The higher the subcarrier spacing, the more slots that can be accommodated per sub- frame [12]. Fig. 3.42 illustrates the NR frame, subframe, slot and mini-slot structure. Different numerologies can be used in diverse deployment scenarios with their correspond- ing performance requirements. For example, the lower the subcarrier spacing, the larger the size, which will be suitable for the lower frequency deployments. At the same time, larger subcarrier spacing will allow shorter latency since the symbol duration will be shorter New Radio Access Physical Layer Aspects (Part 1) 385 10 ms Frame i Frame i + 1 Slot 0 SCS = 15 kHz Slot 0 Slot 1 SCS = 30 kHz Slot 0 Slot 1 Slot 2 Slot 3 SCS = 60 kHz Slot 0 Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 Slot 7 SCS = 120 kHz OFDM symbols Figure 3.42 3GPP NR frame structure [12]. (see Fig. 3.42). Fig. 3.43 shows the relationship of the numerology, cell size, latency, and the carrier frequency [53]. The frame structure provides the basis for the timing of physical signal transmission. The timing scale is different for data, control, and synchronization physical channels. The sam- pling time in NR is defined as T = 1/(AfmaxNFFT) where fmax = 480kHz and NFFT = 4096. In order to support multiple OFDM numerologies, the parameter u and the corresponding CP for a BWP are signaled (configured) by the RRC parameters DL-BWP- mu and DL-BWP-cp for the downlink and UL-BWP-mu and UL-BWP-cp for the uplink [12,21]. The downlink and uplink transmissions are structured in the form of radio frames in the time domain with frame duration Tframe = (AfmaxNFFT/100)2 T = 10 ms, where each frame consists of ten subframes of Tsubframe = (AfmaxN//1000): duration. The num- consecutive OFDM symbols in each subframe is defined as symbols subframe subframe (u). In FDD mode, there is one set of frames in the uplink and one set of frames in the downlink on a carrier. As shown in Fig. 3.44, the ith uplink frame number starts at TTA = (NTA + NTA-offset) T before the start of the corresponding downlink frame at the 