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.1110 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2017) SERIES P: TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Communications involving vehicles Wideband hands-free communication in
2、motor vehicles Recommendation ITU-T P.1110 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 characteristics Series P.30
3、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 Methods for objective and subjec
4、tive 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 of streamed media Series P.
5、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, please refer to the list of
6、ITU-T Recommendations. Rec. ITU-T P.1110 (03/2017) i Recommendation ITU-T P.1110 Wideband hands-free communication in motor vehicles Summary Recommendation ITU-T P.1110 describes performance requirements and test methods for wideband hands-free communication in motor vehicles. This Recommendation co
7、vers: built-in hands-free systems, aftermarket hands-free car kits, corded headsets, and wireless headsets to be used in motor vehicles for communication. This Recommendation addresses the test of complete systems as well as the subsystems hands-free microphone and the telephone with short-range wir
8、eless transmission link used to transmit the speech signals from the hands-free system to the mobile network. For testing purposes, the test set-up and the recommended environmental conditions are described. The methods, the analysis and the performance parameters described in this Recommendation ar
9、e 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 Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T P.1110 2009-12-14 12 11.1002/1000/10659 2.0 ITU-T P.1110 2015-01-13 12 11.1002/1000/12416 3.0 IT
10、U-T P.1110 2017-03-01 12 11.1002/1000/13175 Keywords Hands-free, headset, motor vehicles, quality of service, QoS, wideband. _ * 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:/ha
11、ndle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T P.1110 (03/2017) 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
12、 (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 a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every f
13、our 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 Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, t
14、he necessary standards 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.
15、 However, the Recommendation 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 neg
16、ative equivalents 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 u
17、se of a claimed 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 Recommendatio
18、n, ITU had not received 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:/w
19、ww.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 written permission of ITU. Rec. ITU-T P.1110 (03/2017) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2
20、3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 4 5 Conventions 6 6 How to use this Recommendation 6 6.1 Determining compliance with this Recommendation 6 6.2 Testing at different stages of the development cycle . 7 7 Test arrangement 7 7.1 Test arrangement in a car . 9 8 D
21、igital interfaces for development, debugging and test . 13 8.1 Interfaces and access points 13 8.2 Test set-up and tests 15 9 Test signals and test signal levels . 16 9.1 Signals 16 9.2 Background noise signals . 17 10 Measurement parameters and requirements for microphones used in speakerphone hand
22、s-free systems 19 10.1 Microphone measurements in anechoic conditions 19 10.2 Microphone measurements in the car . 22 11 Measurement parameters and requirements for hands-free terminals 27 11.1 Preparation measurements 27 11.2 Delay . 27 11.3 Loudness ratings . 29 11.4 Sensitivity frequency response
23、s . 32 11.5 Speech quality during single talk . 36 11.6 Listening speech quality stability . 37 11.7 Idle channel noise . 38 11.8 Out-of-band signals 40 11.9 Distortion in send . 42 11.10 Distortion in receive . 42 11.11 Echo performance . 43 11.12 Double talk performance 52 11.13 Background noise t
24、ransmission 59 12 Verification of the transmission performance of short-range wireless transmission enabled phones 63 iv Rec. ITU-T P.1110 (03/2017) Page 12.1 Interface definition and calibration 63 12.2 SRW loudness ratings . 67 12.3 SRW sensitivity frequency responses 69 12.4 SRW noise cancellatio
25、n test in send direction . 70 12.5 SRW speech quality during single talk 71 13 Car-to-car communication 74 14 Guidance on subjective testing . 74 15 Corded headsets 79 15.1 Connector type 79 15.2 Connector wiring and electrical specifications . 79 15.3 Headset receive characteristics . 79 15.4 Heads
26、et transmit characteristics . 79 15.5 Standard behaviour in the presence of corded headsets . 79 16 Wireless headsets 79 16.1 Wireless headset types 79 16.2 Test methodology for verification of standard behaviour 79 16.3 Standard behaviour in the presence of wireless headsets . 79 Annex A Speech qua
27、lity measurements 81 Annex B Principles of Relative Approach 82 Annex C Example for a questionnaire for subjective testing 84 C Performance rating 84 C.1 Overview 84 C.2 Test categories and rating types . 84 C.3 Speech and background noise quality in send direction . 86 C.4 Speech quality in receive
28、 direction (in the car under test) . 92 C.5 Echo cancellation performance 94 C.6 Hands-free system stability tests (car-to-car) . 101 Annex D Standard set of user scenarios 102 Annex E System stability with insufficient far-end echo loss 104 Annex F Microphone related sound field reproduction techni
29、que Multi-point noise simulation method (MPNS) 106 F.1 Loudspeaker setup in the car 106 F.2 Microphone setup in the car . 106 F.3 Background noise recordings and reference noise . 107 F.4 Equalization 107 F.5 Accuracy of the equalization 108 Appendix I A method to determine the listening speech qual
30、ity 109 I.1 One-way speech quality in sending 109 I.2 One-way speech quality in receiving . 109 Bibliography. 110 Rec. ITU-T P.1110 (03/2017) 1 Recommendation ITU-T P.1110 Wideband hands-free communication in motor vehicles 1 Scope The aim of this Recommendation is the definition of user scenarios,
31、test methods and requirements for wideband hands-free communication in motor vehicles. This Recommendation covers: built-in hands-free systems, aftermarket hands-free car kits, corded headsets, and wireless headsets to be used in motor vehicles for communication. Furthermore, the compatibility betwe
32、en narrowband and wideband implementations is addressed. This Recommendation addresses the test of complete systems as well as the subsystems hands-free microphone, and the telephone with short-range wireless transmission link used to transmit the speech signals from the hands-free system to the mob
33、ile network. For testing purposes, the test 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 ITU-T P.501, ITU-T P.502, ITU-T P.340,
34、 ITU-T P.380, b-ETSI ES 202 739, and b-ETSI ES 202 740. Although important subjective testing is outside the scope of this Recommendation, 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 w
35、hich, 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 revision; users of this Recommendation are therefore encouraged to investigate the possibility of
36、 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 this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
37、ITU-T G.122 Recommendation ITU-T G.122 (1993), Influence of national systems on stability and talker echo in international connections. ITU-T O.41 Recommendation ITU-T O.41 (1994), Psophometer for use on telephone-type circuits. ITU-T P.56 Recommendation ITU-T P.56 (1993), Objective measurement of a
38、ctive speech level. ITU-T P.57 Recommendation ITU-T P.57 (2009), Artificial ears. ITU-T P.58 Recommendation ITU-T P.58 (1996), Head and torso simulator for telephonometry. ITU-T P.79 Recommendation ITU-T P.79 (2007), Calculation of loudness ratings for telephone sets. 2 Rec. ITU-T P.1110 (03/2017) I
39、TU-T P.340 Recommendation ITU-T P.340 (2000), Transmission characteristics and speech quality parameters of hands-free terminals. ITU-T P.380 Recommendation ITU-T P.380 (2003), Electro-acoustic measurements on headsets. ITU-T P.501 Recommendation ITU-T P.501 (2009), Test signals for use in telephono
40、metry. ITU-T P.502 Recommendation ITU-T P.502 (2000), Objective test methods for speech communication systems using complex test signals. ITU-T P.581 Recommendation ITU-T P.581 (2000), Use of head and torso simulator (HATS) for hands-free terminal testing. ITU-T P.800 Recommendation ITU-T P.800 (199
41、6), Methods for subjective determination of transmission quality. ITU-T P.800.1 Recommendation ITU-T P.800.1 (2006), Mean Opinion Score (MOS) terminology. ITU-T P.830 Recommendation ITU-T P.830 (1996), Subjective performance assessment of telephone-band and wideband digital codecs. ITU-T P.831 Recom
42、mendation ITU-T P.831 (1998), Subjective performance evaluation of network echo cancellers. ITU-T P.835 Recommendation ITU-T P.835 (2003), Subjective test methodology for evaluating speech communication systems that include noise suppression algorithm. ITU-T P.840 Recommendation ITU-T P.840 (2003),
43、Subjective listening test method for evaluating circuit multiplication equipment. ITU-T P.863 Recommendation ITU-T P.863 (2011), Perceptual objective listening quality assessment. ITU-T P.863.1 Recommendation ITU-T P.863.1 (2013), Application guide for Recommendation ITU-T P.863. IEC 61260 IEC 61260
44、 (1995), Electroacoustics Octave-band and fractional-octave-band filters. ISO 1999 ISO 1999:1990, Acoustics Determination of occupational noise exposure and estimation of noise-induced hearing impairment. ISO 3745 ISO 3745:2003, Acoustics Determination of sound power levels of noise sources using so
45、und pressure Precision methods for anechoic and hemi-anechoic rooms. 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 artificial ear: Device incorporating an acoustic coupler and a calibrated microphone fo
46、r 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. Rec. ITU-T P.1110 (03/2017) 3 3.2.2 codec: Combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite
47、 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 diffuse-field equalization: Equalization of the head and torso simulator (HATS) sound pick-up, equalization of the difference, in dB, between the spectrum
48、 level of the acoustic pressure at the ear-drum reference point (DRP) and the spectrum level of the acoustic 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 of ITU-T P.58. 3.2.5 ear-drum reference point (DRP):
49、A point located at the end of the ear canal, corresponding to the ear-drum position. 3.2.6 free-field equalization: The transfer characteristic of the artificial head is 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. 3.2.7 free-field reference point: A point located in the free sound field, at
