1、 ETSI TS 1Digital cellular telecoUniversal Mobile TelTandemSer(3GPP TS 22.0TECHNICAL SPECIFICATION122 053 V13.0.0 (2016communications system (Phaelecommunications System (m Free Operation (TFO); ervice description; Stage 1 .053 version 13.0.0 Release 13GLOBAL SYSTEMOBILE COMMUN16-01) hase 2+); (UMTS
2、); 13) TEM FOR ICATIONSRETSI ETSI TS 122 053 V13.0.0 (2016-01)13GPP TS 22.053 version 13.0.0 Release 13Reference RTS/TSGS-0422053vd00 Keywords GSM,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 7
3、42 C Association but non 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 a
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9、 owned by the GSM Association. ETSI ETSI TS 122 053 V13.0.0 (2016-01)23GPP TS 22.053 version 13.0.0 Release 13Intellectual 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 pu
10、blicly 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 standards“, which is available from the ETSI Secretariat. Latest updates are available on the ET
11、SI Web server (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, o
12、r may become, essential to the present document. Foreword This Technical Specification (TS) 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
13、 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 terminology In the present document “shall“, “shall not“, “should“, “should not“,
14、 “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 deliverables except when used in direct citation. ETSI ETSI TS 122 053
15、 V13.0.0 (2016-01)33GPP TS 22.053 version 13.0.0 Release 13Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 5g33.1 Definitions 5g33.2 Abbreviations . 6g34 Description . 6g34.1 Applicability of
16、 TFO to Basic Services 6g34.2 Support in Mobile Stations (MS) . 6g34.3 Parameters to be indicated and negotiated . 6g34.4 Provision of Service . 6g34.4.1 Location Independence . 6g34.4.2 Provision of service within and between networks . 6g34.4.3 Subscription and Billing Information . 7g34.5 Quality
17、 of Service (QoS) 7g34.5.1 Impact on Speech Quality . 7g35 Interaction with supplementary services 7g35.1 General . 7g35.2 Explicit Call Transfer (ECT) 7g35.3 Call wait/Call hold 8g35.4 Multiparty . 8g35.5 Service Announcements . 8g36 Interaction with Alternate and Followed by services . 8g37 Intera
18、ction with other speech services 8g38 Interaction with DTMF 8g39 Interaction with Lawful Intercept . 8g3Annex A (informative): Limitations of initial in-band TFO implementations . 9g3Annex B (informative): Change history . 10g3History 11g3ETSI ETSI TS 122 053 V13.0.0 (2016-01)43GPP TS 22.053 version
19、 13.0.0 Release 13Foreword This Technical Specification 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 presen
20、t document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under chang
21、e control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 122 053 V13.0.0 (2016-01)53GPP TS 22.053 version 13.0.0
22、 Release 131 Scope The present document specifies the stage 1 description for the Tandem Free Operation (TFO) feature which provides the capability to avoid tandeming speech codecs in mobile to mobile speech calls. The primary aim is to realise improvements in speech quality. The TFO mode of operati
23、on could also be used to reduce inter-Mobile services Switching Center (MSC) transmission bandwidth requirements. In analogy with ITU-T Recommendations I.130 1, Stage 1 is an overall service description, from the service subscribers and users standpoints, that views the network as a single entity wh
24、ich provides services to the user. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. F
25、or a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the
26、 present document. 1 ITU-T Recommendations I.130 (1988): “Method for the characterization of telecommunication services supported by an ISDN and network capabilities of an ISDN“. 2 GSM 01.04: “Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms“. 3 Definitions and abbre
27、viations GSM 01.04 2 provides a list of abbreviations and acronyms used in GSM specifications. 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: Tandem Free Operation (TFO): avoidance of tandeming speech codecs in mobile to mobile speech calls TFO c
28、all: mobile to mobile call where TFO has been applied Normal call or operation: call where TFO has not been applied Negotiation phase: phase during which the applicability of TFO is assessed through the exchange of information such as the capabilities of the respective transcoders and the types of s
29、peech codecs being used A party: user originating the call B party: user receiving the call (unless the call is forwarded) For simplicity the term MS is also used when UE is meant for 3G systems. The same is valid for TRAU and TC analogously. ETSI ETSI TS 122 053 V13.0.0 (2016-01)63GPP TS 22.053 ver
30、sion 13.0.0 Release 133.2 Abbreviations For the purposes of the present document, the following abbreviations apply: ASCI Avanced Speech Call Items MSC Mobile services Switching Centre PLMN Public Land Mobile Network 4 Description The TFO feature avoids the tandeming of speech codecs that occurs in
31、mobile to mobile speech calls. 4.1 Applicability of TFO to Basic Services TFO shall be applicable to all mobile to mobile speech calls where both parties use the same GSM speech coding standard. TFO shall be supported for all of the GSM speech coding standards (i.e. Full Rate, Half Rate and Enhanced
32、 Full Rate). It would also be desirable to extend the TFO approach to realise quality enhancements when different speech codec standards are in use, e.g. by handing over one of the links to provide common codec types and then applying TFO. 4.2 Support in Mobile Stations (MS) TFO shall not require an
33、y modifications to existing or future mobile stations. There shall be no additional user intervention required to enable or invoke the feature. Correspondingly, it shall not be possible for a user to disable the feature. 4.3 Parameters to be indicated and negotiated The speech codec standards used o
34、n each party shall be indicated and negotiated, if applicable. 4.4 Provision of Service 4.4.1 Location Independence TFO shall be capable of being applied for mobile to mobile calls regardless of the serving networks of the A or B parties. Thus, the A and B parties may be registered on different PLMN
35、s or on the same network. 4.4.2 Provision of service within and between networks Provision of the TFO feature shall be determined by the network operator on a network (or sub-network) wide basis, where equipment to support the feature has been deployed. It shall not be necessary for the service capa
36、bility to be rolled out throughout an entire network before being made operational. TFO between networks shall be applied if appropriate between supporting (sub) networks. In the case where a TFO call is handed over between two parts of a network, but the new part is not provisioned with TFO, the ca
37、ll shall revert to normal operation. In the case where a normal call is handed over between two parts of a network, and the new part is provisioned with TFO, the call will switch to TFO if appropriate. NOTE: TFO operation will normally require that the coded speech is transmitted transparently (i.e.
38、 without errors) between the relevant transcoders (e.g. by bit-stealing). ETSI ETSI TS 122 053 V13.0.0 (2016-01)73GPP TS 22.053 version 13.0.0 Release 134.4.3 Subscription and Billing Information This feature shall not be provisioned on a per-subscriber basis and no record of the application of TFO
39、is necessary for billing purposes. 4.5 Quality of Service (QoS) 4.5.1 Impact on Speech Quality The speech quality and timing requirements depend on the phase of the call and are defined in table 1. In all cases the duration and degradation should be minimised. The timing requirements for the applica
40、tion and removal of TFO are derived from the typical users perception of the feature in the context of typical call set-up times together with handover operation. There is a much stricter requirement on the time taken to revert to normal operation than to apply TFO because when TFO is enabled only o
41、n one side of a call, the speech will be unintelligible. Likewise, failures in the transmission of the coded speech without (significant) errors (e.g. due to routing via an ADPCM link) should be detected rapidly as the speech quality may also be seriously degraded. Table 1: TFO speech quality and ti
42、ming requirements Call phase Reference condition (note 1) Maximum degradation Speed of operation TFO negotiation following call set-up normal transcoding stages “no perceptible degradation“ 2 sec (note 2) 7 sec (note 3) TFO negotiation following TFO interruption or handover normal transcoding stages
43、 “no perceptible degradation“ 7 sec (notes 4 and 5) transition from normal operation to TFO normal transcoding stages “no annoying artefacts“ return from TFO to normal operation TFO transcoding stages “no annoying artefacts“ 160 ms continuous TFO TFO transcoding stages “no degradation“ continuous no
44、rmal operation normal transcoding stages “no degradation“ NOTE 1: All reference conditions are defined as error free with no bit-stealing and with no transmission delay between the TRAUs “normal transcoding stages“ refers to the speech codec(s) selected prior to TFO. NOTE 2: Objective for time taken
45、 to establish TFO after call set-up. NOTE 3: Maximum time allowed for TFO negotiation after call set-up. NOTE 4: Objective for time taken to establish TFO after re-establishment of transparent PCM link. NOTE 5: Once TFO has been successfully established during a call, an unlimitted number of negotia
46、tion attempts may be made after any subsequent interruptions of TFO. NOTE: The timing limits and the quality degradations specified in table 1 are to some extent inter-dependent. 5 Interaction with supplementary services 5.1 General This clause defines the interactions between supplementary services
47、 and TFO. Neither TFO nor attempted TFO establishment shall interfere with the provision or invocation of any supplementary services. 5.2 Explicit Call Transfer (ECT) Following call transfer, the new call route is evaluated and TFO applied if possible, otherwise normal operation applies. ETSI ETSI T
48、S 122 053 V13.0.0 (2016-01)83GPP TS 22.053 version 13.0.0 Release 135.3 Call wait/Call hold Following the establishment of another call, the new call route shall be evaluated and TFO applied if possible, otherwise normal operation applies. 5.4 Multiparty Where more than two parties are involved in a
49、 call, TFO may not be applicable. As a result, when a two-party TFO call is extended to multi-party, all the links shall revert to normal operation. 5.5 Service Announcements TFO shall not disrupt the provision of call progress or similar speech announcements to the user which originate in any of the networks routing a call. 6 Interaction with Alternate and Followed by services There shall be no impact on data transmission due to TFO or attempted TFO establishment. 7 Interaction with other speech services There is no requirement for TFO in ASCI services. 8 In
