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dc.contributor.authorElbir, Ahmet M.
dc.contributor.authorShi, Wei
dc.contributor.authorPapazafeiropoulos, Anastasios K.
dc.contributor.authorKourtessis, Pandelis
dc.contributor.authorChatzinotas, Symeon
dc.date.accessioned2024-01-02T12:45:01Z
dc.date.available2024-01-02T12:45:01Z
dc.date.issued2023-04-11
dc.identifier.citationElbir , A M , Shi , W , Papazafeiropoulos , A K , Kourtessis , P & Chatzinotas , S 2023 , ' Near-Field Terahertz Communications: Model-Based and Model-Free Channel Estimation ' , IEEE Access , vol. 11 , 3266297 , pp. 36409-36420 . https://doi.org/10.1109/ACCESS.2023.3266297
dc.identifier.issn2169-3536
dc.identifier.otherORCID: /0000-0003-1841-6461/work/150047227
dc.identifier.urihttp://hdl.handle.net/2299/27345
dc.description© IEEE. This is an open access article under the Creative Commons Attribution-NonCommercial-NoDerivatives CC BY-NC-ND licence, https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.description.abstractTerahertz (THz) band is expected to be one of the key enabling technologies of the sixth generation (6G) wireless networks because of its abundant available bandwidth and very narrow beamwidth. Due to high frequency operations, electrically small array apertures are employed, and the signal wavefront becomes spherical in the near-field. Therefore, near-field signal model should be considered for channel acquisition in THz systems. Unlike prior works which mostly ignore the impact of near-field beam-squint (NB) and consider either narrowband scenario or far-field models, this paper introduces both a model-based and a model-free techniques for wideband THz channel estimation in the presence of NB. The model-based approach is based on orthogonal matching pursuit (OMP) algorithm, for which we design an NB-aware dictionary. The key idea is to exploit the angular and range deviations due to the NB. We then employ the OMP algorithm, which accounts for the deviations thereby ipso facto mitigating the effect of NB. We further introduce a federated learning (FL)-based approach as a model-free solution for channel estimation in a multi-user scenario to achieve reduced complexity and training overhead. Through numerical simulations, we demonstrate the effectiveness of the proposed channel estimation techniques for wideband THz systems in comparison with the existing state-of-the-art techniques.en
dc.format.extent12
dc.format.extent1195366
dc.language.isoeng
dc.relation.ispartofIEEE Access
dc.subjectBeamsquint
dc.subjectChannel estimation
dc.subjectchannel estimation
dc.subjectEstimation
dc.subjectfederated learning
dc.subjectmachine learning
dc.subjectMatching pursuit algorithms
dc.subjectMIMO communication
dc.subjectnear-field
dc.subjectorthogonal matching pursuit
dc.subjectRadio frequency
dc.subjectSolid modeling
dc.subjectsparse recovery
dc.subjectterahertz
dc.subjectWideband
dc.subjectGeneral Computer Science
dc.subjectGeneral Materials Science
dc.subjectGeneral Engineering
dc.subjectElectrical and Electronic Engineering
dc.titleNear-Field Terahertz Communications: Model-Based and Model-Free Channel Estimationen
dc.contributor.institutionDepartment of Engineering and Technology
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionCommunications and Intelligent Systems
dc.contributor.institutionCentre for Engineering Research
dc.contributor.institutionCentre for Future Societies Research
dc.contributor.institutionCentre for Climate Change Research (C3R)
dc.contributor.institutionSPECS Deans Group
dc.contributor.institutionOptical Networks
dc.contributor.institutionCentre for Computer Science and Informatics Research
dc.description.statusPeer reviewed
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=85153406998&partnerID=8YFLogxK
rioxxterms.versionofrecord10.1109/ACCESS.2023.3266297
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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