1、 ETSI TS 103 224 V1.3.1 (2017-07) Speech and multimedia Transmission Quality (STQ); A sound field reproduction method for terminal testing including a background noise database TECHNICAL SPECIFICATION ETSI ETSI TS 103 224 V1.3.1 (2017-07)2 Reference RTS/STQ-250 Keywords noise, quality, speech, termi
2、nal ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from
3、: http:/www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any existing or perce
4、ived difference in contents between such versions and/or in print, the only prevailing document is the print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revis
5、ion or change of status. Information on the current status of this and other ETSI documents is available at https:/portal.etsi.org/TB/ETSIDeliverableStatus.aspx If you find errors in the present document, please send your comment to one of the following services: https:/portal.etsi.org/People/Commit
6、eeSupportStaff.aspx Copyright Notification No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm except as authorized by written permission of ETSI. The content of the PDF version shall not be modified without the written au
7、thorization of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. ETSI 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are trademarks of ETSI registered for the benefit of its Members. 3GPPTM and LTE are trademarks of ETSI registered for th
8、e benefit of its Members and of the 3GPP Organizational Partners. oneM2M logo is protected for the benefit of its Members. GSM and the GSM logo are trademarks registered and owned by the GSM Association. ETSI ETSI TS 103 224 V1.3.1 (2017-07)3 Contents Intellectual Property Rights 5g3Foreword . 5g3Mo
9、dal verbs terminology 5g3Introduction 6g31 Scope 7g32 References 7g32.1 Normative references . 7g32.2 Informative references 7g33 Symbols and abbreviations . 8g33.1 Symbols 8g33.2 Abbreviations . 8g34 Methods for realistic sound reproduction . 9g35 Recording arrangement 9g35.0 General . 9g35.1 Micro
10、phone array setup 9g35.1.1 Principle limitations 9g35.1.2 Microphone calibration . 10g35.2 Microphone array setup for handset-type and headset terminals 10g35.3 Microphone array setup for hands-free terminals . 11g36 Loudspeaker setup for background noise simulation . 12g36.0 General setup 12g36.1 T
11、est room requirements 13g36.2 Equalization and calibration . 14g36.2.0 Overview of the equalization procedure . 14g36.2.1 Separate level adjustment for each loudspeaker . 14g36.2.2 System identification 14g36.2.3 Pre-processing of the impulse responses 15g36.2.4 Calculation of the inversion filters
12、16g36.2.4.0 Overview . 16g36.2.4.1 Inversion procedure . 17g36.2.4.2 Different microphones for different frequency bands . 18g36.2.4.3 Search for the optimum regularization factor 19g36.2.4.3.0 Introduction . 19g36.2.4.3.1 Basic methodology to find the optimum regularization factor 19g36.2.4.3.2 Ext
13、ended methodology to find the optimum regularization factor for frequencies above 2 kHz 21g36.2.5 First test of equalization and filter adjustment for inversion error compensation . 23g36.2.6 Accuracy of the equalization 24g36.3 Accuracy of the reproduction arrangement 24g36.3.0 Introduction. 24g36.
14、3.1 Comparison between original sound field and simulated sound field . 24g36.3.2 Impact of handset positioner and phone on the simulated sound field . 26g36.3.3 Comparison of terminal performance in the original sound field and the simulated sound field . 27g36.3.3.1 Introduction . 27g36.3.3.2 Back
15、ground noise transmission . 28g36.3.3.2.0 Validation Procedure . 28g36.3.3.2.1 Handset 28g36.3.3.2.2 Handheld Hands-free . 32g36.3.3.2.3 Desktop Hands-Free 33g36.3.3.3 S-/N-/G-MOS Analysis according to ETSI TS 103 106 . 33g36.3.3.3.1 Handset 33g36.3.3.3.2 Hands-free . 35g37 Generalization of the met
16、hod for a more flexible loudspeaker and microphone arrangement. 36g3ETSI ETSI TS 103 224 V1.3.1 (2017-07)4 7.0 Introduction 36g37.1 Loudspeaker configuration . 36g37.2 Microphone setup . 36g37.3 Background noise recordings and reference noise . 36g37.4 Equalization and calibration . 37g37.5 Accuracy
17、 of the equalization 38g37.6 Example use case: equalization inside a vehicle 38g37.6.0 Introduction. 38g37.6.1 Loudspeaker configuration . 38g37.6.2 Microphone setup . 38g37.6.3 Equalization 38g38 Background noise database 39g38.0 Introduction 39g38.1 Reference noise recording 39g38.2 Background noi
18、se signals for terminal testing 40g3History 43g3ETSI ETSI TS 103 224 V1.3.1 (2017-07)5 Intellectual Property Rights Essential patents IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicl
19、y available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI We
20、b server (https:/ipr.etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may
21、 become, essential to the present document. Trademarks The present document may include trademarks and/or tradenames which are asserted and/or registered by their owners. ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no right to use o
22、r reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Specification (TS) has been produced by ETSI Technical Committee
23、 Speech and multimedia Transmission Quality (STQ). The present document describes a sound field recording and reproduction technique which can be applied for all types of terminals but is especially suitable for modern multi-microphone terminals including array techniques. The present document provi
24、des an additional simulation technique which can be used instead of the part 1 of ETSI multi-part deliverable ES/EG 202 396 “Speech quality performance in the presence of background noise“, as identified below: ETSI ES 202 396-1: “Background noise simulation technique and background noise database“
25、i.7; ETSI EG 202 396-2: “Background noise transmission - Network simulation - Subjective test database and results“ i.8; ETSI EG 202 396-3: “Background noise transmission - Objective test methods“ i.9. The background noise simulation can be used in conjunction with the objective test methods as desc
26、ribed in ETSI EG 202 396-3 i.9 and ETSI TS 103 106 i.10. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms f
27、or the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 103 224 V1.3.1 (2017-07)6 Introduction Background noise is present in most of the conversations today. Background noise may impact the speech communication p
28、erformance of terminal and network equipment significantly. Therefore testing and optimization of such equipment is necessary using realistic background noises. Furthermore reproducible conditions for the tests are required which can be guaranteed only under lab type conditions. Since modern termina
29、ls incorporate more advanced noise cancellation techniques, such as multi-microphone based noise cancellation, the use of microphone-array recording techniques and more realistic noise field simulations (compared to the method described in ETSI ES 202 396-1 i.7) are required. The present document ad
30、dresses this topic by specifying a methodology for recording and playback of realistic background noise fields under conditions that are well-defined and able to be calibrated in a lab type environment. Furthermore a database with real background noises is included. ETSI ETSI TS 103 224 V1.3.1 (2017
31、-07)7 1 Scope The quality of background noise transmission is an important factor, which significantly contributes to the perceived overall quality of speech. Terminals, networks, and system configurations including wideband, superwideband, and fullband speech services can be greatly improved with a
32、 proper design of terminals and systems in the presence of background noise. The present document: describes a sound field simulation technique allowing to simulate the real environment using realistic background noise scenarios for laboratory use; contains a database including relevant background n
33、oise samples for subjective and objective evaluation. The present document describes the recording technique used for the sound field simulation, the loudspeaker setup, and the loudspeaker calibration and equalization procedures. Furthermore the present document specifies the test room requirements
34、for laboratory conditions. The simulation environment specified can be used for the evaluation and optimization of terminals and of complex configurations including terminals, networks and others. The main application areas are: outdoor, office, home and car environment. The setup and database as de
35、scribed in the present document are applicable for: Objective performance evaluation of terminals in different (simulated) background noise environments. Speech processing evaluation by using the pre-processed speech signals in the presence of background noise, recorded by a terminal. Subjective eva
36、luation of terminals by performing conversational tests, specific double talk tests, or talking and listening tests in the presence of background noise. Subjective evaluation in third party listening tests by recording the speech samples of terminals in the presence of background noise. 2 References
37、 2.1 Normative references References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the referenced document (including any ame
38、ndments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. Th
39、e following referenced documents are necessary for the application of the present document. Not applicable. 2.2 Informative references References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited v
40、ersion applies. For non-specific references, the latest version of the referenced document (including any amendments) applies. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. ETSI ETSI TS 103 224 V1.3.1 (2017-0
41、7)8 The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. i.1 Berkhout A. J., de Vries D., Speech quality performance in the presence of background noise; Part 1: Background noise simulation
42、 technique and background noise database“. i.8 ETSI EG 202 396-2: “Speech Processing, Transmission and Quality Aspects (STQ); Speech quality performance in the presence of background noise; Part 2: Background noise transmission - Network simulation - Subjective test database and results“. i.9 ETSI E
43、G 202 396-3: “Speech and multimedia Transmission Quality (STQ); Speech Quality performance in the presence of background noise; Part 3: Background noise transmission - Objective test methods“. i.10 ETSI TS 103 106: “Speech and multimedia Transmission Quality (STQ); Speech quality performance in the
44、presence of background noise: Background noise transmission for mobile terminals-objective test methods“. i.11 ISO 3382-1: “Measurement of room acoustic parameters - Part 1: Performance spaces“. 3 Symbols and abbreviations 3.1 Symbols For the purposes of the present document, the following symbols a
45、pply: c Sound velocity C Matrix of FFT coefficients of Compensation Filters H Matrix of FFT coefficients of Impulse Responses 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: DUT Device Under Test FFT Fast Fourier Transform HATS Head And Torso Simulator
46、IR Impulse Response MLS Maximum Length Sequence MOS Mean Opinion Score MRP Mouth Reference Point ETSI ETSI TS 103 224 V1.3.1 (2017-07)9 SNR Signal to Noise Ratio SPL Sound Pressure Level4 Methods for realistic sound reproduction For reproduction of real world sound fields there exists a variety of d
47、ifferent methods, two of them are wave field synthesis i.1 and Ambisonics i.2. Both methods, however, require a large number of microphones and loudspeakers to achieve a sound field reproduction which is sufficiently good for testing purposes. The Wave-Field synthesis setup is that complex and expen
48、sive that it can be neglected for laboratory purposes. Ambisonics, for example, has to be performed using 43 microphones and 43 loudspeakers to reach a good sound field reproduction up to 2 kHz in a sweet spot with radius 15 cm (using the rule of thumb in i.3). It furthermore cannot consider individ
49、ual room characteristics or insufficiencies, but is only designed for rooms offering pure free field conditions. If, e.g. for testing purposes a HATS is positioned in the artificial noise field, the reproduction quality is reduced by an unknown amount. In summary, the Ambisonics approach is due to its design not feasible for the intended testing scenario. The present document introduces an alternative least mean squares method i.4, which requires eight recording channels and eight loudspeakers in order to achieve reasonably good repr
