ransmission can be scheduled to span one or multiple slots when slot aggregation is supported. For each serving cell, if a UE receives the RRC parameter UL-DL-configuration-common, it must set the slot format per slot over the number of slots indicated by this parameter. If the UE is additionally provided with RRC parameter UL-DL-configuration-dedicated for the slot format per slot over a number of slots, the latter parameter overrides only flexible symbols per slot over the number of slots indicated by UL-DL-configuration-common parameter. The UE determines the duration New Radio Access Physical Layer Aspects (Part 1) 391 One slot k = NRB(H)NRB SCS = 120 kHz PRB 0 PRB 1 SCS = 60 kHz PRB 0 PRB 1 PRB 2 PRB 3 SCS = 30 kHz PRB 0 PRB 1 PRB 2 PRB 3 PRB 4 PRB 5 PRB 6 PRB 7 Resource block SCS = 15 kHz PRBOPRB1PRB2PRB3PRB4PRB5PRB6PRB7PRB8PRB9PRB10PRB11PRB12PRB13PRB14PRB15 Resource element (k,1) in resource block resource element (k,T) in resource grid 1=14x2"-1 Figure 3.47 Illustration of NR resource grids and PRBs [12]. of each slot in the number of slots, in each configured BWP, based on the subcarrier spac- ing value provided by higher layer parameter ref-scs. The UE considers symbols in a slot indicated as downlink by higher layer parameter UL-DL-configuration-common or by higher layer parameter UL-DL-configuration-dedicated as available for receiving control/traffic. The UE further considers symbols in a slot as uplink indicated by higher layer parameter UL-DL-configuration-common or by higher layer parameter UL-DL-configuration-dedicated as available for transmission of control/traffic [14,15]. 3.7 Time-Frequency Resources 3.7.1 Physical Resource Blocks The basic scheduling unit in NR is a physical resource block (PRB) comprising 12 subcar- riers in the frequency domain over one OFDM symbol. All subcarriers within a PRB have the same subcarrier spacing and CP length. When an NR system supports multiple numerol- logies, the corresponding PRBs are multiplexed in the time domain such that the boundaries of PRBs are al