Multicasting is a fundamental networking primitive utilized by numerousapplications. This also holds true for cognitive radio networks (CRNs) whichhave been proposed as a solution to the problems that emanate from the staticnon-adaptive features of classical wireless networks. A prime application ofCRNs is dynamic spectrum access (DSA), which improves the efficiency ofspectrum allocation by allowing a secondary network, comprising of secondaryusers (SUs), to share spectrum licensed to a primary licensed networkscomprising of primary users (PUs). Multicasting in CRNs is a challengingproblem due to the dynamic nature of spectrum opportunities available to theSUs. Various approaches, including those based in optimization theory, networkcoding, algorithms, have been proposed for performing efficient multicast inCRNs. In this paper, we provide a self-contained tutorial on algorithms andtechniques useful for solving the multicast problem, and then provide acomprehensive survey of protocols that have been proposed for multicasting inCRNs. We conclude this paper by identifying open research questions and futureresearch directions.
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