title: PAD-MAC: primary user activity-aware distributed MAC for multi-channel cognitive radio networks.
abstract: 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.
authors.affiliation: 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. amjad.ali@khu.ac.kr.
authors.forename: Amjad
authors.initials: A
authors.lastname: Ali
authors.affiliation: 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. piran.mj@gmail.com.
authors.forename: Md Jalil
authors.initials: MJ
authors.lastname: Piran
authors.affiliation: 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. puplepie@naver.com.
authors.forename: Hansoo
authors.initials: H
authors.lastname: Kim
authors.affiliation: 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. ychwh555@naver.com.
authors.forename: Jihyeok
authors.initials: J
authors.lastname: Yun
authors.affiliation: 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. suh@khu.ac.kr.
authors.forename: Doug Young
authors.initials: DY
authors.lastname: Suh
references.citation: ScientificWorldJournal. 2013 Oct 08;2013:424162
references.pmid: 24228002
references.citation: Sensors (Basel). 2014 Aug 08;14(8):14500-25
references.pmid: 25111241