carrying the PDSCH message with respect to the DCI message received, the length L of the PDSCH message and the position S of the first symbol carrying the PDSCH message (SLIV indicator: start and length indicator) S=2 : Symbol position L symbol PDSCH Slot n Slot n+2 Offset Ko PDCCH Figure 4.18. The allocation of the PDSCH message in the time domain (SLIV) The specification offers three types of resource allocation in the time domain. Configuration A is presented in Table 4.11, and configurations B and C can be retrieved from the specification 3GPP TS38.214 Table 5.1.2.1.1-4/5. In the frequency domain, there are two types of resource allocation for the downlink. NG-RAN and 5G-NR Row index dmrs-TypeA- PDSCH Position mapping type Type A Type A Type A Type A Type A Type A Type A Type A Type A Type A Type B Type B Type B Type B Type B Type B Type B Type B Type A Type A Type A Type B Type B Table 4.11. The allocation of PDSCH in the time domain (TS 38.214, Table 5.1.2.1.1-2) for configuration A Type 0 resource allocation consists of allocating groups of consecutive PRBs in frequency, called RBG (Resource Block Group). Each RBG allocated to the mobile UE is signaled by a message, each bit of which corresponds to the allocation or not of the RBG (bitmap allocation). The number of RBs in an RBG depends on the size of the BWP bandwidth (Table 4.12). 5G-NR Radio Interface - The Physical Layer Number of PRB in BWP Configuration 1 Configuration 2 37-72 73-144 145-275 Table 4.12. The length of RBG in function of the bandwidth (TS 38.214, Table 5.1.2.2.1-1) Configuration 1 or 2 is transmitted by the RBGSize field contained in the PDSCH-Config structure of the RRC message. Type 1 resource allocation allocates a set of Virtual Resource Blocks (VRB). Type 1 allocation involves allocating a starting block of resources and a number of VRBs. This information is encoded in a Resource Indication Value (RIV), transmitted in a DCI message. The VRB mapping to PRB resources can be localized (one VRB corresponds to one PRB) or distributed (