{"doi":"10.1109/jsac.2004.839380","title":"Cognitive radio: brain-empowered wireless communications","abstract":"Cognitive radio is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building to learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind: /spl middot/ highly reliable communication whenever and wherever needed; /spl middot/ efficient utilization of the radio spectrum. Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks. 1) Radio-scene analysis. 2) Channel-state estimation and predictive modeling. 3) Transmit-power control and dynamic spectrum management. This work also discusses the emergent behavior of cognitive radio.","journal":"IEEE Journal on Selected Areas in Communications","year":2005,"id":5260,"datarank":36.74378195790067,"base_score":9.389406636049465,"endowment":9.389406636049465,"self_citation_contribution":1.40841099540742,"citation_network_contribution":35.33537096249325,"self_endowment_contribution":1.40841099540742,"citer_contribution":35.33537096249325,"corpus_percentile":99.7,"corpus_rank":852,"citation_count":11960,"citer_count":199,"citers_with_citation_signal":199,"citers_with_endowment":199,"datacite_reuse_total":0,"is_dataset":false,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2005-02-01","authors":[{"id":52762,"name":"S. Haykin","orcid":"0000-0002-0346-261X","position":0,"is_corresponding":true}],"reference_count":88,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-03-01T18:20:47.508186Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}