ETSI TS 126 238 V17.0.0 (2022-05)

Universal Mobile Telecommunications System (UMTS); LTE; 5G; Uplink streaming (3GPP TS 26.238 version 17.0.0 Release 17)

RTS/TSGS-0426238vh00

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 4 - Codec
• Current Stage: 12 - Completion
• Completion Date: 19-May-2022

Standards Content (Sample)

TECHNICAL SPECIFICATION
Universal Mobile Telecommunications System (UMTS);
LTE;
5G;
Uplink streaming
(3GPP TS 26.238 version 17.0.0 Release 17)


3GPP TS 26.238 version 17.0.0 Release 17 1 ETSI TS 126 238 V17.0.0 (2022-05)

Reference
RTS/TSGS-0426238vh00
Keywords
5G,LTE,UMTS
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ETSI
3GPP TS 26.238 version 17.0.0 Release 17 2 ETSI TS 126 238 V17.0.0 (2022-05)
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3GPP TS 26.238 version 17.0.0 Release 17 3 ETSI TS 126 238 V17.0.0 (2022-05)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 6
Introduction . 6
1 Scope . 7
2 References . 7
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Symbols . 9
3.3 Abbreviations . 9
4 System architecture . 9
4.1 General . 9
4.2 System . 9
4.2.1 General . 9
4.2.2 Uplink streaming for MTSI . 11
4.2.3 Uplink streaming for PSS-based distribution . 12
4.3 Terminal . 12
4.4 Procedures . 14
4.4.1 General . 14
4.4.2 FLUS session establishment . 14
4.4.3 FLUS session update . 14
4.4.4 FLUS sink capability discovery . 15
4.4.5 FLUS session termination . 15
4.5 FLUS source systems . 15
4.5.1 Introduction. 15
4.5.2 General source systems . 15
4.5.3 Vendor-specific source system . 17
4.5.4 Default source system . 18
4.5.5 3DOF FLUS source system . 18
4.5.5.1 Introduction . 18
4.5.5.2 Coordinate system . 18
4.5.5.3 Descriptive Parameters . 19
4.5.6 Media production FLUS source system . 20
4.6 Uplink Assistance . 21
4.6.1 Uplink Assistance using UNA mechanisms . 21
4.6.2 Uplink Assistance using RAN Signaling Mechanism . 21
5 Protocols . 22
5.1 General . 22
5.2 IMS-based system . 22
5.2.1 System configuration . 22
5.2.1.1 Introduction . 22
5.2.1.2 FLUS sink configuration and selection . 22
5.2.1.2.1 UE-based FLUS sink . 22
5.2.1.2.2 Network-based FLUS sink . 22
5.2.1.3 FLUS management object . 23
5.2.2 Session management . 24
5.2.3 Data transport . 25
5.3 Generic FLUS system . 25
5.3.1 System configuration . 25
5.3.2 Session management . 25
5.3.2.1a FLUS sink capability discovery . 25
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5.3.2.1b FLUS sink discovery . 25
5.3.2.2 Create a FLUS Sink Configuration . 26
5.3.2.4 Update a FLUS Sink Configuration . 26
5.3.2.5 FLUS session termination . 27
5.3.2.6 Void. 27
5.3.2.7 Void. 27
5.3.2.8 Void. 27
5.3.2.9 Void. 27
5.3.2.10 Session establishment for Remote Control . 28
5.3.2.11 FLUS Source capability discovery . 28
5.3.2.12 Remote FLUS Source configuration creation . 28
5.3.2.14 Update FLUS Source configuration . 29
5.3.2.15 Delete a FLUS Source configuration . 30
5.3.2.16 RAN signaling based uplink assistance. 30
5.3.3 Data transport . 31
5.3.4 List of FLUS sink capabilities . 31
5.3.5 FLUS source characterisation, capabilities and configuration properties . 31
5.3.6 List of FLUS Sink Configuration properties . 33
5.4 RAN Signaling based Uplink Assistance . 35
5.4.1 General . 35
5.4.2 Uplink bitrate recommendation and boost request . 35
5.4.3 ANBR/ANBRQ mapping to MAC signaling and nominal usage . 35
5.4.4 Uplink assistance in the context of QoS . 35
6 Terminal capabilities . 36
6.1 General . 36
7 Uplink Streaming Control Interface . 36
7.1 General . 36
7.1.0 Introduction. 36
7.1.1 Resources . 36
7.1.1.0 General . 36
7.1.1.1 Capabilities Resource . 37
7.1.1.2 Session Resource . 38
7.1.2 Supported Methods . 39
7.1.3 Error Handling . 39
7.2 Discovery . 39
7.3 Capability retrieval . 40
7.4 Uplink streaming configuration . 40
7.4.1 FLUS session properties fetch procedure . 40
7.4.2 FLUS session update procedure. 41
7.4.2.1 Partial modification of FLUS session . 41
7.4.2.2 Full modification of FLUS session . 42
7.5 Session establishment . 43
7.6 Session termination . 44
8 FLUS Security . 44
8.1 IMS-based FLUS . 44
8.2 Non-IMS-based FLUS . 45
9 Media Codec Profiles . 45
9.1 General . 45
9.2 IMS-based FLUS . 45
9.3 Non-IMS-based FLUS . 45
10 Remote Control . 45
10.1 General . 45
10.2 Usage of MQTT . 46
10.3 RC Framing Message Format . 46
Annex A (informative): Example deployment scenarios for FLUS sub-functions . 47
A.0 General . 47
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A.1 Deployment with minimal FLUS sub-functions . 47
A.1.1 Introduction . 47
A.1.2 Deployment with a Media Source and a Control Source co-located in the same device . 47
A.1.3 Deployment with non-colocated Control Source and Media Source . 48
A.2 Deployments with FLUS remote control sub-functions . 48
A.2.1 Introduction . 48
A.2.2 Deployment with stand-alone Control Source and Remote Controller sub-functions . 48
A.2.3 Deployment with a Remote Controller co-located with a Control Sink sub-function . 49
Annex B (informative): Network-Based Media Processing (NBMP) . 51
Annex C (informative): Change history . 53
History . 54

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3GPP TS 26.238 version 17.0.0 Release 17 6 ETSI TS 126 238 V17.0.0 (2022-05)
Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
Introduction
The Framework for Live Uplink Streaming (FLUS) is an enabler for live media streaming from a source entity to a sink
entity. FLUS offers an IMS-based and a non-IMS-based instantiation. The IMS/MTSI-based instantiation enables the
establishment of live media streaming between two UEs or between a source entity and a sink entity, within and across
operator networks. Compared with MTSI, where limited types of QoS for speech or video media are used, FLUS can
provide a wider range of QoS operation, e.g., in the maximum delay, available bandwidth or target packet loss rate.
In the non-IMS-based instantiation, it is possible to operate FLUS as a more generic framework that is controlled
through a RESTful API and that supports other media plane protocols (i.e. not based on IMS or MTSI).
In addition to providing a wider range of QoS operation over radio links, other advanced functionalities of FLUS, such
as the signalling of immersive media, can be used to complement existing 3GPP services.
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1 Scope
The present document defines a FLUS source entity and a FLUS sink entity that can support point-to-point transmission
of speech/audio, video, and text. It defines media handling (e.g., signalling, transport, packet-loss handling, and
adaptation). The goal is to ensure a reliable and interoperable service with a predictable media quality while allowing
for flexibility in the service offerings.
A FLUS source entity, which may be embedded in a single UE, or distributed among a UE and separate audio-visual
capture devices, may support all or a subset of the features specified in this document.
When used as a generic framework, only the F-C procedures for establishing the FLUS session are required to be
supported by the FLUS source and the FLUS sink entities, and no other feature or procedure specified in this document
is mandated. Impact on the service quality and network capacity is left to the discretion of the implementation and the
service utilizing the framework. For example, configuration of media formats and codecs follows the requirements of
the respective service.
When offered as part of a 3GPP IMS/MTSI service, the FLUS source and the FLUS sink entities are required to support
the IMS control plane and media plane procedures, and the service quality is determined by the MTSI service policy.
The specification is written in a forward-compatible way in order to allow additions of media components and
functionality in releases beyond Release 15.
.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] Recommendation ITU-R BS.2051-1 (06/2017): "Advanced Sound System for Programme
Production".
[3] ISO/IEC 23090-2:2019: "Information technology - Coded representation of immersive media -
Part 2: Omnidirectional media format".
[4] 3GPP TS 26.114: "IP Multimedia Subsystem (IMS); Multimedia telephony; Media handling and
interaction".
[5] 3GPP TS 26.235: "Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols
and codecs".
[6] 3GPP TS 24.147: "Conferencing using the IM Multimedia (IM) Core Network (CN) subsystem;
Stage 3".
[7] 3GPP TS 23.003: "Numbering, addressing and identification".
[8] 3GPP TS 33.203: "3G security; Access security for IP-based services".
[9] 3GPP TS 33.210: "3G security; Network Domain Security (NDS); IP network layer security".
[10] 3GPP TS 33.328: "IP Multimedia Subsystem (IMS) media plane security".
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[11] IETF RFC 7231: "Hypertext transfer protocol (HTTP/1.1): Semantics and Content" (June 2014).
[12] 3GPP TS 24.229: "IP multimedia call control protocol based on Session Initiation Protocol (SIP)
and Session Description Protocol (SDP); Stage 3".
[13] 3GPP TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal
Terrestrial Radio Access Network (E-UTRAN) access".
[14] 3GPP TS 23.682: " Architecture enhancements to facilitate communications with packet data
networks and applications".
[16] 3GPP TS 26.501: "5G Media Streaming (5GMS); General description and architecture".
[17] ISO/IEC DIS 23090-8: "Information technology -- Coded representation of immersive media --
Part 8: Network based media processing" (under development).
[18] IETF RFC 4574: "The Session Description Protocol (SDP) Label Attribute" (August 2006).
[19] 3GPP TS 36.321: "Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access
Control (MAC) protocol specification".
[20] 3GPP TS 38.321,: "NR; Medium Access Control (MAC) protocol specification".
[21] OMA-ERELD-DM-V1_2-20070209-A: "Enabler Release Definition for OMA Device
Management, Approved Version 1.2".
[22] 3GPP TR 26.939: " Guidelines on the Framework for Live Uplink Streaming (FLUS)".
[23] 3GPP TS 26.511: "5G Media Streaming (5GMS); Profiles, codecs and formats".
[24] IETF RFC 7798 (2016): "RTP Payload Format for High Efficiency Video Coding (HEVC)"
[25] 3GPP TS 26.445: "Codec for Enhanced Voice Services (EVS); Detailed Algorithmic Description".
[26] IETF RFC 4867 (2007): "RTP Payload Format and File Storage Format for the Adaptive Multi-
Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs".
[27] IETF RFC 6416 (2011): "RTP Payload Format for MPEG-4 Audio/Visual Streams".
[28]  OASIS Standard, MQTT Version 5.0, https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html

[29]  3GPP TS 24.147, Conferencing using the IP Multimedia (IM); Core Network (CN) subsystem;
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 [1] and the following
apply. A term defined in the present document takes precedence over the definition of the same term, if any, in 3GPP
TR 21.905 [1].
FLUS session: A logical association between a FLUS source and a FLUS sink within which media content can be sent
from the source to the sink.
Media session: A subset or part of a FLUS session between a FLUS source and a FLUS sink including the duration to
establish the Media Media session, the time period during which media content can be sent from the FLUS source to the
FLUS sink and the duration to terminate the MMedia session. One or more MMedia sessions are delivered during a
FLUS session. A MMedia session may be established and controlled by a well-defined control protocol.
Media stream: The content sent from a FLUS source to a FLUS sink within a MMedia session.
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3.2 Symbols
For the purposes of the present document, the following symbols apply:

3.3 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1] and the following apply. An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
3GPP TR 21.905 [1].
FLUS Framework for Live Uplink Streaming
HMD Head Mounted Display
IMS IP Multimedia Subsystem
MO Management Object
NBMP Network Based Media Processing
4 System architecture
4.1 General
This clause introduces the system architecture for FLUS.
4.2 System
4.2.1 General
Figure 4.2-1 depicts the architecture showing the relevant entities for providing an uplink streaming service.

Rendering
F
Capture
FLUS source FLUS sink Processing
devices
F
Distribution
Sink Discovery
Server
UE UE or Network
Figure 4.2-1: FLUS architecture
The uplink streaming service architecture is based on a FLUS source located in a UE and a FLUS sink located in either
another UE or the network.
The FLUS source receives media content from one or more capture devices. In the context of this specification, the
capture devices are considered as parts of a UE or are connected to it.
When the FLUS sink is located in a UE, the FLUS sink shall forward media content to a decoding and rendering
function.
When the FLUS sink is located in the network,
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the FLUS sink may forward media content to a processing or distribution sub-function. The processing and
distribution sub-functions are not in scope of the present specification. The FLUS sink may act as a Media
Gateway Function (MGW) and/or an Application Function (AF).
- an optional Sink Discovery Server offers functionality that allows to discover available FLUS sinks.
- each FLUS sink provides functionality to query its capabilities and FLUS sessions.
The F reference point connects a FLUS source to a FLUS sink and optionally to the Sink Discovery Server. The F
reference point enables the discovery of available FLUS sinks. In addition,. the F reference point enables the
establishment and control of a single FLUS session between the FLUS source and FLUS sink.
The F reference point also enables the FLUS sink and the FLUS source to mutually authenticate and authorize each
other.
FLUS source and FLUS sink are each split into:
- Media Source and Sink (F-U end-points),
- Control Source and Sink (F-C end-points),
- Remote Controller and Remote Control Target (F-RC end-points) and
The UE, the FLUS source and the FLUS sink are considered to be logical functions. Functions are not required to be
located in the same physical device; they can be spread over multiple physical devices and interconnected via other
interfaces.
Multiple F-RC end-points can exist in a single FLUS source. F-RC end-points are independent of a FLUS sink and
depend on the offered service.
The F reference point shall support security functionality for confidentiality protection for all subfunctions.
Details of the functions are shown in Figure 4.2-2.
Control F-C Control
Rendering
Source Sink
Media Media
F-U
Processing
Source Sink
Capture
FLUS sink
devices Distribution
Remote
F-RC Remote
Control
Controller
Target
FLUS source
UE UE or Network or other device

Figure 4.2-2: Sub-functions of FLUS
Note that in the above diagram, hatched-filled boxes represent FLUS control plane functionality, solid line boxes
represent mandatory functionality, and dashed-line boxes corresponds to optional functionality. Also, note that F-C and
F-U denote FLUS control and FLUS user plane interactions, respectively, and do not represent reference points.
Control Source and Sink (F-C): FLUS control plane functionality including the associated processing by the FLUS sink
of the uploaded media for subsequent downstream distribution, plus FLUS media instantiation selection. F-C may also
support configuration of static metadata for the Media session.
Remote Controller and Remote Control Target (F-RC): The Remote Control Target on the FLUS source receives
control messages. The messages affect the behaviour of the Media Source in the FLUS source. Examples of commands
issued to the Remote Control Target are start or stop of the media upstreaming process in the FLUS source.
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Media Source and Sink (F-U): FLUS user plane functionality which includes setup of one or more Media sessions and
subsequent media data transmission via Media streams. In some cases, a Media session establishment protocol (e.g.
IMS session set-up for MTSI-based FLUS instantiation) is necessary.
NOTE: F-C is not needed when the FLUS sink is an MTSI client that is only capable of rendering. In such event,
logical control plane functions such as media and session descriptions and support for a FLUS session
establishment are encapsulated in FLUS user plane functionality.
F-C represents the interactions associated with the creation and modification of the configuration of the FLUS sink. F-C
allows the Control Source to:
- select a FLUS media instantiation,
- provision static metadata associated with each Media session present in the FLUS session,
- discover, select and configure the processing and distribution sub-functions.
In addition to the delivery of control messages, F-RC represents the interactions associated with the discovery, creation,
modification and selection of the FLUS sink configuration by the Remote Controller. F-RC allows the Remote
Controller to:
- provide the Media Sink information to the FLUS source,
- select a FLUS media instantiation,
- determine capture device settings and other FLUS source parameters.
The FLUS media instantiation is defined as part of the FLUS session. The user plane (F-U) may also contain the Media
stream establishment procedures when needed. Multiple Media streams may be established for one FLUS session.
A Media stream may contain media components of a single content type, e.g., audio, or media components of different
content types, e.g., audio and video. A FLUS session may be composed of more than one Media stream containing the
same content type, e.g., multiple Media streams of video.

4.2.2 Uplink streaming for MTSI
The architecture of uplink streaming for MTSI is depicted in Figure 4.2-3.

Figure 4.2-3: Uplink streaming for MTSI
The reception function of an MTSI client, i.e., the "MTSI rx client" as shown in Figure 4.2-3, is used to realize the
Media Sink in the FLUS sink. The FLUS sink may be instantiated as another UE or as an MTSI rx client function in the
network.
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F-U contains all MTSI-related signalling.
The transmission function of an MTSI client, MTSI tx client, is used to realize the Media Source in the FLUS source.
4.2.3 Uplink streaming for PSS-based distribution
Figure 4.2-4a shows the most important interfaces for Evolved Packet System (EPS) and 5G System (5GS) for Live
Uplink Streaming Services.
Rx, T8
EPS
SGi
FLUS source
FLUS sink Optional
(UE) (Network) Functions
N6
5GS
5GS
Npcf, Nnef
Figure 4.2-4a: Architecture for Live Uplink Streaming
An uplink streaming service requires at least a FLUS source and a FLUS sink. A FLUS sink is located at the SGi
reference point in case of EPS [13] and at the N6 reference point in case of 5GS [15]. When QoS support is needed, the
FLUS sink may request QoS support using Rx [13] or T8 [14] reference points in case or EPS and using Nnef or Npcf
[15] reference points in case of 5GS.
The architecture of uplink streaming for subsequent PSS distribution is depicted in Figure 4.2-4b.

Figure 4.2-4b: Uplink streaming for PSS
The PSS Content Source is located on the UE side and contains the FLUS source.
4.3 Terminal
The functional components of a terminal including both a FLUS source and a FLUS sink that uses 3GPP access are
shown in figure 4.3-1.
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Speaker Audio Renderer Audio Decoder
Video Renderer Video Decoder
Display
Timed Media
Decoder
Media
Controller
Microphone Audio Pre-
Audio Encoder
System processor
Camera Video Pre-
Video Encoder
System processor
Media Capture Timed Media
System Encoder
User Session Setup
Interface and Control
NOTE 1: It is not required that all components of a FLUS source or a FLUS sink are included in a terminal.
Figure 4.3-1: Functional components of a FLUS source and a FLUS sink
The scope of the present document is to specify media handling and interaction, which includes media control, as well
as transport of media and control data.

As indicated in figure 4.3-1, whether or not to employ or how to realize the audio/video renderer, media controller, or
audio/video pre-processor is left to the configuration of a FLUS source and a FLUS sink, and their implementation. For
these functional components, this document only defines the signalling of the media controller, which will be used to
define the handling of media.
Timed media may include text, graphics, etc.
If a terminal including a FLUS source uses 3GPP access only for uplink media transmission, its functional components
are shown in figure 4.3-2.
Media
Controller
Microphone Audio Pre-
Audio Encoder
System processor
Camera Video Pre-
Video Encoder
System processor
Media Capture Timed Media
System Encoder
User Session Setup
Interface and Control
Figure 4.3-2: Functional components of a FLUS source for uplink media transmission
ETSI
Synchronization
Activation Activation
Packet-based Network Interface Packet-based Network Interface
3GPP L2 3GPP L2
3GPP TS 26.238 version 17.0.0 Release 17 14 ETSI TS 126 238 V17.0.0 (2022-05)
4.4 Procedures
4.4.1 General
A FLUS session may include one or more media streams. Media streams are time-bound to the FLUS session to which
they belong to. When a media stream is active, the FLUS source can send media content to the FLUS sink.
The establishment and / or teardown of a Media session can be remotely controlled / influenced using remote control
and / or assistance messaging.
Figure 4.4-1 depicts an example relationship of a FLUS session with a single Media session containing two media
streams. The FLUS Session is established once the FLUS source and the FLUS sink contain matching configurations.
FLUS Session
Media Session
Media Session
establis
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