 the studies being carried out within ITU-R in the lead up to WRC-19. 5G systems rely on the spectrum within three frequency ranges in order to deliver extensive coverage and throughput and to support all use cases. Those frequency regions include sub- 1 GHz, 1-6 GHz, and above 6 GHz. The sub-1 GHz region will support widespread cover- age across urban, suburban, and rural areas and will enable IoT services. The large wave- lengths below 1 GHz; however, limit the option to use 5G features such as massive MIMO. That's because handheld devices are typically not large enough to accommodate more than two sub-1 GHz antennas, while size, weight, wind resistance, and visual impact considera- tions limit the number of deployable antenna elements at base stations. Frequency range 1-6 GHz offers a good tradeoff between coverage and capacity with spectrum within the 3.3-3.8 GHz range expected to form the basis for many initial 5G deployments under 6 GHz [29]. Macrocell network coverage is uplink limited because the 23 dBm maximum output power of mobile devices is much lower than the base station power which can be in excess of 46 dBm. Therefore, a 3500 MHz uplink falls short of LTE 2100 MHz or LTE 1800 MHz coverage. The frequency range above 6 GHz is needed in order to enable extremely high data rates required for some 5G applications where the focus will be on fre- quency bands above 24 GHz which include growing interest in the 24 GHz and/or 28 GHz bands. There is also some interest in exploring bands in the 6-24 GHz frequency region; however, this range has not been included in WRC-19 sharing studies [30,37]. Introduction and Background lxxxiii One of the main objectives of the telecommunication industry is to connect everything and everywhere by more comprehensively and intelligently integrating LTE (in licensed and unlicensed bands), Wi-Fi, and cellular IoT technologies, together with 5G radio interface. This will allow mobile networks to dynamically allocate resources to support the varying needs of an extremely divers