1、 ETSI TR 126 914 V14.0.0 (2017-04) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Multimedia telephony over IP Multimedia Subsystem (IMS); Optimization opportunities (3GPP TR 26.914 version 14.0.0 Release 14) TECHNICAL REPORT ETSI
2、 ETSI TR 126 914 V14.0.0 (2017-04)13GPP TR 26.914 version 14.0.0 Release 14Reference RTR/TSGS-0426914ve00 Keywords GSM,LTE,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non
3、 lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of
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8、 DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the
9、GSM Association. ETSI ETSI TR 126 914 V14.0.0 (2017-04)23GPP TR 26.914 version 14.0.0 Release 14Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly availab
10、le for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server
11、(https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become,
12、essential to the present document. Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interprete
13、d as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “should“, “should not“, “may“, “need not“, “will“, “will not“, “ca
14、n“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 126 914 V14.0.0 (2017-04)33GPP TR 26.914 version 1
15、4.0.0 Release 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g3Introduction 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 6g33.1 Definitions 6g33.2 Abbreviations . 7g34 Overview 7g34.1 General . 7g34.2 System description . 8g35 Assum
16、ptions . 8g35.1 General assumptions. 8g35.2 Channels . 9g35.3 Media components . 9g35.4 Use scenarios 10g36 Basic point-to-point call in Release 6 . 10g36.1 General . 10g36.2 Session setup 11g36.3 Media flow . 11g36.3.1 General 11g36.3.2 Voice . 12g36.3.3 Video 13g37 Areas of optimizations 13g37.1 G
17、eneral . 13g37.2 Delay jitter handling . 14g37.3 Packet-loss handling . 14g37.4 Handling of inter-working with CS 14g37.5 Handling of inter-working between UTRAN and GERAN 15g37.6 Inter-media synchronization . 15g37.7 SDU segmentation in UTRAN/GERAN 15g37.8 Rate Adaptation 15g37.9 Packetization Over
18、heads 15g37.10 End-2-End Signalling . 16g38 Conclusions and recommendations 16g3Annex A: Change history 17g3History 18g3ETSI ETSI TR 126 914 V14.0.0 (2017-04)43GPP TR 26.914 version 14.0.0 Release 14Foreword This Technical Report has been produced by the 3rdGeneration Partnership Project (3GPP). The
19、 contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as
20、follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates,
21、etc. z the third digit is incremented when editorial only changes have been incorporated in the document. Introduction Multimedia telephony over IP (3GPP TS 22.973 2) is a standardized IMS telephony service in 3GPP Release 7 that builds on the IMS capabilities already provided in 3GPP Releases 5 and
22、 6. The objective of defining a service is to specify the minimum set of capabilities required in the IP Multimedia Subsystem to secure multi-vendor and multi-operator inter-operability for Multimedia Telephony and related Supplementary Services. While the user experience of Multimedia telephony is
23、expected to have some similarity to existing telephony services, the richer capabilities of IMS is exploited. In particular, multiple media components, such as voice and video, can be used and dynamically added or dropped during a call. ETSI ETSI TR 126 914 V14.0.0 (2017-04)53GPP TR 26.914 version 1
24、4.0.0 Release 141 Scope The present document: identifies opportunities for optimization of service quality and efficiency of Multimedia telephony over IP in a qualitative sense; provides the basis for developing a set of optional backward-compatible tools implementing such optimizations. The optimiz
25、ed multimedia telephony targets many different system configurations and operating conditions, e.g. GERAN, UTRAN, inter-working between GERAN, UTRAN, GAN, and different PLMNs. Of the various use cases for multimedia telephony, the main focus of the present document is on voice calls, but the focus a
26、lso includes other core media components, such as video. In particular, areas with optimization opportunities include handling of degraded channels, delay jitter, packet losses, efficiency, inter-working with other voice systems, etc. The scope includes proposing solutions that maintain backward com
27、patibility in order to ensure seamless inter-working with existing services available in the CS domain, such as CS voice telephony and 3G-324M, as well as with terminals of earlier 3GPP releases. Alignment with legacy media formats avoids transcoding and even allows realizing at least parts of the o
28、ptimization gains. All optimizations are hence based on the default codecs specified in 3GPP TS 26.235 3 and 3GPP TS 26.141 6. The optimizations identified in the present document address mainly. media transport and signalling. Most of the SIP signalling is out of scope and is handled by other 3GPP
29、groups. Issues regarding registration to the network and/or to IMS at power-on or at other occurrences are not included either. The optimization tools are not specified in the present document per se, but will be specified as amendments to existing (pre-Release 7) Technical Specifications (3GPP TS 2
30、6.235 3 and 3GPP TS 26.236 4) and possibly new Technical Specifications. Furthermore, a characterization of the optimized multimedia telephony over IMS will be available in a separate Technical Report. 2 References The following documents contain provisions which, through reference in this text, con
31、stitute provisions of the present document. References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. In the case of
32、a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TR 22.973: “IMS Multimedia Telephony Communication
33、Enabler and supplementary services“. 3 3GPP TS 26.235: “Packet switched conversational multimedia applications; Default codecs“. 4 3GPP TS 26.236: “Packet switched conversational multimedia applications; Transport protocols“. 5 3GPP TR 26.935: “Packet Switched (PS) conversational multimedia applicat
34、ions; Performance characterization of default codecs“. 6 3GPP TS 26.141: “IP Multimedia System (IMS) Messaging and Presence; Media formats and codecs“. 7 3GPP TS 43.318: “Generic access to the A/Gb interface; Stage 2“. 8 3GPP TR 45.912: “Feasibility study for evolved GSM/EDGE Radio Access Network (G
35、ERAN)“. ETSI ETSI TR 126 914 V14.0.0 (2017-04)63GPP TR 26.914 version 14.0.0 Release 149 IETF RFC 3550 (2003): “RTP: A Transport Protocol for Real-Time Applications“, H. Schulzrinne, S. Casner, R. Frederick and V. Jacobson. 10 IETF RFC 3551 (2003): “RTP Profile for Audio and Video Conferences with M
36、inimal Control“, H. Schulzrinne and S. Casner. 11 IETF RFC 2327 (1998): “SDP: Session Description Protocol“, M. Handley M. and V. Jacobson. 12 3GPP TS 26.071: “AMR Speech Codec; General description“. 13 3GPP TS 26.090: “AMR Speech Codec; Transcoding functions“. 14 3GPP TS 26.073: “AMR Speech Codec;
37、C-source code“. 15 3GPP TS 26.104: “ANSI-C code for the floating-point Adaptive Multi-Rate (AMR) speech codec“. 16 3GPP TS 26.171: “AMR Speech Codec, wideband; General description“. 17 3GPP TS 26.190: “Speech codec speech processing functions; Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Tr
38、anscoding functions“. 18 3GPP TS 26.173: “ANCI-C code for the Adaptive Multi Rate - Wideband (AMR-WB) speech codec“. 19 3GPP TS 26.204: “ANSI-C code for the floating-point Adaptive Multi-Rate Wideband (AMR-WB) speech codec“. 20 IETF RFC 3267 (2002): “Real-Time Transport Protocol (RTP) Payload Format
39、 and File Storage Format for the Adaptive Multi-Rate (AMR) Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs“, J. Sjoberg, M. Westerlund, A. Lakaniemi and Q. Xie. 21 ITU-T Recommendation H.263 (1998): “Video coding for low bit rate communication“. 22 ITU-T Recommendation H.263 - Annex X (2004): “Pr
40、ofiles and levels definition“. 23 ISO/IEC 14496-2 (2004): “Information technology - Coding of audio-visual objects - Part 2: Visual“. 24 ITU-T Recommendation H.264 (2005): “Advanced video coding for generic audiovisual services“ | ISO/IEC 14496-10:2005: “Information technology - Coding of audio-visu
41、al objects - Part 10: Advanced Video Coding“. 25 IETF RFC 3984 (2005): “RTP Payload Format for H.264 Video“, S. Wenger, M.M. Hannuksela, T. Stockhammer, M. Westerlund and D. Singer. 26 3GPP TS 26.103: “Speech codec list for GSM and UMTS“. 27 IETF RFC 3095 (2001): “RObust Header Compression (ROHC): F
42、ramework and four profiles: RTP, UDP, ESP, and uncompressed“, C. Bormann and al. 28 3GPP TS 26.234: “Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following terms an
43、d definitions apply: example: text used to clarify abstract rules by applying them literally ETSI ETSI TR 126 914 V14.0.0 (2017-04)73GPP TR 26.914 version 14.0.0 Release 143.2 Abbreviations For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 1 and the following apply:
44、 ARQ Automatic repeat ReQuest AS Application Server AVC Advanced Video Coding CSCF Call Session Control Function GAN Generic Access Network H-ARQ Hybrid - ARQ HSDPA High Speed Downlink Packet Access IMS IP Multimedia Subsystem IP Internet Protocol IPv4 Internet Protocol version 4 IPv6 Internet Proto
45、col version 6 ITU-T International Telecommunications Union - Telecommunications MM MultiMedia MMS Multimedia Messaging Service QoS Quality of Service RTP Real-time Transport Protocol SDP Session Description Protocol SIP Session Initiation Protocol TBF Temporary Block Flow ToIP Telephony over IP TTI
46、Transmission Time Interval URL Universal Resource Locator VoIP Voice over IP 4 Overview 4.1 General The rest of the present document is divided into five main clauses. Clause 4 contains an architectural overview of the IMS system indicating the domain relevant to the work reported in the present doc
47、ument. Clause 5 provides the assumptions underlying the work of this report. General assumptions refer to networks, codecs and backward compatibility, etc. The following subclauses give information relevant to the channels, media components as well as use scenarios for multimedia telephony that are
48、relevant to the optimizations targeted by the present document. Clause 6 shows the current status in Release 6 for non-optimized multimedia telephony. The point-to-point voice call has been used as the basic “use case“. The goal for this use case is to show what is needed to create a VoIP telephony
49、service with the same quality as circuit-switched telephony when the channel is virtually error-free. The following subclause also includes the current specifications for using video in multimedia telephony. Clause 7 is a list of areas with optimization opportunities in Release 7. Each area, such as handling of delay jitter, packet losses, inter-working with CS, inter-working between GERAN and UTRAN, etc., is a candidate for optimization where suggestions for standardization will be considered. Clau
