Convergence of IoT and Cognitive Radio Networks: A Survey of Applications, Techniques, and Challenges.

Cognitive Radio Networks (CRNs) have been proposed as a solution to the problem of spectrum scarcity in wireless communication systems. CRNs allow for dynamic spectrum access by secondary users, who can opportunistically use the spectrum when it is not being utilized by primary users. The integration of CRNs with the Internet of Things (IoT) has the potential to bring significant benefits to both wireless communication systems and IoT applications. Spectrum sensing is a crucial component of CRNs, as it enables the secondary users to detect the presence of primary users and opportunistically use the available spectrum. Routing is another important aspect of CRN IOT-based systems, as it enables efficient communication between the devices. Traditional routing protocols may not be suitable for CRN IOT-based systems, due to the dynamic nature of the available spectrum. In this survey paper, we explore the recent research and developments in CRN IOT-based systems, including the architecture, key technologies, and potential applications. Mainly, we will focus on the key aspects of spectrum sensing and routing in CRNs integrated with the IoT. Hence, we review the sensing and routing protocols and discuss their performance in different scenarios. We will also discuss the challenges and future research directions in this field. Overall, this survey aims to provide a comprehensive overview of the state-of-the-art in IOT-based CRNs and to highlight the potential of this technology for addressing the growing demands of wireless communication and IoT applications.