使用非均勻子連接混合波束成形系統之欠定來向角估計

Abstract

混合波束成形（HBF）正成為未來無線網路的關鍵技術，特別是在毫米波（mmWave）頻段。在本論文中，我們提出了一種非均勻子連接混合波束成形（NSC-HBF）系統，能夠實現差分共陣列並用於欠定來向角（AOA）之估計。我們也提出了一種寬波束合成方法，以緩和類比合成之增益不均勻導致的性能下降。為進一步提高效率，我們還改進了共陣列最小均方（co-array LMS）方法，通過直接求解最小平方問題來決定濾波器權重。該方法降低了計算複雜度並消除了迭代過程，以實現更快的處理。我們也討論了陣列接收信號由不相關和相關源混合組成的情景。數值結果展示了使用所提出的NSC-HBF進行欠定來向角估計的可行性，並強調了類比合成碼本設計的重要性。

Hybrid beamforming (HBF) is emerging as a key technology for future wireless networks, particularly in the millimeter-wave (mmWave) bands. In this dissertation, we present a non-uniform sub-connected hybrid beamforming (NSC-HBF) system that enables the implementation of the difference co-array for underdetermined angle-of-arrival (AOA) estimation. We propose a broad beam synthesis method to mitigate performance degradation caused by uneven analog combining gains. To further enhance efficiency, we modify the co-array least mean squares (co-array LMS) method by directly solving the least-squares problem to determine the filter weights. The proposed method reduces computational complexity and eliminates iterative procedures for faster processing. We also address scenarios where the signals received by the array consist of a mixture of uncorrelated and correlated sources. Numerical results demonstrated the feasibility of underdetermined AOA estimation using the proposed NSC-HBF and highlighted the importance of analog combining codebook design.