1、ATIS-0700029 ATIS Standard on Real Time Text Mobile Device Behavior Alliance for Telecommunications Industry Solutions Approved January 30, 2017 Abstract This Standard specifies certain aspects of the mobile device behavior for handling Real Time Text (RTT) to facilitate communication between mobile
2、 devices (including emergency services) across multiple Commercial Mobile Service Providers (CMSPs). ATIS-0700029 ii Foreword As a leading technology and solutions development organization, the Alliance for Telecommunications Industry Solutions (ATIS) brings together the top global information and c
3、ommunications technology (ICT) companies to advance the industrys most-pressing business priorities. ATIS serves the public through improved understanding between carriers, customers, and manufacturers. This standard was developed jointly between ESIF, PTSC, and WTSC. The Emergency Services Intercon
4、nection Forum (ESIF) provides a forum to facilitate the identification and resolution of technical and/or operational issues related to the interconnection of wireline, wireless, cable, satellites, Internet, and emergency services networks. The Packet Technologies and Systems Committee (PTSC) develo
5、ps and recommends standards and technical reports related to services, architectures, and signaling, in addition to related subjects under consideration in other North American and international standards bodies. PTSC coordinates and develops standards and technical reports relevant to telecommunica
6、tions networks in the U.S., reviews and prepares contributions on such matters for submission to U.S. ITU-T and U.S. ITU-R Study Groups or other standards organizations, and reviews for acceptability or per contra the positions of other countries in related standards development and takes or recomme
7、nds appropriate actions. The Wireless Technologies and Systems Committee (WTSC) develops and recommends standards and technical reports related to wireless and/or mobile services and systems, including service descriptions and wireless technologies. WTSC develops and recommends positions on related
8、subjects under consideration in other North American, regional, and international standards bodies. Suggestions for improvement of this document are welcome. They should be sent to the Alliance for Telecommunications Industry Solutions, WTSC, 1200 G Street NW, Suite 500, Washington, DC 20005. At the
9、 time of initiation or issuance of the letter ballot for this document, the committees responsible for its development had the following leadership: S. Sherwood, ESIF Chair (Verizon) R. Hixon, ESIF First Vice-Chair (NENA) R. Marshall, ESIF Second Vice-Chair (Comtech) M. Dolly, PTSC Chair (AT October
10、, 2015.2Ref 2 GSMA IR.92, GSM Association IMS Profile for Voice and SMS; Version 9.0; 08 April 2015.3Ref 3 3GPP TS 23.226, Global Text Telephony (GTT); Stage 2.4Ref 4 ITU-T T.140, Protocol for Multimedia Application Text Conversion, February 1998; including Addendum 1, Marking of missing characters,
11、 February 2000.5 1The support of RTT over Wi-Fi is for further study. 2This document is available from the Alliance for Telecommunications Industry Solutions (ATIS) at: . 3This document is available from the GSM Association (GSMA) at: . 4This document is available from the 3rd Generation Partnership
12、 Project (3GPP) at: . ATIS-0700029 2 Ref 5 IETF RFC 4103, RTP Payload for Text Conversion; June 2005.6Ref 6 ATIS-0700030, Real Time Text End-to-End Service Description Specification; publication anticipated 2017.2Ref 7 3GPP TS 26.114, IP Multimedia Subsystem (IMS); Multimedia Telephony; Media handli
13、ng and interaction.4Ref 8 The Unicode Standard Version 8.0 Core Specification, The Unicode Consortium, June 17, 2015.7Ref 9 3GPP TS 26.226, Cellular text telephone modem; General description.4Ref 10 3GPP TS 22.173, IP Multimedia Core Network Subsystem (IMS) Multimedia Telephony Service and supplemen
14、tary services; Stage 1.4Ref 11 3GPP TS 24.229, IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3.4Ref 12 3GPP TR 21.905, Vocabulary for 3GPP Specifications.4Ref 13 TIA 825-A, A Frequency Shift Keyed Modem for Use on the Pub
15、lic Switched Telephone Network.82.2 Informative References Ref 100 3GPP TS 22.226, Global Text Telephony (GTT); Stage 1.43 Definitions, Acronyms, & Abbreviations For a list of common communications terms and definitions, please visit the ATIS Telecom Glossary, which is located at . 3.1 Definitions R
16、eal Time Text (RTT): Characters entered via keyboard, drawing, speech recognition, or other text creation method on terminal A and rendered in real time on the display of terminal B. The flow is time-sampled so that no specific action is needed from the user to request transmission resulting in text
17、 communication that is perceived by the user as being a real-time view of the text entry. NOTE: In this Standard, “RTT” means IETF RFC 4103-based implementation Ref 5. RTT Call: A call with RTT and voice components. TTY: The term for the text telephones that are based on Baudot and TIA 825-A Ref 13.
18、 NOTE: TTY was originally an abbreviation for Teletype, a device that was later combined with a modem so that it could be used for text conversations over analog phone lines. Voice over LTE: IP Multimedia Subsystem (IMS) Voice service over LTE. 3.2 Acronyms & Abbreviations 3GPP Third Generation Part
19、nership Project ATIS Alliance for Telecommunications Industry Solutions 5This document is available from the International Telecommunications Union Telecommunication Standardization Sector (ITU-T) at: . 6This document is available from the Internet Engineering Task Force (IETF) at: . 7This document
20、is available from the Unicode Consortium at: . 8This document is available from the Telecommunications Industry Association (TIA) at: . ATIS-0700029 3 CMSP Commercial Mobile Service Provider CS Circuit Switched CTM Cellular Text Telephone Modem IETF Internet Engineering Task Force IMS IP Multimedia
21、Subsystem IP Internet Protocol ITU-T International Telecommunications Union Telecommunication Standardization Sector LTE Long Term Evolution ME Mobile Equipment ms millisecond OEM Original Equipment Manufacturer PSAP Public Safety Answering Point PSTN Public Switched Telephone Network RTT Real Time
22、Text TRS Telecommunications Relay Services TS Technical Specification TTY Teletypewriter or Text Telephony UE User Equipment UI User Interface VoLTE Voice over LTE 4 RTT Background Information & End-to-End Service Background information on RTT and the RTT end-to-end service description, including Us
23、e Cases and end-to-end service requirements, will be provided in the ATIS Real Time Text End-to-End Service Description Specification Ref 6. 5 Assumptions 1. It is assumed that the user interface for the RTT capability will utilize accessibility settings and capabilities provided by the underlying m
24、obile device platform. 2. It is assumed that the RTT-capable mobile device has implemented Voice over LTE (VoLTE) capabilities. 3. It is assumed that the RTT-capable mobile device may implement other 3GPP IMS non-voice multimedia capabilities as well. 4. The term “Mobile Device” only refers to the U
25、ser Equipment (UE) component as defined in 3GPP TR 21.905 Ref 12. ATIS-0700029 4 6 High Level Requirements This section defines the high-level requirements for RTT that are applicable to the RTT-capable mobile device. These high level requirements were derived from Ref 100. These requirements are in
26、dependent of the users perception of the feature: All Calls 1. The RTT-capable mobile device shall provide the capability to the user to have real-time text conversations in calls also capable of supporting voice communication. Emergency Calls and Callbacks 2. The RTT-capable mobile device shall ena
27、ble emergency RTT calls toward a PSAP and enable reception of RTT-enabled callbacks from a PSAP. In addition to the high level RTT service requirements that apply to the RTT-capable mobile device, the following general RTT requirements also apply to the RTT-capable mobile device: Session Control 3.
28、User control of a combined RTT and voice session (call control) functions shall follow similar procedures as IMS voice-only sessions. Invoking RTT Conversation 4. It shall be possible to initiate an RTT conversation at call establishment. It shall also be possible to add an RTT component to a voice
29、call already in progress. RTT Conversation Handling During Calls 5. Text transmission shall be done character by character as entered, or characters may be transmitted in small groups. No character should be buffered before transmission more than 300 milliseconds Ref 4. 6. The text transmission shal
30、l support maximum rates of at least 30 characters per second so that human typing speed as well as speech-to-text methods of generating RTT text can be supported. 7 RTT-Capable Mobile Device User Interface Requirements This section defines the minimum set of requirements applicable to RTT-capable mo
31、bile device user interfaces. These requirements are grouped into the following topics: Integrated user interfaces. External interfaces. Text creation, transport, and presentation. Creating and editing input. Alternative presentation of audio and call progress information. 7.1 Integrated User Interfa
32、ces Any text creation and text presentation capabilities that are built into the RTT-capable device shall be useable for RTT text input and presentation. ATIS-0700029 5 7.2 External User Interfaces The RTT-capable mobile device shall support RTT communication input and presentation via the use of ex
33、ternal digital text input and presentation devices connected through standardized interfaces (e.g., Bluetooth) that are integrated into the RTT-capable mobile device. 7.3 Text Creation, Transport, & Presentation 1. Text creation, transport, and presentation shall be per ITU-T T.140 Ref 4 as specifie
34、d in 3GPP TS 26.114 Ref 7, clause 5.2.3. 2. The RTT function shall use the Unicode support Ref 8 provided by the mobile device platform. NOTE: It is expected that the mobile device platform Unicode support Ref 8 also supports the graphic rendition coding as specified in ITU-T T.140 Ref 4. 7.4 Creati
35、ng & Editing Input The RTT-capable mobile device shall provide the capability to allow the user to enter text, backspace (i.e., erase last character), and to send a line separator as defined in the ITU-T T.140 Ref 4. NOTE 1: Per ITU-T T.140 Ref 4, the backspace erasure has no specific limit other th
36、an the current RTT call. A user cannot modify the text input from another user, but they can backspace and modify their own text back beyond any “message-like” delimiters introduced by the user interface. NOTE 2: The user interface could distinguish modifications from original text. 7.5 Presentation
37、 of Audio Alerting & Call Progress Tones 1. The RTT-capable mobile device shall provide visual and tactile indication of network call progress tones and alerting signals (e.g., ringing, answer, and busy conditions). This may include text presentation. 2. The RTT-capable mobile device shall provide v
38、isual and tactile indication for received audio signal activity including but not limited to indications that help the user identify when the other party is speaking. This may include such features as a volume level status bar on the graphical display. 8 Emergency Services Requirements This section
39、provides the RTT-capable mobile device behavior requirements for use of emergency services. The end-to-end description and requirements for RTT emergency services are provided in the RTT End-to-End Service Description specification Ref 6. The network behavior for RTT emergency services is defined in
40、 ATIS-1000068 Ref 1. 1. The user option to not transmit immediately that is described in section 9.7 should be disabled in RTT-capable mobile devices for emergency calls. 2. The dialed digits used by an RTT-capable mobile device to initiate an RTT emergency call shall be the same as the dialed digit
41、s used to initiate a voice emergency call from the mobile device (e.g., 911, 112, 999). 3. 3GPP supplemental services defined in 3GPP TS 22.173 Ref 10, which are disabled for voice emergency calls, shall also be disabled for RTT emergency calls. 4. The location of the RTT-capable mobile device shall
42、 be determined by the same emergency call location determination methodologies used for a voice emergency call. 5. An RTT-capable mobile device shall support emergency callback with RTT to the same extent that it supports emergency callback for calls that are voice-only. ATIS-0700029 6 9 Mobile Devi
43、ce Requirements This section defines the mobile device requirements to support RTT functionality. These mobile device requirements are grouped into the following topics: Device support for TTY or RTT. Simultaneous voice and RTT. Transport support in the device. Establishing an RTT media component du
44、ring call setup. Addition and removal of RTT media component mid-call. Transmission of characters for RTT. User control of voice media usage during an RTT call. 9.1 Device Support for TTY or RTT 1. RTT-capable mobile devices shall implement RTT as defined by 3GPP TS 23.226 “Global Text Telephony” cl
45、ause 5.1 Ref 3, ATIS-1000068 “Support of TTY Service over IP using Global Text Telephony” Ref 1, the text-related sections of 3GPP TS 26.114 Ref 7, and the requirements in this Standard. 2. RTT-capable mobile devices that are also able to operate in the Circuit Switched (CS) domain may support 3GPP
46、TS 26.226, Cellular Text Telephone Modem (CTM) Ref 9, with an internal user interface or an externally-attached TTY when operating in the CS domain. 3. The RTT-capable mobile device shall not require an external TTY device for using RTT communication. 4. The RTT-capable mobile device shall not be re
47、quired to support a locally-connected external TTY for RTT operation. 9.2 Simultaneous Voice & RTT The RTT-capable mobile device shall support voice and RTT operation in both directions of a conversation with all four media streams occurring simultaneously. 9.3 Transport Support in the Device The RT
48、T-capable mobile device shall support RTT transport per RFC 4103 Ref 5 and per ATIS-1000068 Ref 1. 9.4 Establishing an RTT Media Component During Call Origination When enabled by the settings specified in section 10, the RTT-capable mobile device shall provide means to the user to include RTT in an
49、outgoing call attempt. The means of invoking RTT at call origination shall be presented along with the other user call functions such as placing a voice or video call. Independent of the settings in section 10, devices may provide functionality to automatically include RTT in outgoing calls based on preferences for individual contact list entries. 9.5 Establishing an RTT Media Component for Incoming Calls RTT requested by the calling party in an incoming call shall be accepted by the RT
