{"id":"https://openalex.org/W3000950478","doi":"https://doi.org/10.1109/tcomm.2020.2969351","title":"Efficient Angle-Domain Processing for FDD-Based Cell-Free Massive MIMO Systems","display_name":"Efficient Angle-Domain Processing for FDD-Based Cell-Free Massive MIMO Systems","publication_year":2020,"publication_date":"2020-01-24","ids":{"openalex":"https://openalex.org/W3000950478","doi":"https://doi.org/10.1109/tcomm.2020.2969351","mag":"3000950478"},"language":"en","primary_location":{"id":"doi:10.1109/tcomm.2020.2969351","is_oa":false,"landing_page_url":"https://doi.org/10.1109/tcomm.2020.2969351","pdf_url":null,"source":{"id":"https://openalex.org/S196647941","display_name":"IEEE Transactions on Communications","issn_l":"0090-6778","issn":["0090-6778","1558-0857"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310316002","host_organization_name":"IEEE Communications Society","host_organization_lineage":["https://openalex.org/P4310316002","https://openalex.org/P4310319808"],"host_organization_lineage_names":["IEEE Communications Society","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 Transactions on Communications","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/A5046741256","display_name":"Asmaa Abdallah","orcid":"https://orcid.org/0000-0003-3387-9333"},"institutions":[{"id":"https://openalex.org/I98635879","display_name":"American University of Beirut","ror":"https://ror.org/04pznsd21","country_code":"LB","type":"education","lineage":["https://openalex.org/I98635879"]}],"countries":["LB"],"is_corresponding":false,"raw_author_name":"Asmaa Abdallah","raw_affiliation_strings":["Department of Electrical and Computer Engineering, American University of Beirut, Beirut, Lebanon"],"raw_orcid":"https://orcid.org/0000-0003-3387-9333","affiliations":[{"raw_affiliation_string":"Department of Electrical and Computer Engineering, American University of Beirut, Beirut, Lebanon","institution_ids":["https://openalex.org/I98635879"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5038988201","display_name":"Mohammad M. Mansour","orcid":"https://orcid.org/0000-0002-8316-1330"},"institutions":[{"id":"https://openalex.org/I98635879","display_name":"American University of Beirut","ror":"https://ror.org/04pznsd21","country_code":"LB","type":"education","lineage":["https://openalex.org/I98635879"]}],"countries":["LB"],"is_corresponding":false,"raw_author_name":"Mohammad M. Mansour","raw_affiliation_strings":["Department of Electrical and Computer Engineering, American University of Beirut, Beirut, Lebanon"],"raw_orcid":"https://orcid.org/0000-0002-8316-1330","affiliations":[{"raw_affiliation_string":"Department of Electrical and Computer Engineering, American University of Beirut, Beirut, Lebanon","institution_ids":["https://openalex.org/I98635879"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":1,"corresponding_author_ids":[],"corresponding_institution_ids":["https://openalex.org/I98635879"],"apc_list":null,"apc_paid":null,"fwci":3.8238,"has_fulltext":false,"cited_by_count":66,"citation_normalized_percentile":{"value":0.943897,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":97,"max":100},"biblio":{"volume":"68","issue":"4","first_page":"2188","last_page":"2203"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10148","display_name":"Advanced MIMO Systems Optimization","score":0.9998999834060669,"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"}},"topics":[{"id":"https://openalex.org/T10148","display_name":"Advanced MIMO Systems Optimization","score":0.9998999834060669,"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/T12791","display_name":"Full-Duplex Wireless Communications","score":0.9991000294685364,"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/T10069","display_name":"Antenna Design and Analysis","score":0.9987000226974487,"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/telecommunications-link","display_name":"Telecommunications link","score":0.7225052118301392},{"id":"https://openalex.org/keywords/beamforming","display_name":"Beamforming","score":0.7137245535850525},{"id":"https://openalex.org/keywords/mimo","display_name":"MIMO","score":0.7041938900947571},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.6552927494049072},{"id":"https://openalex.org/keywords/channel-state-information","display_name":"Channel state information","score":0.548974335193634},{"id":"https://openalex.org/keywords/overhead","display_name":"Overhead (engineering)","score":0.5381252765655518},{"id":"https://openalex.org/keywords/multipath-propagation","display_name":"Multipath propagation","score":0.5273029804229736},{"id":"https://openalex.org/keywords/electronic-engineering","display_name":"Electronic engineering","score":0.45457738637924194},{"id":"https://openalex.org/keywords/wireless","display_name":"Wireless","score":0.3388091027736664},{"id":"https://openalex.org/keywords/computer-network","display_name":"Computer network","score":0.3122934103012085},{"id":"https://openalex.org/keywords/channel","display_name":"Channel (broadcasting)","score":0.27609241008758545},{"id":"https://openalex.org/keywords/engineering","display_name":"Engineering","score":0.20715206861495972},{"id":"https://openalex.org/keywords/telecommunications","display_name":"Telecommunications","score":0.1707460880279541}],"concepts":[{"id":"https://openalex.org/C138660444","wikidata":"https://www.wikidata.org/wiki/Q5607897","display_name":"Telecommunications link","level":2,"score":0.7225052118301392},{"id":"https://openalex.org/C54197355","wikidata":"https://www.wikidata.org/wiki/Q5782992","display_name":"Beamforming","level":2,"score":0.7137245535850525},{"id":"https://openalex.org/C207987634","wikidata":"https://www.wikidata.org/wiki/Q176862","display_name":"MIMO","level":3,"score":0.7041938900947571},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6552927494049072},{"id":"https://openalex.org/C148063708","wikidata":"https://www.wikidata.org/wiki/Q5072511","display_name":"Channel state information","level":3,"score":0.548974335193634},{"id":"https://openalex.org/C2779960059","wikidata":"https://www.wikidata.org/wiki/Q7113681","display_name":"Overhead (engineering)","level":2,"score":0.5381252765655518},{"id":"https://openalex.org/C161218011","wikidata":"https://www.wikidata.org/wiki/Q11827794","display_name":"Multipath propagation","level":3,"score":0.5273029804229736},{"id":"https://openalex.org/C24326235","wikidata":"https://www.wikidata.org/wiki/Q126095","display_name":"Electronic engineering","level":1,"score":0.45457738637924194},{"id":"https://openalex.org/C555944384","wikidata":"https://www.wikidata.org/wiki/Q249","display_name":"Wireless","level":2,"score":0.3388091027736664},{"id":"https://openalex.org/C31258907","wikidata":"https://www.wikidata.org/wiki/Q1301371","display_name":"Computer network","level":1,"score":0.3122934103012085},{"id":"https://openalex.org/C127162648","wikidata":"https://www.wikidata.org/wiki/Q16858953","display_name":"Channel (broadcasting)","level":2,"score":0.27609241008758545},{"id":"https://openalex.org/C127413603","wikidata":"https://www.wikidata.org/wiki/Q11023","display_name":"Engineering","level":0,"score":0.20715206861495972},{"id":"https://openalex.org/C76155785","wikidata":"https://www.wikidata.org/wiki/Q418","display_name":"Telecommunications","level":1,"score":0.1707460880279541},{"id":"https://openalex.org/C111919701","wikidata":"https://www.wikidata.org/wiki/Q9135","display_name":"Operating system","level":1,"score":0.0}],"mesh":[],"locations_count":1,"locations":[{"id":"doi:10.1109/tcomm.2020.2969351","is_oa":false,"landing_page_url":"https://doi.org/10.1109/tcomm.2020.2969351","pdf_url":null,"source":{"id":"https://openalex.org/S196647941","display_name":"IEEE Transactions on Communications","issn_l":"0090-6778","issn":["0090-6778","1558-0857"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310316002","host_organization_name":"IEEE Communications Society","host_organization_lineage":["https://openalex.org/P4310316002","https://openalex.org/P4310319808"],"host_organization_lineage_names":["IEEE Communications Society","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 Transactions on Communications","raw_type":"journal-article"}],"best_oa_location":null,"sustainable_development_goals":[{"display_name":"Affordable and clean energy","score":0.9100000262260437,"id":"https://metadata.un.org/sdg/7"}],"awards":[],"funders":[{"id":"https://openalex.org/F4320309999","display_name":"American University of Beirut","ror":"https://ror.org/04pznsd21"}],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":42,"referenced_works":["https://openalex.org/W1518945650","https://openalex.org/W1609941950","https://openalex.org/W1939715090","https://openalex.org/W1980560153","https://openalex.org/W1996215314","https://openalex.org/W2018008632","https://openalex.org/W2065784656","https://openalex.org/W2111717285","https://openalex.org/W2113638573","https://openalex.org/W2128131274","https://openalex.org/W2128202699","https://openalex.org/W2136644341","https://openalex.org/W2147601077","https://openalex.org/W2162654459","https://openalex.org/W2189368743","https://openalex.org/W2227902027","https://openalex.org/W2284816874","https://openalex.org/W2286275639","https://openalex.org/W2289191545","https://openalex.org/W2490222774","https://openalex.org/W2501970484","https://openalex.org/W2593893328","https://openalex.org/W2768578820","https://openalex.org/W2770606349","https://openalex.org/W2783852192","https://openalex.org/W2795363189","https://openalex.org/W2799812926","https://openalex.org/W2802123921","https://openalex.org/W2809517472","https://openalex.org/W2897059627","https://openalex.org/W2911410130","https://openalex.org/W2924818594","https://openalex.org/W2962819920","https://openalex.org/W2963391296","https://openalex.org/W2963726408","https://openalex.org/W2963894874","https://openalex.org/W2970732091","https://openalex.org/W3099019646","https://openalex.org/W3102684176","https://openalex.org/W4250589301","https://openalex.org/W6695750744","https://openalex.org/W6785178783"],"related_works":["https://openalex.org/W2059045613","https://openalex.org/W2088352174","https://openalex.org/W4313028534","https://openalex.org/W884630482","https://openalex.org/W4286695888","https://openalex.org/W3084132786","https://openalex.org/W2025723618","https://openalex.org/W4327661444","https://openalex.org/W2161061958","https://openalex.org/W2034991012"],"abstract_inverted_index":{"Cell-free":[0],"massive":[1,28,49,121],"MIMO":[2,29,50,122],"communications":[3,12],"is":[4],"an":[5,243],"emerging":[6],"network":[7],"technology":[8],"for":[9,118,135,147],"5G":[10],"wireless":[11,42],"wherein":[13],"distributed":[14],"multi-antenna":[15],"access":[16],"points":[17],"(APs)":[18],"serve":[19],"many":[20],"users":[21],"simultaneously.":[22],"Most":[23],"prior":[24],"work":[25],"on":[26],"cell-free":[27,120],"systems":[30,39,51],"assume":[31],"time-division":[32],"duplexing":[33,37],"mode,":[34],"although":[35],"frequency-division":[36],"(FDD)":[38],"dominate":[40],"current":[41],"standards.":[43],"The":[44],"key":[45],"challenges":[46],"in":[47,73,183],"FDD":[48],"are":[52],"channel-state":[53],"information":[54],"(CSI)":[55],"acquisition":[56,83],"and":[57,76,93,111,150,214,225,239],"feedback":[58],"overhead.":[59],"To":[60],"address":[61],"these":[62,129],"challenges,":[63],"we":[64,157,175],"exploit":[65],"the":[66,74,80,88,95,126,136,139,148,166,194,199,205,222,230,237,249],"so-called":[67],"angle":[68],"reciprocity":[69],"of":[70,90,97,128,138,190,198,246],"multipath":[71,107,141,207],"components":[72],"uplink":[75,149],"downlink,":[77],"so":[78],"that":[79,164,204,221],"required":[81],"CSI":[82],"overhead":[84],"scales":[85],"only":[86],"with":[87,229,242],"number":[89,96,245],"served":[91],"users,":[92],"not":[94],"AP":[98,180],"antennas":[99,247],"nor":[100],"APs.":[101,250],"We":[102,124,218],"propose":[103],"a":[104,159,177,188],"low":[105],"complexity":[106],"component":[108,208],"estimation":[109,209],"technique":[110,210],"present":[112,176],"linear":[113],"angle-of-arrival":[114],"(AoA)-based":[115],"beamforming/combining":[116],"schemes":[117,130],"FDD-based":[119],"systems.":[123],"analyze":[125],"performance":[127],"by":[131],"deriving":[132],"closed-form":[133],"expressions":[134,146],"mean-square-error":[137],"estimated":[140],"components,":[142],"as":[143,145],"well":[144],"downlink":[151],"spectral":[152,238],"efficiency.":[153],"Using":[154],"semi-definite":[155],"programming,":[156],"solve":[158],"max-min":[160],"power":[161,172,232],"allocation":[162],"problem":[163],"maximizes":[165],"minimum":[167],"user":[168,186],"rate":[169],"under":[170],"per-user":[171],"constraints.":[173],"Furthermore,":[174],"user-centric":[178],"(UC)":[179],"selection":[181],"scheme":[182,234],"which":[184],"each":[185],"chooses":[187],"subset":[189],"APs":[191],"to":[192],"improve":[193],"overall":[195],"energy":[196,240],"efficiency":[197],"system.":[200],"Simulation":[201],"results":[202],"demonstrate":[203],"proposed":[206,223,231],"outperforms":[211],"conventional":[212],"subspace-based":[213],"gradient-descent":[215],"based":[216],"techniques.":[217],"also":[219],"show":[220],"beamforming":[224],"combining":[226],"techniques":[227],"along":[228],"control":[233],"substantially":[235],"enhance":[236],"efficiencies":[241],"adequate":[244],"at":[248]},"counts_by_year":[{"year":2026,"cited_by_count":2},{"year":2025,"cited_by_count":9},{"year":2024,"cited_by_count":8},{"year":2023,"cited_by_count":7},{"year":2022,"cited_by_count":19},{"year":2021,"cited_by_count":16},{"year":2020,"cited_by_count":5}],"updated_date":"2026-07-15T18:14:33.161393","created_date":"2025-10-10T00:00:00"}