellation beamforming; interference rejection; interference subspace; interference suppression; Mathematical analysis; one‐step computation; performance degradation; Permissible error; Projection; robust Capon; Signal and communications theory; signal power; signal subspace projection beamformer; Signal, noise; signal‐to‐noise ratio; steering vector pointing error; Subspaces; Telecommunications and information theory; vector space projection method; Vectors (mathematics); weight vector orthogonal; Wiener–Hopf beamformer; Wiener–Hopf beamformer; array beamformer; interference subspace; signal subspace projection beamformer; covariance matrices; interference suppression; interference cancellation beamforming; performance degradation; cochannel interference; Wiener–Hopf beamformer; Wiener–Hopf beamformer; weight vector orthogonal; integral equations; interference rejection; desired-signal-absent covariance matrix; steering vector pointing error; one-step computation; signal power; signal-to-noise ratio; robust Capon; array signal processing; vector space projection method; diagonal loading; Performance evaluation; Noise reduction; Cochannel interference; Subspace method; Covariance matrix; Vector method; Beam forming; Wiener Hopf method; Degradation; Projection method; Interference suppression; Vector space; Signal processing; Numerical simulation; Damaging; Signal to noise ratio
• ISSN: 1751-9675; 1751-9683; 1751-9683
• DOI: 10.1049/iet-spr.2011.0464

The conventional Wiener–Hopf beamformer is subject to substantial performance degradation in the presence of steering vector pointing errors. By removing the effects of the desired signal, the modified Wiener–Hopf beamformer avoids this problem but allows cochannel interferences to pass through in order to maximise the signal-to-noise ratio. In this study, a novel array beamformer is proposed, which not only reduces the effect of pointing errors, but also asymptotically provides complete interference rejection. In particular, the proposed beamformer utilises a vector space projection method and employs a one-step computation for the desired signal power. Using this, the effects of the desired signal can be extracted to form the desired-signal-absent covariance matrix. Thus, a weight vector orthogonal with the interference subspace can be constructed. Numerical results demonstrate the superior performance of the proposed beamformer in the presence of pointing errors relative to other existing approaches such as ‘diagonal loading’, ‘robust Capon’ and ‘signal subspace projection’ beamformers.