 of writing this book) contain function-specific information for cell reselection functions, Public Warning, etc. The System Information update procedure is similar to LTE in that an indication about System Information change is provided to the UE, which triggers the System Information acquisition procedure. The main difference compared wiht LTE is that the System Informa- tion change indication and presence of Public Warning System message is provided directly in PDCCH itself, called Short Message (specified in 3GPP TS 38.331), rather than by the RRC Paging message. In NR, the network may decide not to continuously broadcast the other SIBs (i.e. SIB2 to SIB9). This concept is called On Demand System Information. When an IDLE UE requires those SIBs that are not broadcast, it can make a request to the network using an RRC System Info Request message for the SIB that it is interested in. This can trigger the broadcast of the SIB in the cell. Another piece of information that is broadcast by the network is UE Paging, which is used to inform an IDLE or INACTIVE UE that there is pending downlink data to the UE and to request the UE to initiate an RRC connection. A Paging message is sent on a specific paging occasion that the UE monitors and includes the UE identity. Paging could be triggered by the core network for UEs in IDLE or by RAN for UEs in INACTIVE. 3.4.5.2.8 Slicing Slicing is a new functionality supported in 5GS to allow partitioning of the RAN and core network resources across the different slices. A slice could be used to provide a particular service or belong to an administrative domain. During a connection establishment, a UE indicates the slice it wants to connect to, which the network uses to select the appropri- ate core network node that supports the requested slice. Beyond this, most of the slicing functionality is internal to the gNB implementation, and the gNB scheduler should ensure that data for a slice uses only its allocated partition and that the slice does not exceed its allocated resources.