1、 ETSI EG 202 534 V1.1.3 (2007-07)ETSI Guide Human Factors (HF);Guidelines for real-time person-to-personcommunication servicesETSI ETSI EG 202 534 V1.1.3 (2007-07) 2 Reference REG/HF-00118 Keywords interaction, service ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 9
2、2 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 7803/88 Important notice Individual copies of the present document can be downloaded from: http:/www.etsi.org The present document may be made available
3、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). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a speci
4、fic network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors
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6、edia. European Telecommunications Standards Institute 2007. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTMand the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members. 3GPPTM is
7、a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI EG 202 534 V1.1.3 (2007-07) 3 Contents Intellectual Property Rights4 Foreword.4 Introduction 5 1 Scope 7 2 References 7 3 Definitions and abbreviations.7 3.1 Definitions7 3.2 Abbreviatio
8、ns .10 4 Guidelines.11 4.1 Service selection guidelines .13 4.2 Text communication.16 4.3 Audio communication 17 4.4 Avatar communication .19 4.5 Data communication.20 4.6 Video communication 21 4.6.1 Video communication: “Face-to-face“21 4.6.2 Video communication: Remote inspection .30 4.6.3 Video
9、communication: Multi-point and heterogeneous networks 35 4.7 Multimedia communication35 4.8 Special user groups.38 4.8.1 Blind and visually impaired people 38 4.8.2 Deaf and hearing impaired people 39 Annex A (informative): Overview of intended guideline users and their requirements43 A.1 Intended g
10、uideline users.43 A.2 Requirement derivation process .43 A.3 Requirements for guidelines.44 A.3.1 Provide information on key topics of concern that will aid development choices .44 A.3.2 Provide information on related concepts44 A.3.3 Provide QoE data that can be used from different perspectives .44
11、 A.3.4 Link QoS and QoE variables45 A.3.5 Provide information about user behaviour that is feasible to apply45 A.4 Requirements for a web-based system .46 Annex B (informative): Background work providing user-based data for the guidelines 47 B.1 Studies designed specifically to input to the current
12、guidelines.47 B.1.1 Laboratory experiments47 B.1.2 Field studies48 B.1.3 Survey 48 B.1.4 Expert review and expert panels.48 B.2 Literature 49 Annex C (informative): Bibliography.50 History 53 ETSI ETSI EG 202 534 V1.1.3 (2007-07) 4 Intellectual Property Rights IPRs essential or potentially essential
13、 to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly 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 t
14、o ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. 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 g
15、iven 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 ETSI Guide (EG) has been produced by ETSI Technical Committee Human Factors (HF). Intended users of t
16、he present document are: Network operators, especially persons responsible for: - strategic network planning; - system integration; - network testing; - marketing; - sales. Equipment manufacturers, especially persons responsible for: - development engineering; - marketing; - sales; - support. Servic
17、e providers, especially persons responsible for: - system integration; - terminal testing; - sales. ETSI ETSI EG 202 534 V1.1.3 (2007-07) 5 Introduction Real-time person-to-person communication services offer users the opportunity to interact using various communication media: text, audio, graphics,
18、 video and data. The communication services that use these media are real-time conversational text, audio-telephony, audio conferencing, avatar-telephony, data conferencing (e.g. a shared presentation or workspace), videotelephony, videoconferencing and multimedia conferencing. These services place
19、different demands on the communication channel and terminal equipment (figure 1). In addition, these services continue to evolve for both mobile and static usage and provide complex choices regarding the most appropriate technologies, media and services that are suitable for different communication
20、situations. TR 102 274 identified the need to develop guidelines for network operators, equipment manufacturers and service providers that address: the configuration and quality of different communication media; the selection between different communication media; acceptability of different communic
21、ation media; future applications for real-time human communication services. Figure 1: Main real-time person-to-person communication media and services Distinction between Quality of Service and Quality of Experience When implementing real-time person-to-person services there are many network, codec
22、 and environment characteristics that may interfere with human communication (Hestnes et al 2003). In a packet switched network the interfering characteristics are bandwidth, packet size, delay, delay jitter, packet loss, burst packet loss and sequencing. The codec characteristics are the media prot
23、ocols (e.g. G.7xx, H.26x, MPEGx), video space resolution, video time resolution, delay, distortion and monitor size. The environmental characteristics are lighting conditions, background patterns, colour and reflex, acoustics, audio echo degradation, viewing distance, camera position and camera para
24、meters. Description of these technical parameters is provided in Heim et al (2001). These technical characteristics are typically a topic of Quality of Service (QoS), with measures of QoS being based on theoretical mathematical and engineering principles and removed from measures of quality as exper
25、ienced by end-users. From a more user-centred perspective the concept of “Quality of Experience“ (QoE) is attracting growing attention (Hestnes et al, 2003, Nokia, 2004). ITU-T SG 12 Q13/12 is addressing “Multimedia QoE/QoS performance requirements and assessment methods“. By developing definitions
26、proposed by Nortel (2003), Siller and Woods (2003) and TR 102 274 the current report suggests that QoE is: The performance of users when using what is presented by a communication service or application user interface. It takes into account the individual Quality of Services and measures the accepta
27、bility of a service or application by including factors such as usability, utility, fidelity and level of support from the application or service provider (e.g. sales, delivery, error corrections). This is a general definition that should be able to encompass more specific concerns. What is importan
28、t for current purposes is that although QoE embodies psychological measures of user behaviour it is also expressed in relation to technical QoS. Therefore, user-centred guidelines for real-time communication services should succeed where possible to combine both QoE and QoS measures to provide an ex
29、pression of the user behaviour when performing a particular communication task with a particular communication service with known levels of QoS (TR 102 274). ETSI ETSI EG 202 534 V1.1.3 (2007-07) 6 Linking QoS and QoE in user-centred guidelines TR 102 274 proposes an approach for deriving user-centr
30、ed guidelines from user test results by extracting and combining QoE and QoS parameters where these data are known. The approach derives a database of detailed intermediate guidelines from which more concise guidelines can be abstracted. The intermediate guidelines are constructed based on the claus
31、e: IF ; USING ; WITH ; THEN . The attributes , , and have sub-attributes and sometimes sub-sub-attributes in order to cover the problem space and to correspond to existing knowledge of media effects on communication behaviour (TR 102 274). For example, the attribute “Communication Situation“ has the
32、 sub-attributes “Task“, “Setting“ and “User“; and “Task“ is defined by sub-sub-attributes including “Duration“, “Situation formality“ and “Urgency“. The “Service prescription“ contains the service used (e.g. telephony or video conferencing), the “technical parameters“ concern QoS measures such as ne
33、twork delay and packet loss and “usage outcome“ includes variables such as user communication efficiency and satisfaction. With this essential information collected and structured, guidelines can be abstracted that aim to state the principal messages of relevance to the intended guideline users (Bro
34、oks et al., 2003). It is these abstracted guidelines (figure 2) that form the main content of the current report. Figure 2: Guidelines are derived from base knowledge through a process of intermediate guideline development that map QoE and QoS variables Maturity and restrictions of the guidelines Th
35、e guidelines are considered initial due to the relative novelty of this area of work. While based on scientifically derived empirical data or expert opinion, the validity of some guidelines remains open for further study. For example, some of the user tests on which the guidelines are based should b
36、e replicated and extended to different user groups and task types. Whereas there may be cross-cultural issues concerned with real-time communication services, the available user test data is mainly restricted to samples within particular countries (e.g. the UK and Norway). Most of the empirical test
37、s involve condition comparisons that reveal where significant differences between independent variables exist and were not designed to identify precise thresholds. Also, most of the laboratory results that exist to date concern dyadic communication (i.e. between two people) that is point-to-point (i
38、.e. between two locations). Some field data exists for group communication (i.e. between three or more people) that is point-to-point. There is currently little data available for multi-point communication (i.e. between three or more locations). ETSI ETSI EG 202 534 V1.1.3 (2007-07) 7 1 Scope The pr
39、esent document provides guidelines for real-time person-to-person communication services. The guidelines are intended for persons working in network operator, equipment manufacturer, service provider and other organizations who may influence the development of services for end-users. This includes s
40、trategic planners, sales persons, customer support personnel and conference meeting facilitators. The services examined concern text communication, audio communication, avatar communication, data communication, video communication and multimedia communication. Service aspects include audio-video syn
41、chrony, video resolution, video delay and packet loss for fixed and mobile networks. Some of the guidelines are developed from initial guidelines contained in TR 102 274 whilst others were created for the present document. Guidelines are provided for topics that have been identified as important for
42、 intended guideline users and for which user-based data existed or could be collected. Therefore, the development of guidelines from published literature is not exhaustive. 2 References No references are considered essential for the use of the present document. Articles and reports on which the tech
43、nical work was based and from which the guidelines were produced are listed in annex C “Bibliography“. 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: asynchrony: when audio and video information that leaves one com
44、municating party at the same time is received by the other communicating party at different times (e.g. typically the audio information arrives before the video information in an asynchronous situation) NOTE: It is calculated as audio delay subtracted from video delay (e.g. if audio delay is 50 ms a
45、nd video delay is 200 ms, then asynchrony is 150 ms; if audio delay is 100 ms and video delay is 50 ms, then asynchrony is -50 ms). audio communication: use of a service that transmits voice in real-time over a telecommunication network, such as ordinary telephony with a handset and loudspeaking aud
46、io conferencing audio conferencing: telephone service that does not rely on amplification of the voice signal in very close proximity to the recipients ear EXAMPLE: Loudspeaking audio communication. audio delay: time required for an audio signal generated at the talkers mouth to reach the listeners
47、ear audio protocol: set of rules defining the way audio information is represented in a network audio telephony: “ordinary“ telephone service using a handset as distinct from loudspeaking audio conferencing avatar communication: use of a service that transmits voice signals in real-time over a telec
48、ommunication network in combination with a graphical (human) representation of the speaker avatar telephony: service for transmitting voice signals in real-time over a telecommunication network in combination with a graphical (human) representation of the speaker ETSI ETSI EG 202 534 V1.1.3 (2007-07
49、) 8 bandwidth: range of frequencies which can safely be conveyed in a communication channel burst packet loss: loss of two or more packets in sequence communication activity: what the end-users (want to) do with a communication service (e.g. social chatting, buying or selling shares, conducting a job interview, etc.) communication media: types of information with which humans communicate NOTE: Examples are text, audio and moving image (graphics and video). This is consistent with the “Nature of information“ component of the ETSI definition of a representation
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