{"id":"https://openalex.org/W3157372124","doi":"https://doi.org/10.1109/jiot.2021.3107242","title":"Enabling Grant-Free URLLC: An Overview of Principle and Enhancements by Massive MIMO","display_name":"Enabling Grant-Free URLLC: An Overview of Principle and Enhancements by Massive MIMO","publication_year":2021,"publication_date":"2021-08-24","ids":{"openalex":"https://openalex.org/W3157372124","doi":"https://doi.org/10.1109/jiot.2021.3107242","mag":"3157372124"},"language":"en","primary_location":{"id":"doi:10.1109/jiot.2021.3107242","is_oa":false,"landing_page_url":"https://doi.org/10.1109/jiot.2021.3107242","pdf_url":null,"source":{"id":"https://openalex.org/S2480266640","display_name":"IEEE Internet of Things Journal","issn_l":"2327-4662","issn":["2327-4662","2372-2541"],"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 Internet of Things Journal","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/A5028035987","display_name":"Jie Ding","orcid":"https://orcid.org/0000-0001-9927-5415"},"institutions":[{"id":"https://openalex.org/I149704539","display_name":"Deakin University","ror":"https://ror.org/02czsnj07","country_code":"AU","type":"education","lineage":["https://openalex.org/I149704539"]}],"countries":["AU"],"is_corresponding":true,"raw_author_name":"Jie Ding","raw_affiliation_strings":["School of Information Technology, Deakin University, Geelong, VIC, Australia"],"raw_orcid":"https://orcid.org/0000-0001-9927-5415","affiliations":[{"raw_affiliation_string":"School of Information Technology, Deakin University, Geelong, VIC, Australia","institution_ids":["https://openalex.org/I149704539"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5109801149","display_name":"Hossein Mashad Nemati","orcid":"https://orcid.org/0000-0003-3309-8182"},"institutions":[{"id":"https://openalex.org/I149704539","display_name":"Deakin University","ror":"https://ror.org/02czsnj07","country_code":"AU","type":"education","lineage":["https://openalex.org/I149704539"]}],"countries":["AU"],"is_corresponding":false,"raw_author_name":"Mahyar Nemati","raw_affiliation_strings":["School of Information Technology, Deakin University, Geelong, VIC, Australia"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"School of Information Technology, Deakin University, Geelong, VIC, Australia","institution_ids":["https://openalex.org/I149704539"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5038446422","display_name":"Shiva Raj Pokhrel","orcid":"https://orcid.org/0000-0001-5819-765X"},"institutions":[{"id":"https://openalex.org/I149704539","display_name":"Deakin University","ror":"https://ror.org/02czsnj07","country_code":"AU","type":"education","lineage":["https://openalex.org/I149704539"]}],"countries":["AU"],"is_corresponding":false,"raw_author_name":"Shiva Raj Pokhrel","raw_affiliation_strings":["School of Information Technology, Deakin University, Geelong, VIC, Australia"],"raw_orcid":"https://orcid.org/0000-0001-5819-765X","affiliations":[{"raw_affiliation_string":"School of Information Technology, Deakin University, Geelong, VIC, Australia","institution_ids":["https://openalex.org/I149704539"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5047152313","display_name":"Ok-Sun Park","orcid":"https://orcid.org/0000-0002-7071-6632"},"institutions":[{"id":"https://openalex.org/I142401562","display_name":"Electronics and Telecommunications Research Institute","ror":"https://ror.org/03ysstz10","country_code":"KR","type":"facility","lineage":["https://openalex.org/I142401562","https://openalex.org/I2801339556","https://openalex.org/I4210144908","https://openalex.org/I4387152098"]}],"countries":["KR"],"is_corresponding":false,"raw_author_name":"Ok-Sun Park","raw_affiliation_strings":["Electronics and Telecommunications Research Institute, Daejeon, South Korea"],"raw_orcid":"https://orcid.org/0000-0002-7071-6632","affiliations":[{"raw_affiliation_string":"Electronics and Telecommunications Research Institute, Daejeon, South Korea","institution_ids":["https://openalex.org/I142401562"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5022303970","display_name":"Jinho Choi","orcid":"https://orcid.org/0000-0002-4895-6680"},"institutions":[{"id":"https://openalex.org/I149704539","display_name":"Deakin University","ror":"https://ror.org/02czsnj07","country_code":"AU","type":"education","lineage":["https://openalex.org/I149704539"]}],"countries":["AU"],"is_corresponding":false,"raw_author_name":"Jinho Choi","raw_affiliation_strings":["School of Information Technology, Deakin University, Geelong, VIC, Australia"],"raw_orcid":"https://orcid.org/0000-0002-4895-6680","affiliations":[{"raw_affiliation_string":"School of Information Technology, Deakin University, Geelong, VIC, Australia","institution_ids":["https://openalex.org/I149704539"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5011281064","display_name":"Fumiyuki Adachi","orcid":"https://orcid.org/0000-0002-5416-0718"},"institutions":[{"id":"https://openalex.org/I201537933","display_name":"Tohoku University","ror":"https://ror.org/01dq60k83","country_code":"JP","type":"education","lineage":["https://openalex.org/I201537933"]}],"countries":["JP"],"is_corresponding":false,"raw_author_name":"Fumiyuki Adachi","raw_affiliation_strings":["Research Organization of Electrical Communication, Tohoku University, Sendai, Japan"],"raw_orcid":"https://orcid.org/0000-0002-5416-0718","affiliations":[{"raw_affiliation_string":"Research Organization of Electrical Communication, Tohoku University, Sendai, Japan","institution_ids":["https://openalex.org/I201537933"]}]}],"institutions":[],"countries_distinct_count":3,"institutions_distinct_count":6,"corresponding_author_ids":["https://openalex.org/A5028035987"],"corresponding_institution_ids":["https://openalex.org/I149704539"],"apc_list":null,"apc_paid":null,"fwci":4.8803,"has_fulltext":false,"cited_by_count":65,"citation_normalized_percentile":{"value":0.95769609,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":95,"max":100},"biblio":{"volume":"9","issue":"1","first_page":"384","last_page":"400"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10964","display_name":"Wireless Communication Security Techniques","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/T10964","display_name":"Wireless Communication Security Techniques","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/T11458","display_name":"Advanced Wireless Communication Technologies","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/T10148","display_name":"Advanced MIMO Systems Optimization","score":0.9997000098228455,"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"}}],"keywords":[{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.7883787751197815},{"id":"https://openalex.org/keywords/telecommunications-link","display_name":"Telecommunications link","score":0.6921606063842773},{"id":"https://openalex.org/keywords/network-packet","display_name":"Network packet","score":0.6193143129348755},{"id":"https://openalex.org/keywords/mimo","display_name":"MIMO","score":0.5957509279251099},{"id":"https://openalex.org/keywords/latency","display_name":"Latency (audio)","score":0.4830687344074249},{"id":"https://openalex.org/keywords/overhead","display_name":"Overhead (engineering)","score":0.4622248411178589},{"id":"https://openalex.org/keywords/computer-architecture","display_name":"Computer architecture","score":0.4542035758495331},{"id":"https://openalex.org/keywords/computer-network","display_name":"Computer network","score":0.4172835350036621},{"id":"https://openalex.org/keywords/computer-engineering","display_name":"Computer engineering","score":0.40193629264831543},{"id":"https://openalex.org/keywords/distributed-computing","display_name":"Distributed computing","score":0.39324963092803955},{"id":"https://openalex.org/keywords/channel","display_name":"Channel (broadcasting)","score":0.2819889783859253},{"id":"https://openalex.org/keywords/telecommunications","display_name":"Telecommunications","score":0.2339925467967987}],"concepts":[{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.7883787751197815},{"id":"https://openalex.org/C138660444","wikidata":"https://www.wikidata.org/wiki/Q5607897","display_name":"Telecommunications link","level":2,"score":0.6921606063842773},{"id":"https://openalex.org/C158379750","wikidata":"https://www.wikidata.org/wiki/Q214111","display_name":"Network packet","level":2,"score":0.6193143129348755},{"id":"https://openalex.org/C207987634","wikidata":"https://www.wikidata.org/wiki/Q176862","display_name":"MIMO","level":3,"score":0.5957509279251099},{"id":"https://openalex.org/C82876162","wikidata":"https://www.wikidata.org/wiki/Q17096504","display_name":"Latency (audio)","level":2,"score":0.4830687344074249},{"id":"https://openalex.org/C2779960059","wikidata":"https://www.wikidata.org/wiki/Q7113681","display_name":"Overhead (engineering)","level":2,"score":0.4622248411178589},{"id":"https://openalex.org/C118524514","wikidata":"https://www.wikidata.org/wiki/Q173212","display_name":"Computer architecture","level":1,"score":0.4542035758495331},{"id":"https://openalex.org/C31258907","wikidata":"https://www.wikidata.org/wiki/Q1301371","display_name":"Computer network","level":1,"score":0.4172835350036621},{"id":"https://openalex.org/C113775141","wikidata":"https://www.wikidata.org/wiki/Q428691","display_name":"Computer engineering","level":1,"score":0.40193629264831543},{"id":"https://openalex.org/C120314980","wikidata":"https://www.wikidata.org/wiki/Q180634","display_name":"Distributed computing","level":1,"score":0.39324963092803955},{"id":"https://openalex.org/C127162648","wikidata":"https://www.wikidata.org/wiki/Q16858953","display_name":"Channel (broadcasting)","level":2,"score":0.2819889783859253},{"id":"https://openalex.org/C76155785","wikidata":"https://www.wikidata.org/wiki/Q418","display_name":"Telecommunications","level":1,"score":0.2339925467967987},{"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/jiot.2021.3107242","is_oa":false,"landing_page_url":"https://doi.org/10.1109/jiot.2021.3107242","pdf_url":null,"source":{"id":"https://openalex.org/S2480266640","display_name":"IEEE Internet of Things Journal","issn_l":"2327-4662","issn":["2327-4662","2372-2541"],"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 Internet of Things Journal","raw_type":"journal-article"}],"best_oa_location":null,"sustainable_development_goals":[{"score":0.4300000071525574,"id":"https://metadata.un.org/sdg/9","display_name":"Industry, innovation and infrastructure"}],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":113,"referenced_works":["https://openalex.org/W89794543","https://openalex.org/W1490674876","https://openalex.org/W1512056429","https://openalex.org/W1518945650","https://openalex.org/W1557486844","https://openalex.org/W1725876082","https://openalex.org/W1971443733","https://openalex.org/W2016994934","https://openalex.org/W2023535408","https://openalex.org/W2084304524","https://openalex.org/W2100394600","https://openalex.org/W2104621895","https://openalex.org/W2105392125","https://openalex.org/W2106864314","https://openalex.org/W2132411069","https://openalex.org/W2134070580","https://openalex.org/W2136035407","https://openalex.org/W2141682101","https://openalex.org/W2141804605","https://openalex.org/W2147601077","https://openalex.org/W2163715935","https://openalex.org/W2262889796","https://openalex.org/W2267702630","https://openalex.org/W2286275639","https://openalex.org/W2343448572","https://openalex.org/W2531364460","https://openalex.org/W2546062527","https://openalex.org/W2547887009","https://openalex.org/W2602677185","https://openalex.org/W2612289971","https://openalex.org/W2625332994","https://openalex.org/W2626574340","https://openalex.org/W2742503793","https://openalex.org/W2761409680","https://openalex.org/W2763351278","https://openalex.org/W2768978586","https://openalex.org/W2772229928","https://openalex.org/W2776794349","https://openalex.org/W2787028854","https://openalex.org/W2796873235","https://openalex.org/W2797535556","https://openalex.org/W2798331883","https://openalex.org/W2804119529","https://openalex.org/W2811347682","https://openalex.org/W2811385491","https://openalex.org/W2884666313","https://openalex.org/W2888640426","https://openalex.org/W2892483155","https://openalex.org/W2896814869","https://openalex.org/W2897214019","https://openalex.org/W2904944036","https://openalex.org/W2914257254","https://openalex.org/W2914957131","https://openalex.org/W2919769513","https://openalex.org/W2956163206","https://openalex.org/W2962706684","https://openalex.org/W2962783428","https://openalex.org/W2963017050","https://openalex.org/W2963250023","https://openalex.org/W2963494103","https://openalex.org/W2963599038","https://openalex.org/W2963797719","https://openalex.org/W2963858294","https://openalex.org/W2964042011","https://openalex.org/W2964181991","https://openalex.org/W2965824823","https://openalex.org/W2973226602","https://openalex.org/W2973380603","https://openalex.org/W2974046131","https://openalex.org/W2981805197","https://openalex.org/W2981959312","https://openalex.org/W2982316100","https://openalex.org/W2985994751","https://openalex.org/W2987900243","https://openalex.org/W2993129648","https://openalex.org/W3000438224","https://openalex.org/W3000535985","https://openalex.org/W3006094616","https://openalex.org/W3014371581","https://openalex.org/W3016251777","https://openalex.org/W3019945581","https://openalex.org/W3025122528","https://openalex.org/W3034332820","https://openalex.org/W3035695040","https://openalex.org/W3044142342","https://openalex.org/W3044836646","https://openalex.org/W3045054942","https://openalex.org/W3045086480","https://openalex.org/W3045596237","https://openalex.org/W3056434754","https://openalex.org/W3080516458","https://openalex.org/W3080932450","https://openalex.org/W3086305818","https://openalex.org/W3089081646","https://openalex.org/W3092108740","https://openalex.org/W3097860381","https://openalex.org/W3099019646","https://openalex.org/W3099509723","https://openalex.org/W3100767898","https://openalex.org/W3101927978","https://openalex.org/W3102202882","https://openalex.org/W3114093483","https://openalex.org/W3119434305","https://openalex.org/W3133060040","https://openalex.org/W3135061354","https://openalex.org/W3135089279","https://openalex.org/W3167013751","https://openalex.org/W3195178360","https://openalex.org/W4250598470","https://openalex.org/W4256258616","https://openalex.org/W4293263215","https://openalex.org/W4312542184","https://openalex.org/W6680021679"],"related_works":["https://openalex.org/W9034678","https://openalex.org/W2565629428","https://openalex.org/W4287208404","https://openalex.org/W2391167130","https://openalex.org/W3214412616","https://openalex.org/W2092071486","https://openalex.org/W4283067488","https://openalex.org/W4291722335","https://openalex.org/W3152961272","https://openalex.org/W3112653499"],"abstract_inverted_index":{"Enabling":[0],"ultrareliable":[1],"low-latency":[2],"communication":[3],"(URLLC)":[4],"with":[5,195],"stringent":[6],"requirements":[7],"for":[8,104],"transmitting":[9],"data":[10],"packets":[11],"(e.g.,":[12],"99.999%":[13],"reliability":[14],"and":[15,48,77,102,109,131,134,151,169,174,189],"1-ms":[16],"latency)":[17],"presents":[18],"considerable":[19],"uplink":[20],"transmission":[21,26],"challenges.":[22],"For":[23],"each":[24],"packet":[25],"over":[27,176],"dynamically":[28],"allocated":[29],"network":[30],"radio":[31,70],"resources,":[32],"the":[33,66,80,83,149,153,163],"conventional":[34],"random":[35],"access":[36],"protocols":[37],"are":[38,63,89],"based":[39],"on":[40],"a":[41,96],"request-grant":[42],"scheme.":[43],"This":[44],"induces":[45],"excessive":[46],"latency":[47],"necessitates":[49],"reliable":[50],"control":[51],"signaling,":[52],"resulting":[53],"in":[54,65,85,191],"overhead.":[55],"To":[56],"address":[57,148],"these":[58],"problems,":[59],"grant-free":[60],"(GF)":[61],"solutions":[62],"proposed":[64],"fifth-generation":[67],"(5G)":[68],"new":[69],"(NR).":[71],"In":[72,91],"this":[73],"article,":[74],"an":[75],"overview":[76],"vision":[78],"of":[79,82,99,113,124,155,165],"state":[81],"art":[84],"enabling":[86,114,192],"GF":[87,115,156,180,193],"URLLC":[88,181,194],"presented.":[90],"particular,":[92],"we":[93,118,161,184],"first":[94],"provide":[95],"comprehensive":[97],"review":[98],"NR":[100],"specifications":[101],"techniques":[103],"URLLC,":[105],"discuss":[106],"underlying":[107],"principles,":[108],"highlight":[110],"impeding":[111],"issues":[112,150],"URLLC.":[116,157],"Furthermore,":[117],"briefly":[119],"explain":[120],"two":[121],"key":[122],"phenomena":[123],"massive":[125],"multiple-input\u2013multiple-output":[126],"(mMIMO)":[127],"(i.e.,":[128],"channel":[129],"hardening":[130],"favorable":[132],"propagation)":[133],"build":[135],"several":[136],"deep":[137],"insights":[138],"into":[139],"how":[140],"celebrated":[141],"mMIMO":[142,168,177],"features":[143,173],"can":[144],"be":[145],"exploited":[146],"to":[147,178],"enhance":[152],"performance":[154],"Moving":[158],"further":[159],"ahead,":[160],"examine":[162],"potential":[164],"cell-free":[166],"(CF)":[167],"analyze":[170],"its":[171],"distinctive":[172],"benefits":[175],"resolve":[179],"issues.":[182],"Finally,":[183],"identify":[185],"future":[186],"research":[187],"directions":[188],"challenges":[190],"CF":[196],"mMIMO.":[197]},"counts_by_year":[{"year":2026,"cited_by_count":1},{"year":2025,"cited_by_count":16},{"year":2024,"cited_by_count":15},{"year":2023,"cited_by_count":17},{"year":2022,"cited_by_count":13},{"year":2021,"cited_by_count":3}],"updated_date":"2026-03-27T05:58:40.876381","created_date":"2025-10-10T00:00:00"}