Section: 9.2.1.2 Cell Reselection
Content: A UE in RRC_IDLE performs cell reselection. The principles of the procedure are the following: - Cell reselection is always based on CD-SSBs located on the synchronization raster (see clause 5.2.4). - The UE makes measurements of attributes of the serving and neighbour cells to enable the reselection process: - For the search and measurement of inter-frequency neighbouring cells, only the carrier frequencies need to be indicated. - Cell reselection identifies the cell that the UE should camp on. It is based on cell reselection criteria which involves measurements of the serving and neighbour cells: - Intra-frequency reselection is based on ranking of cells; - Inter-frequency reselection is based on absolute priorities where a UE tries to camp on the highest priority frequency available; - A Neighbour Cell List (NCL) can be provided by the serving cell to handle specific cases for intra- and inter-frequency neighbouring cells; - Exclude-lists can be provided to prevent the UE from reselecting to specific intra- and inter-frequency neighbouring cells; - Allow-lists can be provided to request the UE to reselect to only specific intra- and inter-frequency neighbouring cells; - Cell reselection can be speed dependent; - Service specific prioritisation; - Slice-based cell reselection information can be provided to facilitate the UE to reselect a cell that supports specific slices. In multi-beam operations, the cell quality is derived amongst the beams corresponding to the same cell (see clause 9.2.4).