d-UL-DL-ConfigurationDedicated allows us to define the configuration of the direction of transmission for each symbol. 4.2.3. The dynamic configuration of the transmission for a group of mobiles When the mobile is in the connected state, it is scheduled by the base station through DCI information control messages. The slot configuration for a group of mobiles is transmitted by an SFI indicator (Slot Format Indicator) carried by the DCI 2.0 message. The Slot Format Indicator is a pointer to a configuration table that contains 256 values (see Slot formats for normal cyclic prefix - 3GPP TS 38.213 V16.1.0, Table 11.1.1-1). At the level of specification Release 16 (V2.0 - July 2020), only 55 combinations are standardized. The value SFI = 255 informs the mobile that the configuration of the slot is determined by the static message. The dynamic slot configuration is reserved for isolated base stations because this configuration makes it possible to allocate radio resources in a very flexible way, via an SFI for a mobile, or for a group of mobiles (e.g. femtocell). The SFI indicator can also indicate the direction of another cell's slot (cross-carrier). 4.3. Physical resource 4.3.1. Resource grid A Resource Element (RE) is the smallest unit that can be assigned to a signal (Figure 4.5). The RE corresponds to an OFDM symbol in the time domain and a subcarrier in the frequency domain. It is thus identified by the pair (k, 1), with 5G-NR Radio Interface - The Physical Layer k representing the index of the subcarrier and 1 representing the index of the OFDM symbol in the time domain, with respect to a relative reference point. 1 sub-frame k=12.N 12 sub-carriers l=14.2 -1 Figure 4.5. Resource grid The RB (Resource Block) corresponds to an allocation of 12 contiguous subcarriers (Figure 4.5). Unlike 4G, the RB 5G resource block corresponds to a frequency allocation. The resource grid is an allocation of tempo-frequency resources intended for an antenna port. It consists of a set of symbols per subframe (see Table 4.6) in the 