GSMA

Official Document IR.92 IMS Profile for Voice and SMS

IR.92 IMS Profile for Voice and SMS

Version 20.0
13 June 2024

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Copyright © 2024 GSM Association

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Table of Contents
1 Introduction 5
1.1 Overview 5
1.2 Relationship to existing standards 6
1.2.1 3GPP specifications 6
1.3 Scope 6
1.4 Definition of Acronyms and Terms 6
1.4.1 Acronyms 6
1.4.2 Terms 9
1.5 Document Cross-References 10
2 IMS Feature Set 15
2.1 General 15
2.2 Support of generic IMS functions 15
2.2.1 SIP Registration Procedures 15
2.2.2 Authentication 17
2.2.3 Addressing 18
2.2.4 Call Establishment and Termination 19
2.2.5 Forking 21
2.2.6 The use of Signalling Compression 22
2.2.7 Early media and announcements 22
2.2.8 SIP Session Timer 23
2.2.9 SIP OPTIONS 23
2.2.10 UE location management in case of EN-DC 24
2.3 Supplementary Services 24
2.3.1 Supplementary Services Overview 24
2.3.2 Supplementary Service Configuration 25
2.3.3 Ad-Hoc Multi Party Conference 27
2.3.4 Communication Waiting 28
2.3.5 Message Waiting Indication 29
2.3.6 Originating Identification Restriction 29
2.3.7 Terminating Identification Restriction 29
2.3.8 Communication Diversion 29
2.3.9 Communication Barring 31
2.3.10 Communication Hold 31
2.3.11 Explicit Communication Transfer - Consultative 31
2.3.12 Originating Identification Presentation 31
2.4 Call Set-up Considerations 32
2.4.1 SIP Precondition Considerations 32
2.4.2 Integration of resource management and SIP 33
2.4.3 Voice Media Considerations 34
2.4.4 Multimedia
Considerations 37
2.4.5 Call Composer Service 38
2.5 Void 38

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2.6 User Agent and Server Headers 38

3 IMS Media 40
3.1 General 40
3.2 Voice Media 40
3.2.1 Codecs 40
3.2.2 RTP Profile and SDP Considerations 41
3.2.3 Data Transport 42
3.2.4 RTCP Usage 42
3.2.5 Speech Payload Format Considerations 44
3.2.6 Jitter Buffer Management Considerations 45
3.2.7 Front End Handling 45
3.3 DTMF Events 45
3.4 Data Channel 45
4 Radio and Packet Core Feature Set 45
4.0 General 45
4.1 Robust Header Compression 45
4.2 LTE Radio Capabilities 46
4.2.1 Radio Bearers 46
4.2.2 DRX Mode of Operation 46
4.2.3 RLC configurations 46
4.2.4 GBR and NGBR Services, GBR Monitoring Function 46
4.2.5 E-UTRA NR Dual connectivity 47
4.3 Bearer Management 47
4.3.1 EPS Bearer Considerations for SIP Signalling, HTTP for XCAP and
HTTP Content Server 47
4.3.2 EPS Bearer Considerations for Voice 48
4.3.3 EPS Bearer Considerations for voice media on emergency PDN
Connection 49
4.4 P-CSCF Discovery 49
5 Common Functionalities 50
5.1 IP Version 50
5.2 Emergency Service 50
5.2.1 General 50
5.2.2 Interactions between supplementary services and PSAP callback 52
5.2.3 UE location management 52
5.3 Roaming Considerations 52
5.4 Accesses in addition to E-UTRAN 52
5.5 Data Off and Services Availability 52
5.5.1 General 52
5.5.2 Supplementary Service Settings Management 53
5.5.3 Voice Calls and SMS over IP 53
5.6 Voice Calls and Smart Congestion Mitigation 53
5.7 Capability Discovery 53
5.8 HTTP Content Server 54
6 SMS Support 54

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6.1 SMS over IP 54

6.2 SMS over NAS 55
Annex A Complementing IMS with CS 56
A.1 General 56
A.2 Domain Selection 56
A.3 SR-VCC 57
A.4 IMS Voice service settings management when using CS access 57
A.5 Emergency Service 57
A.6 Roaming Considerations 58
A.7 Void 58
A.8 Call Waiting in the CS domain 58
A.9 USSD 59
Annex B Features needed in certain regions 60
B.1 General 60
B.2 Global Text Telephony over IP 60
B.3 Service Specific Access Control 61
Annex C MNO provisioning and Late Customization 62
C.1 General 62
C.2 Configuration Methods 62
C.2.1 Remote Client Configuration for MNO provisioning 62
C.2.2 Late Customization 62
C.3 Configuration Parameters 62
C.4 Testing Profiles 67
Annex D USSI 69
D.1 Introduction 69
D.1.1 Overview 69
D.2 IMS Feature Set 70
D.2.1 General 70
D.2.2 Support of generic IMS functions 70
D.2.3 USSI Considerations 70
D.3 SDP negotiation 70
D.4 Common Functionalities 71
D.4.1 Data Off 71
D.5 Complementing IMS with CS 71
D.5.1 General 71
D.5.2 Domain Selection 71
Annex E Features needed for Automotive 71
E.1 General 71
E.2 eCall 72
Annex F Document Management 75
F.1 Document History 75
F.2 Other Information 77

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1 Introduction

1.1 Overview
The IP Multimedia Subsystem (IMS) Profile for Voice and SMS, documented in this
Permanent Reference Document (PRD), defines a profile that identifies a minimum
mandatory set of features which are defined in 3GPP specifications that a wireless device
(the User Equipment (UE)) and network are required to implement in order to guarantee an
interoperable, high quality IMS-based telephony service and IMS-based and SGs-based
Short Message Service (SMS) over Long Term Evolution (LTE) radio access. The content
includes the following aspects:

• IMS basic capabilities and supplementary services for telephony [Chapter 2].
• Real-time media negotiation, transport, and codecs [Chapter 3].
• LTE radio and evolved packet core capabilities [Chapter 4].
• Functionality that is relevant across the protocol stack and subsystems [Chapter 5].
• Additional features that need to be implemented for the UEs and networks that wish
to support concurrent Circuit Switched (CS) coverage [Annex A].
• Additional features that only a subset of the IMS telephony operators needs to
support in certain markets [Annex B].
• UE configuration to provide all necessary information to connect to, and receive voice
service and SMS from, a specific IMS telephony operator [Annex C].
• Support for Unstructured Supplementary Service Data (USSD) Simulation Service in
IMS (USSI) as optional feature [Annex D].

The UE and network protocol stacks forming the scope of the IMS Profile for Voice and SMS
are depicted in figure 1.1 below:

Suppl. Suppl.
Codecs Codecs
services services
HTTP/ HTTP/
SIP XCAP RTP/RTCP SIP XCAP RTP/RTCP

TCP/IP - UDP/IP TCP/IP – UDP/IP TCP/IP - UDP/IP

Bearers/QoS RoHC Bearers/QoS RoHC
LTE LTE
with VoIP optimizations with VoIP optimizations

Mobile device Radio & access network Servers (IMS)

Figure 1.1: Depiction of UE and Network Protocol Stacks in IMS Profile for Voice

The main body of this PRD is applicable for a scenario where IMS telephony is deployed
over LTE in a standalone fashion without relying on any legacy infrastructure, packet or
circuit switched. In order to be compliant with IMS Profile for Voice and SMS, the UEs and
networks must be compliant with all of the normative statements in the main body.

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Annex A defines the profile for an alternative approach where IMS telephony is deployed
with a certain degree of reliance on an existing 3GPP circuit switched network infrastructure.
Whenever there are additional requirements to the main profile, these are explicitly stated. In
order to be compliant with the functionality described in Annex A, the UEs and networks
must be compliant with all of the normative statements in Annex A as well as to all of the
normative statements in the main body of the PRD that are unaltered by Annex A.

1.2 Relationship to existing standards

1.2.1 3GPP specifications

This profile is solely based on the open and published 3GPP specifications as listed in the
Section 1.5. 3GPP Release 8, the first release supporting LTE, is taken as a basis. It should
be noted, however that not all the features mandatory in 3GPP Release 8 are required for
compliance with this profile.

Conversely, some features required for compliance with this profile are based on
functionality defined in 3GPP Release 9 or higher releases.

All such exceptions are explicitly mentioned in the following sections along with the relevant
Release 8 or higher 3GPP release specifications, respectively.

Unless otherwise stated, the latest version of the referenced specifications for the relevant
3GPP release applies.

1.3 Scope
This document defines a profile for voice over IMS over LTE, and for SMS over IP and SMS
over NAS, by listing a number of Evolved Universal Terrestrial Radio Access Network (E-
UTRAN), Evolved Packet Core, IMS core, and UE features that are considered essential to
launch interoperable services. The defined profile is compliant with 3GPP specifications. The
scope of this profile is the interface between UE and network.

The profile does not limit anybody, by any means, to deploy other standardized features or
optional features, in addition to the defined profile.

1.4 Definition of Acronyms and Terms

1.4.1 Acronyms
Acronym Description
3GPP 3rd Generation Partnership Project
AM Acknowledged Mode
AMR Adaptive Multi-Rate
AMR-WB Adaptive Multi-Rate Wideband
APN Access Point Name
AVP Audio Video Profile
AVPF AVP Feedback Profile
BSF Bootstrapping Server Function

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Acronym Description
CB Communication Barring
CDIV Communication Diversion
CFNL Communication Forwarding on Not Logged-in
CFNRc Communication Forwarding on Not Reachable
CN Core Network
CS Circuit Switched
CSFB CS Fallback
CW Communication Waiting
DRB Data Radio Bearer
DRX Discontinuous Reception
DTX Discontinuous Transmission
ECT Explicit Communication Transfer
EPC Evolved Packet Core
eNB eNodeB
EN-DC E-UTRA NR Dual Connectivity
EPS Evolved Packet System
E-UTRAN Evolved Universal Terrestrial Radio Access Network
EVS Enhanced Voice Services
FDD Frequency-Division Duplexing
GBR Guaranteed Bit Rate
GRUU Globally Routable User agent URI
GSM Global System for Mobile communications
GTT-IP Global Text Telephony over IP
ICS IMS Centralized Services
ICSI IMS Communication Service Identifier
IM IP Multimedia
IMPU IP Multimedia Public Identity
IMS IP Multimedia Subsystem
IMS-AKA IMS Authentication and Key Agreement
IMSI International Mobile Subscriber Identity
IP Internet Protocol
IPv4 Internet Protocol Version 4
IPv6 Internet Protocol Version 6
ISIM IM Services Identity Module
LTE Long Term Evolution
MGW Media Gateway
MMTel Multimedia Telephony
MO Managed Object

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Acronym Description
MRFP Media Resource Function Processor
MS Mobile Station
MSD Minimum Set of emergency related Data
MS-ISDN Mobile Subscriber ISDN Number
MWI Message Waiting Indication
NGBR Non-Guaranteed Bit Rate
PCC Policy and Charging Control
PCRF Policy and Charging Rules Function
P-CSCF Proxy - Call Session Control Function
PDN Packet Data Network
PS Packet Switched
QCI Quality of Service Class Indicator
RAT Radio Access Technology
RLC Radio Link Control
RoHC Robust Header Compression
RR Receiver Report
RTCP RTP Control Protocol
RTP Real Time Protocol
SCC AS Service Centralization and Continuity Application Server
SDES Source Description
SDP Session Description Protocol
SG Signalling Gateway
SigComp Signalling Compression
SIP Session Initiation Protocol
SMSoIP SMS over IP
SR Sender Report
SRB Signalling Radio Bearer
SR-VCC Single Radio Voice Call Continuity
TAS Telephony Application Server
TDD Time-Division Duplexing
TFO Tandem-Free Operation
TrFO Transcoder-Free Operation
TTY Teletype Writer
UDP User Datagram Protocol
UE User Equipment
UICC Universal Integrated Circuit Card
UM Unacknowledged Mode
URI Uniform Resource Identifier

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Acronym Description
USSD Unstructured Supplementary Service Data
USSI Unstructured Supplementary Service Data (USSD) using IP Multimedia (IM) Core
Network (CN) subsystem (IMS)
USSI AS USSI Application Server
VoIP Voice Over IP
XCAP XML Configuration Access Protocol
XML eXtensible Markup Language
UDUB User Determined User Busy

1.4.2 Terms
Term Description
3GPP PS A feature which when configured by the HPLMN and activated by the user
Data Off prevents transport via PDN connections in 3GPP access of all IP packets except
IP packets required by 3GPP PS Data Off Exempt Services, as defined in 3GPP
Release 14 TS 22.011 [1]. Data Off can be activated only when the UE roams or
regardless of whether the UE roams or not, depending on UE implementation.
3GPP PS A set of operator services that are allowed even if the 3GPP PS Data Off feature
Data Off has been activated in the UE by the user, as defined in 3GPP Release 14 TS
Exempt 22.011 [1].
Services
3GPP PS Indicates state of usage of the 3GPP PS data off. 3GPP PS data off status at the
Data Off UE can be either "active" or "inactive", as defined in 3GPP Release 14 TS 24.229
status [15].
Region A part of a country, a country or a set of countries.
Call In this document, this term means the "Call Composer service using the
Composer Multimedia Telephony session" as defined of GSMA PRD RCC.20 [106].

This service, when provided by the HPLMN, allows:

the originating UE to send one or more Call Composer Elements with a call
invitation.
the terminating UE to accept Call Composer Elements received in a call invitation.
Call An information element set by the originating user for an outgoing call invitation
Composer and used by the terminating UE when notifying the user of an incoming call
Element invitation. The following Call Composer Elements are defined:
importance,
subject,
picture,
location.
The mapping of Call Composer Elements to SIP headers is as defined in section
2.4.4.2 of GSMA PRD RCC.20 [106].
DCMTSI an MTSI (Multimedia Telephony Service for IMS) client supporting data channel
client
simservs XML XML document used for the MMTEL Supplementary Service Configuration, as
document defined in 3GPP TS 24.623

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Term Description
NG-eCall A manually or automatically initiated IMS emergency call, from a vehicle,
(eCall Over supplemented with a minimum set of emergency related initial data (MSD).
IMS)

1.5 Document Cross-References

Ref Doc Number Title
3GPP TS 22.011 Service Accessibility
3GPP TS 23.003 Numbering, addressing and identification
3GPP TS 23.167 IP Multimedia Subsystem (IMS) emergency sessions
3GPP TS 23.203 Policy and charging control architecture
3GPP TS 23.216 Single Radio Voice Call Continuity (SRVCC); Stage 2
3GPP TS 23.221 Architectural requirements
3GPP TS 23.228 IP Multimedia Subsystem (IMS); Stage 2
3GPP TS 23.237 IP Multimedia Subsystem (IMS) Service Continuity; Stage 2
3GPP TS 23.272 Circuit Switched (CS) fallback in Evolved Packet System (EPS);
Stage 2
3GPP TS 23.401 General Packet Radio Service (GPRS) enhancements for
Evolved Universal Terrestrial Radio Access Network (E-
UTRAN) access
3GPP TS 24.008 Mobile radio interface layer 3 specification; Core Network
protocols; Stage 3
3GPP TS 24.109 Bootstrapping interface (Ub) and network application function
interface (Ua); Protocol details
3GPP TS 24.147 Conferencing using the IP Multimedia (IM) Core Network (CN)
subsystem; Stage 3
3GPP TS 24.173 IMS Multimedia telephony service and supplementary services;
Stage 3
3GPP TS 24.229 IP multimedia call control protocol based on Session Initiation
Protocol (SIP) and Session Description Protocol (SDP); Stage 3
3GPP TS 24.237 IP Multimedia Subsystem (IMS) Service Continuity; Stage 3
3GPP TS 24.301 Non-Access-Stratum (NAS) protocol for Evolved Packet System
(EPS); Stage 3
3GPP TS 24.305 Selective Disabling of 3GPP User Equipment Capabilities
(SDoUE) Management Object (MO)
3GPP TS 24.341 Support of SMS over IP networks; Stage 3
3GPP TS 24.604 Communication Diversion (CDIV) using IP Multimedia (IM)Core
Network (CN) subsystem; Protocol specification
3GPP TS 24.605 Conference (CONF) using IP Multimedia (IM) Core Network
(CN) subsystem; Protocol specification
3GPP TS 24.606 Message Waiting Indication (MWI )using IP Multimedia (IM)
Core Network (CN) subsystem; Protocol specification

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Ref Doc Number Title

3GPP TS 24.607 Originating Identification Presentation (OIP) and Originating
Identification Restriction (OIR) using IP Multimedia (IM) Core
Network (CN) subsystem; Protocol specification
3GPP TS 24.608 Terminating Identification Presentation (TIP) and Terminating
Identification Restriction (TIR) using IP Multimedia (IM) Core
Network (CN) subsystem; Protocol specification
3GPP TS 24.610 Communication HOLD (HOLD) using IP Multimedia (IM) Core
Network (CN) subsystem; Protocol specification
3GPP TS 24.611 Anonymous Communication Rejection (ACR) and
Communication Barring (CB) using IP Multimedia (IM) Core
Network (CN) subsystem; Protocol specification
3GPP TS 24.615 Communication Waiting (CW) using IP Multimedia (IM) Core
Network (CN) subsystem; Protocol Specification
3GPP TS 24.623 Extensible Markup Language (XML) Configuration Access
Protocol (XCAP) over the Ut interface for Manipulating
Supplementary Services
3GPP TS 26.071 Mandatory speech CODEC speech processing functions; AMR
speech Codec; General description
3GPP TS 26.073 ANSI C code for the Adaptive Multi Rate (AMR) speech codec
3GPP TS 26.090 Mandatory Speech Codec speech processing functions;
Adaptive Multi-Rate (AMR) speech codec; Transcoding
functions
3GPP TS 26.093 Mandatory speech codec speech processing functions Adaptive
Multi-Rate (AMR) speech codec; Source controlled rate
operation
3GPP TS 26.103 Speech codec list for GSM and UMTS
3GPP TS 26.104 ANSI-C code for the floating-point Adaptive Multi-Rate (AMR)
speech codec
3GPP TS 26.114 IP Multimedia Subsystem (IMS); Multimedia telephony; Media
handling and interaction
3GPP TS 26.131 Terminal acoustic characteristics for telephony; Requirements
3GPP TS 26.132 Speech and video telephony terminal acoustic test specification
3GPP TS 26.171 Speech codec speech processing functions; Adaptive Multi-
Rate - Wideband (AMR-WB) speech codec; General description
3GPP TS 26.173 ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB)
speech codec
3GPP TS 26.190 Speech codec speech processing functions; Adaptive Multi-
Rate - Wideband (AMR-WB) speech codec; Transcoding
functions
3GPP TS 26.193 Speech codec speech processing functions; Adaptive Multi-
Rate - Wideband (AMR-WB) speech codec; Source controlled
rate operation
3GPP TS 26.204 Speech codec speech processing functions; Adaptive Multi-
Rate - Wideband (AMR-WB) speech codec; ANSI-C code

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Ref Doc Number Title

3GPP TS 27.007 AT command set for User Equipment (UE)
3GPP TS 31.103 Characteristics of the IP Multimedia Services Identity Module
(ISIM) application
3GPP TS 33.203 3G security; Access security for IP-based services
3GPP TS 33.222 Generic Authentication Architecture (GAA); Access to network
application functions using Hypertext Transfer Protocol over
Transport Layer Security (HTTPS)
3GPP TS 36.101 Evolved Universal Terrestrial Radio Access (E-UTRA); User
Equipment (UE) radio transmission and reception
3GPP TS 36.104 Evolved Universal Terrestrial Radio Access (E-UTRA); Base
Station (BS) radio transmission and reception
3GPP TS 36.300 Evolved Universal Terrestrial Radio Access (E-UTRA) and
Evolved Universal Terrestrial Radio Access Network (E-
UTRAN); Overall description; Stage 2
3GPP TS 36.321 Evolved Universal Terrestrial Radio Access (E-UTRA); Medium
Access Control (MAC) protocol specification
3GPP TS 36.323 Evolved Universal Terrestrial Radio Access (E-UTRA); Packet
Data Convergence Protocol (PDCP) specification
3GPP TS 36.331 Evolved Universal Terrestrial Radio Access (E-UTRA);Radio
Resource Control (RRC); Protocol specification
IETF RFC 768 User Datagram Protocol
IETF RFC 3095 RObust Header Compression (ROHC): Framework and four
profiles: RTP, UDP, ESP, and uncompressed
IETF RFC 3261 SIP: Session Initiation Protocol
IETF RFC 3550 RTP: A Transport Protocol for Real-Time Applications
IETF RFC 3551 RTP Profile for Audio and Video Conferences with Minimal
Control
IETF RFC 3556 Session Description Protocol (SDP) Bandwidth Modifiers for
RTP Control Protocol (RTCP) Bandwidth
IETF RFC 3680 A Session Initiation Protocol (SIP) Event Package for
Registrations
IETF RFC 3842 A Message Summary and Message Waiting Indication Event
Package for the Session Initiation Protocol (SIP)
IETF RFC 4575 A Session Initiation Protocol (SIP) Event Package for
Conference State
IETF RFC 4815 RObust Header Compression (ROHC): Corrections and
Clarifications to RFC 3095
IETF RFC 4867 RTP Payload Format and File Storage Format for the Adaptive
Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-
WB) Audio Codecs
IETF RFC 5939 Session Description Protocol (SDP) Capability Negotiation
GSMA PRD IR.65 IMS Roaming and Interworking Guidelines

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Ref Doc Number Title

GSMA PRD IR.67 DNS/ENUM Guidelines for Service Providers and GRX/IPX
Providers
GSMA PRD IR.88 LTE Roaming Guidelines
3GPP TS 24.167 3GPP IMS Management Object (MO); Stage 3
3GPP TS 36.322 Evolved Universal Terrestrial Radio Access (E-UTRA); Radio
Link Control (RLC) protocol specification
ITU-T Protocol for multimedia application text conversation
Recommendation
T.140
3GPP TS 24.628 Common Basic Communication procedures using IP Multimedia
(IM) Core Network (CN) subsystem; Protocol specification
IETF RFC 4961 Symmetric RTP / RTP Control Protocol (RTCP)
IETF RFC 4745 Common Policy: A Document Format for Expressing Privacy
Preferences
IETF RFC 5009 Private Header (P-Header) Extension to the Session Initiation
Protocol
IETF RFC 4825 The Extensible Markup Language (XML) Configuration Access
Protocol (XCAP)
3GPP TS 26.441 Codec for Enhanced Voice Services (EVS); General overview
3GPP TS 26.442 Codec for Enhanced Voice Services (EVS); ANSI C code (fixed-
point)
3GPP TS 26.443 Codec for Enhanced Voice Services (EVS); ANSI C code
(floating-point)
3GPP TS 26.445 Codec for Enhanced Voice Services (EVS); Detailed Algorithmic
Description
3GPP TS 26.446 Codec for Enhanced Voice Services (EVS); AMR-WB Backward
Compatible Functions
3GPP TS 26.447 Codec for Enhanced Voice Services (EVS); Error Concealment
of Lost Packets
3GPP TS 26.449 Codec for Enhanced Voice Services (EVS); Comfort Noise
Generation (CNG) Aspects
3GPP TS 26.450 Codec for Enhanced Voice Services (EVS); Discontinuous
Transmission (DTX)
3GPP TS 26.451 Codec for Enhanced Voice Services (EVS); Voice Activity
Detection (VAD)
3GPP TS 22.030 Man-Machine Interface (MMI) of the User Equipment (UE)
ITEF RFC 3840 Indicating User Agent Capabilities in the Session Initiation
Protocol (SIP)
3GPP TS 24.629 Explicit Communication Transfer (ECT) using IP Multimedia (IM)
Core Network (CN) subsystem; Protocol specification
3GPP TS 24.166 3GPP IP Multimedia Subsystem (IMS) conferencing
Management Object (MO)

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Ref Doc Number Title

IETF RFC 3262 Reliability of Provisional Responses in the Session Initiation
Protocol (SIP)
3GPP TS 24.417 Management Object (MO) for Originating Identification
Presentation (OIP) and Originating Identification Restriction
(OIR) using IP Multimedia (IM) Core Network (CN) subsystem
3GPP TS 24.424 Management Object (MO) for Extensible Markup Language
(XML) Configuration Access Protocol (XCAP) over the Ut
interface for Manipulating Supplementary Services
GSMA PRD TS.32 Technical Adaptation of Devices through Late Customisation
GSMA PRD Service Provider Device Configuration
RCC.14
IETF RFC 4122 Universally Unique IDentifier (UUID) URN Namespace
3GPP TS 24.275 Unstructured Management Object (MO) for Basic
Communication Part (BCP) of IMS Multimedia Telephony
(MMTEL) communication service
3GPP TS 24.368 Non-Access Stratum (NAS) Configuration Management Object
(MO)
3GPP TS 23.090 Unstructured Supplementary Service Data (USSD); Stage 2
3GPP TS 24.390 Unstructured Supplementary Service Data (USSD) using IP
Multimedia (IM) Core Network (CN) subsystem IMS; Stage 3
3GPP TS 24.391 Unstructured Supplementary Service Data (USSD) using IP
Multimedia (IM) Core Network (CN) subsystem (IMS)
Management Object (MO)
OMA-ERELD-DM- Enabler Release Definition for OMA Device Management,
V1_2 Version 1.2
3GPP TS 37.340 Evolved Universal Terrestrial Radio Access (E-UTRA) and NR;
Multi-connectivity
3GPP TS 38.331 NR;Radio Resource Control (RRC); Protocol Specification
GSMA PRD Rich Communication Suite 8.0 Advanced Communications
RCC.07 Services and Client Specification
IETF RFC 7852 Additional Data Related to an Emergency Call
IETF RFC 6228 Session Initiation Protocol (SIP) Response Code for Indication
of Terminated Dialog
GSMA PRD Enriched Calling Technical Specification
RCC.20
3GPP TS 26.267 eCall data transfer; In-band modem solution; General
description
3GPP TS 33.107 3G security; Lawful interception architecture and functions

3GPP TS 23.122 Non-Access-Stratum (NAS) functions related to Mobile Station

(MS) in idle mode
GSMA PRD 2G-3G Sunset Guidelines
NG.121

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2 IMS Feature Set

2.1 General
The IMS profile part lists the mandatory capabilities, which are required over the Gm and Ut
reference points.

2.2 Support of generic IMS functions

2.2.1 SIP Registration Procedures

The UE and the IMS core network must follow the Session Initiated Protocol (SIP)
registration procedures defined in 3GPP TS 24.229 [15]. In addition, when the conditions for
performing an IMS registration in bullets 2, 3, 4, 5 and 6 in section L.3.1.2 of 3GPP TS
24.229 [15] evaluate to true, then the UE must register with the IMS. Selective Disabling of
3GPP User Equipment Capabilities as defined in 3GPP TS 24.305 [18] is not mandated in
this profile, therefore in the case where 3GPP TS 24.305 [18] Managed Object (MO) is not
deployed, it is assumed that IMS is enabled in the terminal and the IMS parameter is set to
the value "enabled" as specified in Annex C.3.

Note 1: UE registering with IMS in other situations is possible.

The home operator can configure the UE with Media_type_restriction_policy for non-roaming
and for roaming case, SMSoIP_usage_policy and RegRetryBaseTime and
RegRetryMaxTime parameters as specified in Annex C.3.

The UE must include the IMS Communication Service Identifier (ICSI) value used to indicate
the IMS Multimedia Telephony service, which being urn: urn-7:3gpp-service.ims.icsi.mmtel
per 3GPP TS 24.173 [14], using procedures as defined in section 5.1.1.2.1 of 3GPP TS
24.229 [15]. The UE must also include the feature tag used to indicate the SMS over IP
service (see section 6), that being +g.3gpp.smsip as defined in section 5.3.2.2 of 3GPP TS
24.341 [19]. If the UE is a Session Continuity UE (SC-UE) (e.g. due to support of SR-VCC
as described in Annex A.3), then the UE must include the g.3gpp.accesstype media feature
tag as specified in section 6.2.2 of Release 11 of 3GPP TS 24.237 [16]. If the Call Composer
service is enabled, then the UE must include the +g.gsma.callcomposer media feature tag
as defined in GSMA PRD RCC.20 [106].

The UE must include the audio media feature tag, as defined in IETF RFC 3840 [86], in the
Contact header field of the SIP REGISTER request, using the procedures of 3GPP TS
24.229 [15].

The UE and the IMS core network must support network-initiated de-registration as defined
in 3GPP TS 24.229 [15].

The UE must subscribe to the registration event package as defined in section 5.1.1.3 of
3GPP TS 24.229 [15].

The UE must include an IMEI URN (see 3GPP TS 23.003 [2] section 13.8) in the
"+sip.instance" header field parameter (Instance ID) of the contact address.

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As stated in Release 14 of 3GPP TS 24.229 [15], the UE must include a user part in the URI
of the contact address such that the user part is globally unique and does not reveal any
private information.

Note 2: To generate this user part, the UE can use a time-based UUID (Universal
Unique Identifier) generated as per subclause 4.2 of IETF RFC 4122 [94].

All IMS public user identities provided in the implicit registration set by the IMS core network
must be alias user identities and must include a tel URI (Uniform Resource Identifier). The
following public user identity must be assigned to the implicit registration set and must be
used by the UE when registering in the IMS:

a) When ISIM is used, the public user identity in the first (or only) record in the
Elementary File in the ISIM (see 3GPP TS 31.103 [44] section 4.2.4); or
b) The temporary public user identity derived from the IMSI (3GPP TS 23.003 [2]).

Note 3: According to 3GPP TS 23.228 [7], a public user identity is an alias of

another public user identity if both identities belong to the same implicit
registration set, are linked to the same service profile and have the same
service data configured for every service.

The UE must set the URI of the From header field of the REGISTER request, for user-
initiated reregistration or for user-initiated deregistration, to the public user identity which was
used in the URI of the From header field of the REGISTER request that created the binding
being refreshed or being removed. The UE must set the URI of the To header field of the
REGISTER request, for user-initiated reregistration and for user-initiated deregistration, to
the public user identity that was used in the URI of the To header field of the REGISTER
request that created the binding being refreshed or being removed.

Note 4: The "tag" header field parameter can differ in the From header field and in
the To header field for the different REGISTER requests.

For backwards compatibility the network must support all formats of URIs compliant with
3GPP TS 24.229 [15].

The UE must perform a re-registration prior to the expiry time of the existing registration as
described in section 5.1.1.4.1 of 3GPP TS 24.229 [15].

If the UE receives a SIP 305 (Use Proxy) response to a re-registration, then the UE must
acquire a P-CSCF different from the currently used P-CSCF and initiate a new initial
registration as described in section 5.1.1.4.1 of 3GPP TS 24.229 [15]. If the UE receives a
SIP 503 (Service Unavailable) response without a Retry-After header field, the SIP 503
(Service Unavailable) response must be treated as a SIP 500 (Server Internal Error)
response (as stated in IETF RFC 3261 [55]) and the UE must initiate a new initial registration
as described in section 5.1.1.4.1 of 3GPP TS 24.229 [15]. For the new initial registration, the
UE must select a different P-CSCF from the P-CSCF list received from last PCO if not all of
them have been attempted, otherwise the UE must re-establish a new PDN connection to
the IMS well-known APN and get a new list of P-CSCFs (as stated in section 4.4) and
choose from one of these P-CSCFs, as specified in section 5.1.1.4.1 of 3GPP TS 24.229
[15].

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If the UE receives a SIP 503 (Service Unavailable) response or any other SIP 4xx, 5xx or
6xx response with Retry-After header as a response to an initial SIP REGISTER request,
then the UE must re-attempt an initial registration via the same P-CSCF after the amount of
time indicated in the Retry-After header field has expired or must immediately re-attempt an
initial registration (as described above) when another P-CSCF is used.

Note 5: The above condition assumes that the UE has IP connectivity when the UE
re-attempts an initial registration.

If the UE receives a SIP 401 Unauthorized response with ealg=null to the initial REGISTER
request, then the UE must send another REGISTER request without encryption over IPsec,
according to the algorithm returned by the P-CSCF as per 3GPP TS 24.229 [15] section
5.1.1.5.1.

Note 6: In a roaming scenario, the encryption is deactivated in the HPMN for its
S8HR outbound roamers if required by the VPMN to meet its regulatory
requirements as described in section 20.1.1 of Release 14 of 3GPP TS
33.107 [108].

A DCMTSI client must support SCTP/DTLS/UDP protocol stack and SDP offer/answer
procedures as defined in 3GPP Release 16 TS 26.114 [35].

The data channel media is defined in the section 6.2.10 of 3GPP Release 16 TS 26.114 [35].
A DCMTSI client in terminal must include the sip.app-subtype media feature tag with a value
"webrtc-datachannel" in the Contact header field of the SIP REGISTER request, using the
procedures defined in section 5.1.1 of 3GPP Release 17 TS 24.229 [15].

Note 7: In this version of the document, the UE is not aware if the network supports
data channel media.

2.2.2 Authentication
The UE and the IMS core network must follow the procedures defined in 3GPP TS 24.229
[15] and 3GPP TS 33.203 [45] for authentication with IMS Authentication and Key
Agreement (IMS-AKA), Sec-Agree and IPsec. Support of integrity protection is mandatory for
both UE and network. Support of confidentiality protection is optional in the network,
considering that lower layer security is available.

The IMS core network must support the procedures for IM Services Identity Module (ISIM)
based authentication. Support for ISIM based authentication in the UE is mandatory.

The UE and IMS core network must support the procedures for USIM based authentication if
there is no ISIM present on the Universal Integrated Circuit Card (UICC) as defined in Annex
E.3.1 of 3GPP TS 23.228 [7] and Annex C.2 of 3GPP TS 24.229 [15]. This includes support
for the P-Associated-URI header to handle barred IMS Public User Identities (IMPUs).

The UE and the IMS core network must support the procedures for authentication at the Ut
reference point as specified in 3GPP TS 24.623 [28].

The UE must and the IMS core network can support the procedures for authentication at the
HTTP Content Server as defined in section 3.2.5.3 of GSMA PRD RCC.07 [103]. If the UE
supports the OpenID Connect procedures for the HTTP Content Server as defined in GSMA

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PRD RCC.07 [103], then the UE must support the user authentication via HTTP embedded
EAP-AKA for the authentication with the OpenID Connect authorization endpoint as defined
in GSMA PRD RCC.14 [93].

If the UE supports the Generic Authentication Architecture procedures specified in 3GPP TS

24.623 [28], 3GPP TS 33.222 [46] and 3GPP TS 24.109 [12], then the UE must construct
the Bootstrapping Server Function (BSF) address as defined in section 16.2 of 3GPP TS
23.003 [2].

Note 1: It is recommended that the UE supports the Generic Authentication

Architecture procedures specified in 3GPP TS 24.623 [28], 3GPP TS 33.222
[46] and 3GPP TS 24.109 [12].

The UE must support receiving an HTTP 2xx response to HTTP requests for XCAP and the
HTTP Content Server without being challenged by an HTTP 401 (Unauthorized) response.

Note 2: The above authentication scenario is possible only if the APN used for HTTP
for XCAP and HTTP Content Server traffic (see section 4.3.1) is routed to
the home network. The home network is able to authenticate the UE without
challenging the UE for Ut authentication.

Note 3: The above authentication scenario is applicable for the HTTP Content
Server if the Call Composer service is enabled, and no values are provided
for the configuration parameters FT HTTP CS USER and FT HTTP CS PWD
(see section C.3), and authentication via HTTP embedded AKA or the
Generic Authentication Architecture is not available.

2.2.3 Addressing

2.2.3.1 Public User Identities

The UE and IMS core network must support Public User Identities as defined in section 13.4
of 3GPP TS 23.003, which includes all of the following types of addresses:

• Alphanumeric SIP-URIs

o Example: sip:voicemail@example.com

• MSISDN represented as a SIP URI:

o Example: sip:+447700900123@example.com;user=phone

• MSISDN represented as a tel URI:

o Example: tel:+447700900123

Note: Further requirements for support of Public User Identities in the network are
specified in IR.65 [65].

2.2.3.2 Local numbers

The UE and IMS core network must support local numbers as defined in Alternative 2 in
Sections 5.1.2A.1.3 and 5.1.2A.1.5 in 3GPP TS 24.229 [15]. That is, the UE must set the dial

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string containing the local number to the user part of SIP URI in the Request URI, and set
the "user=phone" parameter, with the "phone-context" tel URI parameter to the user part.

The UE and network must support home-local numbers and geo-local numbers. The UE
must set the "phone-context" parameter as defined in sections 5.1.2A.1.5 and 7.2A.10 in
3GPP TS 24.229 [15]:

• for home local numbers the UE must set the "phone-context" parameter to the home
domain name, as it is used to address the SIP REGISTER request.
• Example of phone-context for home-local number: if the home network domain used
in SIP REGISTER R-URI is "ims.mnc026.mcc567.3gppnetwork.org" then the "phone
context" parameter is set to the same string.
• for geo-local numbers the UE must set the "phone-context" parameter with additional
visited network information when available.
• Example of phone-context for geo-local number: if the visited network has MCC =
234, MNC = 15, and the home network has MCC = 567, MNC = 26, the "phone
context" parameter is set to the string
"234.15.eps.ims.mnc026.mcc567.3gppnetwork.org".

Note 1: The UE on E-UTRAN knows the access information and hence the "phone-
context" can be set accordingly.

If the local number type is not explicitly indicated by the user in outgoing voice calls to either
geo-local or home-local numbers, then the UE must use the Policy_on_local_numbers
parameter as specified in Annex C.3 to determine the local number type. For outgoing SMS
messages to local numbers, the UE must use home-local numbers.

Note 2: SMS does not currently specify how to route messages to a VPLMN for
onward routing to a destination, therefore, outgoing SMS messages cannot
be destined to geo-local numbers.

2.2.3.3 Other addressing related SIP header fields

The UE and IMS core network must support the P-Called-Party-ID header field; the network
must use this header field as defined in 3GPP TS 24.229 [15].

The support of Globally Routable User agent URIs (GRUUs) by UE or network is not
required.

2.2.4 Call Establishment and Termination

The UE and the IMS core network must follow 3GPP TS 24.229 [15] for establishment and
termination of a call.

The UE and the IMS core network must support reliable provisional responses as defined in
IETF RFC 3262 [89]. The UE must support reliable SIP 18x policy and procedures as
specified in section 5.1.4.1 of 3GPP Release 14 TS 24.229 [15].

The home operator can configure the UE with Timer_T1, Timer_T2 and Timer_T4 parameter
as specified in Annex C.3.

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The UE must be able to accept a SIP INVITE request without a Session Description Protocol
(SDP) offer and the UE must include a SDP offer with audio media in the first non-failure
reliable response to a SIP INVITE request without SDP offer.

Note 1: Other media can be included in the SDP offer in the first non-failure reliable
response.

The UE must include the audio media feature tag, as defined in IETF RFC 3840 [86], in the
Contact header field of the SIP INVITE request, and in the Contact header field of the SIP
response to the SIP INVITE request, as specified in 3GPP TS 24.229 [15].

The UE must indicate in the SDP of the initial INVITE that the audio media is send-receive
i.e. either by including the direction attribute "a=sendrecv" or by omitting the direction
attributes. If the UE receives an initial INVITE that contains "a=sendrecv" or no direction
attribute in the SDP offer, the UE must indicate "a=sendrecv" or no direction attribute in the
SDP answer, regardless of the use of SIP preconditions framework or of the resource
reservation status.

Note 2: Previous versions of 3GPP TS 24.229 [15] mandated the use of the SDP
inactive attribute. 3GPP Release 12 TS 24.229 [15] does not prohibit
specific services from using direction attributes to implement their service-
specific behaviours.

For the purpose of indicating an IMS communication service to the network, the UE must
use an ICSI value in accordance with 3GPP TS 24.229 [15]. The ICSI value used must
indicate the IMS Multimedia Telephony service, which is urn:urn-7:3gpp-
service.ims.icsi.mmtel, as specified in 3GPP TS 24.173 [14].

If the Call Composer service is enabled, then the UE must include the media feature tag for
the Call Composer in the Contact header field of the SIP INVITE request, and in the Contact
header field of the SIP response to the SIP INVITE request, as specified in section 2.4.4 of
GSMA PRD RCC.20 [106].

If the Call Composer service is enabled, then the UE must include in the SIP INVITE request
the header fields for Call Composer elements as defined in section 2.4.4.2 of GSMA PRD
RCC.20 [106].

If the Call Composer service is enabled and the UE receives in an incoming SIP INVITE
request header fields for Call Composer Elements as defined in section 2.4.4.2 of GSM PRD
RCC.20 [106], then the UE must process the header fields as defined in section 2.4.4.3 and
2.4.4.5 of GSMA PRD RCC.20 [106].

If the Call Composer service is not enabled, then the UE must ignore any Call Composer
Elements in the incoming INVITE request.

The usage of preconditions is discussed in Section 2.4.

If the user rejects an incoming call by invoking User Determined User Busy (UDUB) as
described in 3GPP TS 22.030 [85], then the UE must send a SIP 486 (Busy here) response
to the network.

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Note 3: The appropriate SIP response to reject a call on all devices for a multiple-
device scenario and operator and vendor specific services are out-of-scope
of this document.

When the UE sends a CANCEL or BYE request, the UE must include a Reason header field
with a protocol value set to "RELEASE_CAUSE" and follow the procedures specified in
sections 5.1.3.1 and 5.1.5 of 3GPP Release 14 TS 24.229 [15].

2.2.4.1 Considerations for Voice sessions with Data Channel

In addition to the procedures described in section 2.2.4, if the data channel media is
supported, the following statements apply:

The UE and the network must be able to establish a data channel session directly during
session establishment and by adding data channel to a voice or video session by sending
Session Initiation Protocol (SIP) (re-)INVITE request with a Session Description Protocol
(SDP) offer that contains the data channel media descriptor in addition to the existing media
descriptors.

The UE must include the data channel media feature tag, as defined in 3GPP Release 16
TS 26.114 [35], in the Contact header field of the SIP INVITE request, and in the Contact
header field of the SIP response to the SIP INVITE request, as specified in 3GPP Release
17 TS 24.229 [15].

Note: In this version of the document, the UE is not aware if the network supports
data channel media.

The UE must indicate the capability to handle data channel by including a sip.app-subtype
media feature tag with a value "webrtc-datachannel" in the Contact header of an INVITE
request.

The UE must indicate the capability to handle data channel by including a sip.app-subtype
media feature tag with a value "webrtc-datachannel" in the Contact header of any 18x or 200
responses to an INVITE request.

2.2.5 Forking
Forking in the network is outside the scope of the present document. However, for inter-
operability and forward-compatibility reasons, the UE must be ready to receive responses
generated due to a forked request and behave according to the procedures specified in IETF
RFC 3261 [55], section 4.2.7.3 of 3GPP TS 23.228 [7], 3GPP TS 24.229 [15] and section
4.7.2.1 of 3GPP Release 13 TS 24.628 [71]. Furthermore, the UE should be able to maintain
at least forty (40) parallel early dialogs until receiving the final response on one of them and
the UE must support receiving media on one of these early dialogs.

If the originating UE needs to release an early dialog, the UE must send a BYE request
within the early dialog to be released, in accordance with section 15 in IETF RFC 3261 [55],
e.g. when the UE receives the first response that would create an early dialog it cannot
maintain, the UE sends a BYE request on that early dialog without saving dialog data.

It is also possible that the network or the terminating UE will need to release an early dialog
using the 199 (Early Dialog Terminated) response defined in IETF RFC 6228 [105]. To

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support this, the originating UE must include the "199" option tag in the Supported header
field in the initial INVITE request and must understand a 199 (Early Dialog Terminated)
response code and act as specified in section 5.1.3.1 of 3GPP TS 24.229 [15].

Note 1: An early dialog that is maintained is one where a SIP 18x response has
been received and the early dialogue has not been terminated (e.g. by
receipt of a SIP 199 response) prior to receiving a SIP 2xx response.

Note 2: Multiple early dialogs can occur as a result of forking or for other reasons
such as announcements or services.

The IMS core network can support sending and the UE must support receiving a SIP
CANCEL request including a Reason header field with values of:

• SIP; cause=200; text="Call completed elsewhere"

• SIP; cause=603; text="Declined"
• SIP; cause=600; text="Busy Everywhere"

for forked calls as defined in 3GPP Release 12 TS 24.229 [15].

2.2.6 The use of Signalling Compression

The UE must not use SIGCOMP when the initial IMS registration is performed in E-UTRAN
access as specified in Release 10 3GPP TS 24.229 [15].

Note: Although this version of the profile focuses on E-UTRAN, if the initial IMS
registration occurs in other IP Connectivity Accesses then SIGCOMP can be
used by the UE.

2.2.7 Early media and announcements

The UE must behave as specified in section 4.7.2.1 of 3GPP Release 13 TS 24.628 [71].

In addition, the UE must support the P-Early-Media header field as defined in IETF RFC
5009 [74], and must include a P-Early-Media header field with the "supported" parameter to
initial INVITE requests it originates as specified in section 5.1.3.1 of 3GPP TS 24.229 [15].

The UE must also maintain an early media authorization state per dialog as described in
IETF RFC 5009 [74].

As stated in 3GPP TS 24.628 [71], the UE must render locally generated communication
progress information, if:

• an early dialog exists where a SIP 180 response to the SIP INVITE was received;
• no early dialog exists where the last received P-Early-Media header field as
described in IETF RFC 5009 [12] contained "sendrecv" or "sendonly"; and
• in-band information is not received from the network.

For SIP response 181 and 182 to the SIP INVITE, the UE must not locally render tones to
indicate diversion or queueing of calls.

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The UE must evaluate the above rules again after each subsequent request or response
received from the remote party, and when in-band information starts, and when the UE
determines the in-band media to have stopped.

Note 1: A SIP request or response received without a P-Early-Mediaheader does not

change the early media authorization state for the early dialog on which it
was received.

Note 2: In-band information arriving at the UE will always override locally generated
communication progress information as defined in section 4.7.2.1 of TS
24.628 [71].

2.2.8 SIP Session Timer

The UE must support and use IETF RFC 4028 [86] as follows:

• for an initial SIP INVITE request, the UE must include a Supported header with the
option tag "timer" and must either insert Session-Expires header field with the delta-
seconds portion set to 1800, or must not include the Session-Expires header field in
the initial SIP INVITE request;
• if the UE receives a SIP 422 response to an INVITE request, the UE must follow the
procedures of section 7.4 in IETF RFC 4028 [86];
• it is recommended that the UE does not include the "refresher" parameter in the
Session-Expires header field of the SIP INVITE request. If the UE includes the
"refresher" parameter in the Session-Expires header field of the SIP INVITE request,
the UE must set the "refresher" parameter to "uac";
• if a received SIP INVITE request indicates support of the "timer" option tag, and does
not contain the Session-Expires header field, the UE must include a Session-Expires
header field with the delta-seconds portion set to the greater of 1800 or the value
contained in the Min-SE header (if present in the received INVITE) and the
"refresher" parameter with the value "uac" in SIP 2xx response to the SIP INVITE
request; and
• if a received SIP INVITE request indicates support of the "timer" option tag, and
contains the Session-Expires header field without "refresher" parameter, the UE must
include the "refresher" parameter with the value "uac" in the Session-Expires header
field of the SIP 2xx response to the SIP INVITE request, and must set the delta-
seconds portion of the Session-Expires header field of the SIP 2xx response to the
SIP INVITE request to the value indicated in the delta-seconds portion of the
Session-Expires header field of the SIP INVITE request.

Note: The network can choose to influence the session timer negotiation by
modifying any of the related header fields or header field parameters within
the constraints of IETF RFC 4028 [86].

2.2.9 SIP OPTIONS

A Contact header field in a SIP OPTIONS request and in the 200 OK response to a SIP
OPTIONS request must include the IMS Communication Service Identifier (ICSI) value of
"urn:urn-7:3gpp-service.ims.icsi.mmtel", as defined in 3GPP TS 24.173 [14].

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If the Call Composer service is enabled, then a Contact header field in SIP OPTIONS
request and in the 200 OK response to a SIP OPTIONS request must include the media
feature tag for Call Composer as defined in GSMA PRD RCC.20 [106].

2.2.10 UE location management in case of EN-DC

In the case of EN-DC (see section 4.2.5), the UE must use the access network information
based on the primary cell of the Master RAN node (eNB) that is serving the UE for network
location information as specified in section E.1.0 of 3GPP Release 15 of TS 23.228 [7].

Note: This applies regardless whether the IMS traffic is routed via the Master RAN
node or the Secondary RAN node (gNB) or both.

2.3 Supplementary Services

2.3.1 Supplementary Services Overview

Supplementary services must be supported as defined as part of 3GPP MMTel TS 24.173
[14], with the constraints described in this section.

The UE and the Telephony Application Server (TAS) must support the supplementary
services listed in Table 2.1. The provisioning of these supplementary services for a
subscriber is optional and is an operator decision.

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Supplementary Service
Originating Identification Presentation 3GPP TS 24.607 [23] (Note 1)
Terminating Identification Presentation 3GPP TS 24.608 [24]
Originating Identification Restriction 3GPP TS 24.607 [23] (Note 1)
Terminating Identification Restriction 3GPP TS 24.608 [24] (Note 1)
Communication Forwarding Unconditional 3GPP TS 24.604 [20] (Note 1)
Communication Forwarding on not Logged in 3GPP TS 24.604 [20] (Note 1)
Communication Forwarding on Busy 3GPP TS 24.604 [20] (Note 1)
Communication Forwarding on not Reachable 3GPP TS 24.604 [20] (Note 1)
Communication Forwarding on No Reply 3GPP TS 24.604 [20] (Note 1)
Barring of All Incoming Calls 3GPP TS 24.611 [26] (Note 1)
Barring of All Outgoing Calls 3GPP TS 24.611 [26] (Note 1)
Barring of Outgoing International Calls 3GPP TS 24.611 [26] (Note 1, Note 2)
Barring of Outgoing International Calls – ex Home Country 3GPP TS 24.611 [26] (Note 1,Note
2)
Barring of Outgoing International Calls - When Roaming 3GPP TS 24.611 [26] (Note 1,Note 2)
Barring of Incoming Calls - When Roaming 3GPP TS 24.611 [26] (Note 1)
Communication Hold 3GPP TS 24.610 [25] (Note 1)
Message Waiting Indication 3GPP TS 24.606 [22] (Note 1)
Communication Waiting 3GPP TS 24.615 [27] (Note 1)
Ad-Hoc Multi Party Conference 3GPP TS 24.605 [21] (Note 1)
Explicit Communication Transfer - Consultative 3GPP TS 24.629 [87] (Note 1)

Table 2.1 Supplementary services

Note 1: Recommended options are described in sections 2.3.3 – 2.3.12.

Note 2: Barring of International Calls is a 3GPP Release 9 feature.

The UE must and the network can support the Call Composer service. The provisioning of
the Call Composer service for a subscriber is optional and is an operator decision.

Note 3: Support of other supplementary services is out of scope of this document.

2.3.2 Supplementary Service Configuration

For supplementary service configuration, the UE and IMS core network must support XCAP
at the Ut reference point as defined in 3GPP TS 24.623 [28].

The home operator can configure the UE with the "XCAP Root URI" parameter as specified
in Annex C.3 with an XCAP root URI as specified in 3GPP TS 24.623 [28]. If the UE has not
been configured with an XCAP root URI, then the UE must construct an XCAP root URI as
defined in section 13.9 of 3GPP TS 23.003 [2].

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As XCAP User Identity (XUI) the UE must use the default public user identity received in
P-Associated-URI header in the SIP 200 (OK) response for REGISTER.

When not registered with IMS, the UE must use the default public user identity received
during the last successful registration as in Section 2.2.1 in this document.

If the UE receives an HTTP 404 (Not Found) response when attempting to access the entire
simservs XML document (i.e. a node selector is not included in the Request-URI of the
XCAP request), or the UE does not have a stored default public user identity, then:

• if the UE has an ISIM, then the UE must use the public user identity in the first (or
only) record in the EFIMPU Elementary File in the ISIM (see section 4.2.4 of 3GPP
TS 31.103 [44]) as XUI in further XCAP requests sent until the next successful IMS
registration.
• if the UE has a USIM but not an ISIM, then the UE must use the temporary public
user identity derived from the IMSI (see section 13.4B of 3GPP TS 23.003 [2]) as XUI
in further XCAP requests sent until the next successful IMS registration.

Note 1: If the UE attempts to access a fragment of the simservs XML document (i.e.
a node selector is included in the Request-URI of the XCAP request), and
the UE receives a HTTP 404 (Not Found) response, the UE is allowed to
continue attempting to access the simservs XML document. If the UE
continues to receive a HTTP 404 (Not Found) response when attempting to
access a fragment of the simservs XML document, the UE can attempt to
access the entire simservs XML document to determine if the XUI is valid.

Note 2: If the XUI is derived from the IMPU stored on the ISIM or derived from the
temporary IMPU, then the UE does not share such XUI with another UE in
order to prevent the revealing of a potentially barred IMPU.

The UE must configure settings of one supplementary service only per XCAP request. If the
supplementary service to be configured contains a <ruleset> element with multiple <rule>
elements as defined in IETF RFC 4745 [73] (e.g. as for Communication Diversion (CDIV),
Communication Barring (CB)), then the UE must modify at most one <rule> element of the
supplementary service per XCAP request.

The UE must perform HTTP PUT and HTTP DELETE as conditional operations using the If-
Match header field as defined in section 7.11 of IETF RFC 4825 [75].

When modifying a supplementary service, if there is an existing matching <rule> element,

the UE must modify the child elements of the existing <rule> element. Otherwise, if no
matching <rule> element is found, the UE must consider that the supplementary service is
not provisioned for the user and must not insert a new <rule> element with a rule ID different
from any existing rule ID in the XML document.

Note 3: For each supplementary service that is provisioned for the user, the home
operator needs to provide the matching <rule> element in the initial XML
document.

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When deactivating a <rule> element for a supplementary service, and if there is a matching
<rule> element without <rule-deactivated> condition, the UE must insert the <rule-
deactivated> condition in the <conditions> element of the <rule> element.

A <rule> element matches a supplementary service if:

1. the supplementary service requires a <conditions> element, and the conditions (with
exception of the <rule-deactivated> condition) included in the <conditions> element of
the <rule> element are the same as the conditions of the <conditions> element required
by the supplementary service; or
2. the supplementary service does not require a <conditions> element and the <rule>
element:

o does not contain a <conditions> element;

o contains an empty <conditions> element; or
o contains a <conditions> element containing solely the <rule-deactivated>
condition.

The UE must not remove a <rule> element of a supplementary service profiled in this
document.

2.3.3 Ad-Hoc Multi Party Conference

The UE and the IMS core network must support the procedures defined in 3GPP TS 24.605
[21] and clause 5.3.1.3.2 of 3GPP Release 10 TS 24.147 [13], with the clarifications defined
in this sub section.

Note 1: As per section 4.2 of 3GPP TS 24.605 [21], the invocation and operation for
conferencing is described in 3GPP TS 24.147 [13].

For conference creation, the UE and the IMS core network must support Three Way Session
creation as described in section 5.3.1.3.3 of 3GPP TS 24.147 [13]. The UE must apply
option 2b) when inviting the remote user to the conference. If the UE has not been
configured with Conf_Factory_URI parameter as specified in Annex C.3, then the UE must
construct the "Default Conference Factory URI for MMTel" as specified in clause 13.10 of
3GPP Release 12 TS 23.003 [2].

The UE can and the IMS core network must support the procedures in 3GPP TS 24.605 [21]
for subscription to conference state events. The SIP SUBSCRIBE to conference state events
must be sent outside the SIP INVITE dialog between the UE and the conference server. If
the SUBSCRIBE request outside the existing INVITE dialog is rejected by a SIP 403
(Forbidden) response, the UE must send a SUBSCRIBE request in the existing INVITE
dialog, and it should continue the conference call without conference event subscription if
this SUBSCRIBE request is failed, as specified in clause 5.3.1.2 of 3GPP Release 16 TS
24.147 [13]. The UE is recommended to send the SUBSCRIBE request in the INVITE dialog
until the next initial IMS registration.

To ensure compatibility with UEs compliant with older versions of this specification the IMS
core network must support SUBSCRIBE requests received within an INVITE dialog. The IMS
core network can support all, or a subset of the elements and attributes specified in IETF

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RFC 4575 [61]. As a minimum, the IMS core network must support the following elements
and attributes:

• Conference-info: entity
• Maximum-user-count
• Users
• User: entity
• Display-text
• Endpoint: entity
• Status (supported values: connected, disconnected, on-hold)

If the Display-text is not available for a conference participant, the IMS core network should
provide the same value for the <User: Entity> and <Display-Text> fields.

Note 2: This behaviour will enable all participants of the conference to be uniquely
distinguished from each other.

When inviting other users to a conference, the UE and the IMS core network must support
the procedure described in section 5.3.1.5.3 of 3GPP TS 24.147 [13]. The UE must send the
SIP REFER method by using the existing dialog for a conference session between the UE
and the IMS core network (conference server).

The UE must add the Replaces header to the Refer-to header field in the SIP REFER
request, as described in section 5.3.1.5.3 of 3GPP TS 24.147 [13].

Note 3: In Three-Way session creation procedures, the UE has an existing session

with the SIP REFER target.

Note 3a: If the UE needs to correctly identify and distinguish anonymous users, the
UE can send the REFER requests sequentially and wait for conference
event NOTIFY. This procedure can delay the conference establishment.

The UE and the IMS core network must support audio media for the conference session.

Note 4: Support of other media types is out of scope of the document.

Floor control for conferencing as described in section 8 of 3GPP TS 24.147 [13] is not
required.

Consent procedures for list server distribution as described in section 5.3.1.7 of 3GPP TS
24.147 [13] are not required.

The conference server should send notification for Conference Event Package immediately
and, in any case, within 5 seconds.

2.3.4 Communication Waiting

The UE and the IMS core network must support the terminal based service, as described in
3GPP TS 24.615 [27]. The network-based service is not required. The Communication
Waiting (CW) indication as defined in section 4.4.1 of 3GPP TS 24.615 [27] is not required.
The UE is required to support Alert-Info, with values as specified in 3GPP TS 24.615 [27].

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The UE must provide the ability for the user to activate, deactivate and interrogate the
terminal based service without using UE-to-network signalling (e.g. XCAP/Ut).

2.3.5 Message Waiting Indication

The UE must and the IMS core network can support the Message Waiting Indication (MWI)
event package, as defined in 3GPP TS 24.606 [22] and IETF RFC 3842 [60].

2.3.6 Originating Identification Restriction

The UE and the IMS core network must support the SIP procedures in 3GPP TS 24.607
[23]. Service configuration as described in Section 4.10 of 3GPP TS 24.607 [23], is not
required.

2.3.7 Terminating Identification Restriction

The UE and the IMS core network must support the SIP procedures in 3GPP TS 24.608
[24]. Service configuration, as described in section 4.9 of 3GPP TS 24.608 [24], is not
required.

2.3.8 Communication Diversion

The UE and the IMS core network must support the SIP procedures described in 3GPP TS
24.604 [20] for Communication Diversion (CDIV). For CDIV service activation, deactivation,
and interrogation (XCAP operations), the UE and the IMS core network must support the
XML rules for Call Forwarding Unconditional and the conditions, actions and elements listed
in Table 2.2. However, the operator decides which rules are included in the XML document,
e.g. depending on the subscription. The UE must handle a missing rule as defined in section
2.3.2.

The UE and the IMS core network must support the XML rules as described in section 4.9.1
of 3GPP TS 24.604 [20]. The UE must support the History-Info header for identification of
diverting parties at the terminating side and for identification of diverted-to parties at the
originating side. At the terminating side, a History-Info entry must be used for the
identification of the diverting party and that the call has been diverted only if another History-
Info entry exists that has assigned the next index in sequence and includes a cause value in
a cause-param SIP URI parameter as described in section 4.5.2.6.2 of 3GPP TS 24.604
[20]. At the originating side only History-Info entries including a cause value must be used for
presentation of the diverted-to party.

Note 1: The UE can deduce that the received call is a diverted call based on the
cause-param values.

Note 2: Support of subscription options and other conditions and actions are out of
scope of the document.

Type Parameter
Rule containing Busy
condition
Rule containing media (supported media types: audio, audio AND
condition video)

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Type Parameter
Rule containing no-answer
condition
Rule containing not-registered
condition
Rule containing not-reachable (Note 3)
condition
Rule containing rule-deactivated
condition
Action Target
Element NoReplyTimer

Table 2.2 Supported conditions, actions and elements in CDIV

Note: In contrast to the CS domain, IMS networks distinguish between

Communication Forwarding on Not Logged-in (CFNL) (CDIV using a rule
with the condition not-registered) and Forwarding on Not Reachable
(CFNRc) (CDIV using a rule with the condition not-reachable). An operator
may choose to not apply CFNL and would therefore not include the rule
containing the condition not-registered in the XML document.

If both CFNL and CFNRc are included in the XML document by the operator, then the UE
must activate both CFNRc and CFNL to the same target, in order to create compatible user
experience with the CS domain.

In addition to the requirements in section 2.3.2, when configuring settings for the
Communication Diversion supplementary service the UE must configure only one of the
following in an XCAP request:

• Communication diversion supplementary service activation, no-reply-timer or both.

o If the <cp:ruleset> element is present, and a <NoReplyTimer> element is to be

created, the UE must include the <cp:ruleset> element in the HTTP PUT request.

• For the communication diversion services supported in this PRD, elements of one
<rule> element for communication diversion supplementary service only.

Note: It is not possible to create a no-reply timer without including the rule set in a
document where a rule set already exists since this would create an invalid
XML document according to IETF RFC 4825 [75].

If:

• a <rule> element matching a CDIV service exists in the XML document; and
• the <target> child element contains empty string;

then the UE must consider that the CDIV service is not registered for the user otherwise the
UE must consider that the CDIV service is registered for the user.

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2.3.9 Communication Barring

The UE must support the procedures in 3GPP TS 24.611 [26] with the Release 14 additions
to section 4.5.0 and sections 5.3.1.2 and 5.3.1.3 in 3GPP Release 14 TS 24.623 [28]. The
IMS core network must support the SIP procedures in 3GPP TS 24.611 [26] and can support
the procedures in section 5.3.2.5 in 3GPP Release 14 TS 24.623 [28]. For service activation,
deactivation, and interrogation (XCAP operations), the UE and the IMS core network must
support the XML rules for Barring of All Incoming Calls, Barring of All Outgoing Calls and the
conditions listed in Table 2.3. The UE and the IMS core network must support the XML rules
as described in section 4.9.1.3 of 3GPP TS 24.611 [26].

Note: Support of other conditions is out of scope of the document.

Condition
Roaming
International
International-exHC
rule-deactivated

Table 2.3 Supported conditions in CB

In addition to the requirements in section 2.3.2, when configuring settings for the
Communication Barring supplementary service the UE must modify only one of the following
in an XCAP request:

• Incoming communication barring supplementary service activation

• Outgoing communication barring supplementary service activation
• For the communication barring services supported in this PRD, elements of one
<rule> element for communication barring supplementary service only.
2.3.10 Communication Hold
The UE invoking the HOLD service must not send any media to the other party.

2.3.11 Explicit Communication Transfer - Consultative

The UE must and IMS core network can support the procedures for the consultative transfer
defined in 3GPP Release 13 TS 24.629 [87], with the clarifications defined in this sub
section.

The UE as a Transferee must support the procedures with 3rd Party Call Control (3PCC) as
defined in 3GPP Release 13 TS 24.628 [71]. The UE procedure without 3PCC is not
required.

The UE and IMS core network must support audio media for the transferred session.

2.3.12 Originating Identification Presentation

The UE and IMS core network must support the SIP procedures in 3GPP Release 13 TS
24.607 [23].

The UE must support the presentation of the originating user identity both from the identity
within the P-Asserted-Identity header field and the identity within the From header field.

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The UE must support the operator's originating party identity determination policy as defined
in clause 4.5.2.12 of Release 14 TS 24.607 [23] also the UE must support being configured
according to the "FromPreferred" parameter as specified in Annex C.3.

Note: As, by default, the identity in the From header field may not be network
asserted, it is the responsibility of the network to ensure that the From
header field contains a reliable identity of the originating user when it is sent
to the UE.

2.4 Call Set-up Considerations

2.4.1 SIP Precondition Considerations

The UE must support the preconditions mechanism as specified in section 5.1.3.1 and
5.1.4.1 of 3GPP TS 24.229 [15]. If the precondition mechanism is enabled by the
Precondition disabling policy node in Annex C.3, the UE must use the precondition
mechanism.

If preconditions are used, then the UE must use the SIP UPDATE request for precondition
status update. If preconditions are used, and the originating UE receives the selected codec
in the SDP of a SIP 18x response, then the UE must include only the same codec with its
selected configuration parameters in the SDP of the SIP UPDATE request, used for
precondition status update.

The network may disable the use of preconditions in the network as specified in section
5.2.5.6 of GSMA PRD IR.65 [65].

The terminating UE implementation must not rely on the use of preconditions by the
originating UE.

Upon receiving an INVITE request, when preconditions are not used by the originating UE or
preconditions are disabled by the network, and the local resources required at the
terminating UE are not available, the terminating UE, according to 3GPP Release 13 TS
24.229 [15], must:

•send a SIP 183 (Session Progress) response containing SDP. If the received INVITE
request includes a Supported header field with the value "100rel", this 183 (Session
Progress) response must be sent reliably; and
• not use the precondition mechanism;
and unless preconfigured otherwise by the home operator with the
Default_EPS_bearer_context_usage_restriction_policy parameter as specified in Annex C.3,
the terminating UE must:

• not alert the user until resources are reserved successfully on the terminating side;
and
• not send a SIP 180 (Ringing) response until resources are reserved successfully on
the terminating side.

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2.4.2 Integration of resource management and SIP

2.4.2.1 Loss of PDN connectivity

If the Packet Data Network (PDN) connectivity between a UE and the network is lost, the
network must terminate all ongoing SIP sessions related to this UE, according to the
procedures in section 5.2.8 of 3GPP TS 24.229 [15] (e.g. when the P-CSCF receives an
abort session request from the Policy and Charging Rules Function (PCRF)).

If the UE discovers (for example during a TAU procedure) that PDN connectivity had been
lost, then the UE must attempt to re-establish the PDN connection. This will trigger the
network to initiate a new SIP signalling bearer in conjunction with the PDN connection
establishment.

Note: The PDN connectivity may also be lost if the UE moves to GERAN/UTRAN,
see also GSMA PRD IR.88 [67]. It may not be possible to re-establish the
PDN connectivity in GERAN/UTRAN in such deployments.

When the UE regains PDN and IP connectivity, if the IP address has changed or the IMS
registration expired during the period of absence of IP connectivity then the UE must perform
a new initial registration to IMS.

2.4.2.2 Void

2.4.2.3 Loss of media bearer and Radio Connection

If a Guaranteed Bit Rate (GBR) bearer used for voice fails to get established, or is lost mid-
session, then the network must terminate the session associated to the voice stream
according to the procedures in section 5.2.8 of 3GPP TS 24.229 [15] (P-CSCF must be
informed about loss of bearer by the PCRF).

Note 1: The loss of the GBR bearer may be due to loss of radio connection indicated
by an S1 release with cause "Radio Connection With UE Lost" and then
followed by the MME Initiated Dedicated Bearer Deactivation procedure for
the GBR bearer used for voice. Or, the GBR bearer may be lost or not
established, due to the current resource and radio situation. However,
termination of the SIP session due to loss of the voice GBR bearer is the
only way for the system to stop the IMS level charging (quickly) when the UE
loses radio connection.

Note 2: If other media types are used, and a GBR bearer used for another media
type fails to get established, or is lost mid-session, then the network, based
on its policies, has the option to either allow the SIP session to continue as
is, or terminate the SIP session that the GBR bearer is associated with (the
network can handle loss of video in a video call in such a way that the
session continues as voice-only).

If a SIP session includes media streams, and if a dedicated bearer for any media stream
fails to get established, or is lost mid-session, then the UE must, based on its preferences,
modify, reject or terminate the SIP session that the dedicated media bearer is associated
with, according to section 6.1.1 of 3GPP TS 24.229 [15]. The UE can act differently per
media type.

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Note 3: If a voice bearer is lost or fails to get established, the network will, in normal
cases, release the session as described in the beginning of this section. As
a complement to this, the UE must have internal logic to react to the
detection of loss of bearer/radio connection to handle its internal state. For a
multimedia communication, if the radio connection is not lost, but a bearer
not used for voice is lost, then the UE must decide if the session should be
maintained as is, should be modified, or should be released.

If the UE loses radio connectivity and the IMS registration expires prior to regaining radio
connectivity, then upon regaining radio connectivity the UE must perform a new initial
registration to IMS.

2.4.3 Voice Media Considerations

2.4.3.1 General
The SDP offer/answer for voice media must be formatted as specified in section 6.2.2 of
3GPP Release 12 TS 26.114 [35], with the restrictions included in the present document. If
the Enhanced Voice Services (EVS) codec is included, then the offer/answer for voice media
must be formatted as specified in section 6.2.2 of 3GPP Release 12 TS 26.114 [35], with the
restrictions included in the present document.

If multiple audio bandwidths are offered by the UE for speech communication, then the
codec preference order must be as specified in clauses 5.2.1.5 and 5.2.1.6 of 3GPP
Release 12 TS 26.114 [35].

For non-Roaming UE, unless preconfigured otherwise by the home operator with the
Default_EPS_bearer_context_usage_restriction_policy parameter as specified in Annex C.3,
if a dedicated bearer for the media does not exist, the UE must consider itself not having
local resources. If the UE has no local resources, the UE must not send media.

A roaming UE is disallowed from sending media over the default bearer. See also annex
L.2.2.5.1D in 3GPP Release 18 TS 24.229 [15].

Note 1: The existence of a dedicated bearer does not grant by itself the UE authority
to send media. Other conditions need to be fulfilled.

Note 2: The originating and terminating networks can modify the SDP offer for voice
media.

2.4.3.2 AMR and AMR-WB

The UE must include in an initial SDP offer at least:
• one AMR-WB payload type with no mode-set specified, and
• one AMR payload type with no mode-set specified,
both as defined in table 6.1 of 3GPP Release 12 TS 26.114 [35].
The UE must set the b=AS to match the highest codec mode for the offer (maximum codec
bit rate if no mode-set is included).
The UE, upon receiving an initial SDP offer containing a payload description for AMR with no
mode-set included, and accepting the payload description with no mode-set, must include into
the SDP answer the value assigned to the RateSet parameter for AMR as specified in Annex

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C.3. It is recommended to set the RateSet parameter for AMR to the value 0,2,4,7 (i.e. mode-
set=0,2,4,7 included in the SDP answer).
The UE, upon receiving an initial SDP offer containing a payload description for AMR-WB with
no mode-set included, and accepting the payload description with no mode-set, must include
into the SDP answer the value assigned to the RateSet parameter for AMR-WB as specified
in Annex C.3. It is recommended to set the RateSet parameter for AMR-WB to "undefined"
(i.e. no mode-set included). A UE that intends to use AMR-WB 12.65 as highest mode must
have the RateSet parameter set to "0,1,2" and include mode-set=0,1,2 in the SDP answer.
The SDP answer for AMR with no mode-set included must be interpreted by the UE that all
eight AMR modes can be used.
The SDP answer for AMR-WB with no mode-set included must be interpreted by the UE that
all nine AMR-WB modes can be used.
The UE must set the b=AS to match the highest codec mode for the answer (maximum codec
bit rate if no mode-set is included).

2.4.3.3 EVS
If the EVS codec is offered for super-wideband calls by a UE, then the UE that sends the SDP
offer for voice media must include in this SDP offer at least one EVS payload type with one of
the following EVS configurations:

• EVS Configuration A1: br=5.9-13.2; bw=nb-swb.

• EVS Configuration A2: br=5.9-24.4; bw=nb-swb.
• EVS Configuration B0: br=13.2; bw=swb.
• EVS Configuration B1: br=9.6-13.2; bw=swb.
• EVS Configuration B2: br=9.6-24.4; bw=swb.
The UE may also include in this SDP offer ch-aw-recv=x with x set to a value out of the set {-
1,0,2,3,5,7}. The UE must support being configured according to the
"ICM/INIT_PARTIAL_REDUNDANCY_OFFSET_RECV" parameter as specified in Annex
C.3. If the "ICM/INIT_PARTIAL_REDUNDANCY_OFFSET_RECV" parameter is undefined,
then the UE must not include ch-aw-recv into the SDP offer. SDP parameters other than br,
bw, max-red and ch-aw-recv must not be included in a media format description associated
with the EVS codec within the initial SDP offer (for a list of SDP parameters see Table 6.2a in
the 3GPP Release 12 TS 26.114 [35]).

Note 1: If ch-aw-recv is not included in the SDP, this is identical to include ch-aw-
recv=0, as specified in the 3GPP Release 12 TS 26.445 [79].

The configuration of the EVS payload type to be included first in the initial SDP offer for EVS
is defined by the EVS/Br and EVS/Bw parameters as specified in Annex C.3, which must be
configured to one of the five above EVS Configurations.
If the EVS codec is offered for super-wideband calls by a UE, then the UE that sends the initial
SDP offer should also include in this initial SDP offer, one EVS payload type with audio
bandwidth range up to super-wideband and with no restrictions on the bitrate range and no
restriction on the mode-set (Open Offer, OO). If this EVS payload type is not included, then:
• an initial SDP offer with EVS configuration B0 or B1 listed first, must also include a
second payload type with EVS configuration A1; and
• an initial SDP offer with EVS configuration B2 listed first, must also include a second
payload type with EVS configuration A2.

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Note 2: An initial SDP offer with multiple EVS configurations does not need to
include subsequent EVS configurations that are a subsets of the previously
listed ones. For example, including B0 or B1 after A1, or including B2 after
A2 is allowed but does not provide any additional information.

The UE must support all SDP parameters applicable to EVS that can be received in an SDP
offer as specified in 3GPP Release 12 TS 26.114 [35] and 3GPP Release 12 TS 26.445
[79].

A payload type in the received SDP offer is considered to match the EVS configuration "X" if
the values the payload type indicates for the "br" and "bw" parameters that are exactly as
specified above for configuration "X". The inclusion of additional parameters and the values
to which those parameters are set has no bearing on whether this inclusion matches the
standard configuration "X".

A UE that supports super-wideband calls upon receiving and accepting a payload type in the
received SDP offer for EVS for an incoming call, compliant with the offer described above,
must answer according to both the received SDP offer and the UE's EVS configuration (i.e.
EVS/Br and EVS/Bw parameters as specified in see Annex C.3) as described in table 2.4
below:

EVS configuration (preferred payload type) of the UE

that received the SDP Offer
Received SDP Offer for A1 A2 B0 B1 B2
EVS (preferred payload
type listed first, and
other, if any)
A1 and optionally OO A1 A1 A1 A1 A1
(from A1) (from A1) (from A1) (from A1) (from A1)

A2 and optionally OO A1 A2 A1 A1 A2
(from A2) (from A2) (from A2) (from A2) (from A2)

B0 and (A1 and/or OO) B0 B0 B0 B0 B0

(from B0) (from B0) (from B0) (from B0) (from B0)

B1 and (A1 and/or OO) A1 A1 B1 B1 B1

(from A1 or OO) (from A1 or OO) (from B1) (from B1) (from B1)

B2 and (A2 and/or OO) A1 A2 B1 B1 B2

(from A2 or OO) (from A2 or OO) (from B2) (from B2) (from B2)

Table 2.4 SDP content to be included in an SDP answer for a superwideband call

Note 3: This table applies only to received SDP offers compliant with this
specification, e.g. including A1, if B0 or B1 are listed first and including A2, if
B2 is listed first.

If the offer is not compliant with this SDP offer/answer specification, rules in 3GPP Release
12 TS 26.445 [35] still apply.

The SDP answerer should use the same payload type number in the SDP answer as was
used by the payload type selected from the SDP offer. This applies both when the SDP offer

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and the SDP answer contain the same EVS configuration, and if the SDP answer contains a
subset of the chosen configuration from the SDP offer.

The SDP offerer must be able to handle an SDP answer with a different payload type
number than was used in the offer, and use this payload type number in its sent RTP
packets when the payload type number in the SDP answer can be unambiguously
associated with one of the payload types in the offer.

If the SDP offerer cannot unambiguously associate the received payload type number in the
SDP answer with an offered EVS configuration, the SDP offerer should re-issue the SDP
offer at most once, with the following modifications:

• If the ambiguous EVS payload type number from the SDP answer was not used for
another codec in the initial SDP offer, the SDP offerer should add the same EVS
configuration and payload type number that was used by the SDP answer as the
most preferred payload type number in the re-offer.
• If the ambiguous EVS payload type number from the SDP answer was used for
another codec in the initial SDP offer, the SDP offerer should include the EVS
configuration from the SDP answer with a single payload type number that was not
previously used in the SDP offer.
Note 4: An answer with a different payload type number can happen e.g. when the
network nodes perform third party call control. If the re-issue of the SDP
offer results in an ambiguous SDP answer, the SDP offerer can end the call
attempt.

Note 5: This means that the same payload type number will, in most cases be used
in both directions. Table 2.4 contains information on which payload type
from the SDP offer to use in the SDP answer when a subset of the
configuration from the SDP offer is needed ("from …"), and when there can
be an ambiguity in which payload type number from the SDP offer is chosen.

If the selected EVS configuration is A1, B0, or B1 then "mode-set = 0,1,2" must be included in
the SDP answer.
The UE must add only SDP parameters that are applicable to EVS in the SDP answer, and
that are already present in the corresponding received and accepted SDP offer. If the SDP
parameters applicable to EVS are included in the accepted SDP offer, then the UE must
handle these parameters as specified in 3GPP Release 12 TS 26.445 [35].
If the SDP parameter ch-aw-recv is present in the corresponding received and accepted SDP
offer, then the SDP parameter ch-aw-recv must be included in the SDP answer with the same
value as received.
Default values as specified in 3GPP Release 12 TS 26.445 [35] apply for all other SDP
parameters applicable to the EVS that are not included in the SDP answer.

2.4.4 Multimedia Considerations

UEs using the full set of media functions can send SDP offers containing multiple "m=" lines
to indicate the wish to establish a more advanced multimedia session than this profile
defines.

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If one of these "m=" lines indicates the wish of establishing an audio (voice) session (using a
compatible codec), then the UE following this profile must accept the offer and allow the use
of whatever media streams it supports. The UE must set the port number to 0 (zero) for the
media streams it does not support.

Note 1: This means that a voice-only UE will accept a video call request, but the call
will automatically be transformed to a voice-only call. In CS telephony, the
call is rejected when the terminating client cannot support all offered media
(that is a voice-only terminal will reject a video call offer). Hence, this section
describes a behaviour that is new to telephony.

UEs using the full set of media functions, have the option to try to update the session by
sending SIP (re-)INVITE requests that include SDP offers containing multiple "m=" lines, to
indicate the desire to expand the session into a more advanced multimedia session. The UE
following this profile must accept such an offer and allow the use of whatever media streams
the UE supports. The UE must, in the SDP answer, set the port number to 0 (zero) for the
media streams it does not support.

Note 2: This means that a voice-only capable UE will accept a request to update the
session to video using a SIP 200 (OK) response. But since the SDP answer
will disable the video stream, the call will continue as a voice-only call.

2.4.5 Call Composer Service

The UE must and the network can support the Call Composer service.

The Call Composer service is enabled if the value of the configuration parameter
COMPOSER AUTH (see Annex C.3) is set to "2" or "3".

The UE must allow the user to set the Call Composer elements in a SIP INVITE request if
the peer UE also supports the Call Composer Service. The support of the Call Composer at
the peer UE can be determined via:

• The use of Capability Discovery, if supported and enabled as described in section

5.7, otherwise
• The inclusion of the Call Composer media feature tag in the Contact header field in
the last INVITE request or response or, SIP OPTIONS request or response received
from the peer UE.
Note: An application server can choose to remove the Call Composer elements as
specified in section 2.4.4.2 of GSMA PRD RCC.20 [106].

2.5 Void

2.6 User Agent and Server Headers

The UE must include the User-Agent header in all SIP requests and the Server header in all
SIP responses. The UE must include the User-Agent header in HTTP requests for XCAP.
The headers must be compiled as defined in GSMA PRD RCC.07 [103] section C.4.1
including the following amendment:

product-list =/ enabler *(LWS enabler)

[LWS terminal]

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[LWS device-type]
[LWS mno-customisation]
*(LWS list-extension)

The rule "enabler" is defined in GSMA PRD RCC.07 [103] section C.4.1 and is extended as
follows:

enabler =/ GSMA-PRD
GSMA-PRD = "PRD-" PRD-code SLASH major-version-number
PRD-code = "IR92" / token
major-version-number = 1*DIGIT ; the major version number of the GSMA PRD
document version

The rule "terminal" is defined in RCC.07 [103] section C.4.1.

The rules "mno-customization" and "device-type" are defined as an extension to RCC.07

[103] section C.4.1 as follows:

list-extension =/ device-type / mno-customisation

device-type = "device-type" SLASH device-classification
device-classification = token ; token taken from the
; device classification registry defined in IETF RFC 7852 [104]
mno-customisation = "mno-custom" SLASH customization
customization = open-market / customized
open-market = "none"
customized = MCC-MNC / free-text
MCC-MNC = MCC MNC
MCC = 3DIGIT ; the E.212 Mobile Country code assigned to the operator
; country
MNC = 3DIGIT ; the E.212 Mobile Network Code assigned to the
; operator, a two digit MNC is padded out to 3 digits
; by inserting a 0 at the beginning
free-text = token ; a human readable string to identify the
; customization

Examples of User-Agent header constructed according to the rules above:

User-Agent: PRD-IR92/11 term-Vendor1/Model1-XXXX device-type/feature-phone

mno-custom/none
User-Agent: PRD-IR92/12 term-Vendor2/Model2-YYYY device-type/smart-phone
mno-custom/235015
User-Agent: PRD-IR92/13 term-Vendor3/Model3-zzzz device-type/smart-phone
mno-custom/ex.telekom

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Note 1: The User-Agent and Server headers are meant to assist persons in
analyzing the network behavior. It is not intended that their presence,
content or syntax, influence the network behavior.

Note 2: Within a trust domain, network(s) are expected not to add, remove or modify
User-Agent and Server headers. This applies whether a given network
element functions as a SIP proxy or Back to Back User Agent (B2BUA).

3 IMS Media

3.1 General
This section endorses a set of media capabilities specified in 3GPP TS 26.114 [35]. The
section describes the needed SDP support in UEs and in the IMS core network and it
describes the necessary media capabilities both for UEs and for entities in the IMS core
network that terminate the user plane. Examples of entities in the IMS core network that
terminate the user plane are the Media Resource Function Processor (MRFP) and the Media
Gateway (MGW).

3.2 Voice Media

3.2.1 Codecs
The UE must support the Adaptive Multi-Rate (AMR) speech codec, as described in 3GPP
TS 26.071 [29], 3GPP TS 26.090 [31], 3GPP TS 26.073 [30], and 3GPP TS 26.104 [34],
including all eight (8) modes and source rate controlled operations, as described in 3GPP TS
26.093 [32]. The UE must be capable of operating with any subset of these eight (8) codec
modes.

The UE must support the AMR wideband (AMR-WB) speech codec as described in 3GPP
TS 26.114 [35], 3GPP TS 26.171 [38], 3GPP TS 26.190 [40], 3GPP TS 26.173 [39] and
3GPP TS 26.204 [42], including all nine (9) modes and source controlled rate operation
3GPP TS 26.193 [41]. The UE must be capable of operating with any subset of these nine
(9) codec modes. If the EVS codec is supported, then the EVS AMR-WB IO mode of
operation may be used as an alternative implementation of AMR-WB as specified in clause
5.2.1.4 of 3GPP Release 12 TS 26.114 [35].

If super-wideband or fullband speech communication is offered, then the UE must support

and offer the EVS codec as described in 3GPP Release 12 TS 26.114 [35], 3GPP Release
12 TS 26.441 [76], 3GPP Release 12 TS 26.442 [77], 3GPP Release 12 TS 26.443 [78],
3GPP Release 12 TS 26.445 [79], 3GPP Release 12 TS 26.446 [80], 3GPP Release 12 TS
26.447 [81], 3GPP Release 12 TS 26.449 [82], 3GPP Release 12 TS 26.450 [83] and 3GPP
Release 12 TS 26.451 [84].

The UE must support handling of CMR within RTP payload as specified in clause 7.5.2.1.2.2
of 3GPP Release 13 TS 26.114 [35].

When transmitting using the AMR codec, the AMR-WB codec or the EVS codec in the AMR-
WB IO mode of operation, then the UE must be capable of aligning codec mode changes to
every frame border, and must also be capable of restricting codec mode changes to be
aligned to every other frame border e.g. as described for UMTS_AMR_2 in 3GPP TS 26.103

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[33] based on the SDP offer-answer negotiation. The UE must also be capable of restricting
codec mode changes to neighbouring codec modes within the negotiated codec mode set
based on the SDP offer-answer negotiation.

When receiving using the AMR codec, the AMR-WB codec or the EVS codec in the AMR-
WB IO mode of operation, then the UE and the entities in the IMS core network that
terminate the user plane must allow codec mode changes at any frame border and to any
codec mode within the negotiated codec mode set. As an exception, entities in the network
that provide Circuit Switched (CS) interworking and apply Transcoder-Free Operation (TrFO)
of Tandem-Free Operation (TFO) must accept codec mode changes in accordance with the
capabilities at the CS network side.

Entities in the IMS core network that terminate the user plane supporting speech
communication and supporting TFO and/or TrFO must support:

• AMR speech codec modes 12.2, 7.4, 5.9 and 4.75 as described in 3GPP TS 26.071
[29], 3GPP TS 26.090 [31], 3GPP TS 26.073 [30], and 3GPP TS 26.104 [34].
Entities in the IMS core network that terminate the user plane supporting super-wideband
speech communication must support:

• EVS speech codec as described in 3GPP Release 12 TS 26.441 [76], 3GPP Release
12 TS 26.442 [77], 3GPP Release 12 TS 26.443 [78], 3GPP Release 12 TS 26.445
[79], 3GPP Release 12 TS 26.447 [81], 3GPP Release 12 TS 26.449 [82], 3GPP
Release 12 TS 26.450 [83] and 3GPP Release 12 TS 26.451 [84].
Entities in the IMS core network that terminate the user plane supporting wideband speech
communication and supporting TFO and/or TrFO must support:

• AMR-WB speech codec modes 12.65, 8.85 and 6.60 as described in 3GPP TS
26.171 [38], 3GPP TS 26.190 [40], 3GPP TS 26.173 [39], and 3GPP TS 26.204 [42].
Entities in the IMS network that provide transcoding-free interworking to the CS network
must be capable of requesting the UE to restrict codec mode changes to be aligned to every
other frame border and also be capable of requesting the UE to restrict codec mode
changes to neighbouring codec modes within the negotiated codec mode set.

Note: Restrictions in codec mode changes are required only for transcoder-free
interworking with a CS GSM MS (Mobile Station).

3.2.2 RTP Profile and SDP Considerations

3.2.2.1 RTP Profile

The Real Time Protocol (RTP) profile, Audio Video Profile (AVP) IETF RFC 3551 [57] must
be used by the UE and the IMS core network.

3.2.2.2 SDP Offer Considerations

The SDP Capability Negotiation framework described in IETF RFC 5939 [64] must not be
used in the SDP offer by the UE and the IMS core network when the AVP profile is used.

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3.2.2.3 SDP Answer Considerations

The UE and the IMS core network must be able to receive and answer to an SDP offer that
uses SDPCapNeg. The answer must indicate the use of the RTP AVP profile.

Note: In section 6.2.1a of 3GPP TS 26.114 [35], it is recommended that that a UE

or the IMS core network use the SDPCapNeg attributes "tcap"’ and "pcfg" to
indicate the support of both the RTP profiles AVP and AVP Feedback Profile
(AVPF). Hence, to be forward compatible with equipment using the full set of
media functions, a minimum set UE and the IMS core network must be able
to ignore the SDPCapNeg attributes and answer to the RTP AVP profile in
the offer.

3.2.2.4 SDP Bandwidth Negotiation

The UE and network must use the b=AS parameter in SDP offers and answers for
bandwidth negotiation as defined in section 6.2.5.2 of 3GPP Release 10 TS 26.114 [35] for
UEs and networks that support AMR and AMR-WB, and 3GPP Release 12 TS 26.114 [35]
for UEs and networks that support EVS.

3.2.3 Data Transport

The UE and the entities in the IMS core network that terminate the user plane must use RTP
over UDP as described in IETF RFC 3550 [56] and IETF RFC 768 [53], respectively, to
transport voice and use symmetric RTP as defined in IETF RFC 4961 [72].

3.2.4 RTCP Usage

The RTP implementation must include an RTP Control Protocol (RTCP) implementation
according to IETF RFC 3550 [56].

The UE and the entities in the IMS core network that terminates the user plane must use
symmetric RTCP as defined in IETF RFC 4961 [72].

The bandwidth for RTCP traffic must be described using the "RS" and "RR" SDP bandwidth
modifiers at media level, as specified by IETF RFC 3556 [58]. Therefore, a UE must include
the "b=RS:" and "b=RR:" fields in SDP, and a UE and the entities in the IMS core network
that terminate the user plane must be able to interpret them. If the "b=RS:" field or "b=RR:"
field or both these fields are not included in a received SDP (offer or answer), then the UE
must use the recommended default value for the missing field(s) as defined in IETF RFC
3556 [58].

The UE and the entities in the IMS core network that terminate the user plane must send
RTCP packets when media (including early media) is sent or received. Once an RTCP
packet is sent according to received SDP of a SIP dialog, RTCP packets must be sent by
UEs and entities in the IMS core network that terminate the user plane according to the
received SDP of the SIP dialog for the remaining duration of the SIP dialog. For uni-
directional media (e.g. early media or during call hold), RTCP packets must always be sent
by both UEs and entities in the IMS core network that terminate the user plane. If multiple
early dialogs are created due to forking (see section 2.2.5), the UE must send the RTCP
packets according to received SDP answers of those early dialogs for which the IP address
and port received in the SDP match the IP address and port of received media.

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Note 1: The RTCP is based on the periodic transmission of control packets to all
participants in the session, as described in IETF RFC 3550 [56]. In the
context of this document, the primary uses of RTCP are voice quality
monitoring, and to provide link aliveness information while the media are on
hold. The latter implies that the RTCP transmission must continue when the
media are on hold.

The UE and the entities in the IMS core network that terminates the user plane must set the
sending frequency of control packets to a value calculated from the values of "RS" and "RR"
SDP bandwidth modifiers according to rules and procedures in IETF RFC 3550 [56]. The UE
must set the "RS" and "RR" SDP bandwidth modifiers such that RTCP packets are sent to
the UE at least once every 5 seconds, in order to allow a sufficiently tight inactivity detection.

The UE and the entities in the IMS core network that terminate the user plane must support
the transmission of RTCP packets formatted according to the rules in IETF RFC 3550 [56]
and with the following clarifications below.

The UE and the entities in the IMS core network that terminate the user plane must use the
RTCP compound packet format. When sent, the compound packet must include one report
packet and one Source Description (SDES) packet. When no RTP packets have been sent
in the last two reporting intervals, the UE and the entities in the IMS core network that
terminate the user plane should send a Receiver Report (RR). Receiving of a Sender Report
(SR) instead of an RR must be handled and accepted as valid by the UE and the entities in
the IMS core network that terminate the user plane.

The SR, RR and SDES packets must be formatted as described below:

For SR and RR RTCP packets:

• Version 2 must be used; and

• Padding must not be used (and therefore padding bit must not be set).
For SDES RTCP packets:

• version and Padding as described for SR packet must be used;

• the SDES item CNAME must be included in one packet; and
• other SDES items should not be used.
Note 2: Because the randomly allocated SSRC identifier may change, the CNAME
item must be included to provide the binding from the SSRC identifier to an
identifier for the source that remains constant. Like the SSRC identifier, the
CNAME identifier must be unique among all other participants within one
RTP session.

To be forward compatible and interwork with legacy equipment, the UE and the entities in
the IMS core network that terminate the user plane must be able to receive all types of
RTCP packets, according to the rules specified in IETF RFC 3550 [56].

RTCP is controlled on a per session basis by the SDP offer/answer exchange as defined in
3GPP TS 26.114 [35] with the following clarifications:

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• If the UE receives an SDP offer that contains "b=RS" attribute set to zero, then the
UE must set the "b=RS" attribute to zero in an SDP answer to that SDP offer. If the
UE receives an SDP offer that contains "b=RR" attribute set to zero, then the UE
must set the "b=RR" attribute to zero in an SDP answer to that SDP offer. If the UE
receives an SDP offer that contains both "b=RR" and "b=RS" attributes set to zero,
then the UE must not send RTCP packets and must consider RTCP to be disabled
for the session.
• If the UE received an SDP answer containing zero values in both of the "b=RS" and
"b=RR" attributes, then (regardless of the values assigned to these attributes in the
corresponding SDP offer) the UE must not send RTCP packets and must consider
RTCP to be disabled for the session.
• The UE must accept receiving RTCP packets for a session that the UE considers
RTCP to be disabled. The UE is not required to process these received RTCP
packets.
3.2.5 Speech Payload Format Considerations
The Adaptive Multi Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) payload
format(s) specified in IETF RFC 4867 [63] must be supported by the UE and the entities in
the IMS core network that terminate the user plane. If the EVS codec is supported, then the
EVS payload format specified in 3GPP Release 12 TS 26.445 [79] must be supported.

The UE and the entities in the IMS core network that terminates the user plane must support
the bandwidth-efficient and the octet-aligned formats of the AMR and AMR-WB payload
formats. The UE and the entities in the IMS core network that terminates the user plane
must request the use of bandwidth-efficient format of the AMR and AMR-WB payload format
when originating a session.

The UE and the entities in the IMS core network that terminates the user plane must send
the number of speech frames, or fewer, encapsulated in each RTP packet, as requested by
the other end using the ptime SDP attribute.

The UE and the entities in the IMS core network that terminates the user plane must request
to receive one speech frame encapsulated in each RTP packet, but must accept any number
of frames per RTP packet, up to the maximum limit of 12 speech frames per RTP packet.

Note 1: This means that the ptime attribute must be set to 20 and the maxptime
attribute must be set to 240 in the SDP negotiation.

An IMS MGW not supporting redundancy may limit the maxptime attribute to 80 in the SDP
negotiation.

The UE and the entities in the IMS core network that terminates the user plane must be able
to sort out the received frames based on the RTP Timestamp and must remove duplicated
frames, if present. If multiple versions of a frame are received, e.g. encoded with different bit
rates, then the frame encoded with the highest bit rate should be used for decoding.

Note 2: UEs and the entities in the IMS core network that terminate the user plane,
using the full set of media functions, have the option to send frames several
times (for redundancy) to adapt for conditions with high packet-loss ratios. It
is thus important that a UE and the entities in the IMS core network that

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terminate the user plane that use this profile are capable to detect and drop
the duplicated frames.

RTCP-APP must not be used for Codec Mode Requests (CMR) by the UE and the entities in
the IMS core network that terminate the user plane.

Note 3: As the speech media uses the RTP AVP profile as specified in section
3.2.2.1, the adaptation using RTCP may be too slow and therefore
unsuitable.

3.2.6 Jitter Buffer Management Considerations

The minimum performance requirements for jitter buffer management of voice media, as
described in 3GPP TS 26.114 [35] must be met. If the EVS codec is supported, then the jitter
buffer management requirements in section 8.2 of 3GPP Release 12 TS 26.114 [35] must be
met.

3.2.7 Front End Handling

UEs used for IMS voice services must conform to the minimum performance requirements
on the acoustic characteristics of 3G terminals specified in 3GPP TS 26.131 [36]. The codec
modes and source control rate operation (DTX) settings must be as specified in 3GPP TS
26.132 [37].

3.3 DTMF Events

The UE and the IMS core network must support DTMF events as defined in Annex G of
3GPP TS 26.114 [35].

If the UE receives an SDP offer with no telephone-event codec included, then the UE must
not reject the SDP offer for this reason and the UE must not send DTMF events using the
telephone-event codec for the negotiated session.

Note: Transport of DTMF events from the UE using the telephone-event codec
during a session is impossible unless the telephone-event payload type has
been negotiated.

3.4 Data Channel

Section 6.2.10 of 3GPP TS 26.114 [35] applies for both the UE and the entities in the IMS
core network that terminate the user plane.

4 Radio and Packet Core Feature Set

4.0 General
The LTE radio capabilities included in this specification are applicable to UEs and networks
supporting FDD LTE only, TDD LTE only, or both FDD LTE and TDD LTE.

4.1 Robust Header Compression

The UE and the network must support Robust Header Compression (RoHC) as specified in
3GPP TS 36.323 [51], IETF RFC 3095 [54] and IETF RFC 4815 [62]. The UE and network
must be able to apply the compression to packets that are carried over the radio bearer

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dedicated for the voice media. At minimum, the UE and network must support "RTP/UDP/IP"
profile (0x0001) to compress RTP packets and "UDP/IP" profile (0x0002) to compress RTCP
packets. The UE and network must support these profiles for both IPv4 and IPv6.

4.2 LTE Radio Capabilities

4.2.1 Radio Bearers

The UE must support the following combination of radio bearers (see Annex B in 3GPP TS
36.331 [52]):

• SRB1 + SRB2 + 4 x AM DRB + 1 x UM DRB

The network must support the following combination of radio bearers:

• SRB1 + SRB2 + 2 x AM DRB + 1 x UM DRB

One AM Data Radio Bearer (DRB) is utilized for an Evolved Packet System (EPS) bearer
with Quality of Service Class Indicator (QCI) = 5 and another AM DRB for EPS bearer with
QCI = 8/9. UM DRB is utilized for EPS bearer with QCI = 1. EPS bearer usage is described
in section 4.3.

4.2.2 DRX Mode of Operation

In order to maximize lifetime of the UE battery, the UE and the network must support LTE
Discontinuous Reception (DRX) method as specified in 3GPP TS 36.300 [49] and 3GPP TS
36.321 [50] must be deployed.

4.2.3 RLC configurations

Radio Link Control (RLC) entities must be configured to perform data transfer in the following
modes as specified in 3GPP TS 36.322 [69]:

• Unacknowledged Mode (UM) for EPS bearers with QCI = 1

• Acknowledged Mode (AM) for EPS bearers with QCI = 5
• Acknowledged Mode (AM) for EPS bearers with QCI = 8/9
Voice service can tolerate error rates on the order of 1%, while benefiting from reduced
delays, and is mapped to a radio bearer running the RLC protocol in unacknowledged mode
(UM).

EPS bearer usage is described in section 4.3.

4.2.4 GBR and NGBR Services, GBR Monitoring Function

Voice is one of the LTE services that require a GBR bearer as described in 3GPP TS 23.401
[10]. The GBR bearer for voice is realised via dedicated network resources that are allocated
by an admission control function in the eNodeB at bearer establishment. Reports from the
UE, including buffer status and measurements of UE’s radio environment, are required to
enable the scheduling of the GBR bearer as described in 3GPP TS 36.300 [49]. In UL it is
the UE’s responsibility to comply with GBR requirements.

The non-GBR bearer (NGBR) does not support a guaranteed bit rate over the radio link and
is thus not suitable for IMS-based voice services.

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4.2.5 E-UTRA NR Dual connectivity

The UE may support and the network can support E-UTRA NR Dual Connectivity (EN-DC) as
defined in 3GPP Release 15 TS 37.340 [101]. The UE may support EN-DC as specified in
3GPP Release 15 of TS 36.331 [52] and TS 38.331 [102].

4.3 Bearer Management

4.3.1 EPS Bearer Considerations for SIP Signalling, HTTP for XCAP and
HTTP Content Server
For SIP signalling, the IMS application in the UE must use the IMS well-known APN as
defined in GSMA PRD IR.88 [67]; the UE must prevent non-IMS applications from using the
IMS well-known APN.

Unless preconfigured by the home operator with the EPS_initial_attach_ConRefs parameter

as specified in Annex C.3 to provide the IMS well-known APN during initial attach, the UE
must not provide the IMS well-known APN during the E-UTRAN initial attach procedure.

Note 1: The network has to be prepared to receive any APN, including the IMS well-
known APN, during the E-UTRAN initial attach procedure, as per 3GPP TS
23.401 [10] and 3GPP TS 24.301 [17].

Note 2: When preconfiguring the UE to provide the IMS well-known APN during
initial attach, the home operator needs to ensure that the IMS well-known
APN is part of the subscription of the user of the UE in order to avoid attach
failure. How the home operator preconfigures the UE is out of the scope of
this PRD.

If procedures in section 2.2.1 require the UE to register with IMS, and the PDN connection to
the IMS well-known APN does not exist yet (e.g. when the PDN connection established
during the initial attach is to an APN other than the IMS well-known APN) then the UE must
establish a PDN connection to the IMS well-known APN.

Note 3: PDN Connection establishment can be caused by a SIP registration request.

Sending a SIP registration request per the note in section 2.2.1 can cause
PDN Connection establishment even if the IMS voice over PS Session
indicator indicates that IMS voice over PS session is not supported.

Note 4: For all cases when the UE provides the IMS well-known APN, the APN
Operator Identifier is not included by the UE.

A default bearer must be created by the network when the UE creates the PDN connection
to the IMS well-known APN, as defined in 3GPP specifications. A standardised QCI value of
five (5) must be used for the default bearer. The default bearer is used for IMS SIP
signalling.

A default bearer must be created by the network when the UE creates the PDN connection
for emergency bearer services, as defined in 3GPP specifications. A standardised QCI value
of five (5) and an ARP value that is reserved for emergency services must be used for the
default bearer. The default bearer is used for IMS SIP signalling.

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The UE must and the network can support Back-off timer value IE in PDN Connectivity
Reject and the UE must start the ESM back-off timer according to the value indicated by the
Back-off timer value IE as specified in 3GPP Release 12 TS 24.301 [17]. If the Back-off timer
value IE is not included in a PDN Connectivity Reject, and the PDN Connectivity Reject is for
a standalone PDN CONNECTIVITY REQUEST, then the UE must apply a default value of
12 minutes for the ESM back-off timer for the cause values #8 "operator determined
barring", #27 "missing or unknown APN", #32 "service option not supported", and #33
"requested service option not subscribed" as described in section 6.5.1.4.3 of 3GPP Release
12 TS 24.301 [17].

For XCAP and HTTP Content Server requests, the UE must be preconfigured or provisioned
by the home operator with the ToConRef parameter as specified in Annex C.3 with the
Network Identifier part of the APN for Home Operator Services to be used for these requests
(see GSMA PRD IR.88 [67] for more information).

Note 5: How the home operator preconfigures or provisions the UE with the Network
Identifier part of the APN for Home Operator Services is out of the scope of
this PRD.

For XCAP and HTTP Content Server requests, the UE must establish the PDN connection to
the APN for HOS only when required (unless already established), e.g. when the user
modifies a supplementary service’s setting. In case the UE did not re-use an established
PDN connection (e.g. in case the HOS APN is the internet APN), the UE must close the
connection at most 120s after the last transaction has been completed.

4.3.2 EPS Bearer Considerations for Voice

For an IMS session request for a Conversational Voice call (originating and terminating), a
dedicated bearer for IMS-based voice must be created by the network utilising interaction
with dynamic PCC. The network must initiate the creation of a dedicated bearer to transport
the voice media. The dedicated bearer for Conversational Voice must utilise the
standardised QCI value of one (1) and have the associated characteristics as specified in
3GPP TS 23.203 [4]. Since the minimum requirement for the UE is the support of one (1)
UM bearer that is used for voice (see section 7.3.1 and Annex B of 3GPP TS 36.331 [52]),
the network must not create more than one dedicated bearer for voice media. Therefore, the
UE and network must be able to multiplex the media streams from multiple concurrent voice
sessions.

Note 1: A single bearer is used to multiplex the media streams from multiple
concurrent voice sessions; this is necessary in some supplementary
services (e.g. CW, CONF).

Note 2: The sharing of a single GBR bearer for voice means that different QCI
and/or ARP values are not possible for different voice streams.

When the UE has an ongoing conversational voice call, the UE must follow the procedures
for access domain selection related to "Persistent EPS bearer context" as specified in
sections 5.5.3.2.4 and 5.5.3.3.4.3 of 3GPP Release 10 TS 24.301 [17], sections 5.1.3.1 and
L.2A.0 of 3GPP Release 10 TS 24.229 [15], and section 8.2 of 3GPP Release 10 TS 24.237
[16].

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For IMS session termination of a Conversational Voice call, the dedicated bearer must be
deleted utilising interaction with dynamic PCC. The network must initiate the deletion of the
bearer.

4.3.3 EPS Bearer Considerations for voice media on emergency PDN

Connection
For an IMS session request for an emergency call on the PDN connection for emergency
bearer services, and if as a result of SDP offer/answer a voice media is negotiated, then a
dedicated bearer for voice media must be created by the network utilising interaction with
dynamic PCC as specified in 3GPP Release 11 TS 23.401 [10]. The network must initiate
the creation of a dedicated bearer to transport the voice media of an emergency call. The
dedicated bearer for voice media of an emergency call:

• must utilise the standardised QCI value of one (1);

• must have the associated characteristics as specified in 3GPP TS 23.203 [4]; and
• must have an ARP value that is reserved for emergency services.
For IMS session termination of an emergency call, the dedicated bearer must be deleted
utilising the interaction with dynamic PCC. The network must initiate the deletion of the
bearer.

4.4 P-CSCF Discovery

The UE and packet core must support the procedures for P-CSCF discovery via EPS. These
are described in Annex L.2.2.1of 3GPP TS 24.229 [15], as option II for P-CSCF discovery.

The UE must indicate P-CSCF IPv6 Address Request and P-CSCF IPv4 Address Request
when performing the following procedures (see also section 4.3.1):

•during the initial attach when establishing PDN connection to the default APN;
•during the initial attach when establishing PDN connection to the IMS well-known
APN;
• during the establishment of the PDN connection to the IMS well-known APN when
already attached;
• during the attach procedure for emergency bearer services; and
• during the establishment of the PDN connection for emergency bearer services when
already attached.
The UE must use the P-CSCF addresses received during PDN connection establishment to
the IMS well-known APN when accessing non-emergency services, and must use the
P-CSCF addresses received during PDN connection establishment for emergency bearer
services when accessing emergency services, as defined in section 5.1 of this document
and 3GPP TS 24.229 [15].

If the UE receives a Modify EPS Bearer Context Request message containing a list of P-
CSCF addresses that do not include the address of the currently used P-CSCF, the UE must
acquire a P-CSCF different from the currently used P-CSCF and initiate a new initial
registration as described in section L.2.2.1C 3GPP Release 12 TS 24.229.

Note: The above behaviour can result in any ongoing calls being released.

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5 Common Functionalities

5.1 IP Version
The UE and the network must support both IPv4 and IPv6 for all protocols that are used:
SIP, SDP, RTP, RTCP and XCAP/HTTP. At initial attach and PDN connection
establishment, the UE must request the PDN type IPv4v6, as specified in section 5.3.1.1 of
3GPP TS 23.401 [10] and section 6.2.2 of 3GPP TS 24.301 [17]. If both IPv4 and IPv6
addresses are assigned by the network to the UE, the UE must prefer the IPv6 address type
when the UE discovers the P-CSCF. If only an IPv4 address or only IPv6 address is
assigned by the network to the UE then the network must send ESM cause #50 "PDN type
IPv4 only allowed" or #51 "PDN type IPv6 only allowed", respectively, to the UE and the UE
must not request another PDN connection to the APN utilised in the initial attach or PDN
connection establishment for the other IP version, as specified in section 6.2.2 of 3GPP
Release 12 TS 24.301 [17].

After the UE has discovered the P-CSCF and registered to IMS with a particular IPv4 or IPv6
address, the UE must use this IP address for all SIP communication for as long as the IMS
registration is valid. For all SDP and RTP/RTCP communication, the UE must use the IPv4
address used for SIP communication or an IPv6 address with the IPv6 prefix same as the
IPv6 prefix of the IPv6 address used for SIP communication.

Note: There are certain situations where interworking between IP versions is

required. These include, for instance, roaming and interconnect between
networks using different IP versions. In those cases, the network needs to
provide the interworking in a transparent manner to the UE.

5.2 Emergency Service

5.2.1 General
The UE and the network must support emergency services in the IMS domain. In the case of
the UE, this requirement is also applicable where the UE is in a limited service state. Limited
service state refers to the availability of a specific service in the network and is defined in
section 3.5 of 3GPP TS 23.122 [109].

UEs in limited service state can perform an IMS emergency call without emergency
registration. This is also applicable to UEs with reduced/limited voice capabilities, e.g.
inbound roamers where there is no VoLTE Roaming agreement in place.

The network is recommended to support an IMS emergency call from a UE in limited service
state dependent on local policy and regulations. When 2G and 3G networks are sunset, the
network must allow an IMS emergency call.

The UE and the network must support the IMS emergency services as specified in 3GPP
Release 9 TS 24.229 [15], section 6, Annex H, Annex K of 3GPP Release 14 TS 23.167 [3],
and emergency procedures as specified in 3GPP Release 9 TS 24.301 [17].

The UE must support the IMS emergency session specified in section 5.1.6.8.2 of 3GPP
Release 14 TS 24.229 [15] (anonymous IMS emergency session), and the network can

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(dependent on operator policy) support the IMS emergency session procedures specified in
sections 5.2.1, 5.2.10.1, 5.2.10.2 and 5.2.10.5 of 3GPP Release 14 TS 24.229 [15].

The UE and the network must support the PDN disconnect procedure for emergency bearer
services as described in section L.2.2.6.1 of 3GPP Release 14 TS 24.229 [15].

The UE must support the emerg-reg timer defined in table 7.8.1 of 3GPP Release 14 TS
24.229 [15] and related procedure defined in section 5.1.6.1 of 3GPP Release 14 TS 24.229
[15]. The operator can configure the UE with emerg-reg timer parameter as specified in
Annex C3.

If the UE:

• receives the Emergency Service Support indication during EPS attach or tracking
area updating procedures;
• attempts an emergency registration with IMS;
• receives a SIP 3xx, 4xx (except 401), 5xx or 6xx response to the emergency
REGISTER request; and
• is still in a tracking area that has received the Emergency Service Support indication;
then the UE must perform the procedures defined in subclause 5.1.6.8.2 of 3GPP Release
14 TS 24.229 [15].

Note 1: No IMS emergency call is possible if the network does not support
anonymous emergency sessions over IMS (e.g. because operator policy is
restricted by local regulator) and when either

• no agreement for national/international roaming exists,

• IMS emergency registration fails with an IMS emergency registration

failure response 401, or

• UE does not have sufficient credentials to authenticate with the IMS.

When the UE has an ongoing emergency call, the UE must follow the procedures for access
domain selection related to "Persistent EPS bearer context" as specified in sections
5.5.3.2.4 and 5.5.3.3.4.3 of 3GPP Release 10 TS 24.301 [17] and section 8.2 of 3GPP
Release 10 TS 24.237 [16].

Recognizing that some network operators will continue a parallel CS network whilst their IMS
network is deployed, and that support of emergency calls with CS support may be a local
regulatory requirement, emergency calls in the CS domain are addressed in Annex A.

The UE and network must support the 3GPP IM CN subsystem XML body as defined in
section 7.6 of 3GPP TS 24.229 [15].

The usage of the 3GPP IM CN subsystem XML body in the network is an operator option.

Note 2: This implies that the P-CSCF must also support the option that the XML
body is not used.

If the VPMN supports emergency numbers other than 112 and 911, then the network must
provide the Extended Emergency Number List to the UE as specified in 3GPP Release 15

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TS 24.301 [17], unless all the local emergency numbers are provided in the Emergency
Number List where each number is associated with a single emergency service category
value as specified in section 10.5.4.33 of 3GPP Release 15 TS 24.008 [11]. The UE must
support the handling of both Emergency Number List and Extended Emergency Number List
as specified in section 5.3.7 of 3GPP TS 24.301 [17]. The SUPL enabled UE sends the
emergency SUPL messages related to the UE detectable emergency session within the
PDN connection for emergency bearer services. The SUPL enabled UE sends the
emergency SUPL messages related to the non UE detectable emergency session within the
PDN connection to the IMS well known APN. The UE selects the bearer to be used based
on the TFTs of the bearers of the PDN connection. QCI of the selected bearer is provided by
the network.

5.2.2 Interactions between supplementary services and PSAP callback

The network must not invoke the use of supplementary services on a call identified as a
PSAP callback as specified in 3GPP Release 12 TS 24.604 [20], 3GPP Release 12 TS
24.605 [21], 3GPP Release 12 TS 24.610 [25] and 3GPP Release 12 TS 24.611 [26].

Note: UE procedures for PSAP callback are not specified by 3GPP.

5.2.3 UE location management

When initiating an IMS emergency session, the UE must conform to the requirements to
convey its location, using the "Geolocation" header field and the PIDF location object in the
initial SIP INVITE request, as specified in section 5.1.6.8.2 and section 5.1.6.8.3 of 3GPP TS
24.229 [5].

The support of URI that points to the location information is not required.

5.3 Roaming Considerations

This profile has been designed to support IMS voice roaming. For more information on the
IMS voice roaming models see GSMA PRD IR.65 [65] and GSMA PRD IR.88 [67].

The UE must support "null" IMS encryption as specified in 3GPP TS 33.203 [45] annex H and
described in GSMA PRD IR.65 [65] section 2.4.3.

5.4 Accesses in addition to E-UTRAN

UEs that support cellular (e.g. E-UTRAN) and non-cellular accesses that are not
EPC-integrated (e.g. non-EPC integrated Wi-Fi access) must use:

• the cellular access as transport of the Gm reference point; and

• the cellular access as transport of the Ut reference point, unless preconfigured
otherwise by the home operator with the AccessForXCAP parameter as specified in
Annex C.3.
5.5 Data Off and Services Availability

5.5.1 General
The UE must and the network can support 3GPP PS Data Off. When 3GPP PS Data Off is
activated by the user, the UE and the network must not send via any PDN connection any IP

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packet of any service other than 3GPP PS Data Off Exempt Services. This applies both to
non-IMS based services and SIP-based IMS services.

The UE must support to be provisioned with the list of SIP-based 3GPP PS Data Off Exempt
Services as per section 5.67 of 3GPP Release 14 TS 24.167 [68] and section 5.7 of 3GPP
Release 14 TS 24.275 [95].

The UE must support to be provisioned with the list of non-IMS 3GPP PS Data Off Exempt
Services as per section 5.10i of Release 14 3GPP TS 24.368 [96] and 3GPP Release 14 TS
24.424 [91].

The UE must support to be provisioned for data off for the Call Composer service via the
configuration parameter PRE AND POST CALL DATA OFF (see Annex C.3) as specified in
section 2.8.1.5 of GSMA PRD RCC.07 [103].

A UE must report its 3GPP PS data off status, and each change in its 3GPP PS data off
status as specified in 3GPP Release 14 TS 24.229 [15] and in section 6.3.10 and section
6.5.4.2 of 3GPP Release 14 TS 24.301 [17].

If the 3GPP PS data off status changes from "inactive" to "active" the UE must release all
IMS sessions/dialogs that fulfil the conditions in section L.3.1.5 of 3GPP Release 14 TS
24.229 [15]

Note: The UE can disconnect PDN connections that are not required by 3GPP PS
Data Off Exempt Services.

5.5.2 Supplementary Service Settings Management

The UE must be able to perform supplementary service settings management as described
in section 2.3 regardless of whether 3GPP PS Data Off is active. For this reason, the
operator must configure "IMS Supplementary Service configuration via the Ut interface using
XCAP" as 3GPP PS Data Off Exempt Service, see section C.3.

5.5.3 Voice Calls and SMS over IP

The UE must be able to initiate and receive Voice Calls and SMS over IP as described in the
main body of this document regardless whether Data Off is active. For this reason, the
operator must configure "MMTel Voice" and "SMS over IP" as 3GPP PS Data Off Exempt
Services, see section C.3.

5.6 Voice Calls and Smart Congestion Mitigation

The UE must and the network can support Smart Congestion Mitigation as specified in
sections J.2.1.1 and J.2.1.2 of 3GPP Release 12 TS 24.173 [14], section 5.6.1.6 and annex
D of 3GPP Release 12 TS 24.301 [17], and sections 5.3.3.2, 5.3.3.10 and 5.3.3.11 of 3GPP
Release 12 TS 36.331 [52].

5.7 Capability Discovery

The UE and the network can support Capability Discovery as defined in section 2.6 of GSMA
PRD RCC.07 [103]. If Capability Discovery is supported by the UE and the network, then
Capability Discovery is configured via the configuration parameter CAPABILITY

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DISCOVERY MECHANISM (see Annex C.3). Capability Discovery is enabled if the value of
the configuration parameter CAPABILITY DISCOVERY MECHANISM is set to "0" or "1".

If the UE supports Capability Discovery and if Capability Discovery is enabled, then the UE
must follow the procedures for Capability Discovery as defined in GSMA PRD RCC.07 [103]
and the procedures defined for the applicable services.

In this version of the document, capability discovery is applicable for the following services:

• Call Composer.
5.8 HTTP Content Server
For the Call Composer service, the UE must support the procedures for file upload and file
download to the HTTP Content Server. The network must provide a HTTP Content Server if
the Call Composer service is enabled.

The procedures for the file upload to the HTTP Content Server are defined in steps 1, 2, 3
and 4 of section 3.2.5.3.1.1 of GSMA PRD RCC.07 [103] and section 3.2.5.3.1.2 of GSMA
PRD RCC.07 [103]. The operator can specify the HTTP Content Server for upload via the
configuration parameter FT HTTP CS URI, see Annex C.3.

The procedures for the file download from the HTTP Content Server are defined in sections
3.2.5.3.2 and 4.1.15.4 of GSMA PRD RCC.07 [103]. The operator can specify the HTTP
Content Server for download via the configuration parameter FT HTTP DL URI, see Annex
C.3.

6 SMS Support
The UE must, and the network can, support both SMS over IP and SMS over NAS signalling
methods. However, the network must support at least one of the above methods, i.e. either
SMS over IP or SMS over NAS signalling method.

The UE must support the functionality as specified according to section 7.2c of 3GPP TS
23.221 [6]. The UE must:

a) be pre-configured by the operator with the

"SMS_Over_IP_Networks_Indication" parameter as specified in Annex C.3
that determines to use either SMS over IP or SMS over NAS signalling; and
b) be capable of being configured according to the parameter
"SMS_Over_IP_Networks_Indication" in the IMS Management Object defined
in 3GPP TS 24.167 [68], in order to give operator control to configure the UE
to use SMS over the NAS signalling when required.
The UE must include the +g.3gpp.smsip feature tag as defined in section 5.3.2.2 of 3GPP
TS 24.341 [19] in a SIP REGISTER request when the "SMS_Over_IP_Networks_Indication"
is set to the value of 1.

6.1 SMS over IP

The UE must implement the roles of an SM-over-IP sender and an SM-over-IP receiver,
according to sections 5.3.1 and 5.3.2 of 3GPP TS 24.341 [19].

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The status report capabilities, delivery reports, and notification of having memory available,
according to sections 5.3.1.3, 5.3.2.4 and 5.3.2.5 of 3GPP TS 24.341 [19] must be
supported by the UE and the IMS core network.

The IMS core network must take the role of an IP-SM-GW and support the general
procedures in section 5.3.3.1 of 3GPP TS 24.341 [19], and the following functions:

• answering of routing information query and obtaining the routing information

according to the procedures in section 5.3.3.3 in 3GPP TS 24.341 [19]; and
• transport layer interworking according to sections 5.3.3.4 of 3GPP TS 24.341 [19].
6.2 SMS over NAS
The UE and the network must support the necessary procedures as specified in 3GPP TS
23.272 [9], 3GPP TS 23.221 [6] and 3GPP TS 24.301 [17].

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Annex A Complementing IMS with CS

A.1 General
In order to offer its customers a seamless service, the operator may wish to complement the
IMS capable radio coverage by using the CS radio access. The IMS coverage may be less
or more extensive than the concurrent Circuit Switched (CS) coverage. This Annex
describes the additional features that need to be implemented for the UEs and networks that
wish to support such a deployment scenario.

The voice related requirements in this annex are applicable if the UE has the setting of "IMS
PS Voice preferred, CS Voice as secondary".

The requirements in this annex are not applicable if during a combined attach the EPS
network provides an indication that Circuit Switched (CS) services are not supported in the
event of:

• the EPS attach result IE value indicates "EPS only", or

• the Additional update result IE indicates "SMS only".
A.2 Domain Selection
The network and the UE must support the IMS voice over PS session supported indication
as specified in section 4.3.5.8 of 3GPP TS 23.401 [10]

The UE must perform voice domain selection for originating sessions with the setting of "IMS
PS Voice preferred, CS Voice as secondary" as specified in section 7.2a of 3GPP TS 23.221
[6], and must perform the procedures defined in 3GPP TS 24.301 [10].

Note 1: The behaviour of UEs with the setting "IMS PS Voice preferred, CS Voice as
secondary" is illustrated in Annex A.2 of 3GPP TS 23.221 [6].

The UE must perform voice domain selection and be able to retry in the CS domain (CSFB
procedures) as defined in section 5.1.3.1 and Annex L.5 of 3GPP Release 14 TS 24.229
[15].

The network can support the rejection of a SIP INVITE as defined in section 5.2.7.2 of 3GPP
release 14 TS 24.229 [15].

Note 2: The procedure in section 5.2.7.2 of 3GPP TS 24.229 can be used when the
originating P-CSCF receives an indication that radio/bearer resources are
not available and rejects the INVITE request with a SIP 500 (Server Internal
Error) response.

The UE must reject an incoming request if the UE is unable to support speech media on
current PS access as specified in 3GPP TS 23.237 [8] and 3GPP TS 24.237 [16].

The UE must support Idle Mode Signalling Reduction (ISR) as specified in 3GPP Release 9
TS 23.401 [10] and 3GPP Release 9 TS 24.301 [17]. Therefore, the UE must disable ISR
locally if IMS voice is supported in the network.

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A.3 SR-VCC
The network must support the Single Radio Voice Call Continuity (SR-VCC) procedures for
handover from E-UTRAN as described in 3GPP TS 23.216 [5] and 3GPP TS 23.237 [8].

The UE must support the SR-VCC procedures for single active call only as described in
3GPP TS 23.216 [5], 3GPP TS 24.008 [11], 3GPP TS 24.237 [16], and 3GPP TS 24.301
[17].

Note 1: The mechanisms to perform transfer of additional session / held state /

conference call state / alerting calls are out of scope of the present version
of this document.

Note 2: UEs using IMS Centralized Services (ICS) capabilities are out of scope of
the present version of this document.

A.4 IMS Voice service settings management when using CS access

The UE must use service setting management as defined in section 2.3.2 and section 5.5.1
using the current cellular access, over the APN defined in section 4.3.1. UEs that support
non-cellular accesses that are not EPC-integrated (e.g. non-EPC integrated Wi-Fi access),
must comply to the requirements of section 5.4.

Note 1: This applies also when the UE is using CS network for voice service.

If:

• the UE attempts to perform supplementary service settings management via XCAP;

• the UE receives an HTTP failure code as described in section 5.3.1.2.2 of 3GPP
Release 12 TS 24.623 [28];
• the UE is not configured with SS_domain_setting parameter as specified in Annex
C.3 with network operator's preference for the selection of the domain used by the UE
when performing supplementary services setting control for voice services; and
• until the UE performs a power-off/power-on or the UE detects a change of USIM/ISIM
then:

• the UE must not perform supplementary service settings management via XCAP; and
• the UE must instead attempt to perform supplementary service settings management
in the CS domain.
Note 2: By default, the UE is not configured with the SS_domain_setting parameter
as specified in Annex C.3 with the network operator's preference for the
selection of the domain used by the UE when performing supplementary
service settings control for voice services.

A.5 Emergency Service

This section modifies the requirements defined in section 5.2 in the following ways:

The UE must, and the network can, support the procedures and capabilities defined in
section 5.2.

If the support of one or more of the following scenarios is required, then the network must
support the procedures in section 5.2:

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• Deployment scenarios where the IMS VoIP capable radio coverage is not
complemented by CS radio coverage.
• Provide voice service on LTE to UE with incompatible CS domain.
• Provide voice service on LTE to UE supporting LTE only
When emergency service support via CS domain is required, the UE and the network must
support the CS emergency service as used today.

The UE must be able to perform domain selection for emergency calls, and automatically be
able to retry in the CS domain if a SIP INVITE for an IMS emergency session is rejected with
a SIP 3xx, 4xx (except 407), 5xx or 6xx response, as defined in section 7.3 and Annex H of
3GPP Release 9 TS 23.167 [3] and 3GPP Release 9 TS 24.229 [15]. The UE must be able
to detect if the network is not supporting IMS emergency sessions as defined in 3GPP TS
23.401 [10], then select the CS domain for UE detected emergency sessions. The UE must
be able to perform domain selection for emergency calls, and also automatically be able to
retry in the IMS if a UE detected CS emergency call attempt fails and the network supports
IMS emergency sessions, as defined in subclause 7.3 and Annex H of 3GPP Release 9 TS
23.167 [3], 3GPP Release 9 TS 23.401 [10] and 3GPP Release 9 TS 24.229 [15].

The network must be able to reject a SIP INVITE for an IMS emergency session such that
the UE can retry in the CS domain, as defined in 3GPP TS 24.229 [15] and section 6.2.1 of
3GPP TS 23.167 [3].

When IMS emergency service is not possible (e.g. the network does not support IMS
emergency), and when the UE supporting CS Fallback (CSFB), as described in 3GPP TS
23.272 [9], is IMSI attached, then the UE must use the CSFB procedures for CS emergency
service. If the network or the UE do not support CSFB, the UE must autonomously select the
RAT that supports CS.

The UE must support SR-VCC for IMS emergency sessions as specified in 3GPP Release 9
TS 23.216 [5] and 3GPP TS 23.237 [8]. The SR-VCC UE that supports IMS emergency
service must support the SIP instance ID as defined in section 7.2 3GPP TS 24.237 [16].

The network must support SR-VCC for IMS emergency sessions as specified in 3GPP
Release 9 TS 23.216 [5] and 3GPP TS 23.237 [8]. The network must support the SIP
instance ID as defined in 3GPP TS 24.237 [16].

In limited service state, it is recommended that a UE that is CS voice capable should always
camp on a RAT that is likely to support the CS domain, e.g. GERAN or UTRAN or
CDMA2000, as described in 3GPP TS 23.221 [6].

A.6 Roaming Considerations

When voice over IMS, see section 5.3, is not possible then the UE must follow the
procedures defined in Annex A.2 to use CS for voice service.

A.7 Void

A.8 Call Waiting in the CS domain

When the UE on an ongoing call is presented with a new incoming call from the CS core
network and:

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• if the Communication Waiting supplementary service (see section 2.3.4) is

deactivated in the UE, then the UE must reject the incoming call by sending a
RELEASE COMPLETE message with cause #17 "user busy" as specified in 3GPP
TS 24.008 [11]; and
• if the Communication Waiting supplementary service is activated in the UE, the UE
must generate a call waiting indication to the user.
A.9 USSD
For a UE that supports CSFB:

• If the UE has no ongoing IMS session for conversational voice calls and is not in the
process of establishing an IMS session for conversational voice call (originated or
terminated) then the UE must use the CSFB procedures as described in 3GPP TS
23.272 [9] for originating and terminating USSD requests in the CS domain.
• If the UE has one or more ongoing IMS sessions for conversational voice call or is in
the process of establishing an IMS session for conversational voice call (originated or
terminated) then:
o the UE must not attempt originating USSD requests in the CS domain; and
o if paging procedure takes place, the UE must reject the request to perform CS
fallback for terminating USSD requests as specified in 3GPP TS 24.301 [17].

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Annex B Features needed in certain regions

B.1 General
This Annex describes features that operators need to support in certain regions due to local
regulatory requirements.

B.2 Global Text Telephony over IP

In some regions, there are regulatory requirements that allows deaf/hearing impaired people
to use text based communication known as Teletype Writer (TTY) to other users and
government offices (e.g. to provide equal access to emergency services to all users). In this
document, the evolution of the legacy CS-based TTY in IMS is referred to as Global Text
Telephony over IP (GTT-IP).

Note: GTT-IP is also referred to as Real Time Text in some standards. The use of
GTT-IP in this section infers both GTT-IP and Real Time Text.

The following requirements outline how the GTT-IP service should be implemented in
regions where required.

The UE must include the text media feature tag, as defined in IETF RFC 3840 [86], in the
Contact header field of the SIP REGISTER request, in the Contact header field of the SIP
INVITE request, and in the Contact header field of the SIP response to the SIP INVITE
request, using procedures defined in 3GPP TS 24.229 [15].

GTT-IP messages must use ITU-T Recommendation T.140 [70] real-time text according to
the rules and procedures specified in 3GPP TS 26.114 [35] with the following clarifications:

• The call with GTT-IP component must contain both "text" and "audio" media RTP
streams negotiated using existing SDP offer/answer procedures.
Note 2: The implementation of calls with single "text" media is not supported.

• For real-time text, RTCP reporting must be turned on by setting the SDP bandwidth
modifiers "RS" and "RR" as specified in section 3.2.4.
• The sampling time used must be 300 ms.
• Change of the sampling time (rate adaptation) is not required.
For an IMS session request for a call with GTT-IP component (originating and terminating), a
dedicated bearer for the T.140 text media must be created by the network using interaction
with dynamic PCC. The network must initiate the creation of a dedicated bearer to transport
the text media.

For a scenario when GTT-IP component is added or removed during the session, the
existing dedicated bearer must be modified to add or to remove text media using interaction
with dynamic PCC.

The dedicated bearer for a call with GTT-IP component may use:

• a Non-GBR bearer with a QCI value of 8 or 9 as stated in annex E.4 of 3GPP

Release 10 TS 26.114 [35]; or
• a GBR bearer with a QCI value of 1.

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For networks residing in regions where regulatory requirements include requirements for low
end-to-end latency and packet loss, the usage of a GBR bearer with a QCI of 1 for transport
of both audio and real-time text RTP streams is recommended.

There is no support of SR-VCC of T.140 text media (i.e. the T.140 text media is dropped
after handover to CS).

For IMS session release of a call with GTT-IP component, the dedicated bearer must be
deleted by the network using interaction with dynamic PCC. The network must initiate the
deletion of the bearer.

B.3 Service Specific Access Control

In some regions, e.g. Japan, there are regulatory requirements that require the need to
release only voice calls while allowing high priority calls and access for other packet service
(e.g. email, web, disaster message board), as under disaster or emergency events, the
mass simultaneous voice call requests are usually the main cause for network congestion.

To fulfil the regulatory requirements, the UE for such regions must support Service Specific
Access Control (SSAC) as specified in 3GPP Release 9 TS 22.011 [1], 3GPP Release 9 TS
36.331 [52], 3GPP Release 9 TS 24.173 [14] and 3GPP Release 9 TS 27.007 [43].

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Annex C MNO provisioning and Late Customization

C.1 General
This annex describes the capabilities to support MNO provisioning and late customization for
the UE (e.g. for open market devices). An open market device:
• Supports non-roaming and roaming cases;
• Has a default configuration suitable for many MNOs; and
• Can be configured to the MNO’s needs.
C.2 Configuration Methods

C.2.1 Remote Client Configuration for MNO provisioning

The UE and the network must support one of the two configuration methods in order to
support MNO provisioning for the parameters that are defined in 3GPP (see also Table
C.3.1):
• OMA DM V1.2 with http binding as specified in OMA-ERELD-DM-V1_2 [100]; or
• Service provider device configuration as specified in GSMA PRD RCC.14 [93].
Note 1: The requirement on which configuration method to support may differ
between regions.

C.2.2 Late Customization

The UE must support late customization as specified in GSMA PRD TS.32 [92] for the
parameters that are in Table C.3.1 and can support late customization for the remaining
parameters of GSMA PRD TS.32 [92].

C.3 Configuration Parameters

Table C.3.1 contains the configuration parameters with their default values that must be
supported by the UE and the network. The UE must use the default value for each
parameter in Table C.3.1 unless configured differently by any of the methods as described in
section C.2.

Note: The parameters in Table C.3.1 are a subset of parameters in section 3.9 of
GSMA PRD TS.32 [92].

Parameter Default Defined in See

value also
clause
IMS 0-Enabled Section 5.13 of 3GPP TS 24.305 [18] as 2.2.1
/<X>/IMS
Media_type_restriction_policy Voice only Section 5.43 of 3GPP Release 14 TS 2.2.1
(Voice and/or Video over LTE allowed 24.167 [68] (interior node
allowed) /<X>/Media_type_restriction_policy) and
3GPP Release 14 TS 24.229 [15]

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Parameter Default Defined in See

value also
clause
Media_type_restriction_policy Voice only Section 5.43 and 5.48 of 3GPP Release 2.2.1,
(Voice and/or Video over LTE allowed 14 TS 24.167 [68] (interior node 5.3
allowed while roaming) /<X>/Media_type_restriction_policy and
leaf /<X>/Roaming) and 3GPP Release
14 TS 24.229 [15]
SMSoIP_usage_policy 2 - SMSoIP Section 5.71 of 3GPP Release 14 TS 2.2.1
(When to use SMSoIP) irrespective 24.167 [68] ( /<X>/
of IMS voice SMSoIP_usage_policy)
support
RegRetryBaseTime 30 Sec Section 5.35 of 3GPP TS 24.167 [68] ( 2.2.1
/<X>/ RegRetryBaseTime)
RegRetryMaxTime 1800 sec Section 5.35 of 3GPP TS 24.167 [68] 2.2.1
(/<X>/ RegRetryMaxTime)
Policy_on_local_numbers 1 -Home- Section 5.62 of 3GPP Release 14 TS 2.2.3.2
(Local number type for voice local number 24.167 [68] ( /<X>/
and video calls) Policy_on_local_numbers)
Timer_T1 2 sec Section 5.10 of 3GPP TS 24.167 [68] 2.2.4
(/<X>/Timer_T1)
Timer_T2 16 sec Section 5.11 of 3GPP TS 24.167 [68] 2.2.4
(/<X>/Timer_T2)
Timer_T4 17 sec Section 5.12 in 3GPP TS 24.167 [68] 2.2.4
(/<X>/Timer_T4)
Reliable 18x policy 1 – Indicates Section 5.56 of 3GPP Release 14 TS 2.2.4
(Sending SIP 18x reliably) that the SIP 24.167 [68] (/<X>/ Reliable_18x_policy
18x /<X>/ Send_18x_Reliably)
responses and 3GPP Release 14 TS 24.229 [15]
(other than
SIP 183
response)
are to be
sent reliably
XCAP Root URI No default 3GPP TS 24.623 [28] 2.3.2
Conf_Factory_URI None Section 5.4 of 3GPP TS 24.166 [88] 2.3.3
(Conference Factory URI) (/<X>/Conf_Factory_URI)
FromPreferred 0 - From 3GPP Release 14 TS 24.607 [23] and 2.3.12
header field; section 5.4 of 3GPP Release 14 TS
is not used 24.417 [90] (/<X>/FromPreferred)
for
determinatio
n of the
originating
party identity
in OIP
service

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Parameter Default Defined in See

value also
clause
Precondition_disabling_policy 0 – the UE is Section 5.60 of 3GPP Release 14 TS 2.4.1
(SIP Preconditions used) allowed to 24.167 [68]
use the (/<X>/Precondition_disabling_policy)
precondition and section 5.1.5A of 3GPP Release 14
mechanism TS 24.229 [15]
Default_EPS_bearer_context_u Prohibited Section 5.49 of 3GPP Release 14 TS 2.4.3.1
sage_restriction_policy 24.167 [68] (interior node
(Voice Media on default (QCI=5) /<X>/Default_EPS_bearer_context_usa
bearer) ge_restriction_policy) and 3GPP
Release 184 TS 24.229 [15]
This parameter is not used by the UE
while roaming. See clause 2.4.3.1.
RateSet for AMR 0,2,4,7 Defined in clause 15.2 of 3GPP Release 2.4.3.2
("mode-set = 9 TS 26.114 [35]
0,2,4,7" (/<X>/Speech/<X>/RateSet) with
included in (/<X>/Speech/<X>/Codec= "amr")
the SDP
answer)
RateSet for AMR-WB Undefined Defined in clause 15.2 of 3GPP Release 2.4.3.2
(no mode-set 9 TS 26.114 [35]
parameter (/<X>/Speech/<X>/RateSet)
included in (/<X>/Speech/<X>/Codec= "amr-wb")
the SDP
answer)
EVS/Br 5.9-24.4 Defined in clause 15.2 of 3GPP Release 2.4.3.3
13 TS 26.114 [35]
(/<X>/Speech/<X>/EVS/Br) and clause
5 of 3GPP Release 13 TS 26.441 [76]
(Table 1)
EVS/Bw nb-swb Defined in clause 15.2 of 3GPP Release 2.4.3.3
13 TS 26.114 [35]
(/<X>/Speech/<X>/EVS/Bw) and clause
5 of 3GPP Release 13 TS 26.441 [76]
(Table 1)
ICM/INIT_PARTIAL_REDUNDA undefined Defined in clause 17.2 of 3GPP Release 2.4.3.3
NCY_OFFSET_RECV (ch-aw-recv 13 TS.26.114 [35]
not included /<X>/Speech/<X>/
in SDP offer) ICM/INIT_PARTIAL_REDUNDANCY_O
FFSET_RECV
ToConRef Internet APN Section 5.9 of 3GPP Release 14 TS 4.3.1
(Network Identifier part of the 24.424 [91]
HOS APN) (/<X>/XCAP_conn_params_policy/<X>/
XDM_MO_ref) and 3GPP Release 14
TS 24.623 [28]

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Parameter Default Defined in See

value also
clause
EPS_initial_attach_ConRefs No APN Section 5.57 of 3GPP Release 14 TS 4.3.1
(APN in initial attach) 24.167 [68] (interior node
/<X>/EPS_initial_attach_ConRefs) and
3GPP Release 14 TS 24.229 [15]
AccessForXCAP 1 – 3GPP 3GPP TS 24.424 [89] and section 5.4
accesses 5.2.1.3 of 3GPP Release 14 TS 24.623
only [28] (/<X>/AccessForXCAP)
SS_XCAP_config_exempt 1 - Indicates Section 5.11 of 3GPP TS 24.424 [91] 5.5.2
that the SS (/<X>/3GPP_PS_data_off/SS_XCAP_c
configuration onfig_exempt).
via XCAP is
a 3GPP PS
data off
exempt
service
MMTEL_voice_exempt 1 - Indicates Section 5.7 of 3GPP TS 24.275 [95] 5.5.3
that the (/<X>/3GPP_PS_data_off/MMTEL_voic
MMTEL e_exempt)
voice is a
3GPP PS
data off
exempt
service
SMSoIP_exempt 1 - Indicates Section 5.67 of 3GPP TS 24.167 [68] 5.5.3
that the SMS (/<X>/3GPP_PS_data_off/SMSoIP_exe
over IP is a mpt)
3GPP PS
data off
exempt
service
SS_domain_setting No default Section 5.41 of 3GPP Release 12 TS A.4
24.167 [68] (/<X>/SS_domain_setting)
SMS_Over_IP_Networks_Indica 1 – SMS Section 5.28 of 3GPP TS 24.167 [68] 6
tion service is (/<X>/SMS_Over_IP_Networks_Indicati
preferred to on)
be invoked
over the IP
networks

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Parameter Default Defined in See

value also
clause
Device_management_over_PS 1 - Indicates Section 5.10i of 3GPP TS 24.368 [96] C.2
that the (/<X>/3GPP_PS_data_off/Exempted_se
device rvice_list/<X>/Device_management_ove
management r_PS)
over PS is a
3GPP PS
data off
exempt
service
USSI_exempt 1 - Indicates Section 5.4B of 3GPP Release 14 TS
that USSI is 24.391 [99]
a 3GPP PS (/<X>/3GPP_PS_data_off/USSI_exempt
data off )
exempt
service
emerg-reg 10 sec Section 5.61 of 3GPP Release 14 TS 5.2.1
24.167 [68] (/<X>/Timer_Emerg-reg)
COMPOSER AUTH 0 - Indicates Section 2.1.2 of RCC.20 [106] 2.3.14
that Call (/<X>/Services/composerAuth)
Composer The values "2" and "3" indicate that the
service is Call Composer service is enabled.
disabled If the value "3" is configured and the UE
only supports Call Composer, the UE
must behave as defined for a value of
"2".
If any other value is configured, the UE
must behave as defined for a value of
"0".
FT HTTP CS URI As defined in Section A.2.4 of RCC.07 [103] 2.3.13
section A.1.4 (/<X>/Messaging/FileTransfer/ftHTTPC
of RCC.07 SURI)
[103]
FT HTTP DL URI No default Section A.2.4 of RCC.07 [103] 2.3.13
(/<X>/Messaging/FileTransfer/ftHTTPDL
URI)
FT HTTP CS USER No default Section A.2.4 of RCC.07 [103] 2.2.2
(/<X>/Messaging/FileTransfer/ftHTTPC
SUser)
FT HTTP CS PWD No default Section A.2.4 of RCC.07 [103] 2.2.2
(/<X>/Messaging/FileTransfer/ftHTTPC
SPwd)

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Parameter Default Defined in See

value also
clause
PRE AND POST CALL DATA 1 - indicates Section A.2.2 of RCC.07 [103] 5.5.1
OFF that Call (/<X>/Services/Ext/DataOff/preAndPost
Composer CallDataOff)
services are
cellular data
off exempt
services
CAPABILITY DISCOVERY 2 - OFF Section A.2.5 of RCC.07 [103] 5.7
MECHANISM (/<X>/CapDiscovery/defaultDisc)

Table C.3.1 Configuration parameters and their default values

C.4 Testing Profiles

In order to streamline device testing a number of recommended settings (device service
profiles) has been defined. Six such service oriented profiles have been defined. Table C.4.1
contains the suggested settings of each of the configuration parameters across the six IMS
profiles. Additional parameters are defined in other appropriate PRDs.

Parameter Profiles and parameter values

Voice Voice Voice Voice Voice Voice
over over & SMS & SMS & SMS & SMS
LTE LTE over over over over
LTE LTE WiFi WiFi
Profile Profile Profile Profile Profile Profile
#1 #2 #3 #4 #5 #6
IMS Enabled
Media_type_restriction_policy Voice & Video Voice Voice & Video
(Voice and/or Video over LTE Only
allowed)
Media_type_restriction_policy Voice Only Voice & Voice Voice & Video
(Voice and/or Video over LTE Video Only
allowed while roaming)
SMSoIP_usage_policy Only with voice
(When to use SMSoIP)
RegRetryBaseTime 30s
RegRetryMaxTime 1800s
Policy_on_local_numbers Geo- Home- Geo- Home-Local
(Local number type for voice Local Local Local
and video calls)
Timer_T1 2s
Timer_T2 16s
Timer_T4 17s

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Parameter Profiles and parameter values

Voice Voice Voice Voice Voice Voice
over over & SMS & SMS & SMS & SMS
LTE LTE over over over over
LTE LTE WiFi WiFi
Profile Profile Profile Profile Profile Profile
#1 #2 #3 #4 #5 #6
Reliable 18x policy Do not Send Do not Send reliably
(Sending SIP 18x reliably) send reliably Send
reliably reliably
XCAP Root URI Specific Empty Specific Empty
URI URI
Conf_Factory_URI Specific Empty Specific Empty
(Conference Factory URI) URI URI
FromPreferred From P-Ass-ID From P-Ass-ID

Precondition_disabling_policy Precons Precons Precons Precons Enabled

(SIP Preconditions used) Disabled Enabled Disabled
Default_EPS_bearer_context_u Disallow
sage_restriction_policy
(Voice Media on default (QCI=5)
bearer)
RateSet for AMR 0,2,4,7 Empty 0,2,4,7 Empty 0,2,4,7 Empty
RateSet for AMR-WB Empty
EVS/Br 9.6-24.4 Empty 9.6-24.4 Empty
EVS/Bw Empty wb-swb Empty wb-swb Empty
ICM/INIT_PARTIAL_REDUNDA ch-aw- Undefined ch-aw- Undefined
NCY_OFFSET_RECV recv recv
ToConRef HOS Empty HOS Empty
(Network Identifier part of the APN APN
HOS APN)
EPS_initial_attach_ConRefs No APN
(APN in initial attach)
AccessForXCAP 3GPP 3GPP 3GPP 3GPP Any access
Access Access
Access Access
Preferred / Preferred /
Only EPC via Only EPC via
WLAN WLAN
Secondary Secondary

SS_XCAP_config_exempt Exempt
MMTEL_voice_exempt Exempt
SMSoIP_exempt Not Exempt Exempt
SS_domain_setting PS Only

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Parameter Profiles and parameter values

Voice Voice Voice Voice Voice Voice
over over & SMS & SMS & SMS & SMS
LTE LTE over over over over
LTE LTE WiFi WiFi
Profile Profile Profile Profile Profile Profile
#1 #2 #3 #4 #5 #6
SMS_Over_IP_Networks_Indica SMSoIP Not Used SMSoIP Preferred
tion
Device_management_over_PS Exempt
USSI_exempt Exempt
emerg-reg 10s
COMPOSER AUTH Service Service Service Service Service Service
Enabled Disabled Enabled Disabled Enabled Disabled
FT HTTP CS URI Empty
FT HTTP DL URI Empty
FT HTTP CS USER Empty
FT HTTP CS PWD Empty
PRE AND POST CALL DATA Exempt Not Exempt Not Exempt
OFF Exempt
CAPABILITY DISCOVERY Enabled Disabled Enabled Disabled
MECHANISM

Table C.4.1 – Parameter Settings across the 6 IMS profiles

Annex D USSI

D.1 Introduction

D.1.1 Overview
The support of USSI is optional for both the UE and the Network. This Annex describes the
additional functionalities that need to be implemented for the UEs and networks that do
support USSI. The scope includes the following aspects:

• IMS basic capabilities [Chapter D.2]

• Media negotiation [Chapter D.3]
• Functionality that is relevant across the protocol stack and subsystems [Chapter D.4]
• Additional features that need to be implemented for the UEs and networks that wish
to support concurrent CS coverage [Chapter D.5]
This Annex is applicable for a scenario where IMS is deployed without relying on any CS
infrastructure. In this case the UEs and networks must be compliant with all of the normative
statements in this Annex.

Chapter D.5 defines the profile for an alternative approach where USSD is deployed with a
certain degree of reliance on an existing 3GPP CS network infrastructure.

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In this version of the PRD, only voice-capable UEs and networks are considered.

D.2 IMS Feature Set

D.2.1 General
This Annex lists the additional mandatory capabilities compared to the main body and Annex
A that are required over the Gm reference point.

D.2.2 Support of generic IMS functions

D.2.2.1 General
The UE and the network must fulfil the requirements for addressing as specified in section
4.5.4.1 of 3GPP Release 12 TS 24.390 [98].

Note: Geo-local numbering is not used in USSI.

D.2.2.2 SIP Registration Procedures

A UE must perform a SIP Registration as specified in 2.2.1 and must include a
g.3gpp.nw-init-ussi media feature tag in the Contact header field as specified in 3GPP
Release 12 TS 24.390 [98].

D.2.3 USSI Considerations

D.2.3.1 General
The following sub-sections provide considerations for the UE and network specific to USSI.

D.2.3.2 UE initiated
The UE must support the invocation and operation of user initiated USSI as defined in
sections 4.5.4.1 and 4.5.3 of 3GPP Release 12 TS 24.390 [98].

The USSI AS (USSI Application Server) must support the actions defined in section 4.5.4.2
of 3GPP Release 12 TS 24.390 [98].

D.2.3.3 Network initiated

The USSI AS may support the invocation and operation of network initiated USSI as defined
in section 4.5.5.1 of 3GPP Release 12 TS 24.390 [98].

The UE must support the actions defined in section 4.5.5.2 of 3GPP Release 12 TS 24.390
[98].

D.3 SDP negotiation

The UE and the IMS core network must support the SDP negotiation to not use media
resources for UE initiated USSI and network initiated USSI as described in sections 4.5.2
and 4.5.2A (respectively) of 3GPP Release 12 TS 24.390 [98].

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D.4 Common Functionalities

D.4.1 Data Off

The UE must fulfil the requirements as specified in section 5.5.1.

The UE must be able to initiate and receive USSI messages as described in this Annex
regardless whether 3GPP PS (Packet Switched) Data Off is active i.e. the UE continues to
use (does not disconnect) the PDN connection via the IMS well-known APN. For this reason,
the operator must configure "USSI_exempt" as 3GPP PS Data Off Exempt Services, see
section C.3.

D.5 Complementing IMS with CS

D.5.1 General
In order to offer its customers a seamless service, the operator may wish to complement the
USSI capable radio coverage by utilising the CS radio access and/or the CS core network
for USSD. The USSI capable radio coverage may be less or more extensive than the
CS/USSD coverage. These clauses describe the additional features that need to be
implemented for the UEs and networks that wish to support such a deployment scenario.

The UE and the network must support the necessary procedures as specified in 3GPP
Release 12 TS 23.090 [97].

D.5.2 Domain Selection

The UE must support the selection of an appropriate method for UE originating USSD
request delivery as specified in section 7.2e of 3GPP Release 12 TS 23.221 [6]. The support
of the USSI Management Object as defined in 3GPP Release 12 TS 24.391 [99] by the UE
and network is not required.

Note: When the originating voice domain selection is PS, the absence of support
in the UE of the Management Object defined in 3GPP Release 12 TS
24.391 [99] provides as a result, the UE to send an originating USSD
request using IMS according to 3GPP Release 12 TS 24.390 [98]. If the
home network does not support USSI and in order to ensure the correct
delivery of UE initiated USSD requests (i.e. via CS), the home network
needs to ensure that USSI requests are rejected with a 404 (Not found)
response as specified in 3GPP Release 12 TS 24.390 [98].

The UE must support the selection of an appropriate method for UE terminating USSD
request delivery as specified in section 7.2b of 3GPP Release 12 TS 23.221 [6].

If USSD (via the CS network) is used, then the procedures of Annex A.9 shall be applicable.

Annex E Features needed for Automotive

E.1 General
This Annex describes the relevant features that operators need to support for automotive.
Those features can be required due to local regulatory requirements.

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E.2 eCall
Pursuant to regulation in some regions, e.g. Europe since 2018, there are regulatory
requirements that require to embed eCall systems in new vehicles allowing the user to reach
out for emergency services either automatically or manually. For this matter, the evolution of
the legacy CS-based eCall in IMS in this document is required.

To fulfil the regulatory requirements for such regions, the UE and the network must support
NG-eCall as specified in this Annex.

The UE must support the general NG-eCall procedures as specified in subclause 5.1.6.11 of
3GPP Release 14 TS 24.229 [15].

The UE must support to detect network support for NG-eCall as specified in subclause
5.2.2.7 of 3GPP Release 14 TS 36.331 [52].

The serving network must provide an Access Stratum broadcast indication to UEs as to
whether eCall Over IMS is supported as specified in section 5.2.2.7 of 3GPP Release 14 TS
36.331 [52]. With the eCallOverIMS-Support indication, the UE in limited service state
determines whether the cell supports eCall over the IMS services via EPC for UEs.

The UE must indicate the eCall type of emergency service indicator (automatic or manual)
by setting the Request-URI to the appropriate value in the emergency session establishment
request as specified in section 5.1.6.11.2 of 3GPP Release 14 TS 24.229 [15].

The UE must include the Minimum Set of Data (MSD) in the initial SIP INVITE message as
specified in section 5.1.6.11.2 of 3GPP Release 14 TS 24.229 [15].

During an emergency session established for an NG-eCall type of emergency service, if the
UE receives a SIP INFO request, the UE must act in accordance with section 5.1.6.11.3 of
Release 14 TS 24.229 [15].

If the UE does not detect that NG-eCall is supported by the IP-CAN, and there is a CS
access available, the UE must make a CS eCall attempt in accordance with Annex H.6, table
H.2 of Release 14 TS 23.167 [3]. If the UE does not detect that NG-eCall is supported by the
IP-CAN, and there is no CS access available e.g. due to CS phase out, the UE must
proceed in accordance with annex H.6 and subclause 7.7.2 of Release 14 TS 23.167 [3].

Where the transfer of the Minimum Set of Data (MSD) is not acknowledged by the PSAP,
the UE must fall back to the in-band transfer of the MSD, as in CS domain defined in 3GPP
Release 14 TS 26.267 [107].

For testing and terminal configuration purposes of NG-eCalls, the UE must use a service
URN in accordance with the local operator policy that is different from
"urn:service:sos.ecall.manual" and "urn:service:sos.ecall.automatic" as described in
subclause 5.1.6.11.1 of 3GPP Release 14 TS 24.229 [15]. It is recommended that the UE
uses the test URN as specified in section 8 of RFC 8147, unless local regulation, local
PSAPs or operators requires a different test URN.

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Annex F Annex F UE Behaviour in a post 2G/3G sunset

environment - Informative

F.1 General
This Annex describes UE behaviour in a post 2G/3G sunset environment, i.e. where both
2G and 3G RAN is no longer available in the serving network. See also GSMA PRD NG.121
[110] annex B.

F.2 Assumptions
With reference to GSMA PRD NG.121 [110] annex B, an IR.92 compliant device is a “Type
3” device, specifically :-

• A voice-centric device (see 3GPP TS 23.221 [6] and 3GPP TS 24.301 [7]) which shall
preferentially attempt to register on a network that supports voice service.
• A device that supports IMS Voice as well as being CS voice capable.
• A device that supports both PS and CS emergency call (see section 5.2 and Annex
A.5),
• A device that supports both SMSoIP as well as SMSoNAS as described in section 6.

In a post sunset era, the serving network is assumed to:-

• Have no 2G/3G RAN,

• Have a 4G RAN (LTE) and core network (EPC),
• Support IMS Voice,
• Support IMS / PS Emergency Call,
• Support SMS either via SMSoIP or SMSoNAS

o In the latter case, SMSoNAS is supported either via the legacy SGs interface from
the MME to remaining legacy MSC equipment or else via the DIAMETER based
SGd interface.

F.3 Service Availability

It is assumed that service availability becomes an issue in the post sunset era for the
roaming scenario only, i.e. it is assumed that for the non-roaming scenario :-

• Voice services have migrated to IMS based voice,

• PS emergency call is supported by the Network,
• SMS can be supported either via SMSoIP or SMSoNAS,

o It is strongly recommended to migrate to SMSoIP to avoid any dependency on the

VPMN in the roaming scenario – see below.

• Any required services provided via CS have also been migrated (e.g. USSD migration
to USSI – see annex A.9 and Annex D).

In the roaming scenario, the service availability is dependent on the roaming agreement and
the required services in the HPMN:-

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• IMS based voice services are available via the HPMN if IMS is enabled and there is
an IMS Voice Roaming agreement in place – see GSMA PRD NG.121 [110] annex
B.2.7.

o If IMS based voice services are not available, then the device behaviour is
implementation specific:-
o The device would mark the network as not suitable and would continue to search
for a voice capable network for an implementation specific duration prior to:-

• disabling E-UTRA, resulting in no service,

• disabling E-UTRA prior to re-enabling E-UTRA after an implementation
specific period and doing a re-scan, which also results in no service,
• attaching to the 4G network in order to obtain a 4G data service.
• Ability to place emergency call over IMS is subject to the VPLMN configuration.
However, it should not be dependent on an IMS Voice Roaming agreement. Users in
limited service should also attempt to use this network to access emergency services
and the Network may or may not allow the call attempt based on local regulations –
see section 5.2.
• SMS can be supported either via SMSoIP or SMSoNAS,

o For SMSoNAS, there is a dependency on the VPMN as :-

▪ The VPMN must support the SGs interface between the MME and
legacy MSC equipment and thence via MAP to the HPMN,
▪ Both the VPMN and HPMN must support the DIAMETER based SGd
interface.

o If the VPMN chooses not to support the legacy SGs interface nor the DIAMETER
based SGd interface, then there is no SMS service to the inbound roamer.

• USSD is no longer available to inbound roamers. The HPMN must migrate to USSI.

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Annex G Document Management

G.1 Document History

Version Date Brief Description of Change Approval Editor /
Authority Company
0.1 28/01/2010 New PRD (RILTE Doc 06/004). RILTE #6 John Boggis,
Vodafone
0.2 19/02/2010 Updated to take account of RILTE (email John Boggis,
changes proposed by Itsuma approval after Mtg Vodafone
Tanaka from NTT Docomo #6)
1.0 18/03/2010 DAG #67 comments IREG email John Boggis,
approval before Vodafone
mtg # 58
EMC # 81
2.0 29/07/2010 CR001 to IR.92 Enhancements IREG email John Boggis,
and corrections to the document approval before Vodafone
mtg # 59
EMC # 86
3.0 22/12/2010 CR002 to IR.92 Enhancements IREG # 59 John Boggis,
and corrections to the document EMC # 89 Vodafone
4.0 22/3/2011 Implementation of CR003, RILTE/IREG email John Boggis,
CR004, CR005 and CR006. approval before Vodafone
IREG #60
EMC # 91
5.0 28/12/2011 Implementation of CR007 to RILTE/IREG email John Boggis,
CR015. approval before Vodafone
IREG #61
EMC # 99
6.0 28/12/2011 Implementation of CR016 and IREG #62 John Boggis,
CR017 PSMC # 102 Vodafone
7.0 25/02/2013 Implementation of CR1001, IREG #63 Nick Russell,
CR1002, CR1003 and CR1004. RIM Ltd.
7.1 10/09/2013 Implementation of CR1005 IREG RILTE #32 Nick Russell,
BlackBerry Ltd.
8.0 07/04/2014 Implementation of CR1006, IREG RILTE #37 Nick Russell,
CR1008, CR1009, CR1011, and IREG #66 BlackBerry Ltd.
CR1012, CR1013, CR1015,
CR1016, CR1018, CR1019,
CR1020, CR1021, CR1022,
CR1023, CR T9, CR T10, and
CR T14
9.0 02/04/2015 Implementation of CR1024, NG #1 Nick Russell,
CR1025, CR1027, CR1029, BlackBerry Ltd.
CR1030, CR1031, CR1032,
CR1033, CR1034, CR1035,
CR1036, CR1037, CR1038,
CR1039, CR1040, CR1041,
CR1042, CR1043, CR1044,
CR1045, CR1046, CR1047,
CR1048, CR1051, CR1052,
CR1055, CR1056, and CR1059.

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Version Date Brief Description of Change Approval Editor /

Authority Company
10.0 19/05/2016 Implementation of CR1063, NG #3 Nick Russell,
CR1060, CR1067, CR1064, BlackBerry Ltd.
CR1065, CR1068
(IR92CR46MeEl1), CR1069,
CR1072 CR1071, CR1070,
CR1076, CR1077, CR1073,
CR1075, CR1078, CR1074,
CR1066, CR1079, CR1081,
CR1087, CR1090, CR1082,
CR1083, CR1080, CR1088,
CR1089, CR1084, CR1086,
CR1085, CR1091, CR1092,
CR1093, CR1094, CR1095,
CR1097, CR1101, CR1102,
CR1103, CR1104, CR1096,
CR1098, CR1099, CR1105,
CR1106, CR1108, CR1110.
11.0 15/06/2017 Implementation of CR1111, NG #5 Nick Russell
CR1112, CR1113, CR1114, (BlackBerry
CR1115, CR1116, CR1117, Ltd.), Keith
Drage (Nokia).
CR1118, CR1119, CR1120,
CR1122, CR1123, CR1124,
CR1125, CR1126, CR1127,
CR1128, CR1129, CR1130,
CR1131, CR1132, CR1133,
CR1134, CR1135, CR1136,
CR1137, CR1138, CR1139,
CR1140, CR1141, CR1143,
CR1145, CR1146, CR1147 and
CR1148
12.0 02/05/2018 Implementation of CR1149, NG#7 Mari Melander
CR1150, CR1151, CR1152, (Telekom
CR1153, CR1154, CR1155, Deutschland
GmbH)
CR1156, CR1157, CR1158,
CR1159, CR1160, CR1161,
CR1162, CR1163
13.0 17/04/2019 Implementation of CR1164, NG#9 Mari Melander
CR1165, CR1167, CR1168, (Telekom
CR1169, CR1170, CR1171, Deutschland
GmbH), Haitao
CR1172, CR1173, CR1174,
Wei (Huawei)
CR1175, CR1176, CR1177,
CR1179, CR1180, CR1181,
CR1182, CR1183, CR1184,
CR1185 and CR1186

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Version Date Brief Description of Change Approval Editor /

Authority Company
14.0 29/04/2020 Implementation of CR1187, NG#11 Haitao Wei
CR1188, CR1189, CR1190, (Huawei)
CR1191, CR1192, CR1193,
CR1194, CR1196, CR1197,

15.0 14/05/2020 IR.92 CR1198 Clarification for NG#11 Haitao Wei

MMTEL Call Composer Service (Huawei)
IR.92 CR1199 EVS Clarifications
16.0 20/04/2021 Implementation of CR1200, NG#13 Haitao Wei
CR1201, CR1202, CR1203, (Huawei)
CR1204, CR1205, CR1206,
CR1207, CR1208, CR1209,
CR1210, CR1211, CR1212,
CR1213, CR1214
17.0 25/06/2022 Implementation of CR1215, NG#15 Haitao Wei
CR1216 (Huawei)
18.0 04/04/2023 Implementation of CR1217, NG#17 Haitao Wei
CR1218, CR1219, CR1220 (Huawei)
19.0 11/02/2024 CR1006 and CR1007 NG#18 Javier Sendin,
GSMA
20.0 12/06/2024 CR1223 NG#19 Javier Sendin
(GSMA)

G.2 Other Information

Type Description
Document Owner NG UPG
Editor / Company Haitao Wei, Huawei

It is our intention to provide a quality product for your use. If you find any errors or omissions,
please contact us with your comments. You may notify us at prd@gsma.com

Your comments or suggestions & questions are always welcome.

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