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 (01/2015) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Communications involving vehicles Wideband hands-free communication in motor vehicles Reco
2、mmendation ITU-T P.1110 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 Ob
3、jective 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 Transmis
4、sion 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 measuremen
5、ts 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.1110 (01/2015) i Recommendation ITU-T P.1110 Wideband hands-free communication in motor
6、 vehicles Summary Recommendation ITU-T P.1110 describes performance requirements and test methods 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 mo
7、tor 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 wireless transmission link used to transmit the speech signals from the hands-free system to the mobile network. For testing p
8、urposes, 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 Recommendations ITU-T P.501, ITU-T P.502, ITU-T P.340, and ITU-T
9、 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 Keywords Hands-free, headset, motor vehicles, quality of service (QoS), wideband. _ * To access the Recommendation, type the URL
10、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.1110 (01/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the
11、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 a view to standar
12、dizing 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 Recommendations is cove
13、red 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 conciseness to indic
14、ate 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 Recommendation is achieve
15、d 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 party. INTELLECTUAL PR
16、OPERTY 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 Rights, whether asser
17、ted 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, implementers are cautioned t
18、hat 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 permission of ITU. Re
19、c. ITU-T P.1110 (01/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 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 Recommen
20、dation 6 6.2 Testing at different stages of the development cycle . 6 7 Test arrangement 7 7.1 Test arrangement in a car . 9 8 Digital 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 10 Me
21、asurement 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 . 22 11 Measurement parameters and requirements for hands-free terminals 26 11.1 Preparation measurements 26
22、 11.2 Delay . 26 11.3 Loudness ratings . 28 11.4 Sensitivity frequency responses . 31 11.5 Speech quality during single talk . 35 11.6 Listening speech quality stability . 36 11.7 Idle channel noise . 37 11.8 Out-of-band signals 39 11.9 Distortion in send direction 40 11.10 Distortion in receive dir
23、ection 41 11.11 Echo performance without background noise 42 11.12 Double talk performance 51 11.13 Background noise transmission 59 12 Verification of the transmission performance of short-range wireless transmission enabled phones 62 12.1 Interface definition and calibration 63 12.2 SRW loudness r
24、atings . 66 iv Rec. ITU-T P.1110 (01/2015) Page 12.3 SRW sensitivity frequency responses 68 12.4 SRW noise cancellation test in send direction . 69 12.5 SRW speech quality during single talk 70 13 Car-to-car communication 73 14 Guidance on subjective testing . 73 15 Corded headsets 77 15.1 Connector
25、 type 77 15.2 Connector wiring and electrical specifications . 78 15.3 Headset receive characteristics . 78 15.4 Headset transmit characteristics . 78 15.5 Standard behaviour in the presence of corded headsets . 78 16 Wireless headsets 78 16.1 Wireless headset types 78 16.2 Test methodology for veri
26、fication of standard behaviour 78 16.3 Standard behaviour in the presence of wireless headsets . 78 Annex A Speech quality measurements 79 Annex B Principles of Relative Approach 80 Annex C Example for a questionnaire for subjective testing 82 C Performance rating 82 C.1 Overview 82 C.2 Test categor
27、ies and rating types . 82 C.3 Speech and background noise quality in send direction . 85 C.4 Speech quality in receive direction (in the car under test) . 90 C.5 Echo cancellation performance 92 C.6 Hands-free system stability tests (car-to-car) . 99 Annex D Standard set of user scenarios 100 Annex
28、E System stability with insufficient far-end echo loss 102 Appendix I A method to determine the listening speech quality 104 I.1 One-way speech quality in sending 104 I.2 One-way speech quality in receiving . 104 Bibliography. 105 Rec. ITU-T P.1110 (01/2015) 1 Recommendation ITU-T P.1110 Wideband ha
29、nds-free communication in motor vehicles 1 Scope The aim of this Recommendation is the definition of user scenarios, 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
30、 headsets, and wireless headsets to be used in motor vehicles for communication. Furthermore, the compatibility between 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
31、with short-range wireless 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 th
32、is Recommendation are based on test signals and test procedures, as defined in ITU-T P.501, ITU-T P.502, ITU-T P.340, 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
33、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 time of publication, the editions indicated were valid. All Recommendations and other refere
34、nces 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 valid ITU-T Recommendations is regularly published. The reference t
35、o a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 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), Ps
36、ophometer for use on telephone-type circuits. ITU-T P.56 Recommendation ITU-T P.56 (1993), Objective measurement of active 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
37、Recommendation ITU-T P.79 (2007), Calculation of loudness ratings for telephone sets. 2 Rec. ITU-T P.1110 (01/2015) ITU-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), Electr
38、o-acoustic measurements on headsets. ITU-T P.501 Recommendation ITU-T P.501 (2009), Test signals for use in telephonometry. 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)
39、, Use of head and torso simulator (HATS) for hands-free terminal testing. ITU-T P.800 Recommendation ITU-T P.800 (1996), 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 I
40、TU-T P.830 (1996), Subjective performance assessment of telephone-band and wideband digital codecs. ITU-T P.831 Recommendation 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 s
41、peech communication systems that include noise suppression algorithm. ITU-T P.840 Recommendation ITU-T P.840 (2003), 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
42、-T P.863.1 Recommendation ITU-T P.863.1 (2013), Application guide for Recommendation ITU-T P.863. IEC 61260 IEC 61260 (1995), Electroacoustics Octave-band and fractional-octave-band filters. ISO 1999 ISO 1999:1990, Acoustics Determination of occupational noise exposure and estimation of noise-induce
43、d hearing impairment. ISO 3745 ISO 3745:2003, Acoustics Determination of sound power levels of noise sources using sound 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 defin
44、es 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. Rec. ITU-T P.1110 (01/2015)
45、 3 3.2.2 codec: Combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions of transmission in the same equipment. 3.2.3 composite source signal (CSS): Signal composed in time by various signal elements. 3.2.4 diffuse-field equalization: Equalizat
46、ion of the head and torso simulator (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 point (HRP) in a diffuse sound field with t
47、he HATS absent using the reverse nominal curve given in Table 3 of ITU-T P.58. 3.2.5 ear-drum reference point (DRP): 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
48、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 least at 1.5 m distance from a sound source radiati
49、ng in free air (in case of a head and torso simulator (HATS), in the centre of the artificial head with no artificial head present). 3.2.8 hands-free reference point (HFRP): A point located on the axis of the artificial mouth, at 50 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 b-ITU-T P.51. 3.2.9 hands-free termin
