roundbreaking technology com- ponents and functionalities, and development of a set of new radio access technologies. Nevertheless, IMT-2020 systems continue to interwork with and complement the existing IMT systems and their enhancements [1-12]. IMT-2020 can be considered from multiple aspects including the users, manufacturers, application developers, network operators, and service and content providers as the usage scenarios of IMT-2020 will continue to expand. Therefore, it is expected that the technolo- gies for IMT-2020 can be applied in a broader range of usage scenarios and can support a wider range of environments, diverse service capabilities, and technology options compared to IMT-Advanced and IMT-2000 systems. The task of ITU-R WP 5D is to determine a set Introduction and Background Ixxvii experienced data rate (Mbps) Peak data High capacity High data rates rate (Gbps) Spectrum efficiency (bps/Hz) capacity Mobility (km/h) (Mbps/m2) Advanced IMT-2020 URLLC Ultra-high security Ultra-high reliability Ultra-low latency High mobility Network energy efficiency (Joules/bit) Latency (ms) Ultra-low energy Ultra-low complexity Ultra-high density Large coverage Connection density (devices/km2) Figure 16 Comparison of IMT-advanced and IMT-2020 features and requirements [1]. of representations of IMT-2020 systems that can satisfy the requirements related to techni- cal performance for IMT-2020 radio interfaces in the aforementioned test environments. Similar to IMT-Advanced process, the proponents could propose a single radio interface technology or a set of radio interface technologies to fulfill the requirements. The technical characteristics of IMT-2020 systems chosen for evaluation have been explained in detail in Report ITU-R M.[IMT-2020.SUBMISSION] including service and spectrum aspects as well as the requirements related to technical performance, which are based on Report ITU-R M.[IMT-2020.TECH PERF REQ]. These requirements are summa- rized in Table 3, together with the high-level assessment methods which i