Channel Estimation in RIS-aided Multi-User OFDM Communication Systems

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dc.authoridMUTLU, URAL/0000-0003-2595-0531
dc.contributor.authorMutlu, Ural
dc.contributor.authorKabalci, Yasin
dc.contributor.authorCengiz, Alperen
dc.date.accessioned2024-11-07T13:23:59Z
dc.date.available2024-11-07T13:23:59Z
dc.date.issued2024
dc.departmentNiğde Ömer Halisdemir Üniversitesi
dc.description6th Global Power, Energy and Communication Conference (GPECOM) -- JUN 04-07, 2024 -- Budapest, HUNGARY
dc.description.abstractReconfigurable Intelligent Surfaces (RIS) are planar arrays constructed of independently controllable passive reflecting elements that change the phase and the amplitude of the reflected signals between Base Station (BS) and User Equipment (UE). To facilitate the coherent combination of the reflected signals, the Channel State Information (CSI) of the channels should be known by the communication network. The main issue with CSI estimation in unstructured channels is the high number of channels and the long training time that is required to apply orthogonal training reflection patterns at the RIS. With multiple users, the required training period becomes even longer. Therefore, this study proposes allocating the users with orthogonal pilot sequences, which are transmitted over the orthogonal frequency division multiplexing (OFDM) frequency domain with the aim of separating the user signals in the frequency domain. In the study, the cascaded channels are separated in the time domain by a reflection pattern consisting of a DFT matrix and the users are separated in the frequency domain by the use of the Hadamard matrix. The algorithms are simulated over a 3GPP-defined Tapped Delay Line (TDL) channel model as well as a Rayleigh fading channel. The results show that due to the use of orthogonal sequences, channel estimation improves in flat fading channels, while the performance is also of acceptable level in frequency selective channels.
dc.description.sponsorshipIEEE
dc.identifier.doi10.1109/GPECOM61896.2024.10582568
dc.identifier.endpage770
dc.identifier.isbn979-8-3503-5108-8
dc.identifier.isbn979-8-3503-5109-5
dc.identifier.issn2832-7667
dc.identifier.scopus2-s2.0-85199075721
dc.identifier.scopusqualityN/A
dc.identifier.startpage765
dc.identifier.urihttps://doi.org/10.1109/GPECOM61896.2024.10582568
dc.identifier.urihttps://hdl.handle.net/11480/13852
dc.identifier.wosWOS:001268516300011
dc.identifier.wosqualityN/A
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherIEEE
dc.relation.ispartofProceedings 2024 Ieee 6th Global Power, Energy and Communication Conference, Ieee Gpecom 2024
dc.relation.publicationcategoryKonferans Öğesi - Uluslararası - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_20241106
dc.subjectChannel Estimation
dc.subjectHadamard
dc.subjectMU-MIMO
dc.subjectOFDM
dc.subjectRIS
dc.titleChannel Estimation in RIS-aided Multi-User OFDM Communication Systems
dc.typeConference Object

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