{"id":"https://openalex.org/W3134567856","doi":"https://doi.org/10.1109/twc.2021.3062235","title":"Sparse or Dense: A Comparative Study of Code-Domain NOMA Systems","display_name":"Sparse or Dense: A Comparative Study of Code-Domain NOMA Systems","publication_year":2021,"publication_date":"2021-03-04","ids":{"openalex":"https://openalex.org/W3134567856","doi":"https://doi.org/10.1109/twc.2021.3062235","mag":"3134567856"},"language":"en","primary_location":{"id":"doi:10.1109/twc.2021.3062235","is_oa":false,"landing_page_url":"https://doi.org/10.1109/twc.2021.3062235","pdf_url":null,"source":{"id":"https://openalex.org/S63459445","display_name":"IEEE Transactions on Wireless Communications","issn_l":"1536-1276","issn":["1536-1276","1558-2248"],"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 Transactions on Wireless Communications","raw_type":"journal-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":true,"oa_status":"green","oa_url":"https://eprints.soton.ac.uk/493092/1/Sparse-or-Dense-final.pdf","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5100629531","display_name":"Zilong Liu","orcid":"https://orcid.org/0000-0002-5851-4261"},"institutions":[{"id":"https://openalex.org/I110002522","display_name":"University of Essex","ror":"https://ror.org/02nkf1q06","country_code":"GB","type":"education","lineage":["https://openalex.org/I110002522"]}],"countries":["GB"],"is_corresponding":false,"raw_author_name":"Zilong Liu","raw_affiliation_strings":["School of Computer Science and Electronics Engineering, University of Essex, Colchester, U.K"],"raw_orcid":"https://orcid.org/0000-0002-5851-4261","affiliations":[{"raw_affiliation_string":"School of Computer Science and Electronics Engineering, University of Essex, Colchester, U.K","institution_ids":["https://openalex.org/I110002522"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5100329747","display_name":"Lie\u2010Liang Yang","orcid":"https://orcid.org/0000-0002-2032-9327"},"institutions":[{"id":"https://openalex.org/I43439940","display_name":"University of Southampton","ror":"https://ror.org/01ryk1543","country_code":"GB","type":"education","lineage":["https://openalex.org/I43439940"]}],"countries":["GB"],"is_corresponding":false,"raw_author_name":"Lie-Liang Yang","raw_affiliation_strings":["School of Electronics and Computer Science, University of Southampton, Southampton, U.K"],"raw_orcid":"https://orcid.org/0000-0002-2032-9327","affiliations":[{"raw_affiliation_string":"School of Electronics and Computer Science, University of Southampton, Southampton, U.K","institution_ids":["https://openalex.org/I43439940"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":2,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":null,"apc_paid":null,"fwci":6.1029,"has_fulltext":true,"cited_by_count":103,"citation_normalized_percentile":{"value":0.97419965,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":89,"max":100},"biblio":{"volume":"20","issue":"8","first_page":"4768","last_page":"4780"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11458","display_name":"Advanced Wireless Communication Technologies","score":1.0,"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/T11458","display_name":"Advanced Wireless Communication Technologies","score":1.0,"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/T10851","display_name":"Optical Wireless Communication Technologies","score":0.9950000047683716,"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/T12042","display_name":"Satellite Communication Systems","score":0.9948999881744385,"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/noma","display_name":"Noma","score":0.8914282321929932},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.6811661720275879},{"id":"https://openalex.org/keywords/code","display_name":"Code (set theory)","score":0.5271339416503906},{"id":"https://openalex.org/keywords/algorithm","display_name":"Algorithm","score":0.33266347646713257},{"id":"https://openalex.org/keywords/telecommunications","display_name":"Telecommunications","score":0.25022315979003906},{"id":"https://openalex.org/keywords/programming-language","display_name":"Programming language","score":0.09659308195114136},{"id":"https://openalex.org/keywords/telecommunications-link","display_name":"Telecommunications link","score":0.0884680449962616}],"concepts":[{"id":"https://openalex.org/C2775918612","wikidata":"https://www.wikidata.org/wiki/Q994794","display_name":"Noma","level":3,"score":0.8914282321929932},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6811661720275879},{"id":"https://openalex.org/C2776760102","wikidata":"https://www.wikidata.org/wiki/Q5139990","display_name":"Code (set theory)","level":3,"score":0.5271339416503906},{"id":"https://openalex.org/C11413529","wikidata":"https://www.wikidata.org/wiki/Q8366","display_name":"Algorithm","level":1,"score":0.33266347646713257},{"id":"https://openalex.org/C76155785","wikidata":"https://www.wikidata.org/wiki/Q418","display_name":"Telecommunications","level":1,"score":0.25022315979003906},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.09659308195114136},{"id":"https://openalex.org/C138660444","wikidata":"https://www.wikidata.org/wiki/Q5607897","display_name":"Telecommunications link","level":2,"score":0.0884680449962616},{"id":"https://openalex.org/C177264268","wikidata":"https://www.wikidata.org/wiki/Q1514741","display_name":"Set (abstract data type)","level":2,"score":0.0}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1109/twc.2021.3062235","is_oa":false,"landing_page_url":"https://doi.org/10.1109/twc.2021.3062235","pdf_url":null,"source":{"id":"https://openalex.org/S63459445","display_name":"IEEE Transactions on Wireless Communications","issn_l":"1536-1276","issn":["1536-1276","1558-2248"],"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 Transactions on Wireless Communications","raw_type":"journal-article"},{"id":"pmh:oai:eprints.soton.ac.uk:493092","is_oa":true,"landing_page_url":"http://doi.org/10.1109/TWC.2021.3062235>).","pdf_url":"https://eprints.soton.ac.uk/493092/1/Sparse-or-Dense-final.pdf","source":{"id":"https://openalex.org/S4306401019","display_name":"ePrints Soton (University of Southampton)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I43439940","host_organization_name":"University of Southampton","host_organization_lineage":["https://openalex.org/I43439940"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"Article"}],"best_oa_location":{"id":"pmh:oai:eprints.soton.ac.uk:493092","is_oa":true,"landing_page_url":"http://doi.org/10.1109/TWC.2021.3062235>).","pdf_url":"https://eprints.soton.ac.uk/493092/1/Sparse-or-Dense-final.pdf","source":{"id":"https://openalex.org/S4306401019","display_name":"ePrints Soton (University of Southampton)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I43439940","host_organization_name":"University of Southampton","host_organization_lineage":["https://openalex.org/I43439940"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"Article"},"sustainable_development_goals":[],"awards":[{"id":"https://openalex.org/G1972339859","display_name":null,"funder_award_id":"EP/P034284/1","funder_id":"https://openalex.org/F4320334627","funder_display_name":"Engineering and Physical Sciences Research Council"},{"id":"https://openalex.org/G5449388699","display_name":null,"funder_award_id":"EP/P03456X/1","funder_id":"https://openalex.org/F4320334627","funder_display_name":"Engineering and Physical Sciences Research Council"},{"id":"https://openalex.org/G5991684347","display_name":"New Air Interface Techniques for Future Massive Machine-Type Communications","funder_award_id":"EP/P034284/1","funder_id":"https://openalex.org/F4320334627","funder_display_name":"Engineering and Physical Sciences Research Council"},{"id":"https://openalex.org/G7806824190","display_name":"New Air Interface Techniques for Future Massive Machine Communications","funder_award_id":"EP/P03456X/1","funder_id":"https://openalex.org/F4320334627","funder_display_name":"Engineering and Physical Sciences Research Council"}],"funders":[{"id":"https://openalex.org/F4320334627","display_name":"Engineering and Physical Sciences Research Council","ror":"https://ror.org/0439y7842"}],"has_content":{"pdf":true,"grobid_xml":true},"content_urls":{"pdf":"https://content.openalex.org/works/W3134567856.pdf","grobid_xml":"https://content.openalex.org/works/W3134567856.grobid-xml"},"referenced_works_count":49,"referenced_works":["https://openalex.org/W1721817043","https://openalex.org/W1922937245","https://openalex.org/W1991528082","https://openalex.org/W1992036418","https://openalex.org/W1997002146","https://openalex.org/W2003420583","https://openalex.org/W2008104692","https://openalex.org/W2036725859","https://openalex.org/W2042519026","https://openalex.org/W2083213425","https://openalex.org/W2085486577","https://openalex.org/W2098076345","https://openalex.org/W2100087741","https://openalex.org/W2101617851","https://openalex.org/W2105638725","https://openalex.org/W2108656301","https://openalex.org/W2117778302","https://openalex.org/W2117890770","https://openalex.org/W2121837475","https://openalex.org/W2124894634","https://openalex.org/W2131897194","https://openalex.org/W2139104935","https://openalex.org/W2143441977","https://openalex.org/W2150940322","https://openalex.org/W2156787051","https://openalex.org/W2163524462","https://openalex.org/W2168830205","https://openalex.org/W2171470636","https://openalex.org/W2463692443","https://openalex.org/W2464137485","https://openalex.org/W2500307208","https://openalex.org/W2522847968","https://openalex.org/W2541373058","https://openalex.org/W2556254512","https://openalex.org/W2586156909","https://openalex.org/W2593105899","https://openalex.org/W2754335200","https://openalex.org/W2769456309","https://openalex.org/W2782870384","https://openalex.org/W2798333393","https://openalex.org/W2887860413","https://openalex.org/W2896032744","https://openalex.org/W2900805756","https://openalex.org/W2962896080","https://openalex.org/W2963656297","https://openalex.org/W3007990687","https://openalex.org/W3046340539","https://openalex.org/W3101450547","https://openalex.org/W3104874376"],"related_works":["https://openalex.org/W4391375266","https://openalex.org/W2899084033","https://openalex.org/W2748952813","https://openalex.org/W3030525848","https://openalex.org/W4385197910","https://openalex.org/W2340639785","https://openalex.org/W3010814398","https://openalex.org/W4385197899","https://openalex.org/W3005957545","https://openalex.org/W2076432172"],"abstract_inverted_index":{"This":[0,111],"paper":[1],"is":[2,11,75,99,112],"focused":[3],"on":[4],"code-domain":[5],"non-orthogonal":[6],"multiple":[7,39,45,165],"access":[8,40,46,166],"(CD-NOMA),":[9],"which":[10,48,98],"an":[12],"emerging":[13],"paradigm":[14],"to":[15,29,94,101,115,125,151,189,204],"support":[16],"massive":[17],"connectivity":[18],"for":[19,144,156],"future":[20],"machine-type":[21],"wireless":[22],"networks.":[23],"We":[24,140,159],"take":[25],"a":[26,90],"comparative":[27],"approach":[28],"study":[30],"two":[31,162],"types":[32,163],"of":[33,56,85,105,133,164,206],"overloaded":[34],"CD-NOMA,":[35],"i.e.,":[36],"sparse":[37],"code":[38,44],"(SCMA)":[41],"and":[42,149,178,183],"dense":[43],"(DCMA),":[47],"are":[49],"distinctive":[50],"from":[51,121],"each":[52,138],"other":[53],"in":[54,70,108,113,195],"terms":[55],"their":[57,65],"codebooks":[58],"having":[59,200],"sparsity":[60,128],"or":[61],"not.":[62],"By":[63],"analysing":[64],"individual":[66],"diversity":[67],"orders":[68],"(DO)":[69],"Rayleigh":[71,196],"fading":[72,197],"channels,":[73,198],"it":[74],"found":[76],"that":[77,185,205],"DCMA":[78,157,186],"can":[79],"be":[80],"designed":[81],"with":[82],"the":[83,102,109,126,130,145],"aid":[84],"generalized":[86,153],"sphere":[87,154],"decoder":[88,155],"(i.e.,":[89,129,171],"nonlinear":[91],"multiuser":[92],"detector)":[93],"enjoy":[95],"full":[96],"DO":[97,123],"equal":[100,124],"maximum":[103],"number":[104,132],"resource":[106,134],"nodes":[107,135],"system.":[110],"contrast":[114],"SCMA":[116],"whose":[117],"error":[118,192],"rate":[119,193],"suffers":[120],"limited":[122],"codebook":[127,146],"effective":[131],"occupied":[136],"by":[137],"user).":[139],"conduct":[141],"theoretical":[142],"analysis":[143],"design":[147],"criteria":[148],"propose":[150],"use":[152],"detection.":[158],"numerically":[160],"evaluate":[161],"schemes":[167],"under":[168],"\u201c":[169,179],"4\u00d76\u201d":[170],"six":[172],"users":[173],"communicate":[174],"over":[175],"four":[176],"subcarriers)":[177],"5\u00d710\u201d":[180],"NOMA":[181],"settings":[182],"reveal":[184],"gives":[187],"rise":[188],"significantly":[190],"improved":[191],"performance":[194],"whilst":[199],"decoding":[201],"complexity":[202],"comparable":[203],"SCMA.":[207]},"counts_by_year":[{"year":2026,"cited_by_count":4},{"year":2025,"cited_by_count":22},{"year":2024,"cited_by_count":23},{"year":2023,"cited_by_count":22},{"year":2022,"cited_by_count":21},{"year":2021,"cited_by_count":10},{"year":2020,"cited_by_count":1}],"updated_date":"2026-07-25T15:57:00.446498","created_date":"2025-10-10T00:00:00"}