ETSI TS 122 226 V9.0.0 (2010-01) Technical Specification Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Global text telephony (GTT); Stage 1: Service description (3GPP TS 22.226 version 9.0.0 Release 9) 3GPP TS 22.226 version 9.0.0 Release 9 1 ETSI TS 122 226 V9.0.0 (2010-01) Reference RTS/TSGS-0122226v900 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 à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N° 7803/88 Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). 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Latest updates are available on the ETSI Web server (http://webapp.etsi.org/IPR/home.asp). 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, 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 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. ETSI 3GPP TS 22.226 version 9.0.0 Release 9 3 ETSI TS 122 226 V9.0.0 (2010-01) Contents Intellectual Property Rights ................................................................................................................................ 2 Foreword ............................................................................................................................................................. 2 Foreword ............................................................................................................................................................. 4 Introduction ........................................................................................................................................................ 4 1 Scope ........................................................................................................................................................ 6 2 References ................................................................................................................................................ 6 3 Definitions and abbreviations ................................................................................................................... 7 3.1 Definitions .......................................................................................................................................................... 7 3.2 Abbreviations ..................................................................................................................................................... 7 4 High level Requirements .......................................................................................................................... 7 5 General Requirements .............................................................................................................................. 8 5.1 Text conversation host environments ................................................................................................................. 8 5.2 Text conversation management .......................................................................................................................... 8 5.3 Registration of text conversation capabilities ..................................................................................................... 9 5.4 Session control ................................................................................................................................................... 9 5.5 Invoking text conversation ................................................................................................................................. 9 5.6 Text conversation handling during calls ............................................................................................................. 9 5.7 Alerting ............................................................................................................................................................ 10 5.8 Addressing ........................................................................................................................................................ 10 5.9 Roaming ........................................................................................................................................................... 10 6 Security and reliability ........................................................................................................................... 10 7 Charging ................................................................................................................................................. 10 8 External Interfaces .................................................................................................................................. 11 8.1 External interfaces in the terminal .................................................................................................................... 11 8.2 External interfaces to other networks ............................................................................................................... 11 9 Interworking ........................................................................................................................................... 11 10 Additional services ................................................................................................................................. 12 10.1 Emergency services .......................................................................................................................................... 12 10.2 Relay services ................................................................................................................................................... 12 11 Network implementation considerations ................................................................................................ 12 Annex A (informative): Background .................................................................................................... 13 A.1 Total Conversation ........................................................................................................................................... 13 A.2 Interworking ..................................................................................................................................................... 13 A.3 Additional services ........................................................................................................................................... 14 Annex B (informative): Initial requirements ....................................................................................... 15 B.1 Transmission Performance ............................................................................................................................... 15 B.2 Man Machine Interface (MMI) ........................................................................................................................ 16 B.3 Compatibility .................................................................................................................................................... 16 B.4 Complexity of Implementation and Roll Out ................................................................................................... 17 B.5 Referenced consumer requirements.................................................................................................................. 18 Annex C (informative): Change history ............................................................................................... 18 History .............................................................................................................................................................. 20 ETSI 3GPP TS 22.226 version 9.0.0 Release 9 4 ETSI TS 122 226 V9.0.0 (2010-01) Foreword This Technical Specification has been produced by the 3rd Generation 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 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 change 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. Introduction Real time, character by character text conversation is a component that increases usability in a conversational session. Global Text Telephony is a feature that adds the capability to use a text conversation component in a session. It is called Global Text or GTT here. Interworking with corresponding features in other networks is an important part of Global Text. Specifically, the different kinds of PSTN text telephone systems supported by the international text telephone modem standard ITU-T V.18 are included in the modes for interworking. One important reason to offer the Global Text feature is to enable emergency service access to people who are depending on a written dialogue. A more elaborated background is found in Annex A, and requirements in Annex B. Figure 1 gives an overview of the user environment for Global Text. ETSI 3GPP TS 22.226 version 9.0.0 Release 9 5 ETSI TS 122 226 V9.0.0 (2010-01) Fixed textphone user Fixed multimedia user Fixed Network IP textphone or multimedia user Cellular Network Mobile, IP text capable network terminals GTTFE Cellular Network Figure 1. Global Text service environment ETSI 3GPP TS 22.226 version 9.0.0 Release 9 6 ETSI TS 122 226 V9.0.0 (2010-01) 1 Scope This Technical Specification defines the stage one description of the Global Text Telephone Feature, GTT.. Stage one is the set of requirements which shall be supported for the provision of the real-time text conversation feature, seen primarily from the subscriber"s and service providers" points of view. This TS includes information applicable to network operators, service providers, terminal and network manufacturers. This TS contains the core requirements for the Global Text Telephony feature, which are sufficient to provide a complete feature to incorporate in conversational services. This TS defines the requirements for GTT to be understood as a framework to enable real-time transmission of text, for the purpose of a text based or text supported conversation between users. Text may be transported alone or in combination with other media in the session, especially video and voice. Thus the GTT enables text conversation to be included in any mobile conversational service. Interworking with existing text telephony in PSTN as well as emerging forms of standardised text conversation in all networks is within the scope of this document. Interoperation with Multimedia Messaging Services is also within scope of this feature. Note: The Global Text Telephony feature may be enhanced due to e.g. operator's or regulator's requirements, however such additional functionality shall not compromise conformance to the core requirements documented in this TS. 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. - For 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 present document. [1] 3GPP TS 22.101: "Service Principles". [2] ETSI ETR 333; Text Telephony; User requirements and Recommendations [3] ITU-T H.248 Annex F Facsimile, Text conversation and call discrimination packages (2000) [4] ITU-T Recommendation T.140 (1998) – Text conversation protocol for multimedia application. With amendment 1 (2000). [5] ITU-T Recommendation F.700 (2000) – Framework recommendation for audiovisual/multimedia services. [6] ITU-T Recommendation V.18 (2000) – Operational and interworking requirements for DCE:s operating in the text telephone mode. [7] 3GPP TS 22.140: "Multimedia Messaging Service; Stage 1" [8] 3GPP TS 23.140: "Multimedia Messaging Service; Functional description; Stage 2" [9] IETF RFC 2793. (2000) RTP Payload for text conversation. ETSI 3GPP TS 22.226 version 9.0.0 Release 9 7 ETSI TS 122 226 V9.0.0 (2010-01) [10] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications". 3 Definitions and abbreviations 3.1 Definitions Total Conversation: A service offering standardised simultaneous text, video and voice conversation or a subset thereof. Host environment : The session environment where the text component is added. E.g. Circuit switched voice, IP Multimedia etc. Text Conversation: A real time conversation in text with transmission character by character as entered. Further definitions are listed in 3GPP TR 21.905 [10]. 3.2 Abbreviations For the purposes of this document the following abbreviations apply: EDT European Deaf Telephone GTT Global Text Telephony; The feature that adds real time text conversation to any 3GPP conversational environment GTTFE Global Text Telephony Feature Environment – The network components and functions forming GTT TTY Here used as the term for the text telephone type dominating in USA. DTMF Here used as a term for the text telephone type used in Holland, using DTMF tones. VCO Voice Carry Over: Alternating (or parallel) sending of Speech and receiving Text HCO Hear Carry Over: Alternating (or parallel) receiving Speech and transmission of Text FCC Federal Communications Commission (of United States of America) PER Printable character Error Rate MMI Man Machine Interface SIM Subscriber Identification Module ITU International Telecom Standardisation Union GSM Global System for Mobile communication 3GPP Third Generation Partnership Project CS Circuit Switched IP Internet Protocols Further abbreviations are listed in TR 21.905 [10]. 4 High level Requirements The following list gives the high level requirements of the GTT. These are requirements which are independent of the user"s perception of the feature:- - Service definition Global Text shall provide a real time conversational text feature. A general definition is found in Recommendation ITU-T F.700[5]. - Global Text Telephony host environments A standardised method for Global Text Telephony shall at least be specified for each host environment in the mobile networks that can carry voice. - Standards compliant and forward compatible text conversation ETSI 3GPP TS 22.226 version 9.0.0 Release 9 8 ETSI TS 122 226 V9.0.0 (2010-01) Global Text Telephone mechanisms shall provide the capability to support current and evolving text telephony and text conversation features by re-using existing standards as far as possible and proposing extensions (as necessary) to existing standards (i.e. the global text telephony feature shall support the evolution of Total Conversation technologies in all networks). - Consistent text conversation Regardless of the selected host environment, the far end terminal, the interworking facilities involved, GTT shall be capable of providing a consistent way of handling the conversation. - Global Text Telephone access Within the capabilities of networks and terminals, the user shall be provided consistent access to the GTT regardless of the access point. For example: the user shall be capable of accessing the text conversation features through a number of different access points, including networks based on 3GPP specifications, access through dedicated multimedia terminals, and access through combinations of mobile phones combined with text user interface devices. - Interoperability Global Text Telephony shall support interoperability with existing and emerging text telephone systems and text conversation features. Global Text Telephony shall support a minimum set of environments where text conversation is supported to ensure full interoperability between different terminals and networks. - Emergency calls The implementation of Global Text Telephony shall enable a user to make emergency calls to, and receive calls from, an emergency call centre via a text telephony device used in conjunction with GTT enabled user equipment. 5 General Requirements Network operators have many differing requirements, and GTT shall be supported in the network in a manner which allows network operators to consider different configurations depending on their network and commercial requirements. Thus, an identified set of functionalities and protocols shall be standardised to ensure interoperability across networks and terminals to support GTT. The following general requirements shall be supported. 5.1 Text conversation host environments The protocol environments for text conversation shall be the same as the ones used for other multimedia conversation calls and voice calls. The selected environment for a session is called the host environment. Supported host environments are: - Packet switched multimedia - Circuit switched multimedia. - The text conversation carried by an data transmission procedure, possible to combine with a voice session. - Circuit switched voice telephony, with the text conversation carried in-band in the voice channel. 5.2 Text conversation management It shall be possible to allow GTT use without GTT specific subscription. ETSI 3GPP TS 22.226 version 9.0.0 Release 9 9 ETSI TS 122 226 V9.0.0 (2010-01) Note: There is no requirement for GTT feature specific subscription, but for "normal GTT calls" a subscription for telephony is required. For "emergency GTT call" no subscription of any kind is required. Session start up delay and loss of initial characters should be minimised as far as practicably possible. The text transport method should remain transparent to the network, unless specific functionality is required to provide a satisfactory quality of service. 5.3 Registration of text conversation capabilities The availability of text conversation capabilities in the user terminal may need to be communicated to the network at call establishment in order to access the GTT service. However, a user is expected to be able to access the GTT service without explicit GTT registration with the operator. 5.4 Session control The session control (call control ) functions shall use the same procedures as the selected host environment. Additional operations needed to invoke the text component may be automated by the text conversation user interface. It shall be possible to establish text-only calls as well as calls with other media components. 5.5 Invoking text conversation Calls with terminals where text conversation is used shall bemonitored for requests to start the text feature. When either party in a call begins usage of the text feature, an effort shall be made to establish text conversation. It shall be possible to start text conversation during a call already established in voice or video mode by adding the text component. The mode selected for text conversation ( IP Multimedia, CS Multimedia, Voice path etc. ) shall be determined according to a prioritised procedure. Modes allowing simultaneous voice and text shall by default have higher priority, while the user shall be given opportunities to prioritise text-only modes. The default order shall be: IP Multimedia, CS Multimedia, data path text plus voice, voice path text. The user shall be given call progress information and text invocation progress information in text or other non-audible media. 5.6 Text conversation handling during calls Text transmission shall be done character by character as entered, or in small groups transmitted so, that no character is delayed before transmission more than 0.5 seconds. (as stated in ITU-T T.140 [4]) The text transmission shall allow a rate of at least 10 characters per second so that human typing speed as well as speech to text methods of generating conversation text can be supported. The end-to-end delay of characters shall be less than two seconds, measured between two mobile users, or between one mobile user and any interworking fixed network user, assuming that the fixed network does not contribute with more than one second to this figure. The character corruption rate should be less than 1% in conditions where users experience the voice transmission quality to be low but useful. The transmission of the text conversation shall be made according to the character set and operations defined in ITU-T T.140. [4]. This requirement enables smooth interworking with minimal loss of functionality between different text conversation environments. The allowed limitations in character set support specified in ITU-T T.140 shall be obeyed, so that two terminals always have a minimum common character set available for conversation. Figure 2 gives an example of a possible layout of a real time text conversation according to ITU-T T.140. ETSI