Proposed General Updates to Terms of Reference for SA4 Working Group

Summary and Background

This document proposes general updates to the SA4 Working Group Terms of Reference (ToR) in preparation for 6G work. The proposal is separate from AI-related updates covered in S4-260xxx. The document is submitted for agreement at SA4 and subsequent approval at SA plenary in March 2026.

Main Technical Contributions

Scope of Responsibilities Updates

Codec Development Expansion

• Broadened codec scope: Updated language to include "codecs for speech, audio, video, graphics and other newly emerging media types" (previously more limited scope)
• Enhanced media handling: Added explicit mention of "transport and handling of such media including related session descriptions and storage formats"

Service Architecture Enhancements

• Cloud and edge computing: Explicit inclusion of "media-centric cloud and edge computing architectures" in the definition of streaming and real-time communication services
• Media APIs: Added "media APIs" and "media profiles" to the list of SA4 responsibilities
• Session descriptions: Formalized responsibility for session descriptions

Third-Party Services Support

• New responsibility area: Added explicit scope for supporting third-party media services and applications to benefit from 3GPP system functionalities
• Network and client interfaces: Defined responsibility for providing suitable network and client interfaces/APIs
• Traffic characteristics: Includes definition of traffic characteristics and QoE requirements for emerging services (particularly XR applications)

AI/ML Integration

• AI/ML for multimedia: Added explicit mention of "artificial intelligence (AI)/Machine Learning (ML) for multimedia" as part of SA4's service scope

Sub-Working Group Structure

The document formalizes the structure of four SA4 Sub-Working Groups with detailed Terms of Reference:

Multimedia Broadcast Streaming (MBS) SWG

• Core focus: Integration of codecs, system and delivery aspects for download, streaming, and messaging services
• Key responsibilities:
• Content formats and delivery protocols for unicast, multicast, and broadcast streaming
• Messaging services
• Cloud and edge computing architectures
• Media APIs
• QoE and energy efficiency metrics reporting
• Traffic characteristics definition

Real-Time Communication (RTC) SWG

• Core focus: Integration of codecs and system aspects for real-time communication services including multimedia telephony and XR communications
• Key responsibilities:
• Content formats and delivery protocols for services with real-time constraints
• Updates to cloud and edge computing architectures
• Media APIs
• QoE metrics reporting
• Traffic characteristics for real-time services

Video SWG

• Core focus: Specification of codecs for video, graphics, images, and other visual media types including immersive formats
• Key responsibilities:
• Visual quality evaluation and test methodology
• Characterization of visual formats
• QoE metrics definition
• AI/ML applications: Explicit inclusion of AI/ML applied to multimedia scenarios
• Neural network model formats
• Model optimization and compression aspects

Audio SWG

• Core focus: Development and maintenance of specifications for speech/audio codecs and quality evaluation
• Key responsibilities:
• Transport and media handling aspects
• Testing, verification, characterization, and selection criteria
• End-to-end performance including terminal characteristics
• Immersive audio formats for multimedia telephony and XR communications
• Capture and rendering aspects of audio media delivery
• Ultra-low bitrate coding: Explicitly added to support voice services via non-terrestrial networks (NTN)

Governance and Decision-Making

• Hierarchical structure: Formalized that SA4 SWGs operate under SA4 WG
• Decision confirmation: All SWG documents require confirmation at SA4 level

External Collaboration

The annex lists key external organizations for coordination:
- ISO/IEC JTC 1/SC 29
- SVT, DASH-IF
- 5G-MAG
- Khronos
- GSMA
- IETF
- ITU-T Study Groups 12 and 16

Key Changes Summary

The main updates reflect:
1. Preparation for 6G work
2. Formalization of cloud/edge computing architectures
3. Explicit AI/ML integration (with detailed AI proposal in separate document)
4. Enhanced support for third-party services
5. Formalization of four SWG structure with detailed ToRs
6. Addition of ultra-low bitrate coding for NTN support
7. Strengthened focus on emerging media types and XR services