Chapter 6 - A comprehensive survey on heterogeneous cognitive radio networks

Abstract

With the fast adoption of Internet of Things devices in our lives, the demand for the wireless spectrum has increased manyfold. With existing static spectrum allocation policies in use, it has become extremely difficult to find a spectrum to deploy new applications or to enhance existing ones. To overcome this spectrum scarceness, regulatory bodies around the world have permitted opportunistic spectrum access of unoccupied television bands, known as TV white spaces, by unlicensed users. The decision to open up TV channels for unlicensed access has elicited many standardization activities around the world such as IEEE 802.22, 802.19.1, 802.11af, and ECMA 392 for intelligent networking. The TV channels are expected to be used by many unlicensed networks with different requirements for bandwidth and transmission power based on their architecture while protecting incumbent licensed users from harmful interference. Thus, the heterogeneous coexistence in TV channels is expected to be the most challenging issue in the future that needs an open discussion. In this chapter, we highlight some major challenges to the coexistence of heterogeneous cognitive radio networks in TV white space that need immediate attention for various standardization activities. Various resource allocation schemes and medium access control protocols have been discussed. Considering the heterogeneity of the network, various security aspects and algorithms are reviewed. Finally, various standardization activities around the globe for unlicensed use of TV white space are highlighted to support dynamic spectrum sharing among heterogeneous networks in TV white spaces.