= and = 3, respectively, can be utilized in FR2 to provide additional robustness of the transmitted signal to radio frequency impairments such as phase noise. The additional parameters related to the support of different numerologies in NR are summarized in Table 3.5.1. 3.5.3 Frame Structure Similar to LTE, NR also supports the concept of frame in time (3GPP TS 38.211). A frame has a duration of 10 ms irrespective of the SCS used and is divided into two half frames, each with five subframes. Each subframe always has a duration of 1 ms and is further subdivided into one or multiple slots depending on the scaling parameter (see Figure 3.5.1). The number of OFDM symbols within a slot is always 14 and does not change with SCS. 3 5G System Overview Radio Frame, 10 ms subframe Subcarrier Number of slot#0 slot# u -1 spacing slots 15 kHz Slot#0 30 kHz Slot#0 Slot#1 OFDM symbols = 14 60 kHz Slot#0 Slot#1 Slot#2 Slot#3 120 kHz Slot#0 Slot#1 Slot#2 Slot#3 Slot#4 Slot#5 Slot#6 Slot#7 RB#N -1 Figure 3.5.1 Frame structure supported by NR. Similar to LTE-A, a set of 12 subcarriers in the frequency domain across 14 OFDM sym- bols in the time domain is grouped into a physical resource block (PRB). The total number of the available PRBs depends on the SCS and the frequency range. The maximum sup- ported bandwidth is 100 MHz in FR1 and 400 MHz in FR2. The supported bandwidth sizes and the maximum number of PRBs in Release-15 NR are summarized in Table 3.5.2. In NR, PRB boundaries corresponding to different SCS values are frequency aligned rel- ative to a common reference point termed "Point A" as illustrated in Figure 3.5.2. Such frequency alignment is supported for efficient multiplexing of transmissions corresponding to different numerologies in the same cell or for the same UE. NR supports conventional slot-level based scheduling denoted in NR as Type A mapping. Slot-level transmission can only start at specific OFDM symbols, but has flexible duration Table 3.5.2 Supported bandwidth sizes in Release-15 NR for different subcarrie