leaved to provide frequency diversity. CORESET In the frequency domain, the CORESET consists of a block of N RB resources defined by the CORESET-freg-dom parameter This parameter is transmitted to the mobile by RRC signaling. CORESET In the time domain, the CORESET is spread over N symbols defined by the CORESET-time-dur parameter and carried by the RRC signaling. CORESET The number of REG forming the CORESET is defined by the N REG parameter. Unlike the LTE radio interface, the physical NR-PDCCH channel is not transmitted over the entire frequency band, but only in a BWP sub-partition. The physical NR-PDCCH channel is similar to the physical LTE E-PDCCH channel. 5G-NR Radio Interface - The Physical Layer 5G-NR Carrier CORESET CORESET DM-RS PDCCH REG 5 = 1 RB REG 0 to REG 5 Figure 4.17. The PDDCH channel in a slot and at PRB The physical PDCCH and the physical DM-RS associated with the PDCCH are transmitted in an aggregation of contiguous CCEs (1, 2, 4, 8 or 16 aggregations). The aggregation number is defined by the aggregation level parameter. The number of bits that can be transmitted in the PDCCH is equal to 54 RE X 2 bits X Aggregation level, i.e. 108, 216, 432, 864, 1728 bits for the aggregation of 1, 2, 4, 8 or 16 CCE respectively. The DCI information is transmitted in the CORESET. This is information relating to the physical layer and the MAC layer, called L1/L2 control signaling. The CCE is the smallest unit in the search space for the blind decoding of DCI information. The search space is a subset of resource elements within CORESET. This subset is scanned by the UE mobiles to detect the presence of DCI information intended for There are two types of search space: - the Common Search Space (CSS); - the UE Search Space (USS, Specific Search Space). The search for the presence of DCI information is carried out using an RNTI (Radio Network Temporary Identifier). 122 NG-RAN and 5G-NR RNTIs are used to identify information which is dedicated to a UE in the cell or a group of UEs. RNTI is a 16-bit identifier a