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。为克服严重衰减，太赫兹无线系统采用大规模阵列，其中近场波束分裂严重降低了信道获取的精度。与以往仅研究窄带波束赋形或远场模型的工作不同，我们通过一种近场波束分裂感知的正交匹配追踪方法估计宽带太赫兹信道。我们利用相应的角度与距离偏差，设计了包含近场导向矢量的NBA字典。我们的OMP算法考虑了此偏差，从而实际减轻了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。