{"id":"https://openalex.org/W7160865521","doi":"https://doi.org/10.1109/lwc.2026.3691810","title":"Two-Stage Hierarchical Near-Field Beam Training for Extremely Large-Scale RIS","display_name":"Two-Stage Hierarchical Near-Field Beam Training for Extremely Large-Scale RIS","publication_year":2026,"publication_date":"2026-01-01","ids":{"openalex":"https://openalex.org/W7160865521","doi":"https://doi.org/10.1109/lwc.2026.3691810"},"language":null,"primary_location":{"id":"doi:10.1109/lwc.2026.3691810","is_oa":false,"landing_page_url":"https://doi.org/10.1109/lwc.2026.3691810","pdf_url":null,"source":{"id":"https://openalex.org/S2500830676","display_name":"IEEE Wireless Communications Letters","issn_l":"2162-2337","issn":["2162-2337","2162-2345"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319808","host_organization_name":"Institute of Electrical and Electronics Engineers","host_organization_lineage":["https://openalex.org/P4310319808"],"host_organization_lineage_names":["Institute of Electrical and Electronics Engineers"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"IEEE Wireless Communications Letters","raw_type":"journal-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":false,"oa_status":"closed","oa_url":null,"any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5135846757","display_name":"Dingcheng Yang","orcid":"https://orcid.org/0000-0001-5313-4481"},"institutions":[{"id":"https://openalex.org/I141649914","display_name":"Nanchang University","ror":"https://ror.org/042v6xz23","country_code":"CN","type":"education","lineage":["https://openalex.org/I141649914"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Dingcheng Yang","raw_affiliation_strings":["Information Engineering School, Nanchang University, Nanchang, China"],"raw_orcid":"https://orcid.org/0000-0001-5313-4481","affiliations":[{"raw_affiliation_string":"Information Engineering School, Nanchang University, Nanchang, China","institution_ids":["https://openalex.org/I141649914"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5135879896","display_name":"Zhaoqi Zhang","orcid":null},"institutions":[{"id":"https://openalex.org/I141649914","display_name":"Nanchang University","ror":"https://ror.org/042v6xz23","country_code":"CN","type":"education","lineage":["https://openalex.org/I141649914"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Zhaoqi Zhang","raw_affiliation_strings":["Information Engineering School, Nanchang University, Nanchang, China"],"raw_orcid":"https://orcid.org/0009-0009-1326-5204","affiliations":[{"raw_affiliation_string":"Information Engineering School, Nanchang University, Nanchang, China","institution_ids":["https://openalex.org/I141649914"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5135875627","display_name":"Yu Xu","orcid":"https://orcid.org/0000-0002-3108-7757"},"institutions":[{"id":"https://openalex.org/I141649914","display_name":"Nanchang University","ror":"https://ror.org/042v6xz23","country_code":"CN","type":"education","lineage":["https://openalex.org/I141649914"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Yu Xu","raw_affiliation_strings":["Information Engineering School, Nanchang University, Nanchang, China"],"raw_orcid":"https://orcid.org/0000-0002-3108-7757","affiliations":[{"raw_affiliation_string":"Information Engineering School, Nanchang University, Nanchang, China","institution_ids":["https://openalex.org/I141649914"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5039544535","display_name":"Fahui Wu","orcid":"https://orcid.org/0000-0001-8653-8079"},"institutions":[{"id":"https://openalex.org/I141649914","display_name":"Nanchang University","ror":"https://ror.org/042v6xz23","country_code":"CN","type":"education","lineage":["https://openalex.org/I141649914"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Fahui Wu","raw_affiliation_strings":["Information Engineering School, Nanchang University, Nanchang, China"],"raw_orcid":"https://orcid.org/0000-0001-8653-8079","affiliations":[{"raw_affiliation_string":"Information Engineering School, Nanchang University, Nanchang, China","institution_ids":["https://openalex.org/I141649914"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5135855896","display_name":"Changsheng You","orcid":"https://orcid.org/0000-0003-3245-9361"},"institutions":[{"id":"https://openalex.org/I3045169105","display_name":"Southern University of Science and Technology","ror":"https://ror.org/049tv2d57","country_code":"CN","type":"education","lineage":["https://openalex.org/I3045169105"]}],"countries":["CN"],"is_corresponding":false,"raw_author_name":"Changsheng You","raw_affiliation_strings":["Department of Electrical and Electronic Engineering, Southern University of Science and Technology (SUSTech), Shenzhen, China"],"raw_orcid":"https://orcid.org/0000-0003-3245-9361","affiliations":[{"raw_affiliation_string":"Department of Electrical and Electronic Engineering, Southern University of Science and Technology (SUSTech), Shenzhen, China","institution_ids":["https://openalex.org/I3045169105"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":2,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":null,"apc_paid":null,"fwci":0.0,"has_fulltext":false,"cited_by_count":0,"citation_normalized_percentile":{"value":0.52959242,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":null,"biblio":{"volume":"15","issue":null,"first_page":"3169","last_page":"3173"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T12466","display_name":"Near-Field Optical Microscopy","score":0.12470000237226486,"subfield":{"id":"https://openalex.org/subfields/2204","display_name":"Biomedical Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T12466","display_name":"Near-Field Optical Microscopy","score":0.12470000237226486,"subfield":{"id":"https://openalex.org/subfields/2204","display_name":"Biomedical Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11392","display_name":"Energy Harvesting in Wireless Networks","score":0.10930000245571136,"subfield":{"id":"https://openalex.org/subfields/2208","display_name":"Electrical and Electronic Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11038","display_name":"Advanced SAR Imaging Techniques","score":0.06469999998807907,"subfield":{"id":"https://openalex.org/subfields/2202","display_name":"Aerospace Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/training","display_name":"Training (meteorology)","score":0.5224999785423279},{"id":"https://openalex.org/keywords/beam","display_name":"Beam (structure)","score":0.4991999864578247},{"id":"https://openalex.org/keywords/signal-to-noise-ratio","display_name":"Signal-to-noise ratio (imaging)","score":0.26089999079704285},{"id":"https://openalex.org/keywords/artificial-neural-network","display_name":"Artificial neural network","score":0.25060001015663147}],"concepts":[{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6179999709129333},{"id":"https://openalex.org/C2777211547","wikidata":"https://www.wikidata.org/wiki/Q17141490","display_name":"Training (meteorology)","level":2,"score":0.5224999785423279},{"id":"https://openalex.org/C168834538","wikidata":"https://www.wikidata.org/wiki/Q3705329","display_name":"Beam (structure)","level":2,"score":0.4991999864578247},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.3723999857902527},{"id":"https://openalex.org/C31972630","wikidata":"https://www.wikidata.org/wiki/Q844240","display_name":"Computer vision","level":1,"score":0.29899999499320984},{"id":"https://openalex.org/C24326235","wikidata":"https://www.wikidata.org/wiki/Q126095","display_name":"Electronic engineering","level":1,"score":0.2743000090122223},{"id":"https://openalex.org/C13944312","wikidata":"https://www.wikidata.org/wiki/Q7512748","display_name":"Signal-to-noise ratio (imaging)","level":2,"score":0.26089999079704285},{"id":"https://openalex.org/C50644808","wikidata":"https://www.wikidata.org/wiki/Q192776","display_name":"Artificial neural network","level":2,"score":0.25060001015663147},{"id":"https://openalex.org/C104267543","wikidata":"https://www.wikidata.org/wiki/Q208163","display_name":"Signal processing","level":3,"score":0.2345000058412552},{"id":"https://openalex.org/C120665830","wikidata":"https://www.wikidata.org/wiki/Q14620","display_name":"Optics","level":1,"score":0.23389999568462372}],"mesh":[],"locations_count":1,"locations":[{"id":"doi:10.1109/lwc.2026.3691810","is_oa":false,"landing_page_url":"https://doi.org/10.1109/lwc.2026.3691810","pdf_url":null,"source":{"id":"https://openalex.org/S2500830676","display_name":"IEEE Wireless Communications Letters","issn_l":"2162-2337","issn":["2162-2337","2162-2345"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319808","host_organization_name":"Institute of Electrical and Electronics Engineers","host_organization_lineage":["https://openalex.org/P4310319808"],"host_organization_lineage_names":["Institute of Electrical and Electronics Engineers"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"IEEE Wireless Communications Letters","raw_type":"journal-article"}],"best_oa_location":null,"sustainable_development_goals":[],"awards":[{"id":"https://openalex.org/G2306650112","display_name":null,"funder_award_id":"Grant 62461040","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"},{"id":"https://openalex.org/G2560958934","display_name":null,"funder_award_id":"62461040","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"},{"id":"https://openalex.org/G4139620101","display_name":null,"funder_award_id":"20252BAC200610","funder_id":"https://openalex.org/F4320306076","funder_display_name":"National Science Foundation"},{"id":"https://openalex.org/G5601691005","display_name":null,"funder_award_id":"62261035","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"},{"id":"https://openalex.org/G8686674110","display_name":null,"funder_award_id":"62401241","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"},{"id":"https://openalex.org/G8821159892","display_name":null,"funder_award_id":"Grant 62261035","funder_id":"https://openalex.org/F4320321001","funder_display_name":"National Natural Science Foundation of China"}],"funders":[{"id":"https://openalex.org/F4320306076","display_name":"National Science Foundation","ror":"https://ror.org/021nxhr62"},{"id":"https://openalex.org/F4320321001","display_name":"National Natural Science Foundation of China","ror":"https://ror.org/01h0zpd94"}],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":0,"referenced_works":[],"related_works":[],"abstract_inverted_index":{"The":[0],"extremely":[1],"large-scale":[2],"reconfigurable":[3],"intelligent":[4],"surface":[5],"(XL-RIS)":[6],"is":[7,27],"a":[8,42,55,98],"highly":[9],"promising":[10],"technology":[11],"for":[12,25,47],"the":[13,19,50,60,72,79,85,89,93,101,117,120,128,133,145,154],"sixth-generation":[14],"(6G)":[15],"wireless":[16],"communications.":[17],"However,":[18],"conventional":[20],"near-field":[21],"beam":[22,33,73,114,139,155],"training":[23,34,156],"(NFBT)":[24],"XL-RIS":[26],"intractable":[28],"and":[29,69,92],"incurs":[30],"excessively":[31],"high":[32,160],"overhead.":[35],"To":[36],"solve":[37],"this":[38,108],"problem,":[39],"we":[40,53,104,123],"propose":[41],"two-stage":[43,147],"hierarchical":[44,56,109,148],"NFBT":[45,106,125,149],"scheme":[46,150],"XL-RIS.":[48],"In":[49,119],"first":[51,134],"stage,":[52,122],"generate":[54],"codebook":[57,110],"based":[58,126],"on":[59,107,127],"proposed":[61,146],"3D":[62],"binary-tree":[63],"search":[64,74],"strategy,":[65],"which":[66],"can":[67,151],"iteratively":[68],"evenly":[70],"divide":[71],"region":[75],"into":[76],"sub-regions,":[77],"wherein":[78],"sampling":[80],"point":[81],"pair":[82],"formed":[83],"by":[84],"center":[86],"points":[87],"of":[88,132],"BS":[90],"sub-region":[91,95],"user":[94],"corresponds":[96],"to":[97,111,136],"codeword":[99,131],"in":[100,116],"codebook.":[102],"Then,":[103],"perform":[105,124],"achieve":[112,137],"coarse":[113],"alignment":[115],"downlink.":[118],"second":[121],"globally":[129],"optimal":[130],"stage":[135],"fine-grained":[138],"alignment.":[140],"Numerical":[141],"results":[142],"show":[143],"that":[144],"significantly":[152],"reduce":[153],"overhead":[157],"while":[158],"achieving":[159],"rate.":[161]},"counts_by_year":[],"updated_date":"2026-05-21T06:26:12.895304","created_date":"2026-05-12T00:00:00"}
