在非理想環境下基於新型廣義旁波瓣消除器之強健可適性波束成型技術

Abstract

可適性波束成型技術主要是用來提取欲接收信號並消除干擾信號和雜訊的技術，其中LCMV(Linearly Constrained Minimum Variance)波束成型器與廣義旁波瓣消除器(Generalized Sidelobe Canceller)更是此領域相當重要的技術，這種技術需要的已知資訊為欲接收信號的入射角方向。 本論文主要針對修改傳統廣義旁波瓣消除器(GSC)，提出新型廣義旁波瓣消除器(NBMGSC)，藉由結合雜訊阻隔矩陣與改良式廣義旁波瓣消除器(MGSC)所提出來的架構。而這種方法，不僅使強健性演算法複雜度降低，加入了雜訊阻隔矩陣後，更降低誤差進而提升了效能，此外我們也將已提出的強健式演算法與新型廣義旁波瓣消除器作結合，使得運算複雜度降低及效能提升以對抗多重的非理想環境。 在非理想環境中我們考量到更複雜的非理想環境情形，而其中包含單一非理想環境:指引向量誤差(Steering Vector Mismatch)、已知天線耦合效應(Mutual Coupling Effect)、未知天線耦合效應(Unknown Mutual Coupling Effect)及同調環境(Coherent Environment)，以及結合上述單一非理想環境所組合出之多重非理想環境。我們所提出的解決方法，仍可以解決在多重非理想環境下的情形。

Adaptive array beamforming is the technique which can not only extracts signals of interest from specific angles but also suppresses interferences and noise. LCMV(Linearly Constrained Minimum Variance) beamformer and GSC(Generalized Sidelobe Canceller) are the important techniques in the antenna array signal processing which need the direction of the desired signal as a priori information. The main part of this thesis is to modify GSC(Generalized Sidelobe Canceller) and then proposes the NBMGSC (Noise Block Modified Generalized Sidelobe Canceller) by combining noise block matrix and MGSC(Modified Generalized Sidelobe Canceller). This approach can not only decreases the computational complexity but also suppresses the interference to improve the system performance. We also let NBMGSC(Noise Block Modified Generalized Sidelobe Canceller) combine with the proposed robustness algorithms. It can decrease the computational complexity and improve the system performance to against the multiple non-ideal environments. For the non-ideal environments, it includes steering vector mismatch, coherent environment, mutual coupling effect and unknown mutual coupling and then we combine the above non-ideal environments and we use the proposed method to against the multiple non-ideal environments.