3GPP SA4 XCHANGE Notes

16/03/2023 - SA4 XCHANGE

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Implemented a Minimum Viable Product for 5G Media Streaming based on downlink Content Hosting.
- Recently expanded this to include 5GMS AF provisioning at reference point M1d and 5GMS AS configuration at M3d.
Basic Rel-17 reference implementations of the 5GMSd Application Function and 5GMSd Application Server that support the key features of Content Hosting for downlink media streaming.
- Provisioning Sessions, Server Certificates and Content Hosting Configurations can be provisioned in the 5GMSd AF via an implementation of the M1d Provisioning API, complemented by a test client.
- Server Certificates and Content Hosting Configurations can be configured by the 5GMSd AF in the 5GMSd AS via a simple prototype implementation of an M3d Configuration API, complemented by a test client.
There are also basic reference implementations of the Media Player and Media Session Handler for Android.
- The Media Session Handler, which runs as a shared Android background service, is driven by a basic implementation of the M6 Media Session Handling client API. It can retrieve its configuration for a specific Provisioning Session from the 5GMSd AF using the M5d Service Access Information API. Single index.json file that only contains provisioningSessionIDs, mediaPlayerEntry and M5 URL

Once the app starts, the mediaPlayerEntries are populated to the selection dropdown
An entry in the dropdown is selected
The MediaStreamHandler sends an IPC message to the Media Session Handler Background Service updating the lookup table (mapping between provisioningSessionIDs and mediaPlayerEntries)
A stream is selected and the mediaPlayerEntry is send via IPC to the MediaSessionHandler
The Media Session Handler Background Service contacts the AF (or a mocked REST server) using the route syntax defined in 26.512 11.2.2: {apiRoot}/3gpp-m5/{apiVersion}/service-access-information/ adding the {provisioningSessionId}. provisioningSessionId derived via lookup table.
Once it has received the Service Access Information it sends back an IPC message to the Media Stream Handler with the mediaPlayerEntry
The Media Stream Handler plays the MPD defined in mediaPlayerEntry using M7 interface and Exoplayer.
Media Stream Handler collects metrics. Metric reporting endpoint to be defined.

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- 5G-MAG and SA4 MBS subworking group have held two joint meetings already (in the run up to SA4#121 Toulouse and SA4#122) and these concentrated on maintenance of TS 26.512 Rel-16 and Rel-17.
- The changes to that specification agreed recently in Athens are due to go to SA#99 next week for approval and publication, and we have already started to implement them at risk.
- For the forthcoming meeting cycle, there is a mixture of issues relating to:
  - TS 26.512, based on the reference implementation experience.
  - TS 26.517, primarily notifying gaps that have been identified.
- 5G-MAG is aware that both SA4#123-e and SA4#124 Berlin feed into SA#100 Taipei, so the next opportunity to see agreed changes after Easter will be in late June.
5G-MAG intends to participate in the upcoming 3GPP Rel-19 Workshops in our role as Market Representation Partner of 3GPP. We would like to understand the plans for SA4 on such workshops (schedule, thoughts, …)