1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T P.1140 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2015) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Communications involving vehicles Speech communication requirements for emergency calls or
2、iginating from vehicles Recommendation ITU-T P.1140 ITU-T P-SERIES RECOMMENDATIONS TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Vocabulary and effects of transmission parameters on customer opinion of transmission quality Series P.10 Voice terminal characteristics Series P.30 P.300 Refe
3、rence systems Series P.40 Objective measuring apparatus Series P.50 P.500 Objective electro-acoustical measurements Series P.60 Measurements related to speech loudness Series P.70 Methods for objective and subjective assessment of speech quality Series P.80 P.800 Audiovisual quality in multimedia se
4、rvices Series P.900 Transmission performance and QoS aspects of IP end-points Series P.1000 Communications involving vehicles Series P.1100 Models and tools for quality assessment of streamed media Series P.1200 Telemeeting assessment Series P.1300 Statistical analysis, evaluation and reporting guid
5、elines of quality measurements Series P.1400 Methods for objective and subjective assessment of quality of services other than voice services Series P.1500 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T P.1140 (06/2015) i Recommendation ITU-T P.1140 Speech communi
6、cation requirements for emergency calls originating from vehicles Summary Recommendation ITU-T P.1140 defines use cases, requirements and associated test methods for speech communication for emergency call communications originating from vehicles using a dedicated emergency call system covering buil
7、t-in emergency call systems (manufacturer installed) as well as after-market emergency call kits. This Recommendation contains an electronic attachment containing the set of freely-available test signals referred to within the Recommendation. History Edition Recommendation Approval Study Group Uniqu
8、e ID* 1.0 ITU-T P.1140 2015-06-29 12 11.1002/1000/12519 Keywords Hands-free, motor vehicle, emergency call. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1
9、002/1000/ 11830-en. ii Rec. ITU-T P.1140 (06/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a pe
10、rmanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, estab
11、lishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary sta
12、ndards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Re
13、commendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalent
14、s are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed
15、Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not r
16、eceived notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T
17、/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T P.1140 (06/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 3 4 Abbreviations and acronyms 4 5 Conventions 5
18、 6 Test Setup and Preparation . 5 6.1 Test arrangement 5 6.2 Test arrangement in a car . 6 6.3 Positioning of the emergency call IVS . 7 6.4 Operation Modes of emergency call IVS . 8 6.5 Artificial mouth 8 6.6 Artificial ear 8 6.7 Influence of the transmission system . 9 6.8 Calibration and equaliza
19、tion . 9 6.9 System simulator settings . 9 6.10 Environmental conditions . 9 7 Test signals and test signal levels . 10 7.1 Signals 10 7.2 Background noise signals . 11 8 Measurement parameters and requirements for IVS terminals 12 8.1 Preparation measurements 12 8.2 Delay . 12 8.3 Loudness ratings
20、. 14 8.4 Variation of RLR in presence of background noise . 15 8.5 Sensitivity frequency responses . 16 8.6 Speech intelligibility during single talk 19 8.7 Idle channel noise . 19 8.8 Echo performance without background noise 21 8.9 Switching characteristics 23 8.10 Double talk performance 24 8.11
21、Background noise transmission 29 Annex A Alternative method for determining the roundtrip delay . 31 Bibliography. 32 Electronic attachment: Set of freely-available test signals referred to within the Recommendation.Rec. ITU-T P.1140 (06/2015) 1 Recommendation ITU-T P.1140 Speech communication requi
22、rements for emergency calls originating from vehicles 1 Scope This Recommendation1 defines use cases, requirements and associated test methods for the speech communication for emergency call communications originating from vehicles using a dedicated emergency call system. This covers: built-in emerg
23、ency call systems (manufacturer installed) after-market emergency call kits. For test purposes, the test set-up and the recommended environmental conditions are described. This Recommendation addresses the test of complete systems and covers the following use cases: The call is originated either aut
24、omatically (or possibly manually) in the accident, in hands-free mode. The call is between the vehicle from where the emergency call is originated and the nearest PSAP. The requirements take into account talking and listening from all locations in the vehicle cabin. The requirements take into accoun
25、t “silent calls“, where information is obtained from background noise picked up by the emergency call system. The requirements focus primarily on achieving a sufficient level of intelligibility and communication efficiency. The methods, the analysis and the performance parameters described in this R
26、ecommendation are based, where applicable on test signals and test procedures as defined in ITU-T P.501, ITU-T P.502, ITU-T P.340 and ITU-T P.1100. This Recommendation in principle covers speech communication requirements and tests for emergency call systems in narrowband and wideband mode. However,
27、 this version of the Recommendation covers narrowband only, wideband is for further study. This Recommendation addresses the crash situation by simulating a post-crash situation as realistically as possible with respect to the impact of a post-crash situation on the acoustical environment. It is ass
28、umed that the performance of an in-vehicle system (IVS) after a crash is adequately covered by simulating a post-crash situation in an un-crashed car, provided that the system is still functional and the acoustical elements remain at their original locations. Specific tests after a car crash are not
29、 within the scope of this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations a
30、nd other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently _ 1 This Recommendation contains an electronic attac
31、hment containing the set of freely-available test signals referred to within the Recommendation. 2 Rec. ITU-T P.1140 (06/2015) valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recom
32、mendation. ITU-T G.100.1 Recommendation ITU-T G.100.1 (2015), The use of the decibel and of relative levels in speechband telecommunications. ITU-T G.111 Recommendation ITU-T G.111 (1993), Loudness ratings (LRs) in an international connection. ITU-T G.122 Recommendation ITU-T G.122 (in force), Influ
33、ence of national systems on stability and talker echo in international connections. ITU-T G.711 Recommendation ITU-T G.711 (in force), Pulse code modulation (PCM) of voice frequencies. ITU-T P.56 Recommendation ITU-T P.56 (in force), Objective measurement of active speech level. ITU-T P.57 Recommend
34、ation ITU-T P.57 (in force), Artificial ears. ITU-T P.58 Recommendation ITU-T P.58 (in force), Head and torso simulator for telephonometry. ITU-T P.79 Recommendation ITU-T P.79 (in force), Calculation of loudness ratings for telephone sets. ITU-T P.340 Recommendation ITU-T P.340 (in force), Transmis
35、sion characteristics and speech quality parameters of hands-free terminals. ITU-T P.501 Recommendation ITU-T P.501 (in force), Test signals for use in telephonometry. ITU-T P.502 Recommendation ITU-T P.502 (in force), Objective test methods for speech communication systems using complex test signals
36、. ITU-T P.581 Recommendation ITU-T P.581 (2014), Use of head and torso simulator for hands-free and handset terminal testing. ITU-T P.830 Recommendation ITU-T P.830 (in force), Subjective performance assessment of telephone-band and wideband digital codecs. ITU-T P.1100 Recommendation ITU-T P.1100 (
37、in force), Narrow-band hands-free communication in motor vehicles. IEC 61260 IEC 61260:1995, Electroacoustics Octave-band and fractional-octave-band filters. Rec. ITU-T P.1140 (06/2015) 3 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation def
38、ines the following terms: 3.2.1 artificial ear: Device incorporating an acoustic coupler and a calibrated microphone for the measurement of the sound pressure and having an overall acoustic impedance similar to that of the median adult human ear over a given frequency band. 3.2.2 codec: Combination
39、of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions of transmission in the same equipment. 3.2.3 composite source signal (CSS): Signal composed in time by various signal elements. 3.2.4 communication efficiency: Speed and accuracy of interactive commu
40、nications between people over a telecommunication system. 3.2.5 diffuse-field equalization: Equalization of the HATS sound pick-up, equalization of the difference, in dB, between the spectrum level of the acoustic pressure at the ear drum reference point (DRP) and the spectrum level of the acoustic
41、pressure at the HATS reference point (HRP) in a diffuse sound field with the HATS absent using the reverse nominal curve given in Table 3 ITU-T P.58. 3.2.6 ear-drum reference point (DRP): Point located at the end of the ear canal, corresponding to the ear-drum position. 3.2.7 free-field equalization
42、: The transfer characteristics of the artificial head are equalized in such a way that, for frontal sound incidence in anechoic conditions, the frequency response of the artificial head is flat. This equalization is specific to the HATS used. 3.2.8 free-field reference point: Point located in the fr
43、ee sound field, at least in 1.5 m distance from a sound source radiating in free air (in case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head present). 3.2.9 hands-free reference point (HFRP): A point located on the axis of the artificial mouth, at 5
44、0 cm from the outer plane of the lip ring, where the level calibration is made, under free-field conditions. It corresponds to the measurement point 11, as defined in ITU-T P.51. 3.2.10 hands-free terminal: Telephone set that does not require the use of hands during the communications session; examp
45、les are headset, speakerphone and group-audio terminal. 3.2.11 head and torso simulator (HATS) for telephonometry: Manikin extending downward from the top of the head to the waist, designed to simulate the sound pick-up characteristics and the acoustic diffraction produced by a median human adult an
46、d to reproduce the acoustic field generated by the human mouth. 3.2.12 inboard ear: Ear closest to the centreline of the vehicle. 3.2.13 maximum setting of the volume control: When a receive volume control is provided, the maximum setting of the volume control is chosen. NOTE The maximum volume shou
47、ld be carefully chosen in order to provide sufficient loudness for typical driving conditions but not to overload the audio system and introduce non-linearities in the echo path. 3.2.16 mouth reference point (MRP): The month reference point is located on the axis and 25 mm in front of the lip plane
48、of a mouth simulator. 3.2.17 nominal setting of the volume control: When a receive volume control is provided, the setting which is closest to the nominal receive loudness rating of 2 dB. 4 Rec. ITU-T P.1140 (06/2015) 3.2.18 receive loudness rating (RLR): The loudness loss between an electric interf
49、ace in the network and the listening subscribers ear (the loudness loss is here defined as the weighted (dB) average of driving electromotive force to measured sound pressure). 3.2.19 send loudness rating (SLR): The loudness loss between the speaking subscribers mouth and an electrical interface in the network (the loudness loss is here defined as the weighted (dB) average of driving sound pressure to measured voltage). 3.2.20 wideband speech: Voice service with enhanced
