1、 ETSI TS 122 053 V14.0.0 (2017-03) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); Tandem Free Operation (TFO); Service description; Stage 1 (3GPP TS 22.053 version 14.0.0 Release 14) TECHNICAL SPECIFICATION GLOBAL SYSTEM FOR MOBILE COM
2、MUNICATIONSRETSI ETSI TS 122 053 V14.0.0 (2017-03)13GPP TS 22.053 version 14.0.0 Release 14Reference RTS/TSGS-0422053ve00 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 742 C Associa
3、tion 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 and/or print
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9、wned by the GSM Association. ETSI ETSI TS 122 053 V14.0.0 (2017-03)23GPP TS 22.053 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 publ
10、icly 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 ETSI
11、 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, or
12、may become, essential to the present document. Foreword The present document may refer to 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 be
13、tween 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“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3
14、.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 V14.0.0 (2017-03)33GPP TS 22.053 version 14.0.0 Release 14Contents Intellectual Property Rights 2g3Forew
15、ord . 2g3Modal verbs terminology 2g3Foreword . 4g31 Scope 5g32 References 5g33 Definitions and abbreviations . 5g33.1 Definitions 5g33.2 Abbreviations . 6g34 Description . 6g34.1 Applicability of TFO to Basic Services 6g34.2 Support in Mobile Stations (MS) . 6g34.3 Parameters to be indicated and neg
16、otiated . 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 of Service (QoS) 7g34.5.1 Impact on Speech Quality . 7g35 Interaction with supplementary services 7g35.1
17、 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 Interaction with other speech services 8g38 Interaction with DTMF 8g39 Interaction with Lawful Intercept . 8g3A
18、nnex A (informative): Limitations of initial in-band TFO implementations 9g3Annex B (informative): Change history . 10g3History 11g3ETSI ETSI TS 122 053 V14.0.0 (2017-03)43GPP TS 22.053 version 14.0.0 Release 14Foreword This Technical Specification (TS) has been produced by ETSI 3rd Generation Partn
19、ership 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 by the TSG with an identifying change of release date and an incr
20、ease 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 of substance, i.e. technical enhancemen
21、ts, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. ETSI ETSI TS 122 053 V14.0.0 (2017-03)53GPP TS 22.053 version 14.0.0 Release 141 Scope The present document specifies the stage 1 description for the Tandem Free Operat
22、ion (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 operation could also be used to reduce inter-Mobile services Switching Center (MSC) transmission bandwidth
23、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 which provides services to the user. 2 References The following documents contain provisions which, th
24、rough 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 do not apply. For a non-specific reference, the latest
25、 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 ITU-T Recommendations I.130 (1988): “Method for the characterization of telecom
26、munication 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 abbreviations GSM 01.04 2 provides a list of abbreviations and acronyms used in GSM specifications. 3.1 D
27、efinitions 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 call: mobile to mobile call where TFO has been applied Normal call or operation: call where TFO has n
28、ot 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 speech codecs being used A party: user originating the call B party: user receiving the call (unless
29、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 V14.0.0 (2017-03)63GPP TS 22.053 version 14.0.0 Release 143.2 Abbreviations For the purposes of the present document, the following abbr
30、eviations 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 mobile to mobile speech calls. 4.1 Applicability of TFO to Basic Services TFO shall be applicable to
31、 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 Full Rate). It would also be desirable to extend the TFO approach to realise quality enhancements w
32、hen 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 any modifications to existing or future mobile stations. There shall be no additional user interventio
33、n 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 on each party shall be indicated and negotiated, if applicable. 4.4 Provision of Service 4.4.1 Locati
34、on 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 PLMNs or on the same network. 4.4.2 Provision of service within and between networks Provision of the TF
35、O 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 capability to be rolled out throughout an entire network before being made operational. TFO between netw
36、orks 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 call shall revert to normal operation. In the case where a normal call is handed over between two part
37、s 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. without errors) between the relevant transcoders (e.g. by bit-stealing). ETSI ETSI TS 122 053 V14.0
38、.0 (2017-03)73GPP TS 22.053 version 14.0.0 Release 144.4.3 Subscription and Billing Information This feature shall not be provisioned on a per-subscriber basis and no record of the application of TFO is necessary for billing purposes. 4.5 Quality of Service (QoS) 4.5.1 Impact on Speech Quality The s
39、peech 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 application and removal of TFO are derived from the typical users perception of the feature in the context
40、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 on one side of a call, the speech will be unintelligible. Likewise, failures in the transmission of t
41、he 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 timing requirements Call phase Reference condition (note 1) Maximum degradation Speed of operation TFO
42、 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 “no perceptible degradation“ 7 sec (notes 4 and 5) transition from normal operation to TFO normal t
43、ranscoding 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 normal operation normal transcoding stages “no degradation“ NOTE 1: All reference conditions are defin
44、ed 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 to establish TFO after call set-up. NOTE 3: Maximum time allowed for TFO negotiation after call set
45、-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 negotiation attempts may be made after any subsequent interruptions of TFO. NOTE: The timing limits and the
46、 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 and TFO. Neither TFO nor attempted TFO establishment shall interfere with the provision or invocati
47、on 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 TS 122 053 V14.0.0 (2017-03)83GPP TS 22.053 version 14.0.0 Release 145.3 Call wait/Call hold Followin
48、g 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 call, TFO may not be applicable. As a result, when a two-party TFO call is extended to multi-party,
49、 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 Interaction with DTMF DTMF transmission performance during TFO shall be no worse than during normal op
