S4-260085 - AI Summary

Procedure for IVAS bandwidth computation

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Summary of 3GPP CR S4-260085

Change Request Details

  • Specification: TS 26.114 v18.12.0
  • CR Number: 0605
  • Category: F (Correction)
  • Release: Rel-18
  • Work Item: IVAS_Codec

Main Technical Contribution

Problem Statement

The document identifies an inconsistency in the bandwidth computation procedure for the IVAS codec specified in clause Z.2 compared to the general session setup procedures defined in clause 6.2.7.2 of TS 26.114. Specifically, the IVAS-specific procedure includes RTCP bandwidth in the b=AS (Application-Specific maximum bandwidth) calculation, while other codecs and general procedures do not.

Technical Solution

The CR proposes a correction to clause Z.2 "Procedure for computing the bandwidth" to align the IVAS codec bandwidth calculation with existing procedures for other codecs.

Modified Bandwidth Calculation Procedure

The updated procedure for computing b=AS when no extra bandwidth is allocated for redundancy:

  1. Use the highest negotiated bitrate for the IVAS codec included in the SDP (using ibr or ibr-recv parameters if specified)
  2. Calculate bitrate for the RTP payload header
  3. Add bandwidth needed for PI (Primary Importance) data (using pi-br or pi-br-recv parameters if specified)
  4. Add bandwidth needed for IP, UDP and RTP headers assuming 50 frames per second:
  5. 16 kbps for IPv4
  6. 24 kbps for IPv6
  7. ~~Add bandwidth needed for RTCP~~ (REMOVED)
  8. The b=AS bandwidth is the sum of the above listed bitrates after rounding up to nearest integer kbps

Key Change: Step 5 (adding RTCP bandwidth) has been removed from the calculation procedure, and the subsequent step has been renumbered from 6 to 5.

Impact

The CR ensures consistency across TS 26.114 by removing the RTCP bandwidth component from the IVAS-specific b=AS calculation, aligning it with the treatment of other codecs in the specification. This eliminates ambiguity in bandwidth modifier handling for IVAS codec implementations.

Document Information
Source:
Ericsson LM, Samsung Electronics Co., Ltd, Nokia
Type:
CR
For:
Agreement
Original Document:
View on 3GPP
Title: Procedure for IVAS bandwidth computation
Agenda item: 7.4
Agenda item description: Release 19 and earlier matters
Doc type: CR
For action: Agreement
Secretary remarks: Source modified on 2/3/2026. Original source : Ericsson LM, Samsung Electronics Co., Ltd, Nokia
Release: Rel-18
Specification: 26.114
Version: 18.12.0
Related WIs: IVAS_Codec
CR number: 605.0
CR category: F
Clauses affected: Z.2
CN: True
CR: 605.0
ME: True
Spec: 26.114
Contact: Tomas Jansson Toftgård
Uploaded: 2026-02-03T20:24:30.307000
Contact ID: 72490
Revised to: S4-260318
TDoc Status: revised
Clauses Affected: Z.2
Reservation date: 02/02/2026 09:28:20
Secretary Remarks: Source modified on 2/3/2026. Original source : Ericsson LM, Samsung Electronics Co., Ltd, Nokia
Agenda item sort order: 16