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.1100 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2015) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Communications involving vehicles Narrow-band hands-free communication in motor vehicles R
2、ecommendation ITU-T P.1100 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 Reference systems Series P.40
3、 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 services Series P.900 Trans
4、mission 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 guidelines of quality measure
5、ments 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.1100 (01/2015) i Recommendation ITU-T P.1100 Narrow-band hands-free communication in
6、 motor vehicles Summary Recommendation ITU-T P.1100 describes performance requirements and test methods for narrow-band hands-free communication in vehicles. This Recommendation covers: build-in hands-free systems; after-market hands-free car kits; corded headsets; and wireless headsets; to be used
7、in vehicles for communication while driving. This Recommendation addresses the test of complete systems as well as the subsystems of hands-free microphone and telephone with short-range wireless transmission link used to interconnect the hands-free system to the mobile network. For testing, the test
8、 set-up and the recommended environmental conditions are described. The methods, the analysis and the performance parameters described in this Recommendation are based on test signals and test procedures as defined in Recommendations ITU-T P.501, ITU-T P.502, ITU-T P.340 and ITU-T P.380. History Edi
9、tion Recommendation Approval Study Group Unique ID* 1.0 ITU-T P.1100 2008-10-22 12 11.1002/1000/9545 2.0 ITU-T P.1100 2011-03-01 12 11.1002/1000/11078 3.0 ITU-T P.1100 2015-01-13 12 11.1002/1000/12415 Keywords Hands-free, headset, motor vehicle, quality of service, QoS. _ * To access the Recommendat
10、ion, 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.1100 (01/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations speciali
11、zed 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 them with
12、 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 ITU-T Recom
13、mendations 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 used for co
14、nciseness 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 the Recomme
15、ndation 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 of any part
16、y. 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 Property Rig
17、hts, 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, implemente
18、rs 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 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written per
19、mission of ITU. Rec. ITU-T P.1100 (01/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 3 4 Abbreviations and acronyms 4 5 Conventions 5 6 How to use this Recommendation 6 6.1 Determining compliance with this Recommendation 6 6.2 Testing at different stages of the developme
20、nt cycle . 6 7 Test arrangement 7 7.1 Test arrangement in a car . 8 8 Digital interfaces for development, debugging and test . 12 8.1 Interfaces and access points 12 8.2 Test set-up and tests 14 9 Test signals and test signal levels . 15 9.1 Signals 15 9.2 Background noise signals . 16 10 Measuremen
21、t parameters and requirements for microphones used in speakerphone hands-free systems 18 10.1 Microphone measurements in anechoic conditions 18 10.2 Microphone measurements in the car . 21 11 Measurement parameters and requirements for hands-free terminals 26 11.1 Preparation measurements 26 11.2 De
22、lay . 26 11.3 Loudness ratings . 28 11.4 Sensitivity frequency responses . 31 11.5 Speech quality during single talk . 34 11.6 Listening speech quality stability . 35 11.7 Idle channel noise . 36 11.8 Out-of-band signals 38 11.9 Distortion in send . 39 11.10 Distortion in receive . 40 11.11 Echo per
23、formance without background noise 40 11.12 Double talk performance 50 11.13 Background noise transmission 56 12 Verification of the transmission performance of short-range wireless (SRW) transmission enabled phones 60 12.1 Interface definition and calibration 60 12.2 SRW loudness ratings . 63 iv Rec
24、. ITU-T P.1100 (01/2015) Page 12.3 SRW sensitivity frequency responses 65 12.4 SRW noise cancellation test in send . 67 12.5 SRW speech quality during single talk 67 13 Car-to-car communication 70 14 Guidance on subjective testing . 71 15 Corded headsets 76 15.1 Connector type 76 15.2 Connector wiri
25、ng and electrical specifications . 76 15.3 Headset receive characteristics . 76 15.4 Headset transmit characteristics . 76 15.5 Standard behaviour in the presence of corded headsets . 76 16 Wireless headsets 76 16.1 Wireless headset types 76 16.2 Test methodology for verification of standard behavio
26、ur 76 16.3 Standard behaviour in the presence of wireless headsets . 76 Annex A Speech quality measurements 77 Annex B Principles of relative approach 78 Annex C Example of a questionnaire for subjective testing . 80 C.1 Performance rating overview 80 C.2 Test categories and rating types . 80 C.3 Sp
27、eech and background noise quality in send direction . 82 C.4 Speech quality in receive direction (in the car under test) . 88 C.5 Echo cancellation performance 90 C.6 Hands-free system stability tests (car-to-car) . 97 Annex D Standard set of user scenarios 98 Annex E System stability with insuffici
28、ent far end echo loss . 101 Appendix I A method to determine the listening speech quality 103 I.1 One-way speech quality in send . 103 I.2 One-way speech quality in receive . 103 Bibliography. 104 Rec. ITU-T P.1100 (01/2015) 1 Recommendation ITU-T P.1100 Narrow-band hands-free communication in motor
29、 vehicles 1 Scope The aim of this Recommendation is to define use cases and test methods for narrow-band hands-free communication in vehicles. This Recommendation covers: built-in hands-free systems; after-market hands-free car kits; corded headsets; and wireless headsets; to be used in vehicles for
30、 communication while driving. This Recommendation addresses the test of complete systems as well as the subsystems of hands-free microphone and telephone with short-range wireless transmission link used to interconnect the hands-free system to the mobile network. For testing, the test set-up and the
31、 recommended environmental conditions are described. The methods, the analysis and the performance parameters described in this Recommendation are based 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.380. Although important, subjective testing is
32、outside the scope of this Recommendation, some guidance on how to conduct subjective tests can be found in clause 14. 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 t
33、ime of publication, the editions indicated were valid. All Recommendations and 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.
34、A list of the currently 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 Recommendation. ITU-T G.100.1 Recommendation ITU-T G.100.1 (2001), The use of the decibel and of relative le
35、vels 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 stability and talker echo in international connections. ITU-T G.711 Recomme
36、ndation ITU-T G.711 (in force), Pulse code modulation (PCM) of voice frequencies. ITU-T P.48 Recommendation ITU-T P.48 (in force), Specification for an intermediate reference system. 2 Rec. ITU-T P.1100 (01/2015) ITU-T P.56 Recommendation ITU-T P.56 (in force), Objective measurement of active speech
37、 level. ITU-T P.57 Recommendation 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.64 Recommendation ITU-T P.64 (in force), Determination of sensitivity/frequency characteristics of local telephone systems.
38、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 quality parameters of hands-free terminals. ITU-T P.380 Recommendation ITU-T P.380 (in force), Electro-acous
39、tic measurements on headsets. 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 P.581 (2000
40、), Use of head and torso simulator (HATS) for hands-free terminal testing. ITU-T P.800 Recommendation ITU-T P.800 (in force), Methods for subjective determination of transmission quality. ITU-T P.800.1 Recommendation ITU-T P.800.1 (in force), Mean Opinion Score (MOS) terminology. ITU-T P.863 Recomme
41、ndation ITU-T P.863 (in force), Perceptual objective listening quality assessment ITU-T P.863.1 Recommendation ITU-T P.863.1 (in force), Application guide for recommendation ITU-T P.863.1 . IEC 60268-4 IEC 60268-4 (2014), Sound system equipment Part 4: Microphones. IEC 61260 IEC 61260 (1995) Electro
42、acoustics - Octave-band and fractional-octave-band filters. Rec. ITU-T P.1100 (01/2015) 3 3 Definitions This Recommendation defines the following terms: 3.1 artificial ear: Device incorporating an acoustic coupler and a calibrated microphone for the measurement of the sound pressure and having an ov
43、erall acoustic impedance similar to that of the median adult human ear over a given frequency band. 3.2 codec: Combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions of transmission in the same equipment. 3.3 composite source signal (CSS): Si
44、gnal composed in time by various signal elements. 3.4 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 a
45、t the HATS Reference Point (HRP) in a diffuse sound field with the HATS absent using the reverse nominal curve given in Table 3 of ITU-T P.58. 3.5 ear-drum reference point (DRP): Point located at the end of the ear canal, corresponding to the ear-drum position. 3.6 free-field equalization: The trans
46、fer 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. 3.7 free-field reference point: Point located in the free sound fiel
47、d, 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). 3.8 hands-free reference point (HFRP): A point located on the axis of the artificial mouth, at 50 cm from the o
48、uter 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. 3.9 hands-free terminal: Telephone set that does not require the use of hands during the communications session; examples are headset, s
49、peakerphone and group-audio terminal. 3.10 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 generated by the human mouth. 3.11 headset hands-free terminal: Device which includes a telephone receiver and transmitter which is typical
