S4-260032 - AI Summary

1,25 ms frame duration now available in TS 103 634 V1.6.1 (LC3plus)

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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.

Document Information

TDoc:
S4-260032

Source:
ETSI TC DECT

Type:
LS in

For:
Information

Original Document:
View on 3GPP

Title: 1,25 ms frame duration now available in TS 103 634 V1.6.1 (LC3plus)

Agenda item: 5.3

Agenda item description: Other groups

Doc type: LS in

For action: Information

Original LS: DECT(25)000298r1

To: SA4

Contact: Andrijana Brekalo

Uploaded: 2026-01-21T16:11:06.363000

Contact ID: 91743

TDoc Status: postponed

Reservation date: 21/01/2026 16:06:08

Agenda item sort order: 8