A vital element in the standardization process has been the identification and global harmonization of frequency bands for the operation of International Mobile Telecommunications (IMT), thereby enabling interoperability, roaming and global economies of scale. This chapter provides a perspective of the key technical requirements and spectrum aspects to address to finalize the standard in 2020. Regional/global operation of these systems was hampered by having multiple incompatible standards as well as different frequency bands and channel arrangements being used in different parts of the world. IMT-2020 systems are mobile systems that include the new capabilities of IMT that go beyond those of IMT-Advanced. IMT-2020 systems will need to support low to high mobility applications and a wide range of data rates in accordance with user and service demands in multiple usage scenarios. The radio access network architecture should support a wide range of options for inter-cell coordination schemes.