1、 ETSI TR 123 977 V14.0.0 (2017-05) Universal Mobile Telecommunications System (UMTS); Bandwidth And Resource Savings (BARS) and speech enhancements for Circuit Switched (CS) networks (3GPP TR 23.977 version 14.0.0 Release 14) TECHNICAL REPORT ETSI ETSI TR 123 977 V14.0.0 (2017-05)13GPP TR 23.977 ver
2、sion 14.0.0 Release 14Reference RTR/TSGS-0223977ve00 Keywords 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 lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/
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9、ssociation. ETSI ETSI TR 123 977 V14.0.0 (2017-05)23GPP TR 23.977 version 14.0.0 Release 14Contents Contents 2g3Foreword . 4g3Modal verbs terminology 4g31 Scope 5g32 References 5g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Symbols 6g33.3 Abbreviations . 6g34 Network deploym
10、ent scenarios to be studied . 7g34.1 GSM network architecture before Release 4 7g34.2 UMTS network architecture in Release 99 . 8g34.3 Packet transport network between MGWs in an A/Iu mode BICN 9g34.4 TDM transit network between A/Iu mode PLMNs 10g34.5 Packet transport transit network between PLMNs
11、. 11g35 Call Scenarios to be studied . 13g35.1 Mobile to Mobile call Scenarios . 14g35.1.1 BSC to RNC call via BICN 14g35.1.2 BSC to BSC call via BICN . 15g35.1.3 RNC to BSC call via BICN 17g35.1.4 RNC to RNC call via BICN 18g35.2 Mobile to PSTN call scenarios . 20g35.2.1 BSC to PSTN call via BICN .
12、 20g35.2.2 RNC to PSTN call via BICN 22g35.3 Roaming and multi-network call scenarios 23g35.3.1 BSC (HPLMN) to BSC (VPLMN) call 23g35.3.2 BSC (HPLMN) to RNC (VPLMN) call 23g35.3.3 RNC (HPLMN) to BSC (VPLMN) call 23g35.3.4 RNC (HPLMN) to RNC (VPLMN) call . 24g35.4 CS domain to IMS interworking scenar
13、io 24g35.5 A selection of handover scenarios 25g35.5.1 BSC to BSC call via BICN with Intra GERAN handover AMR-AMR 25g35.5.2 BSC to BSC call via BICN with Intra GERAN handover to AMR - EFR . 26g35.5.3 BSC to BSC call via BICN: second Handover to EFR AMR EFR . 28g35.5.4 BSC to BSC call via BICN: third
14、 handover to AMR EFR EFR . 28g35.5.5 RNC to RNC call via BICN with inter-system handover . 29g35.5.6 BSC to RNC call via BICN with second intersystem handover . 30g36 General requirements for architectural solutions . 30g36.1 Overall requirements 30g36.2 Status of specifications for TFO and TrFO in
15、3GPP 31g36.2.1 Support of codec types in TFO and TrFO on various interfaces. 31g37 Requirements and architectural solutions for Resource Savings 31g37.1 AMR-NB configurations 32g37.2 AMR-WB configurations . 32g38 Requirements and architectural solutions for bandwidth savings 33g38.1 Background 33g38
16、.2 Requirements 33g38.3 Architectural solutions . 34g38.3.1 A-ter interface to the MGW 34g38.3.2 MGW collocated with TRAU . 35g39 Requirements and architectural solutions for speech quality Improvements . 35g3ETSI ETSI TR 123 977 V14.0.0 (2017-05)33GPP TR 23.977 version 14.0.0 Release 149.1 Requirem
17、ents 35g39.2 Architectural solutions . 36g39.2.1 Mobile to mobile calls scenarios: 5.1.1 and 5.1.3 . 36g39.2.2 Mobile to PSTN calls: scenarios 5.2.x 36g39.3 Summary 36g310 Requirements and architectural solutions for avoiding duplication in transcoder development 36g310.1 Background and requirements
18、 36g310.2 Architectural solutions . 37g310.2.1 A-ter interface to the MGW 37g310.2.1.1 Description / concept. 37g310.2.1.2 Difficulties with this concept 37g310.2.1.3 Migration aspects 38g310.2.1.4 Sample message flow 40g311 Conclusions 41g3Annex A: Example for migrating a service to TrFO 43g3A.1 Se
19、rvice description . 43g3A.2 Realization 43g3A.2.1 Overview 43g3A.2.2 High level description 43g3A.2.3 Message flow for a Release 99 network . 44g3A.2.4 Message flow with BICC and TrFO . 47g3A.2.5 Message flow with split architecture without TrFO . 49g3A.2.6 Message flow with split architecture and T
20、rFO . 51g3A.3 Summary and conclusions 52g3Annex B: Change history 53g3History 54g3ETSI ETSI TR 123 977 V14.0.0 (2017-05)43GPP TR 23.977 version 14.0.0 Release 14Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to
21、technical specifications 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/que
22、ryform.asp. Modal verbs 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 all
23、owed in ETSI deliverables except when used in direct citation. The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identi
24、fying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes
25、 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. ETSI ETSI TR 123 977 V14.0.0 (2017-05)53GPP TR 23.977 version 14.0.0 Release 141 Scope The objective of this technical report is
26、 to identify the full set of requirements for bandwidth and resource savings and improved speech quality, with specific consideration to networks supporting A/Gb mode and the bearer independent circuit-switched core network (BICN). The different architectural solutions to meet these requirements wil
27、l be assessed. Consideration shall be made to existing architectures and solutions to provide harmony between 2G nodes, UMTS nodes and external networks (PSTN/ISDN). Backward compatibility to existing solutions and ease of network introduction/upgrade shall be given high importance. 2 References The
28、 following documents contain provisions which, through reference in this text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions d
29、o not apply. - For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TS 23.002: “Network
30、 architecture“. 2 3GPP TS 23.153: “Out of band transcoder control; Stage 2“. 3 3GPP TS 23.053: “Tandem Free Operation (TFO); Service description; Stage 2“. 4 3GPP TS 28.062: “Inband Tandem Free Operation (TFO) of speech codecs; Service description; Stage 3“. 5 3GPP TS 26.103: “Speech codec list for
31、GSM and UMTS“. 6 3GPP TR 26.975: “Performance Characterization of the AMR Speech Codec“. 7 3GPP TR 26.976: “Performance characterization of the Adaptive Multi-Rate Wideband (AMR-WB) speech codec“. 8 3GPP TS 26.102: “Mandatory speech codec; Adaptive Multi-Rate (AMR) speech codec; Interface to Iu, Uu
32、and Nb“. 9 Void. 10 3GPP TS 48.060: “In-band control of remote transcoders and rate adaptors for full rate traffic channels“. 11 3GPP TS 48.061: “In band control of remote transcoders and rate adaptors for half rate traffic channels“. 12 3GPP TS 52.021: “Network Management (NM) procedures and messag
33、es on the A-bis interface“. 13 3GPP TS 29.163: “Interworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networks“. 14 ITU-T Recommendation Q.1912.5: “BICC SIP Interworking“. 15 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 16 3GPP TS 29.007: “General
34、 requirements on interworking between the Public Land Mobile Network (PLMN) and the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)“. ETSI ETSI TR 123 977 V14.0.0 (2017-05)63GPP TR 23.977 version 14.0.0 Release 1417 3GPP TS 48.008: “Mobile Switching Centre - Ba
35、se Station System (MSC-BSS) interface; Layer 3 specification“. 18 3GPP TS 26.101: “Mandatory speech codec speech processing functions; Adaptive Multi-Rate (AMR) speech codec frame structure“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the defin
36、itions in TR 21.905 15 apply as well as the following terms and definitions. Bearer Independent Core Network : This term refers to a core network (CN) comprised of MSC Server, CS-MGW and GMSC Server nodes to support MSC and GMSC functionality, as defined in TS 23.002 1. Codec Configuration : The Cod
37、ec Configuration of a codes type ,like AMR, includes mainly the Active Codec Set, the setting of the OM flag and DTX parameters, etc. MIPS: Mega (Million) Instructions Per Second. This is a measure for the required DSP capacity. It is here in this context related to the “ETSI-DSP“ as defined in 3GPP
38、 SA4 for the complexity characterisation of the 3GPP Speech Codec algorithms. 3.2 Symbols For the purposes of the present document, the following symbols apply: Ater the reference point internal to the BSC functional entity, between the transcoders and the rest of the BSC functions. Abis interface b
39、etween the BTS and the BSC 3.3 Abbreviations For the purposes of the present document, the abbreviations in TR 21.905 15 apply as well as the following abbreviations: BICN Bearer Independent Core Network BICC Bearer Independent Call Control DSP Digital Signal Processor DC Decoding MSC-S MSC Server O
40、oBTC Out of Band Transcoder Control PT TFO Protocol Termination R Reframing TC Transcoding UP User Plane Termination ETSI ETSI TR 123 977 V14.0.0 (2017-05)73GPP TR 23.977 version 14.0.0 Release 144 Network deployment scenarios to be studied 4.1 GSM network architecture before Release 4 PSTN PSTN BSC
41、 A MSC B MSC A TRAU Trans- Coder A BSC B TRAU Trans- Coder B Ater AterISUP TDM A A PoI B PoI A Call Control Signalling A and TDM Interface: 64kb/s Ater Interface PoI: Point of Interconnect A A ISUP ISUP TDM TDM Figure 4.1-1: GSM Network Architecture before release 4 In GSM networks according to rele
42、ases before release 4 the MSCs are interconnected on the user plane by TDM links (real or virtual) with 64 kb/s for speech traffic. The only speech codec type known between MSCs is G.711 PCM. There are typically several Points-of-Interconnect to the underlying PSTN, with 64kb/s for the speech traffi
43、c in PCM. The MSCs control and interconnect the BSCs via the A-Interface (user plane and control plane), but they have no direct influence on the Codec Type selected by the BSC on the GSM radio access. The MSC can make a suggestion on the Codec Type, but the BSC decides finally. The MSCs have no mea
44、ns at all to signal the Codec Configuration to the BSCs or between MSCs. This is a drawback. The transcoders belong logically to the GSM_BSS. Speech is transported on the Ater interface in compressed form using the same codec type and configuration as on the radio interface. Tandem Free Operation (T
45、FO) is defined on PCM links for all GSM Codec Types. TFO allows by inband signalling to tunnel the compressed speech through the TDM core network. TFO provides the possibility to bypass and omit the encoding functions, saves DSP resources, improves the speech quality in mobile-mobile calls, allows n
46、ew speech services like wideband speech, but does not provide transmission cost saving. ETSI ETSI TR 123 977 V14.0.0 (2017-05)83GPP TR 23.977 version 14.0.0 Release 144.2 UMTS network architecture in Release 99 PSTN PSTN RNC A MSC B MSC A Trans- Coder A RNC B Trans- Coder B Iu IuISUP TDM PoI B PoI A
47、 Call Control Signalling TDM Interface: 64kb/s Iu Interface PoI: Point of Interconnect Iu Iu ISUP ISUP TDM TDM Figure 4.2-1: UMTS network architecture in Release 99 In UMTS networks according to release 99 the MSCs are interconnected on the user plane by TDM links (real or virtual) with 64 kb/s for
48、speech traffic. The only speech codec type known between MSCs is G.711 PCM. There are typically several Points-of-Interconnect to the underlying PSTN, with 64kb/s for the speech traffic in PCM. The MSCs control and interconnect the RNCs via the Iu-Interface (user plane and control plane). The MSC se
49、lects and commands the Codec Type on the UTRAN radio access and makes a suggestion on the Codec Configuration, but the RNC can select a sub-configuration. The Transcoders are located on central places physically and logically inside the mobile core network as integral parts of the MSCs. They are controlled by the MSCs via internal interfaces. But also the RNC controls the transcoder via the Iu interface (Iu_Init). Speech is transported on the Iu-interface in compressed form using the same codec type and configuration as
