, which are measured over the air in the far-field of the antennas; thus they include the antenna patterns and directivity effects [1]. In OTA test procedures, the spatial characteris- tics of the BS including the antenna system are evaluated. In base stations equipped with AAS, where the active parts of the transceiver are integrated with the antenna system, it is not always possible to conduct the measurements at the antenna connector. For this reason, 3GPP Rel-13 specified the RF requirements for the AAS base stations in a set of separate RF specifications that are applicable to LTE and the previous generations. The radiated RF requirements and OTA testing are being specified for the new radio for the FR1 and FR2 bands, which have bor- rowed a large portion of the previously developed AAS specifications. Note that the term AAS is not used within the NR base station RF specifications, rather the requirements are specified for different BS types. The AAS-type BS requirements are based on the generalized AAS BS radio architecture shown in Fig. 5.4 [5]. The architecture consists of a transceiver unit array that is connected to a composite antenna structure that contains a radio distribution network and an antenna array. The transceiver unit array comprises a number of transmitter and receiver units, which are connected to the composite antenna structure via a number of connectors on the transceiver array boundary (TAB). The TAB connectors correspond to the antenna connectors on a non- AAS BS and serve as a reference point for the conducted requirements. The radio distribution network is a passive unit which distributes or aggregates the transmitter outputs or the receiver inputs to the corresponding antenna elements, respectively. It must be noted that the actual implementation of an AAS BS may be different in terms of the physical location of different parts, array geometry, type of antenna elements, etc. Based on the architecture shown in Fig. 5.4, two types of requirements can be defined. Conducted requirements