I). The MSI is transmitted via the MIB (Master Information Block) and SIB1 in the case of 5G-SA or in the RRC ConnectionReconfiguration message in the case of 5G-NSA. Minimum System Information (MIS) Master Information System Information Block Block 1 OSI (Other SI) System Information Block 2 to 9 Logical Channel Transport Channel DL-SCH Physical Channel PDSCH Figure 7.2. Remaining minimum information system. For a color version of this figure, see www.iste.co.uk/launay/5g.zip 7.2. CORESET The concept of CORESET (Control Resource SET) was introduced on the 5G-NR interface to limit the control frequency domain to the capacities of devices. Unlike the 4G radio interface for which the physical PDCCH (Physical Downlink Control Channel) control channel occupies the entire bandwidth of the carrier, on the 5G-NR interface, the mobile is specifically configured to listen to a subspace of tempo-frequency resources corresponding to the control search space. DCI (Downlink Control Information) information is transmitted in the CORESET space. One, two or at most three CORESETs are configured in each BWP. CORESET is a set of configurable Resource Elements (RE). The configuration is stored in the ControlResourceSET element. NG-RAN and 5G-NR The Resource Elements (RE) in a CORESET are grouped together by RBs (Resource Blocks), called the Resource Element Group (REG). The PDCCH physical channel and the DM-RS (Demodulation-Reference Signal) reference signals associated with the physical channel are transmitted in a CORESET. The PDCCH (Physical Downlink Control Channel) is made up of an aggregation of control channel elements (CCEs). A CCE is made up of six REGs. The PDCCH channel carries DCI messages. Each message is defined by a DCI format. Depending on the size of the message, it is necessary to aggregate 1, 2, 4, 8 or 16 CCEs. The CORESET is formed by CCEs grouped into RB (REG) associated with the DM-RS reference signals. REGs can be interlaced to provide frequency diversity or can be contiguous for beam localization (beamformi