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.Comment: Accepted Paper in 2023 IEEE International Conference on Acoustics,
Speech and Signal Processing (ICASSP