 count is reset [8]. When a UE is paged, the paging message is broadcast over a group of cells. In NR the basic principle of UE tracking is the same for idle and inactive modes, although the grouping is to some extent different in the two cases. The NR cells are grouped into RAN areas, where each RAN area is identified by a RAN area ID (RAI). The RAN areas are grouped into larger tracking areas, where each tracking area is identified by a tracking area ID (TAI). As a result, each cell belongs to one RAN area and one tracking area, the identities of which are provided as part of the cell SI. The tracking areas are the basis for device tracking at core-network level. Each device is assigned a UE registration area by the CN, consisting of a list of TAIs. When a device enters a cell that belongs to a tracking area not included in the assigned UE registration area, it accesses the network, including the CN, and per- forms a NAS registration update. The CN registers the device location and updates the device registration area and provides the device with a new TAI list that includes the new TAI. The reason that the device is assigned a set of TAIs is to avoid repeated NAS regis- tration updates, every time that the device crosses the border of two neighbor tracking areas. By keeping the old TAI within the updated UE registration area, no new update is needed, if the device moves back to the old TAI. The RAN area is the basis for device tracking on RAN level. The UEs in the inactive mode can be assigned an RNA that con- sists of either a list of cell identities; a list of RAIs; or a list of TAIs [17]. The procedure for RNA update is similar to the update of the UE registration area. When a device enters a cell that is not included in its RNA, it accesses the network and per- forms an RNA update. The radio network registers the device location and updates the device RNA. Since the change of tracking area always implies the change of the device RAN area, an RNA update is implicitly performed every time a device performs a