“…Enhancement in spectrum utilization efficiency is the key challenge for CRNs, and a major concern of the research community as well. Multiple spectrum allocation techniques are proposed to improve efficiency in CRN [11]- [13]. In the next section, we will first provide state-of-the-art works proposed in the literature to enhance spectral efficiency, significant contributions of CRs in IoT environments, the background of virtualization techniques in wireless communications, and the research contribution and novelty of our proposed work.…”