This chapter provides detailed insights into wireless spectrum, spectrum considerations for introducing 5G radio based on future traffic growth, and new identified spectrum for International Telecommunication Union-Radio Sector (ITU-R) World Radio Conference (WRC)-19 definitions. It also provides insights into different regulations and new regulation approaches considered for wireless communications. This chapter discusses characteristics of new spectrum from a signal propagation point of view and how it needs to be considered in radio system design. Finally, frequency bands for 3rd Generation Partnership Project (3GPP) New Radio operation are introduced.