This clause describes the enhancements to the IMS architecture supporting data channel services to additionally support AR services. Two modes for AR services are supported: UE centric and network centric.
Multiple realization alternatives for network assisted AR are available depending on device capability and what requirements the AR application has on the media transport protocol used between the UE and the network assisted AR function. AR services can be delivered via the following mechanisms:
The AR application server provides network assisted rendering by having all AR media being transported using an established application data channel between the UE and the AR application server. This scenario represents a standard P2A/A2P data channel application as per clause AC.7.2 and consequently not requiring any further description.
An IMS Media Function (MF)/Media Resource Function (MRF) having the Augmented Reality Media Function (ARMF) capability, provides required network assisted AR media processing.
The user of UE-A upgrades the IMS session with AR experience.
UE-A initiates a re-INVITE adding media descriptors required by the AR application to be established E2E, e.g. RTP and/or application data channels. Application data channel may be anchored in the MF/MRF.
In this scenario, the UE performs AR media rendering based on the AR data from its local application.
Figure AC.9.3.2-1 depicts an example for a call flow procedure to establish a network centric AR IMS session from UE-A perspective with complete rendering in the network for one of the UEs (UE-A) involved in AR communication. The main steps in the call flow are as follows:
If the negotiation result is successful in step 3, the UE-A initiates new P2A application data channels, which are used for AR data transmission between the UE-A and the network. During the P2A application data channel establishment procedure, the DCSF will instruct the MF via IMS AS how to establish the data channel and corresponding media processing specification.
IMS initiates a Media re-Negotiation request with UE-B, to connect UE-B's audio/video media stream to MF.
The UE-A can request to change the network rendering content if the status changed in the UE-A, such as low power, low computing power, etc.