A.3 xMB Procedure example for Live DASH services (with Service Continuity)

29.1163GPPRelease 18Representational state transfer over xMB reference point between content provider and BM-SCTS

This procedure example describes the xMB-C procedures for a Live DASH service with service continuity. See 3GPP TS 26.247 [18] for the specification of DASH services. Service continuity allows UEs to enter or leave the MBMS service areas while receiving a Live DASH service. UEs can switch to unicast as defined in clause 7.6 of 3GPP TS 26.346 [3] when leaving the MBMS service area.

In case of service continuity support, the system offers representations via unicast and via MBMS Bearers. A unified MPD (cf. clause 7.6 of 3GPP TS 26.346 [3]) contains the corresponding retrieval information. When service continuity is supported, the Content Provider provides MPD and Initialization Segments for both unicast and MBMS bearer access and also the associated Media Segments. The Content Handler functions forwards the content to a DASH (unicast) Server. The DASH (unicast) server can use a Content Delivery Network (CDN) for unicast delivery.

A push interface is used here as ingestion method for the xMB-U user-plane data. The source of the user plane data (Content Provider Source) are the DASH Media Segments as produced by a Live Encoder / Segmenter, which produces the content for unicast and MBMS bearer delivery. The Media Presentation Description and Initialization Segment for the Live DASH session are provided separately to the BM-SC.

The Service Announcement Function (SAF) of the BM-SC creates the needed metadata fragments for the MBMS User Service. To support service continuity, the SAF adds base pattern elements to the userServiceDescription element. The MBMS Client in the UE matches the base pattern against a portion of the entire request URL. The SAF creates unified MPD by adding information specific elements to it. The SAF makes the service announcement information available via unicast and via MBMS.

A content handler function of the BM-SC handles the separation of unicast and MBMS bearer content. The content handler function makes the content available in operators CDN for unicast access.