使用子空間限制及對角負載的增強型最小化變異數無 失真響應波束成形

Robust Minimum Variance Distortionless Response (MVDR) Beamformer Using Subspace-Constrained Diagonal Loading

蔡岳廷(Yueh-Ting Tsai)

指導教授 ： 蘇柏青

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201600576

摘要

在這篇論文中, 首先, 在入射角失真的議題之下為了增強最小化變異
數無失真響應波束成形, 一個子空間限制的對角負載法被提出。子空間
限制的對角負載法首先決定一個由訊號共變異數矩陣及所需訊號可能
存在的範圍內的導向向量所估算出的子空間, 然後子空間限制的對角負
載法在這個子空間中計算出所要的權重向量。而為了使所需訊號的大
小響應接近1, 我們使用了對角負載法。因為增加了額外的限制確保干
涉訊號的壓制量, 子空間限制的對角負載法可以比傳統的對角負載法有
更好的出口的所需訊號對干涉訊號加雜訊的比值表現。第二部分, 為了
解決導向向量錯誤的問題, 我們提出了增強型子空間限制的對角負載
法, 而此方法是藉由改變子空間限制的對角負載法選擇子空間的方法達
成。第三部分, 因為子空間限制的對角負載法以及增強型子空間限制的
對角負載法都不能夠動態地估算出對角負載的係數以及決定子空間, 我
們提出了自適性增強型子空間限制的對角負載法, 這個方法使用了卡彭
能量密度波譜以及特徵值分解技術。模擬結果顯示子空間限制的對角
負載法, 增強型子空間限制的對角負載法, 以及自適性增強型子空間限
制的對角負載法都有出色的出口的所需訊號對干涉訊號加雜訊的比值
表現。

關鍵字

最小化變異數無失真響應波束成形

並列摘要

In this thesis, first, a new subspace-constrained diagonal loading (SSCDL)method is presented for robust minimum variance distortionless (MVDR) response beamformer with DoA mismatch issue. The SSC-DL first determines a subspace, which is estimated by the signal covariance matrix and steering vectors in the possible range of desired signal. Then SSC-DL computes the weight vector constrained in a determined subspace. In order to force the magnitude response of the desired signal to approach unity, diagonal loading (DL) method is used. Because the additional constraints are added to ensure an interference suppression capability, the SSC-DL can achieve better SINR performance when compared with the conventional DL method. Second, In order to deal with the steering vector errors, we proposed enhanced SSC-DL (ESSC-DL) method which changes the construction method of the subspace. Third, due to SSC-DL and ESSC-DL both can’t estimate the diagonal loading factor and determine the subspace dynamically, we proposed adaptive ESSC-DL method using the Capon power spectrum density and eigen decomposition technique. Simulation results shows that SSC-DL, ESSC-DL and adaptive ESSC-DL have outstanding output SINR performance.

並列關鍵字

minimum variance distortionless response

參考文獻

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