1、 ETSI TR 1Digital cellular telecoUniversal Mobile TelMultimedia telephony Study on improved ehandling for Multimed(3GPP TR 26.9TECHNICAL REPORT 126 924 V13.0.0 (2016communications system (Phaelecommunications System (LTE; y over IP Multimedia Subsysted end-to-end Quality of Servicedia Telephony Serv
2、ice for IM.924 version 13.0.0 Release 1316-08) hase 2+); (UMTS); stem (IMS); ice (QoS) IMS (MTSI) 13) ETSI ETSI TR 126 924 V13.0.0 (2016-08)13GPP TR 26.924 version 13.0.0 Release 13Reference DTR/TSGS-0426924vd00 Keywords LTE,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Te
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8、 reproduction in all media. European Telecommunications Standards Institute 2016. All rights reserved. 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
9、of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TR 126 924 V13.0.0 (2016-08)23GPP TR 26.924 version 13.0.0 Release 13Intellectual Property Rights IPRs essential or potentially essential to the present document may have
10、been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available 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 standard
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12、enced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, 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
13、 or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted 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
14、terminology In the present document “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ 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 deliverable
15、s except when used in direct citation. ETSI ETSI TR 126 924 V13.0.0 (2016-08)33GPP TR 26.924 version 13.0.0 Release 13Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 7g3Introduction 7g31 Scope 8g32 References 8g33 Definitions and abbreviations . 9g33.1 De
16、finitions 9g33.2 Abbreviations . 9g34 Overview 9g35 Current QoS reservation mechanisms during session setup . 10g35.1 System description . 10g35.2 Simple SDP negotiation and bearer setup 11g35.3 Other system aspects 12g35.4 Relationship between QoS parameters and rate adaptation 12g35.4.1 Introducti
17、on. 12g35.4.2 MBR=GBR bearer 13g35.4.3 MBRGBR bearer 13g35.4.4 Different QoS settings in different networks 13g36 Use cases 14g36.1 General description. 14g36.2 Use case A: Single fixed-rate speech codec . 14g36.2.1 General description . 14g36.2.2 Gap analysis 15g36.3 Use case B: Several fixed-rate
18、speech codecs 16g36.3.1 General description . 16g36.3.1.1 Overview . 16g36.3.1.2 SDP impacts on media handling . 16g36.3.1.3 Bearer allocation based on first SDP offer/answer 17g36.3.1.4 Bearer allocation based on second SDP offer/answer . 19g36.3.2 Gap analysis after 1st SDP offer/answer . 20g36.3.
19、2.1 Common 20g36.3.2.2 IMS-A chooses Option 1; IMS-B chooses Option 1 . 20g36.3.2.3 IMS-A chooses Option 2; IMS-B chooses Option 2 . 21g36.3.2.4 IMS-A chooses Option 1; IMS-B chooses Option 2 . 21g36.3.2.5 IMS-A chooses Option 2; IMS-B chooses Option 1 . 22g36.3.2.6 Root-cause analysis when b=AS is
20、used for resource reservation 23g36.3.2.7 Root-cause analysis when codec-specific information is used for resource reservation . 24g36.3.2.8 Handling of over-allocation and under-allocation . 24g36.3.3 Gap analysis after 2nd SDP offer/answer . 24g36.4 Use case C: Single multi-rate speech codec (AMR)
21、, no extra bandwidth allocated for redundancy . 25g36.4.1 General description . 25g36.4.2 Gap analysis 28g36.5 Use case D: Single multi-rate speech codec (AMR) with extra bandwidth allocated for redundancy . 28g36.5.1 General description . 28g36.5.2 Gap analysis 30g36.6 Use case E: Several multi-rat
22、e speech codecs (AMR and AMR-WB) . 30g36.6.1 General description . 30g36.6.2 Gap analysis 31g36.7 Use case F: Single video codec, symmetric usage . 32g3ETSI ETSI TR 126 924 V13.0.0 (2016-08)43GPP TR 26.924 version 13.0.0 Release 136.7.1 General description . 32g36.7.2 Gap analysis 33g36.7.3 Root-cau
23、se analysis. 35g36.8 Use case G: Single video codec, asymmetric usage, sending video with a bitrate matching the codec level 35g36.8.1 General description . 35g36.8.2 Gap analysis 36g36.8.3 Root-cause analysis. 36g36.9 Use case H: Single video codec, asymmetric usage, sending video with a bitrate lo
24、wer than the supported codec level . 37g36.9.1 General description . 37g36.9.2 Gap analysis 38g36.9.3 Root-cause analysis. 38g36.10 Use case I: Multiple video codecs 39g36.10.1 General description . 39g36.10.2 Gap analysis 41g36.10.3 Root-cause analysis. 41g36.11 Use case J: Single video codec, symm
25、etric usage, bitrate variations . 41g36.11.1 General description . 41g36.11.2 Gap analysis 46g36.12 Use case K: Several multi-rate speech codecs (AMR, AMR-WB and EVS), small difference in EVS usage between operators . 46g36.12.1 General description . 46g36.12.2 Gap analysis 47g36.13 Use case L: Seve
26、ral multi-rate speech codecs (AMR, AMR-WB and EVS), large difference in EVS usage between operators . 47g36.13.1 General description . 47g36.13.2 Gap analysis 48g37 Recommended requirements 48g37.1 Discussion on individual recommended requirements . 48g37.1.1 General 48g37.1.2 Use case A: Single fix
27、ed-rate speech codec 48g37.1.3 Use case B: Several fixed-rate speech codecs. 48g37.1.4 Use case C: Single multi-rate speech codec (AMR), no extra bandwidth allocated for redundancy 49g37.1.5 Use case D: Single multi-rate speech codec (AMR) with extra bandwidth allocated for redundancy 50g37.1.6 Use
28、case E: Several multi-rate speech codecs (AMR and AMR-WB) . 50g37.1.7 Use case F: Single video codec, symmetric usage 50g37.1.8 Use case G: Single video codec, asymmetric usage, sending video with a bitrate matching the codec level 50g37.1.9 Use case H: Single video codec, asymmetric usage, sending
29、video with a bitrate lower than the supported codec level 51g37.1.10 Use case I: Multiple video codecs 51g37.1.11 Use case J: Single video codec, symmetric usage, bitrate variations 51g37.1.12 Use case K: Several multi-rate speech codecs (AMR, AMR-WB and EVS), small difference in EVS usage between o
30、perators . 51g37.1.13 Use case L: Several multi-rate speech codecs (AMR, AMR-WB and EVS), large difference in EVS usage between operators . 52g37.2 Discussion on proposed requirements for new SDP attributes . 52g37.3 Discussion on proposed general requirements for the solution 52g37.4 Summary of pro
31、posed requirements . 53g37.5 Definition of new bandwidth information parameters 54g37.5.1 Overview 54g37.5.2 Maximum Supported Bandwidth 54g37.5.3 Maximum Desired Bandwidth 54g37.5.4 Minimum Desired Bandwidth. 55g37.5.5 Minimum Supported Bandwidth. 55g38 Potential solution(s) 55g38.1 Potential solut
32、ion A: Session re-negotiation 55g38.1.1 Introduction. 55g38.1.2 Description of the solution 56g3ETSI ETSI TR 126 924 V13.0.0 (2016-08)53GPP TR 26.924 version 13.0.0 Release 138.1.3 Compliance with proposed requirements 56g38.1.4 Impact on networks and terminals 56g38.2 Potential solution B: New band
33、width modifiers in SDP offer and answer without SDP MiscCapNeg . 57g38.2.1 Introduction. 57g38.2.2 Description of the solution 57g38.2.2.1 General solution 57g38.2.2.2 New bandwidth modifiers . 57g38.2.2.3 Procedures . 58g38.2.2.4 Session negotiation example . 58g38.2.2.5 Modifying the bandwidth inf
34、ormation in the SDP offer . 60g38.2.2.6 Resource reservation in different networks . 60g38.2.3 Compliance with proposed requirements 61g38.2.4 Impact on networks and terminals 61g38.3 Potential solution C: New bandwidth modifiers and SDPMiscCapNeg in SDP offer and answer . 61g38.3.1 Introduction. 61
35、g38.3.2 Description of the solution 61g38.3.2.1 General solution 61g38.3.2.2 Procedures . 62g38.3.2.3 Session negotiation example . 62g38.3.2.4 Modifying the bandwidth information in the SDP offer . 63g38.3.2.5 Resource reservation in different networks . 64g38.3.3 Compliance with proposed requireme
36、nts 64g38.3.4 Impact on networks and terminals 64g38.4 Potential solution D: New attribute for bandwidth information in SDP offer and answer for each RTP payload type . 65g38.4.1 Introduction. 65g38.4.2 Description of the solution 65g38.4.2.1 General solution 65g38.4.2.2 New attribute . 65g38.4.2.3
37、Procedures. 66g38.4.2.4 Session negotiation example . 66g38.4.2.5 Modifying the bandwidth information in the SDP offer . 66g38.4.2.6 Resource reservation in different networks . 67g38.4.3 Compliance with proposed requirements 67g38.4.4 Impact on networks and terminals 67g38.5 Potential solution E: N
38、ew bandwidth modifiers only in SDP answer 67g38.5.1 Introduction. 67g38.5.2 Description of the solution 67g38.5.2.1 General solution 67g38.5.2.2 New bandwidth modifiers . 67g38.5.2.3 Session negotiation example . 67g38.5.2.4 Modifying the bandwidth information in the SDP offer . 68g38.5.2.5 Resource
39、 reservation in different networks . 68g38.5.3 Compliance with proposed requirements 68g38.5.4 Impact on networks and terminals 68g38.6 Potential solution F: New SDP attribute in SDP offer and answer for entire media line . 68g38.6.1 Introduction. 68g38.6.2 Description of the solution 68g38.6.2.1 Ge
40、neral solution 68g38.6.2.2 New SDP attribute 69g38.6.2.3 Procedures. 69g38.6.2.4 Session negotiation example . 69g38.6.2.5 Modifying the bandwidth information in the SDP offer . 69g38.6.2.6 Resource reservation in different networks . 70g38.6.3 Compliance with proposed requirements 70g38.6.4 Impact
41、on networks and terminals 70g38.7 Potential solution G: New SDP attribute only in SDP answer . 70g38.7.1 Introduction. 70g38.7.2 Description of the solution 70g38.7.2.1 General solution 70g38.7.2.2 New SDP attribute 71g38.7.2.3 Procedures. 71g3ETSI ETSI TR 126 924 V13.0.0 (2016-08)63GPP TR 26.924 ve
42、rsion 13.0.0 Release 138.7.2.4 Session negotiation example . 71g38.7.2.5 Modifying the bandwidth information in the SDP offer . 71g38.7.2.6 Resource reservation in different networks . 71g38.7.3 Compliance with proposed requirements 71g38.7.4 Impact on networks and terminals 72g38.8 Potential soluti
43、on H: Bitrate variations 72g38.8.1 Introduction. 72g38.8.2 Description of the solution 72g38.8.3 Compliance with proposed requirements 73g38.8.4 Impact on networks and terminals 73g39 Conclusion and recommendations 73g3Annex A: Determining suitable averaging window length . 74g3A.1 Introduction 74g3
44、A.2 Suitable averaging window for video . 74g3A.2.1 Reasonable video encoder configuration 74g3A.2.2 Normal transmission. 74g3A.2.3 Sending a large I frame 75g3A.2.4 Compensating for a large I frame . 75g3A.2.5 Sending an even larger I frame . 76g3A.2.6 Using a longer averaging window 77g3A.2.7 Sele
45、ction of averaging window length . 77g3A.3 Other services . 78g3A.3.1 Conversational speech using EVS VBR . 78g3A.3.2 Streaming and other non-conversational services 78g3Annex B: Change history 80g3History 81g3ETSI ETSI TR 126 924 V13.0.0 (2016-08)73GPP TR 26.924 version 13.0.0 Release 13Foreword Th
46、is Technical Report has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released b
47、y the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is inc
48、remented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. Introduction Multimedia Telephony for IMS (MTSI) is a standardized service for conversational telephony,
49、 TS 22.173 2. The media handling and interaction are specified in TS 26.114 3. MTSI has been specified such that the user experience of multimedia telephony is equivalent to or better than corresponding circuit-switched telephony services while still having efficient resource usage. Multimedia telephony also exploits the richer capabilities of IMS where media components can be used symmetrically or asymmetrically in different directions. ETSI ETSI TR 126 924 V13.0.0 (2016-08)83GPP TR 26.924 version 13.0.0 Release 131 Scope TS 26.114 define media handling and interaction f
