5.4.3.3 Paging Priority

Paging Priority is a feature that allows the AMF to include an indication in the Paging Message sent to NG-RAN that the UE be paged with priority. The decision by the AMF whether to include Paging Priority in the Paging Message is based on the ARP value in the message received from the SMF for an IP packet waiting to be delivered in the UPF. If the ARP value is associated with select priority services (e.g. MPS, MCS), the AMF includes Paging Priority in the Paging Message. When the NG-RAN receives a Paging Message with Paging Priority, it handles the page with priority.

The AMF while waiting for the UE to respond to a page sent without priority receives another message from the SMF with an ARP associated with select priority services (e.g. MPS, MCS), the AMF sends another Paging message to the (R)AN including the Paging Priority. For subsequent messages, the AMF may determine whether to send the Paging message with higher Paging Priority based on local policy.

For a UE in RRC_INACTIVE state, the NG-RAN determines Paging Priority based on the ARP associated with the QoS Flow as provisioned by the operator policy and the service priority. Service priority is specified as RAN Paging Priority in TS 38.413 [34]. Service priority (values 1 to 256) provides the AN with the importance of the downlink data and signalling. The AMF derives this service priority based on available information as described in clause 5.4.6.3. The method to derive the service priority is implementation dependent and can be controlled by an operator.