6.6 Miscellaneous procedures

24.5013GPPNon-Access-Stratum (NAS) protocol for 5G System (5GS)Release 17Stage 3TS

6.6.1 Exchange of extended protocol configuration options

The UE and the SMF can exchange protocol configuration options via 5GSM procedures.

The protocol configuration options shall be exchanged via the Extended protocol configuration options IE.

6.6.2 Remote UE report procedure

6.6.2.1 General

The purpose of the 5G ProSe remote UE report procedure is for a UE acting as 5G ProSe layer-3 UE-to-network relay to notify the network that a 5G ProSe remote UE is connected to the 5G ProSe layer-3 UE-to-network relay UE or disconnected from the 5G ProSe layer-3 UE-to-network relay UE as specified in 3GPP TS 23.304 [6E].

6.6.2.2 Remote UE report procedure initiation

In order to initiate the 5G ProSe remote UE report procedure, the UE shall create a REMOTE UE REPORT message.

The UE shall include information of newly connected or disconnected 5G ProSe remote UEs to the network in the REMOTE UE REPORT message by setting the values of the Remote UE context connected IE or the Remote UE context disconnected IE to the 5G ProSe remote UE identities that are being connected or disconnected, respectively.

Editor’s note: It is FFS what are the types of 5G ProSe remote UE identities that can be included in the REMOTE UE REPORT message as this is waiting for stage-2 definitions.

The UE shall set the PDU session ID IE to the value of the PDU session associated with the 5G ProSe remote UE connected to the 5G ProSe layer-3 UE-to-network relay UE or disconnected from the 5G ProSe layer-3 UE-to-network relay UE.

The UE shall allocate a PTI value currently not used and shall set the PTI IE of the REMOTE UE REPORT message to the allocated PTI value.

The UE shall transport the REMOTE UE REPORT message and the PDU session ID, using the NAS transport procedure as specified in subclause 5.4.5, and the UE shall start timer T3586 (see example in figure 6.6.2.2.1).

Figure 6.6.2.2.1: Remote UE report procedure

6.6.2.3 Remote UE report procedure accepted by the network

Upon receipt of the REMOTE UE REPORT message, the SMF shall send a REMOTE UE REPORT RESPONSE message to the UE. The SMF shall include the PTI from the REMOTE UE REPORT message.

Upon receipt of the REMOTE UE REPORT RESPONSE message, the UE shall stop timer T3586 and enter the state PROCEDURE TRANSACTION INACTIVE.

6.6.2.4 Abnormal cases in the UE

The following abnormal cases can be identified:

a) Expiry of timer T3586:

On the first expiry of the timer T3586, the UE shall resend the REMOTE UE REPORT message and shall reset and restart timer T3586. This retransmission is repeated two times, i.e. on the third expiry of timer T3586, the UE shall abort the procedure and release any resources for this procedure.

NOTE: After the abortion of the remote UE report procedure, the remote UE report procedure for the remote UE(s) can be restarted and how to restart the procedure is left to UE implementation.

6.6.2.5 Abnormal cases on the network side

No abnormal cases have been identified.