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Read-only Review: 5.3

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Meeting: TSGS4_135_India
Generated: 2026-04-07 09:31:05

TDoc Number	Title	Source	Summary	Proposals	Comments
S4-260030	LS on Invitation to Nominate Representatives to ITU-T JCA-MV and Provide Input to the Metaverse Standardization Roadmap	JCA-MV	No summary available	No proposals available	No comments
S4-260031 (pdf)	LS on initiation of new work item Q.IMS-INT-RS “IMS interconnection restoration architecture and procedures”	ITU-T Study Group 11	LS on Initiation of New Work Item Q.IMS-INT-RS "IMS Interconnection Restoration Architecture and Procedures" Document Overview This is a Liaison Statement (LS) from ITU-T Study Group 11 to 3GPP (for information) announcing the initiation of a new work item Q.IMS-INT-RS on "IMS interconnection restoration architecture and procedures" during the ITU-T SG11 meeting in Geneva, November 17-26, 2025. Main Technical Contribution New Work Item Initiation ITU-T SG11 has initiated work on Q.IMS-INT-RS, which specifies restoration architecture and procedures based on a shared backup interconnection point to enhance service resilience in IMS interconnection scenarios. Scope of Q.IMS-INT-RS The draft Recommendation covers the following technical areas: 1. Restoration Architecture Defines the restoration architecture for IMS interconnection Focuses on shared backup interconnection point mechanisms 2. Service Interruption Conditions Specifies conditions under which IMS interconnection service interruptions occur Identifies scenarios requiring restoration procedures 3. Restoration Signaling Procedures Details the signaling procedures for IMS interconnection restoration Defines protocol interactions for failover and recovery 4. Interface Descriptions Provides interface descriptions specific to IMS interconnection restoration Defines reference points and protocols for restoration mechanisms Collaboration Request ITU-T SG11 is seeking collaboration with 3GPP on this subject matter, given the relevance to IMS interconnection which is a key area of 3GPP specifications. Reference Documents The baseline text of Q.IMS-INT-RS is available in SG11-TD657/GEN (attached to the LS).	This document does not contain any proposals. It is a liaison statement from ITU-T Study Group 11 to 3GPP informing about the initiation of a new work item, but it does not include any technical proposals in the formats specified.	No comments
S4-260032 (pdf)	1,25 ms frame duration now available in TS 103 634 V1.6.1 (LC3plus)	ETSI TC DECT	Summary of DECT Liaison Statement on LC3plus 1.25ms Frame Duration Availability Document Overview This is a Liaison Statement from ETSI TC DECT to 3GPP SA4 (S4-260032) responding to a previous 3GPP request (S4-241377) regarding LC3plus integration in 3GPP ISAR. The document announces the availability of a new LC3plus specification version with ultra-low-delay capabilities. Main Technical Contributions New LC3plus Version Release ETSI TC DECT announces the publication of ETSI TS 103 634 V1.6.1 (October 2025), which includes both updated specification text and reference software. Ultra-Low-Delay Mode Specifications The key technical addition is a new 1.25ms frame duration mode with the following characteristics: Frame duration: 1.25ms Total algorithmic delay: 2.5ms Bitrate range: 128 to 512 kbps per channel Target application: 3GPP audio services with very tight latency requirements Additional Updates in V1.6.1 The revision includes several maintenance and compatibility improvements: Bug fixes and maintenance for all legacy modes Improved compatibility of floating-point software with the STL WMC (Weighted Million Operations) complexity estimation tool Context and Future Updates ETSI TC DECT indicates this update directly addresses 3GPP SA4's previous liaison regarding LC3plus integration in ISAR and commits to providing future updates on new revisions of ETSI TS 103 634.	This document does not contain any technical proposals. It is a Liaison Statement from ETSI TC DECT to 3GPP SA4 informing them about the availability of a new version of ETSI TS 103 634 (LC3plus) with 1.25ms frame duration support. The document only contains informational content and explicitly states "Not required" in the Actions section.	No comments
S4-260033 (pdf)	Reply LS to CTA WAVE on CMCD phase 2	CTA WAVE	Reply LS to CTA WAVE on CMCD Phase 2 Document Information Meeting: 3GPP TSG-SA4 Meeting #135 (S4-260033) Date: 9-13 February 2026, Goa, India Response to: S4-251997 Release: Rel-20 Work Item: FS_AMD_Ph2, AMD_PRO-MED Source: CTA WAVE To: 3GPP TSG SA WG4 Cc: SVTA DASH-IF WG, ISO/IEC JTC1 SC29 WG03 (MPEG Systems) Contact: Will Law (wilaw@akamai.com) Overview This is a Liaison Statement (LS) from CTA WAVE to 3GPP SA4 regarding CMCD (Common Media Client Data) Phase 2 development. The document serves as a reply to a previous LS (S4-251997). Key Technical Contributions CMCD Version 2 Status The LS indicates that CTA WAVE has provided an email received and a CMCDv2 Release Candidate as attachments to this liaison statement. Coordination Activities This liaison represents ongoing coordination between: - CTA WAVE (Consumer Technology Association Web Application Video Ecosystem) - 3GPP SA4 (Service and System Aspects Working Group 4 - Codec and Media) - SVTA DASH-IF WG (Streaming Video Technology Alliance - DASH Industry Forum Working Group) - ISO/IEC JTC1 SC29 WG03 (MPEG Systems) Work Item Context The LS is associated with two work items: - FS_AMD_Ph2: Feasibility Study on Adaptive Media Delivery Phase 2 - AMD_PRO-MED: Adaptive Media Delivery for Professional Media Purpose This reply LS appears to be providing 3GPP SA4 with the latest CMCDv2 Release Candidate documentation for review and consideration in the context of the ongoing Adaptive Media Delivery Phase 2 work and Professional Media activities in Release 20.	Proposals from Document S4-260033 This document does not contain any proposals. It is a Liaison Statement (LS) template with header information only, and does not include any technical proposals in any of the standard formats.	No comments
S4-260284 (pdf)	LS on Subjective quality evaluation of AI-based ultra-low bitrate voice codecs	ITU-T Study Group 12	LS on Subjective Quality Evaluation of AI-based Ultra-low Bitrate Voice Codecs Document Information Source: ITU-T Study Group 12 Reference: SG12-LS18 (SG12-TD298R1) Date: Geneva, 9-18 September 2025 For Information to: 3GPP SA4 Deadline: June 2026 Background and Context ITU-T SG12 reviewed multiple contributions during its September 2025 meeting addressing ML- and AI-based speech processing features and their evaluation using subjective tests and objective models. A key contribution (SG12-C40) from Rohde & Schwarz SwissQual AG presented P.800 listening test results that included several AI-based ultra-low bitrate codecs. Main Technical Findings Performance of AI-based Ultra-low Bitrate Codecs The P.800 listening tests demonstrated that several AI-based ultra-low bitrate codecs scored better than traditional low-bitrate codecs, proving their usefulness in the telecommunication context. Limitations of Current Test Methodologies While the P.800 overall MOS rating procedure appears generally appropriate for evaluating these codecs, SG12 identified potential limitations: Timbre shifts may not be adequately reflected in traditional MOS ratings Small drops in information that could be critical in mission-critical calls might not be captured New test methods that better reflect these perceptual effects may be necessary E-model Integration Concerns SG12 concluded that it would be premature to incorporate these AI-based codecs into the E-model (by deriving equipment impairment factors) due to: Subjective effects not yet fully covered by available test methods Rapid evolution and changes in the respective codec technologies Request for Feedback ITU-T SG12 is seeking feedback from 3GPP SA4 based on their experience before deciding to: Start development of new appropriate subjective test methodologies Develop potential corresponding prediction models The liaison includes attachment SG12-C40 describing a subjective ACR LOT testing of AI-based and ultra-low bitrate codecs in a full-scale real field context.	This document does not contain any proposals. The document is a liaison statement from ITU-T Study Group 12 to 3GPP SA4 regarding subjective quality evaluation of AI-based ultra-low bitrate voice codecs. While it discusses test results and considerations for evaluation methodologies, it does not include any explicitly marked proposals in any of the standard formats.	No comments
S4-260288 (pdf)	Allowing the use of Type 4.3 and Type 4.4 artificial ears for 3GPP testing	CTIA Certification Audio Working Group	No summary available	No proposals available	No comments

LS on Initiation of New Work Item Q.IMS-INT-RS "IMS Interconnection Restoration Architecture and Procedures"

Document Overview

This is a Liaison Statement (LS) from ITU-T Study Group 11 to 3GPP (for information) announcing the initiation of a new work item Q.IMS-INT-RS on "IMS interconnection restoration architecture and procedures" during the ITU-T SG11 meeting in Geneva, November 17-26, 2025.

Main Technical Contribution

New Work Item Initiation

ITU-T SG11 has initiated work on Q.IMS-INT-RS, which specifies restoration architecture and procedures based on a shared backup interconnection point to enhance service resilience in IMS interconnection scenarios.

Scope of Q.IMS-INT-RS

The draft Recommendation covers the following technical areas:

1. Restoration Architecture

Defines the restoration architecture for IMS interconnection
Focuses on shared backup interconnection point mechanisms

2. Service Interruption Conditions

Specifies conditions under which IMS interconnection service interruptions occur
Identifies scenarios requiring restoration procedures

3. Restoration Signaling Procedures

Details the signaling procedures for IMS interconnection restoration
Defines protocol interactions for failover and recovery

4. Interface Descriptions

Provides interface descriptions specific to IMS interconnection restoration
Defines reference points and protocols for restoration mechanisms

Collaboration Request

ITU-T SG11 is seeking collaboration with 3GPP on this subject matter, given the relevance to IMS interconnection which is a key area of 3GPP specifications.

Reference Documents

The baseline text of Q.IMS-INT-RS is available in SG11-TD657/GEN (attached to the LS).

This document does not contain any proposals. It is a liaison statement from ITU-T Study Group 11 to 3GPP informing about the initiation of a new work item, but it does not include any technical proposals in the formats specified.

Summary of DECT Liaison Statement on LC3plus 1.25ms Frame Duration Availability

Document Overview

This is a Liaison Statement from ETSI TC DECT to 3GPP SA4 (S4-260032) responding to a previous 3GPP request (S4-241377) regarding LC3plus integration in 3GPP ISAR. The document announces the availability of a new LC3plus specification version with ultra-low-delay capabilities.

Main Technical Contributions

New LC3plus Version Release

ETSI TC DECT announces the publication of ETSI TS 103 634 V1.6.1 (October 2025), which includes both updated specification text and reference software.

Ultra-Low-Delay Mode Specifications

The key technical addition is a new 1.25ms frame duration mode with the following characteristics:

Frame duration: 1.25ms
Total algorithmic delay: 2.5ms
Bitrate range: 128 to 512 kbps per channel
Target application: 3GPP audio services with very tight latency requirements

Additional Updates in V1.6.1

The revision includes several maintenance and compatibility improvements:

Bug fixes and maintenance for all legacy modes
Improved compatibility of floating-point software with the STL WMC (Weighted Million Operations) complexity estimation tool

Context and Future Updates

ETSI TC DECT indicates this update directly addresses 3GPP SA4's previous liaison regarding LC3plus integration in ISAR and commits to providing future updates on new revisions of ETSI TS 103 634.

This document does not contain any technical proposals. It is a Liaison Statement from ETSI TC DECT to 3GPP SA4 informing them about the availability of a new version of ETSI TS 103 634 (LC3plus) with 1.25ms frame duration support. The document only contains informational content and explicitly states "Not required" in the Actions section.

Reply LS to CTA WAVE on CMCD Phase 2

Document Information

Meeting: 3GPP TSG-SA4 Meeting #135 (S4-260033)
Date: 9-13 February 2026, Goa, India
Response to: S4-251997
Release: Rel-20
Work Item: FS_AMD_Ph2, AMD_PRO-MED
Source: CTA WAVE
To: 3GPP TSG SA WG4
Cc: SVTA DASH-IF WG, ISO/IEC JTC1 SC29 WG03 (MPEG Systems)
Contact: Will Law (wilaw@akamai.com)

Overview

This is a Liaison Statement (LS) from CTA WAVE to 3GPP SA4 regarding CMCD (Common Media Client Data) Phase 2 development. The document serves as a reply to a previous LS (S4-251997).

Key Technical Contributions

CMCD Version 2 Status

The LS indicates that CTA WAVE has provided an email received and a CMCDv2 Release Candidate as attachments to this liaison statement.

Coordination Activities

This liaison represents ongoing coordination between: - CTA WAVE (Consumer Technology Association Web Application Video Ecosystem) - 3GPP SA4 (Service and System Aspects Working Group 4 - Codec and Media) - SVTA DASH-IF WG (Streaming Video Technology Alliance - DASH Industry Forum Working Group) - ISO/IEC JTC1 SC29 WG03 (MPEG Systems)

Work Item Context

The LS is associated with two work items: - FS_AMD_Ph2: Feasibility Study on Adaptive Media Delivery Phase 2 - AMD_PRO-MED: Adaptive Media Delivery for Professional Media

Purpose

This reply LS appears to be providing 3GPP SA4 with the latest CMCDv2 Release Candidate documentation for review and consideration in the context of the ongoing Adaptive Media Delivery Phase 2 work and Professional Media activities in Release 20.

Proposals from Document S4-260033

This document does not contain any proposals. It is a Liaison Statement (LS) template with header information only, and does not include any technical proposals in any of the standard formats.

LS on Subjective Quality Evaluation of AI-based Ultra-low Bitrate Voice Codecs

Document Information

Source: ITU-T Study Group 12
Reference: SG12-LS18 (SG12-TD298R1)
Date: Geneva, 9-18 September 2025
For Information to: 3GPP SA4
Deadline: June 2026

Background and Context

ITU-T SG12 reviewed multiple contributions during its September 2025 meeting addressing ML- and AI-based speech processing features and their evaluation using subjective tests and objective models. A key contribution (SG12-C40) from Rohde & Schwarz SwissQual AG presented P.800 listening test results that included several AI-based ultra-low bitrate codecs.

Main Technical Findings

Performance of AI-based Ultra-low Bitrate Codecs

The P.800 listening tests demonstrated that several AI-based ultra-low bitrate codecs scored better than traditional low-bitrate codecs, proving their usefulness in the telecommunication context.

Limitations of Current Test Methodologies

While the P.800 overall MOS rating procedure appears generally appropriate for evaluating these codecs, SG12 identified potential limitations:

Timbre shifts may not be adequately reflected in traditional MOS ratings
Small drops in information that could be critical in mission-critical calls might not be captured
New test methods that better reflect these perceptual effects may be necessary

E-model Integration Concerns

SG12 concluded that it would be premature to incorporate these AI-based codecs into the E-model (by deriving equipment impairment factors) due to:

Subjective effects not yet fully covered by available test methods
Rapid evolution and changes in the respective codec technologies

Request for Feedback

ITU-T SG12 is seeking feedback from 3GPP SA4 based on their experience before deciding to:

Start development of new appropriate subjective test methodologies
Develop potential corresponding prediction models

The liaison includes attachment SG12-C40 describing a subjective ACR LOT testing of AI-based and ultra-low bitrate codecs in a full-scale real field context.

This document does not contain any proposals. The document is a liaison statement from ITU-T Study Group 12 to 3GPP SA4 regarding subjective quality evaluation of AI-based ultra-low bitrate voice codecs. While it discusses test results and considerations for evaluation methodologies, it does not include any explicitly marked proposals in any of the standard formats.

Total TDocs: 6 | PDFs: 5 | Comments: 0