Channel Hopping Rendezvous in Cognitive Radio Networks for Internet of Things

Abstract

Recent years have witnessed significant growth in the number of smart wireless devices termed as newlineInternet of Things (IoT). IoT is a network of heterogeneous interconnected things embedded with newlinedifferent sensors and actuators that interact with each other using addressing methods based on newlinestandard communication protocols. With the expansion in the number of IoT devices, the demand newlinefor wireless spectrum has also been increased tremendously while the spectrum is limited. newlineHowever, with such rapid development in the IoT domain, the unlicensed wireless spectrum such newlineas Industrial, Scientific and Medical (ISM) band has become overcrowded. On the other hand, it newlinehas been observed that a very low portion of the licensed spectrum is being utilized efficiently due newlineto the static spectrum assignment policy. The concept of Cognitive Radio Networks (CRNs) has newlineemerged as a promising solution to overcome spectrum scarcity issues and enhance spectrum newlineutilization efficiency. CRNs make use of the fact that not all licensed users or Primary Users (PUs) newlineare active all the time, and the temporarily unused portion of the spectrum can be used newlineopportunistically by unlicensed users or Secondary Users (SUs). Each SU has the ability to sense newlinethe channel state and fast switching. While SUs are allowed to use the vacant spectrum, newlineinterference to PUs must be protected. In a smart IoT application environment, this situation often newlineencounters that the allocated spectrum is not used uniformly because of uneven spectrum newlinerequirements of various IoT applications. With the current development trends, it is estimated that newlineCR-based IoT frameworks would become an absolute necessity for the expansion of IoT newlineapplications. In the last few years, CRN has been widely researched because of its potential to be newlinean effective solution to the problem of spectrum scarcity. However, establishing a common newlinecommunication link between heterogeneous wireless devices requires them to rendezvous on a newlinecommonly available channel which is a great challenge in