The sixth-generation networks envision the terahertz (THz) band as one of the key enabling technologies because of its ultrawide bandwidth. To combat the severe attenuation, the THz wireless systems employ large arrays, wherein the near-field beam-split (NB) severely degrades the accuracy of channel acquisition. Contrary to prior works that examine only either narrowband beamforming or far-field models, we estimate the wideband THz channel via an NB-aware orthogonal matching pursuit (NBA-OMP) approach. We design an NBA dictionary of near-field steering vectors by exploiting the corresponding angular and range deviation. Our OMP algorithm accounts for this deviation thereby ipso facto mitigating the effect of NB. Numerical experiments demonstrate the effectiveness of the proposed channel estimation technique for wideband THz systems.

翻译：第六代网络将太赫兹频段视为关键技术之一，因其具备超宽带宽特性。为应对严重衰减，太赫兹无线系统采用大规模阵列，其中近场波束分裂会显著降低信道获取精度。与现有仅研究窄带波束成形或远场模型的工作不同，我们提出一种基于波束分裂感知的正交匹配追踪方法实现宽带太赫兹信道估计。通过利用角度与距离偏移特性，我们设计了由近场导向向量构成的NBA字典。该OMP算法明确考虑了此偏移量，从而固有地减轻了NB效应。数值实验验证了所提信道估计技术在宽带太赫兹系统中的有效性。