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 (03/2017) SERIES P: TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Communications involving vehicles Speech communication requirements for
2、 emergency calls originating from vehicles Recommendation ITU-T P.1140 ITU-T P-SERIES RECOMMENDATIONS TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Vocabulary and effects of transmission parameters on customer opinion of transmission quality Series P.10 Voice terminal
3、characteristics Series P.30 P.300 Reference 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 Meth
4、ods for objective and subjective assessment of speech and video quality Series P.800 Audiovisual quality in multimedia services 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
5、 of streamed media Series P.1200 Telemeeting assessment Series P.1300 Statistical analysis, evaluation and reporting guidelines of quality measurements Series P.1400 Methods for objective and subjective assessment of quality of services other than speech and video Series P.1500 For further details,
6、please refer to the list of ITU-T Recommendations. Rec. ITU-T P.1140 (03/2017) i Recommendation ITU-T P.1140 Speech communication requirements for emergency calls originating from vehicles Summary Recommendation ITU-T P.1140 defines use cases, requirements and associated test methods for speech comm
7、unication for emergency call communications originating from vehicles using a dedicated emergency call system covering built-in emergency call systems (manufacturer installed) as well as after-market emergency call kits. This Recommendation contains an electronic attachment containing the set of fre
8、ely-available test signals referred to within the Recommendation. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T P.1140 2015-06-29 12 11.1002/1000/12519 2.0 ITU-T P.1140 2017-03-01 12 11.1002/1000/13177 Keywords Emergency call, hands-free, motor vehicle. _ * To access the R
9、ecommendation, 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/11.1002/1000/11830-en. ii Rec. ITU-T P.1140 (03/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nation
10、s specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on
11、 them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of I
12、TU-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 standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is u
13、sed for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with t
14、he 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 equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required o
15、f 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 Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Pr
16、operty 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 received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However,
17、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/ipr/. ITU 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior w
18、ritten permission of ITU. Rec. ITU-T P.1140 (03/2017) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 3 4 Abbreviations and acronyms 4 5 Conventions 5 6 Test set-up and preparation . 6 6.1 Test arrangement 6 6.2 Test arrangement in a car . 6 6.3 Positioning of the emergency cal
19、l IVS . 7 6.4 Operation modes of emergency call IVS 8 6.5 Artificial mouth 8 6.6 Artificial ear 9 6.7 Influence of the transmission system . 9 6.8 Calibration and equalization . 9 6.9 System simulator settings . 9 6.10 Environmental conditions . 9 7 Test signals and test signal levels . 10 7.1 Signa
20、ls 10 7.2 Background noise signals . 11 8 Measurement parameters and requirements for narrowband IVS terminals 13 8.1 Preparation measurements 13 8.2 Delay . 13 8.3 Loudness ratings . 15 8.4 Variation of RLR in the presence of background noise . 16 8.5 Sensitivity frequency responses . 17 8.6 Speech
21、 intelligibility during single talk 20 8.7 Idle channel noise . 20 8.8 Echo performance . 22 8.9 Switching characteristics 24 8.10 Double talk performance 25 8.11 Background noise transmission 30 9 Measurement parameters and requirements for wideband IVS terminals 31 9.1 Preparation measurements 31
22、9.2 Delay . 31 9.3 Loudness ratings . 33 9.4 Variation of RLR in the presence of background noise . 34 9.5 Sensitivity frequency responses . 35 9.6 Speech intelligibility during single talk 37 iv Rec. ITU-T P.1140 (03/2017) Page 9.7 Idle channel noise . 38 9.8 Echo performance without background noi
23、se 39 9.9 Switching characteristics 42 9.10 Double talk performance 43 9.11 Background noise transmission 49 Annex A Alternative method for determining the roundtrip delay . 50 Annex B Microphone related sound field reproduction technique Multi-point noise simulation (MPNS) method 51 B.1 Loudspeaker
24、 set-up in the car . 51 B.2 Microphone set-up in the car 51 B.3 Background noise recordings and reference noise . 52 B.4 Equalization 52 B.5 Accuracy of the equalization 52 Bibliography. 54 Electronic attachment: The set of freely-available test signals referred to within the Recommendation. Rec. IT
25、U-T P.1140 (03/2017) 1 Recommendation ITU-T P.1140 Speech communication requirements 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
26、vehicles using a dedicated emergency call system. This covers: built-in emergency 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
27、systems and covers the following use cases: The call is originated either automatically (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 listeni
28、ng from all locations in the vehicle cabin. The requirements take into account “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.
29、 The methods, the analysis and the performance parameters described in this Recommendation 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 covers speech communication requirements and tests for
30、emergency call systems in narrowband and wideband mode. 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 assumed that the performance of an in-
31、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 within the scope of this Recommend
32、ation. 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 and other references are subject to
33、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 valid ITU-T Recommendations is regularly published. The reference to a document within
34、this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. _ 1 This Recommendation contains an electronic attachment containing the set of freely-available test signals referred to within the Recommendation. 2 Rec. ITU-T P.1140 (03/2017) ITU-T G.100.1 Recommenda
35、tion 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), Influence of national systems on stabili
36、ty 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 Recommendation ITU-T P.57 (in force), Artifi
37、cial 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), Transmission characteristics and speech qua
38、lity 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. ITU-T P.581 Recommendation ITU-T
39、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 (in force), Narrow-band hands-free c
40、ommunication in motor vehicles. IEC 61260 IEC 61260:1995, Electroacoustics Octave-band and fractional-octave-band filters. Rec. ITU-T P.1140 (03/2017) 3 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 art
41、ificial 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 of an analogue-to-digital encoder a
42、nd 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 communications between people over a tel
43、ecommunication 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 pressure at the HATS reference poin
44、t (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: The transfer characteristics of t
45、he 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 free sound field, at least in 1.5 m d
46、istance 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 50 cm from the outer plane of the li
47、p 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; examples are headset, speakerphone and g
48、roup-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 and to reproduce the acoustic field g
49、enerated 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 should 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 refer
