uencies - for instance, MM wave for high capacity. In this case, time dispersion is even less. So, for instance, a cyclic prefix of 0.59 us would be enough if a 120 kHz subcarrier spacing is utilized. Note that this kind of deployment will also provide lower latency compared to the other preceding cases, due to the shorter slot duration of 120 kHz subcarrier spacing. Now, let's understand the frame structure of NR by comparing it to LTE. Frame structure NR uses the same frame duration as LTE, which is 10 milliseconds. The frame is divided into tens of subframes with 1 millisecond each, as in LTE. At this point, the similarities between LTE and NR frame structures end. The NR subframe is not related to the scheduling unit or Transmission Time Interval (TTI), as it was in LTE. NR just provides a common time reference to which all numerologies can refer, and NR is assigned to different units, slots, and mini-slots. Waveform, numerology, and frame structure One radio frame (10 ms) One subframe (1 ms) Numerology 15 kHz 30 kHz 60 kHz 120 kHz 240 kHz (only SSB) One slot One "mini slot" (Type B) Figure 4.19 - NR frame structure The slots are composed of 14 OFDM symbols, and the slot duration depends on the subcarrier spacing. The slots are aligned with subframe boundaries, and they are a typical scheduling unit for type A for PDSCH or PUSCH. Increasing the subcarrier spacing shortens the OFDM symbol duration in time; hence, it reduces the slot duration accordingly. This can be seen in the preceding figure. A slot at 15 kHz corresponds to 1 millisecond, and the length reduces to the powers of 2 as the subcarrier spacing increases. So, the number of slots in a subframe changes depending on the subcarrier spacing. This also influences the TTI length, which can be from 1 millisecond at 15 kHz to 125 microseconds 120 kHz subcarrier spacings. A mini-slot is a unit shorter than a slot. It can be either 2, 4, or 7 OFDM symbols and can start at any symbol boundary. It is a typical scheduling unit for type B for PDSCH or PUSCH. Le