5 Protocol using SIP for telepresence

24.1033GPPRelease 17Stage 3Telepresence using the IP Multimedia (IM) Core Network (CN) Subsystem (IMS)TS

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

5.1 Introduction

SIP, as specified in 3GPP TS 24.229 [2] and 3GPP TS 24.147 [3], is used as the basic session control protocol to create an IM session supporting telepresence.

The usage of SIP for the point to point call supporting telepresence is following the procedures as specified in 3GPP TS 24.229 [2]. The usage of SIP for the multiparty conference supporting telepresence is following the procedures as specified in 3GPP TS 24.147 [3].

To support an IM session supporting telepresence, a "+sip.clue" Contact header field parameter is defined in clause 3 of IETF RFC 8848 [6].

5.2 Functional entities

5.2.1 User Equipment (UE)

For the purpose of IM session supporting telepresence, the TP UE shall implement the role of a participant in both point to point call and multiparty conference as described in subclause 5.3.1.

5.2.2 Media Resource Function Controller (MRFC)

For the purpose of IM session supporting telepresence, the MRFC shall support the procedures as described in subclause 5.2.2 of 3GPP TS 24.147 [3].

5.2.3 Conferencing Application Server (Conferencing AS)

For the purpose of IM session supporting telepresence, the TP enabled conferencing AS shall implement the role of a conference focus, as described in subclause 5.3.2.

5.3 Role

5.3.1 Participant

During registration the TP UE follows the procedures specified in subclause 5.1.1 of 3GPP TS 24.229 [2] as a basis, and it shall include a "+sip.clue" Contact header field parameter in the SIP REGISTER request.

To establish an IM session supporting telepresence, the TP UE shall use the procedures as specified in subclause 5.1 of 3GPP TS 24.229 [2] for point to point call, and follow the conference procedures as specified in subclause 5.3.1 of 3GPP TS 24.147 [3] for multiparty conference, in both the TP UE shall include a "+sip.clue" Contact header field parameter in the SIP INVITE and SIP UPDATE requests and responses.

5.3.2 Conference Focus

The TP conference focus follows the procedures specified in subclause 5.3.2 of 3GPP TS 24.147 [3] appropriate to the functional entity in which the conference focus is implemented.

The TP conference focus shall include the "+sip.clue" Contact header field parameter when generating a SIP request or response for the establishment of an IM conference supporting telepesence.