naa a22 4500 510794742 CHVBK 20180411083332.0 cr unu---uuuuu 180411e20130401xx s 000 0 eng 10.1007/s11277-012-0674-7 doi (NATIONALLICENCE)springer-10.1007/s11277-012-0674-7 Routing in Distributed Cognitive Radio Networks: A Survey [Elektronische Daten] [Hasan Al-Rawi, Kok-Lim Yau] Cognitive Radio Networks (CRNs) have been receiving significant research attention recently due to their ability to solve issues associated with spectrum congestion and underutilization. In a CRN, unlicensed users (or Secondary Users, SUs) are able to exploit and use underutilized licensed channels, but they must evacuate the channels if any interference is caused to the licensed users (or Primary Users, PUs) who own the channels. Due to the dynamicity of spectrum availability in CRNs, design of protocols and schemes at different layers of the SU's network stack has been challenging. In this article, we focus on routing and discuss the challenges and characteristics associated with it. Subsequently, we provide an extensive survey on existing routing schemes in CRNs. Generally speaking, there are three categories of challenges, namely channel-based, host-based, and network-based. The channel-based challenges are associated with the operating environment, the host-based with the SUs, and the network-based with the network-wide SUs. Furthermore, the existing routing schemes in the literature are segregated into three broad categories based on the relationship between PUs and SUs in their investigation, namely intra-system, inter-system, and hybrid-system; and within each category, they are further categorized based on their types, namely Proactive, Reactive, Hybrid, and Adaptive Per-hop. Additionally, we present performance enhancements achieved by the existing routing schemes in CRNs. Finally, we discuss various open issues related to routing in CRNs in order to establish a foundation and to spark new interests in this research area. Springer Science+Business Media, LLC., 2012 Cognitive radio nationallicence Routing nationallicence Route discovery nationallicence Route selection nationallicence Route maintenance nationallicence Al-Rawi Hasan Department of Computer Science and Networked System, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia aut Yau Kok-Lim Department of Computer Science and Networked System, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia aut Wireless Personal Communications Springer US; http://www.springer-ny.com 69/4(2013-04-01), 1983-2020 0929-6212 69:4<1983 2013 69 11277 https://doi.org/10.1007/s11277-012-0674-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11277-012-0674-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Al-Rawi Hasan Department of Computer Science and Networked System, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia aut NATIONALLICENCE 700 1- Yau Kok-Lim Department of Computer Science and Networked System, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 46150, Petaling Jaya, Selangor, Malaysia aut NATIONALLICENCE 773 0- Wireless Personal Communications Springer US; http://www.springer-ny.com 69/4(2013-04-01), 1983-2020 0929-6212 69:4<1983 2013 69 11277 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer