W.3 Application usage of SIP

24.2293GPPIP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP)Release 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

W.3.1 Procedures at the UE

W.3.1.0 Registration and authentication

The procedures specified in Annex U.3.1.0 apply with the following clarification:

– the UE shall perform reregistration of a previously registered public user identity bound to any one of its contact addresses when changing to an IP-CAN for which usage is specified in annex U or annex L.

W.3.1.0a IMS_Registration_handling policy

The IMS_Registration_handling policy indicates whether the UE deregisters from IMS after a configured amount of time after receiving an indication that the IMS Voice over PS Session is not supported.

The UE may support the IMS_Registration_handling policy.

If the UE supports the IMS_Registration_handling policy, the UE may support being configured with the IMS_Registration_handling policy using one or more of the following methods:

a) the IMS_Registration_Policy node of the EF_{IMSConfigData} file described in 3GPP TS 31.102 [15C];

b) the IMS_Registration_Policy node of the EF_{IMSConfigData} file described in 3GPP TS 31.103 [15B]; and

c) the IMS_Registration_Policy node of 3GPP TS 24.167 [8G].

If the UE is configured with both the IMS_Registration_Policy node of 3GPP TS 24.167 [8G] and the IMS_Registration_Policy node of the EF_{IMSConfigData} file described in 3GPP TS 31.102 [15C] or 3GPP TS 31.103 [15B], then the IMS_Registration_Policy node of the EF_{IMSConfigData} file shall take precedence.

NOTE 1: Precedence for files configured on both the USIM and ISIM is defined in 3GPP TS 31.103 [15B].

If the UE is registered with IMS and the IMSVoPS indicator, provided by the lower layers (see 3GPP TS 24.501 [258]), indicates voice is not supported, the UE shall:

A) if the Stay_Registered_When_VoPS_Not_Supported leaf indicates requirement to stay registered, the UE needs not to deregister and maintains the registration as required for IMS services; or

NOTE 2: The UE will periodically refresh the registration when needed.

B) if the Stay_Registered_When_VoPS_Not_Supported leaf indicates requirement to deregister and the Deregistration_Timer leaf used to configure the NoVoPS-dereg timer defined in table 7.8.1 contains a timer value for the time to wait before deregistrerting from IMS, start a timer with the value indicated in the policy and:

a) if the timer expires before the UE receives an indication from the lower layers that IMS voice is supported:

1) if there is no ongoing IMS session, the UE either performs reregistration as specified in subclause 5.1.1.4 and shall only include feature tags associated with services that are independent of IMSVoPS indicator or deregister from the IMS following the procedures specified in subclause 5.1.1.6; or

2) if there is ongoing IMS session, and

i) if the UE does not receive indication from the lower layer that the IMS voice is supported before the ongoing IMS session is terminated, the UE either performs reregistration as specified in subclause 5.1.1.4 and shall only include feature tags associated with services that are independent of IMSVoPS indicator or deregister from the IMS following the procedures specified in subclause 5.1.1.6 as soon as the ongoing IMS based service is terminated; or

ii) if the UE receives indication from the lower layer that the IMS voice is supported before the ongoing IMS session is terminated, cancel the timer; or

NOTE 3: How the UE selects reregistration or deregistration is implementation dependent (e.g., SMS service)

b) if the UE receives an indication from the lower layers that IMS voice is supported before the timer expires, cancel the timer.

If the IMS_Registration_handling policy is not configured, the UE behaviour is implementation specific.

W.3.1.1 P-Access-Network-Info header field

The UE shall always include the P-Access-Network-Info header field where indicated in subclause 5.1.

W.3.1.1A Cellular-Network-Info header field

The UE:

1) using the 5GCN via Wireless Local Access Network (WLAN) as IP-CAN to access the IM CN subsystem; and

2) supporting one or more cellular radio access technology (e.g. NR);

shall always include the Cellular-Network-Info header field specified in subclause 7.2.15, if the information is available, in every request or response in which the P-Access-Network-Info header field is present.

W.3.1.2 Availability for calls

Not applicable.

W.3.1.2A Availability for SMS

Void.

W.3.1.3 Authorization header field

Void.

W.3.1.4 SIP handling at the terminating UE when precondition is not supported in the received INVITE request, the terminating UE does not have resources available and IP-CAN performs network-initiated resource reservation for the terminating UE

Not applicable.

W.3.1.5 3GPP PS data off

Not applicable.

W.3.1.6 Transport mechanisms

Void.

W.3.1.7 RLOS

Not applicable.

W.3.2 Procedures at the P-CSCF

W.3.2.0 Registration and authentication

Void.

W.3.2.1 Determining network to which the originating user is attached

The procedures specified in Annex U.3.2.1 apply.

W.3.2.2 Location information handling

Void.

W.3.2.3 Prohibited usage of PDU session for emergency bearer services

The procedures specified in Annex U.3.2.3 apply.

W.3.2.4 Support for paging policy differentiation

Void.

W.3.2.5 Void

W.3.2.6 Resource sharing

The feature is not supported in this release of the specification.

W.3.2.7 Priority sharing

The feature is not supported in this release of the specificaiton

W.3.2.8 RLOS

Not applicable.

W.3.3 Procedures at the S-CSCF

W.3.3.1 Notification of AS about registration status

Not applicable.

W.3.3.2 RLOS

Not applicable.