# Summary of 3GPP TR 26.501 Change Request

## Document Information
- **CR Number**: S4-260253
- **Specification**: TR 26.958 v0.1.1
- **Work Item**: FS_3DGS_MED (Study on 3D Gaussian Splatting for Media)
- **Category**: B (addition of feature)
- **Release**: Rel-20

## Main Objective

This CR proposes to add a new clause (6.X) to TR 26.958 addressing the mapping of 3D Gaussian Splatting (3DGS) services to 3GPP 5G QoS Identifier (5QI) parameters as specified in TS 23.501.

## Technical Contributions

### Background on 5QI (Clause 6.X.1)

The CR provides a comprehensive table of relevant pre-defined 5QI values from TS 23.501 that have similar QoS characteristics to 3DGS services, including:

- **GBR Resources**: 
  - 5QI 1-4: Conversational voice/video, real-time gaming, buffered streaming (PDB: 50-300ms, PER: 10⁻² to 10⁻⁶)
  - 5QI 71-76: Live uplink streaming (PDB: 300-500ms, PER: 10⁻⁴ to 10⁻⁸)
  - 5QI 80: Low latency eMBB/AR applications (PDB: 10ms, PER: 10⁻⁶)
  
- **Delay-Critical GBR**:
  - 5QI 88: Motion tracking data, split AI/ML inference (PDB: 10ms, PER: 10⁻³)
  - 5QI 89-90: Visual content for cloud/edge/split rendering (PDB: 15-20ms, PER: 10⁻⁴)

- **Non-GBR Resources**:
  - 5QI 5-10: IMS signaling, buffered streaming, interactive gaming (PDB: 100-1100ms)

### 3DGS Application Flows for 5QI Mapping (Clause 6.X.2)

The CR identifies distinct application flows requiring QoS treatment:

1. **Delivery of 3DGS media content application flows**
2. **Delivery from/to UE of static 3DGS scene content**
3. **Delivery from network to UE of dynamic or view-based 3DGS content**
4. **Delivery of user pose, gaze information, LOD information from UE to network** for network-assisted rendering or delivery

### Recommendations (Clause 6.X.3)

The CR establishes the following recommendations for the study outcome:

- **Mapping Identification**: A mapping of 3DGS application flows to appropriate 5QI values should be identified
- **Reference 5QI Values**: Existing 5QI values (from clause 6.X.1) with similar QoS/QoE expectations and RAN resource priority should be used as reference for determining appropriate 5QI values and QoS characteristics limits for 3DGS services
- **New 5QI Definition**: If existing 5QI values are insufficient, liaison with appropriate 3GPP groups (likely SA2) should be initiated to define new 5QI values and corresponding QoS characteristics specifically for 3DGS services

## Rationale

The CR addresses a gap in the FS_3DGS_MED study by providing guidance on how 3DGS services should be treated within the 5G System QoS framework, ensuring proper traffic handling behavior through appropriate QoS Flow configuration.