Modifications for PCF-initiated Inactive to Idle State

This section describes about the inactive to idle state activities in the PCF-initiated modification call flow procedure.

The following figure describes the Modifications for PCF-initiated Inactive to Idle State call flow.

Call Flow for the Modifications for PCF-initiated Inactive to Idle State
Call Flow Description for the Modifications for PCF-initiated Inactive to Idle State

Step

Description

1

The PCF sends the SMF Policy Association Modification Request to the SMF.

It’s an interchangeable action as it also receives the same message from the SMF.

2

The SMF sends the Namf Comm N1N2MessageTransfer Request to the AMF.

It’s an interchangeable action as it also receives the same message from the AMF.

3

The AMF sends the PDU Session Resource Modify Request to the RAN.

Note

During this step, the gNB performs the paging activities as the gNB pushes the UE to the RRC_IDLE mode.

4

The RAN sends the PDU Session Resource Modify Response Unsuccessful message to the AMF.

It also includes the unknown failure cause message.

5

The AMF sends the Nsmf PDUSession UpdateSMContext (N2SMlnfo) response message to the SMF.

It’s an interchangeable action as it also receives the same message from the SMF.

Note

During this step, the SMF waits for the RRC_Release procedure to get completed.

6

The SMF resends the PDU Session Resource Modify message to the AMF.

Note

This step follows the 3GPP TS 23.502 AN release procedure.