t purpose. Now, let us understand what an SFI is. Slot Format Indication SFI indicates whether an OFDM signal is configured as a downlink, an uplink, or flexible (also known as special). Flexible configuration means that the transmission direction of a slot might be either a downlink or an uplink. This slot format indication can also provide the link direction information for one or multiple slots. Each device is configured with a table of different possible link direction assignments, and the SFI will carry an index to that table, which is provided here. 5G Air Interface and Physical Layer Procedures - Part 1 Format Symbol number in a slot 56 - 254 Reserved UE determines the slot format for the slot based on tdd-UL-DL-ConfigurationCommon, tdd-UL-DL- ConfigurationCommon2, or tdd-UL-DL-ConfigDedicated and, if any, on detected DCI formats Figure 4.28 - Slot formats - normal CP SFI can be either dynamic or static. The dynamic SFI is carried over a Downlink Control Information (DCI) message. This is a separate DCI from the one carrying the downlink and uplink grants. This Summary could potentially cause inconsistencies between SFIs, because SFI could signal one resource downlink and the DCI uplink grant could indicate the same resource as an uplink, for instance. Note that a static or semi-static SFI indication will be provided through Radio Resource Control (RRC) signaling. In this section, we've learned about the OFDM waveform that is used in NR, like in LTE. We've also analyzed the NR numerology that is designed for different NR use case requirements. We've also seen how this scalable numerology affects slot duration and what advantages it brings. Furthermore, we showed different NR scheduling schemes and slot formats. Summary In this chapter, we introduced you to NR general physical layer procedures and channel structure. We made comparisons of bandwidths, energy efficiency, and spectral efficiency between LTE and NR. Then, we covered all the important aspects regarding the NR waveform, numerology, and frame stru