es are tightly coupled to the beamforming aspects, which are directly constrained by the UE form factor and use case. It is thus dif- ferent for a smartphone, a customer premises equipment (CPE) used in fixed wireless access, or a vehicle; the main parameters are as follows: The EIRP, which depends on both the power capability (battery capacity) and the prac- tical phase array size SC, which depends on the need to cover the entire sphere With regard to these two criteria: A smartphone has to cover all directions as it is both mobile and is manipulated, has limited room available for arrays, and limited battery power: thus, full SC is needed and a moderate EIRP can be achieved. A CPE has mostly to cover the outside and can be a few cm square: thus, half SC is sufficient, and a higher EIRP is feasible. A vehicle mostly has to cover the horizon and above it and has less stringent size and power supply limitations than a smartphone: thus, less than half SC and a higher EIRP is feasible. Finally, for relays and repeaters, space and supply are not critical limitations, and they can be physically oriented: thus, half SC and a high EIRP are targeted. These different UE characteristics have resulted in four UE power classes being defined for FR2 as summarized in Table 12.7, for which requirements are defined in terms of the minimum EIRP, maximum TRP, and SC CCDF. The maximum EIRP corresponds to the regulatory limits for different types of UE. 12.4.4.2 ACLR vs. FR1 One of the early (2017) 5G NR studies in FR2 was to assess adjacent channel coexistence performance accounting for the beamforming aspects. Coexistence requirements result Table 12.7 FR2 UE power classes for band n257. UE Power Min EIRP Max EIRP Max TRP Min EIRP CDF class UE type (dBm) (dBm) (dBm) (percentile/dBm) Fixed wireless 85%/32.0 access (FWA) UE Vehicular UE 60%/18.0 Handheld UE 50%/11.0 High power 20%/25.0 non-handheld UE 12.4 5G Standalone Performance Aspects in mmWave Frequency Range 2 in two KPIs: the ACLR for the transmit side and the ACS (Adjacent 