{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T19:14:06Z","timestamp":1784574846021,"version":"3.55.0"},"reference-count":49,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2015,3,30]],"date-time":"2015-03-30T00:00:00Z","timestamp":1427673600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Science, ICT &amp; Future Planning, Korea in the ICT R&amp;D Program 2014"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Cognitive radio (CR) has emerged as a promising technology to solve problems related to spectrum scarcity and provides a ubiquitous wireless access environment. CR-enabled secondary users (SUs) exploit spectrum white spaces opportunistically and immediately vacate the acquired licensed channels as primary users (PUs) arrive. Accessing the licensed channels without the prior knowledge of PU traffic patterns causes severe throughput degradation due to excessive channel switching and PU-to-SU collisions. Therefore, it is significantly important to design a PU activity-aware medium access control (MAC) protocol for cognitive radio networks (CRNs). In this paper, we first propose a licensed channel usage pattern identification scheme, based on a two-state Markov model, and then estimate the future idle slots using previous observations of the channels. Furthermore, based on these past observations, we compute the rank of each available licensed channel that gives SU transmission success assessment during the estimated idle slot. Secondly, we propose a PU activity-aware distributed MAC (PAD-MAC) protocol for heterogeneous multi-channel CRNs that selects the best channel for each SU to enhance its throughput. PAD-MAC controls SU activities by allowing them to exploit the licensed channels only for the duration of estimated idle slots and enables predictive and fast channel switching. To evaluate the performance of the proposed PAD-MAC, we compare it with the distributed QoS-aware MAC (QC-MAC) and listen-before-talk MAC schemes. Extensive numerical results show the significant improvements of the PAD-MAC in terms of the SU throughput, SU channel switching rate and PU-to-SU collision rate.<\/jats:p>","DOI":"10.3390\/s150407658","type":"journal-article","created":{"date-parts":[[2015,3,30]],"date-time":"2015-03-30T10:50:23Z","timestamp":1427712623000},"page":"7658-7690","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["PAD-MAC: Primary User Activity-Aware Distributed MAC for Multi-Channel Cognitive Radio Networks"],"prefix":"10.3390","volume":"15","author":[{"given":"Amjad","family":"Ali","sequence":"first","affiliation":[{"name":"Department of Electronics and Radio Engineering, College of Electronics and Information, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Suwon, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md.","family":"Piran","sequence":"additional","affiliation":[{"name":"Department of Electronics and Radio Engineering, College of Electronics and Information, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Suwon, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hansoo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electronics and Radio Engineering, College of Electronics and Information, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Suwon, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jihyeok","family":"Yun","sequence":"additional","affiliation":[{"name":"Department of Electronics and Radio Engineering, College of Electronics and Information, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Suwon, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Doug","family":"Suh","sequence":"additional","affiliation":[{"name":"Department of Electronics and Radio Engineering, College of Electronics and Information, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Suwon, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,3,30]]},"reference":[{"key":"ref_1","unstructured":"FCC ET Docket No 03-222: Notice of Proposed Rule Making and Order. Available online: http:\/\/web.cs.ucdavis.edu\/liu\/289I\/Material\/FCC-03-322A1.pdf."},{"key":"ref_2","unstructured":"Report of the Spectrum Efficiency Working Group, 2002. Available online: http:\/\/www.fcc.gov\/sptf\/reports.html."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1023\/A:1011426600077","article-title":"Cognitive Radio for Flexible Mobile Multimedia Communications","volume":"6","author":"Mitola","year":"2001","journal-title":"Mob. Netw. Appl."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"141","DOI":"10.5626\/JCSE.2011.5.2.141","article-title":"Ubiscript: A script language for ubiquitous environment","volume":"5","author":"Lee","year":"2011","journal-title":"J. Comput. Sci. Eng."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Letaief, K.B. (2009, January 6\u20138). Pathways towards Next Generation Cognitive Ubiquitous Networks. Yunnan, China.","DOI":"10.1109\/CMC.2009.368"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1109\/JSAC.2004.839380","article-title":"Cognitive radio: Brain-empowered wireless communications","volume":"23","author":"Haykin","year":"2005","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1109\/JSAC.2008.080111","article-title":"Cross-layer based opportunistic mac protocols for QOS provisionings over cognitive radio wireless networks","volume":"26","author":"Su","year":"2008","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Su, H., and Zhang, X. (2007, January 14\u201316). Opportunistic mac protocols for cognitive radio based wireless networks. Baltimore, MD, USA.","DOI":"10.1109\/CISS.2007.4298329"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Su, H., and Zhang, X. (2008, January 23\u201326). Cream-MAC: An efficient cognitive radio-enabled multi-channel MAC protocol for wireless networks. Newport Beach, CA, USA.","DOI":"10.1109\/WOWMOM.2008.4594853"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Huang, J., Zhang, Z., Wang, H., and Liu, H. (2011, January 5\u20139). Video transmission over Cognitive Radio networks. Houston, TX, USA.","DOI":"10.1109\/GLOCOMW.2011.6162543"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Hasslinger, G., Schwahn, A., and Hartleb, F. (2013, January 14\u201319). 2-State semi-Markov processes beyond Gilbert-Elliott: Traffic and channel models based on 2nd order statistics. Turin, Italy.","DOI":"10.1109\/INFCOM.2013.6566938"},{"key":"ref_12","unstructured":"Zhao, J., Zheng, H., and Yang, G. (2005, January 8\u201311). Distributed coordination in dynamic spectrum allocation networks. Baltimore, MD, USA."},{"key":"ref_13","unstructured":"Kanodia, V., Sabharwal, A., and Knightly, E. (2004, January 25\u201329). MOAR: A multi-channel opportunistic auto-rate media access protocol for ad hoc networks. San Jose, CA, USA."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1007\/s11036-006-0049-y","article-title":"Adaptive channel allocation spectrum etiquette for cognitive radio networks","volume":"11","author":"Nie","year":"2006","journal-title":"Mob. New. Appl."},{"key":"ref_15","unstructured":"Zheng, H., and Cao, L. (2005, January 8\u201311). Device-centric spectrum management. Baltimore, MD, USA."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Talat, S., and Wang, L. (2009, January 23\u201325). QoS-guaranteed channel selection scheme for cognitive radio networks with variable channel bandwidths. Milpitas, CA, USA.","DOI":"10.1109\/ICCCAS.2009.5250552"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1109\/TMC.2010.147","article-title":"A spectrum decision framework for cognitive radio networks","volume":"10","author":"Lee","year":"2011","journal-title":"IEEE Trans. Mob. Comput."},{"key":"ref_18","unstructured":"Ali, A., Iqbal, M., Saifullah, S., and Song, J.B. (2012, January 19\u201324). QoS-based Channel and Radio Assignment Algorithm for Mesh Cognitive Radio Networks Intended for HealthCare. Rome, Italy."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Xu, Y., Anpalagan, A., Wu, Q., Wang, J., Sheng, L., and Gao, Z. (2013, January 7\u201310). Game-theoretic channel selection for interference mitigation in cognitive radio networks with block\u2013fading channels. Shanghai, China.","DOI":"10.1109\/WCNC.2013.6554581"},{"key":"ref_20","unstructured":"Li, X., Sun, Y., Yu, F.R., and Zhao, N. (2013, January 9\u201313). A novel interference alignment scheme based on antenna selection in cognitive radio networks. Atlanta, GA, USA."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1007\/s11042-011-0937-4","article-title":"QoS provisioning wireless multimedia transmission over cognitive radio networks","volume":"67","author":"Yuming","year":"2013","journal-title":"Multimed. Tools Appl."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Zeng, Y., Mittal, N., Venkatesan, S., and Chandrasekaran, R. (2010, January 7\u20139). Fast neighbor discovery with lightweight termination detection in heterogeneous cognitive radio networks. Istanbul, Turkey.","DOI":"10.1109\/ISPDC.2010.32"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1109\/JSAC.2007.070409","article-title":"Decentralized cognitive MAC for opportunistic spectrum access in ad hoc networks: A POMDP framework","volume":"25","author":"Qing","year":"2007","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1109\/JSAC.2008.080110","article-title":"HC-MAC: A hardware-constrained cognitive MAC for efficient spectrum management","volume":"26","author":"Jia","year":"2008","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1109\/TVT.2009.2029552","article-title":"A Distributed Multichannel MAC Protocol for Multihop Cognitive Radio Networks","volume":"59","author":"Timmers","year":"2010","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1109\/TMC.2007.70758","article-title":"OS-MAC: An Efficient MAC Protocol for Spectrum-Agile Wireless Networks","volume":"7","author":"Hamdaoui","year":"2008","journal-title":"IEEE Trans. Mob. Comput."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1109\/JSAC.2008.080115","article-title":"Wireless Mesh Networks with Dynamic Spectrum Access","volume":"26","author":"Chowdhury","year":"2008","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"14500","DOI":"10.3390\/s140814500","article-title":"Resource Optimization Scheme for Multimedia-Enabled Wireless Mesh Networks","volume":"14","author":"Ali","year":"2014","journal-title":"Sensors"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Cai, L.X., Liu, Y., Shen, X., Mark, J.W., and Zhao, D. (2010, January 6\u201310). Distributed QoS-aware MAC for multimedia over cognitive radio networks. Miami, FL, USA.","DOI":"10.1109\/GLOCOM.2010.5683743"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Ghaboosi, K., Latva-aho, M., and Xiao, Y. (2008, January 15\u201317). Distributed Multi-channel Cognitive MAC Protocol for IEEE 802.11s Wireless Mesh Networks. Singapore.","DOI":"10.1109\/CROWNCOM.2008.4562477"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3928","DOI":"10.1109\/TVT.2013.2258952","article-title":"An efficient MAC protocol with selective grouping and cooperative sensing in cognitive radio networks","volume":"62","author":"Liu","year":"2013","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"716","DOI":"10.1109\/TVT.2011.2179323","article-title":"Energy-efficient cooperative spectrum sensing by optimal scheduling in sensor-aided cognitive radio networks","volume":"61","author":"Deng","year":"2012","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Cordeiro, C., and Challapali, K. (2007, January 17\u201320). C-MAC: A cognitive MAC protocol for multichannel wireless networks. Dublin, Ireland.","DOI":"10.1109\/DYSPAN.2007.27"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"901","DOI":"10.1109\/JIOT.2014.2310425","article-title":"Design of a scalable hybrid MAC protocol for heterogeneous M2M networks","volume":"1","author":"Liu","year":"2014","journal-title":"IEEE Internet Things J."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Maharjan, S., Zhang, Y., Yuen, C., and Gjessing, S. (2011, January 17\u201322). Distributed spectrum sensing in cognitive radio networks with fairness consideration: Efficiency of correlated equilibrium. Valencia, Spain.","DOI":"10.1109\/MASS.2011.143"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1109\/JSYST.2011.2159640","article-title":"Modeling channel allocation for multimedia transmission over infrastructure based cognitive radio networks","volume":"5","author":"Jiang","year":"2011","journal-title":"IEEE Syst. J."},{"key":"ref_37","unstructured":"IEEE 802.22, Working Group on Wireless Regional Area Networks (WRAN). http:\/\/grouper.ieee.org\/groups\/802\/22\/."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2141","DOI":"10.1109\/TMC.2013.156","article-title":"Sensing-Transmission Edifice Using Bayesian Nonparametric Traffic Clustering in Cognitive Radio Networks","volume":"75","author":"Ahmed","year":"2014","journal-title":"IEEE Trans. Mob. Comput."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"874","DOI":"10.1109\/LCOMM.2012.041112.120507","article-title":"Performance analysis of spectrum sensing with multiple status changes in primary user traffic","volume":"16","author":"Tang","year":"2012","journal-title":"IEEE Commun. Lett."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2091","DOI":"10.1109\/TVT.2013.2238960","article-title":"Time-dimension models of spectrum usage for the analysis, design and simulation of cognitive radio networks","volume":"62","author":"Casadevall","year":"2013","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"544","DOI":"10.1109\/JSAC.2013.130319","article-title":"Primary user traffic estimation for dynamic spectrum access","volume":"31","author":"Gabran","year":"2013","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1232","DOI":"10.1109\/TWC.2011.012411.100611","article-title":"Energy detection based cooperative spectrum sensing in cognitive radio networks","volume":"10","author":"Atapattu","year":"2011","journal-title":"IEEE Trans. Wirel. Commun."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Nieminen, J., Jantti, R., and Qian, L. (2010, January 6\u20139). Primary user detection in distributed cognitive radio networks under timing inaccuracy. Singapore.","DOI":"10.1109\/DYSPAN.2010.5457865"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Zhu, J., Zou, Y., and Zheng, B. (2009). Cooperative detection for primary user in cognitive radio networks. EURASIP J. Wirel. Commun. Netw.","DOI":"10.1155\/2009\/617320"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1109\/90.502236","article-title":"Efficient fair queuing using deficit round-robin","volume":"4","author":"Shreedhar","year":"1996","journal-title":"IEEE\/ACM Trans. Netw."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"424162","DOI":"10.1155\/2013\/424162","article-title":"Power and Time Slot Allocation in Cognitive Relay Networks Using Particle Swarm Optimization","volume":"2013","author":"Dadashzadeh","year":"2013","journal-title":"Sci. World J."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1109\/TNET.2005.845546","article-title":"Impact of interference on connectivity in ad hoc networks","volume":"13","author":"Dousse","year":"2005","journal-title":"IEEE\/ACM Trans. Netw."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"116","DOI":"10.1109\/SURV.2009.090109","article-title":"A Survey of Spectrum Sensing Algorithms for Cognitive Radio Applications","volume":"11","author":"Yucek","year":"2009","journal-title":"IEEE Commun. Surv. Tutor."},{"key":"ref_49","first-page":"28","article-title":"Improving the performance of cognitive radios through classification, learning, and predictive channel selection","volume":"2","author":"Hoyhtya","year":"2011","journal-title":"Adv. Electron. Telecommun."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/7658\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:44:05Z","timestamp":1760215445000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/4\/7658"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,3,30]]},"references-count":49,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2015,4]]}},"alternative-id":["s150407658"],"URL":"https:\/\/doi.org\/10.3390\/s150407658","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,3,30]]}}}