In this paper, a novel two-dimensional parameter estimation method is proposed for frequency-selective millimeter-wave (mmWave) channels by probing a limited number of Kronecker products of discrete Fourier transform (DFT) beams, which are efficiently implemented in the analog domain by a novel combination of Butler matrices. The proposed strategy firstly estimates the channel parameters by using a modified parameter estimation via interpolation based on a DFT grid (PREIDG) algorithm. In a second step, high-resolution channel parameter estimation is achieved even in the low signal-to-noise-ratio (SNR) using the space-alternating generalized expectation-maximization (SAGE) algorithm. The proposed modified PREIDG algorithm outperforms state-of-the-art methods, e.g., the auxiliary beam pair (ABP) method while the SAGE algorithm achieves the derived Cramér-Rao lower bound (CRLB). Numerical results demonstrate that excellent estimation performance can be achieved for angle of departure (AoD) azimuth and elevation with addition to delay and complex path gain of each path even in the low SNR regime.

中文翻译：

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使用巴特勒矩阵的毫米波系统二维信道参数估计

本文通过探测有限数量的离散傅立叶变换（DFT）光束的Kronecker乘积，提出了一种针对频率选择毫米波（mmWave）信道的二维参数估计新方法，该方法在模拟域中得到了有效实现由Butler矩阵的新颖组合而成。提出的策略首先通过基于DFT网格（PREIDG）算法的插值修改参数估计来估计信道参数。第二步，使用空间交替广义期望最大化（SAGE）算法，即使在低信噪比（SNR）中也可以实现高分辨率信道参数估计。提出的改进的PREIDG算法优于最新方法，例如，辅助波束对（ABP）方法，而SAGE算法可实现派生的Cramér-Rao下界（CRLB）。数值结果表明，即使在低SNR情况下，除每个路径的延迟和复杂路径增益外，对于偏离角（AoD）方位角和仰角都可以实现出色的估计性能。