Beamforming Design for Minimizing the Signal Power Estimation Error

We study the properties of beamformers in their ability to either maintain or estimate the true signal power of the signal of interest (SOI). Our focus is particularly on the Capon beamformer and the minimum mean squared error (MMSE) beamformer. The Capon beamformer, also known as the minimum power...

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Detalhes bibliográficos
Autores: Ollila E., Mestre X., Raninen E.
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2026
País:España
Recursos:Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Repositorio:r-CTTC. Repositorio Institucional Producción Científica del Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
OAI Identifier:oai:dnet:r-cttc______::31724a54d506075b6cfde3343c89012c
Acesso em linha:https://cttc.fundanetsuite.com/Publicaciones/ProdCientif/PublicacionFrw.aspx?id=8941
Access Level:acceso abierto
Palavra-chave:Beamforming
Capon
MPDR
MVDR
MMSE
signal power estimation
shrinkage
Descrição
Resumo:We study the properties of beamformers in their ability to either maintain or estimate the true signal power of the signal of interest (SOI). Our focus is particularly on the Capon beamformer and the minimum mean squared error (MMSE) beamformer. The Capon beamformer, also known as the minimum power distortionless response (MPDR) or the minimum variance distortionless response (MVDR) beamformer, is a widely used method in array signal processing. A curious feature of both the Capon and the MMSE beamformers is their tendency to either overestimate or underestimate the signal power. That is, the power estimates of their output signals are not asymptotically unbiased (as the sample size approaches infinity). To address this issue, we propose to shrink the Capon beamformer by finding a scaling factor that minimizes the mean squared error (MSE) of the signal power estimate. The new beamformer, referred to as the Capon(+ )beamformer, is evaluated against the Capon and MMSE beamformers in terms of signal power bias and MSE, and signal waveform MSE. The Capon(+ ) beamformer strikes a better balance between signal power and waveform estimation while also exhibiting minimal bias, which approaches zero as the sample size increases.