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TECHNICAL SPECIFICATION
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for Super-Wideband / Fullband
handsfree and conferencing terminals from
a QoS perspective as perceived by the user
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2 ETSI TS 102 925 V1.2.1 (2018-10)
Reference
RTS/STQ-208-2
Keywords
QoS, terminal
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3 ETSI TS 102 925 V1.2.1 (2018-10)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 8
3 Definitions of terms and abbreviations. 9
3.1 Terms . 9
3.2 Abbreviations . 9
4 Applications and Codec considerations. 10
4.1 Applications . 10
4.2 Codec considerations . 10
4.2.0 Introduction. 10
4.2.1 Super-wideband (SWB) . 11
4.2.2 Fullband (FB). 12
5 Test equipment and associated considerations . 13
5.0 Introduction . 13
5.1 Test Set-up. 13
5.1.0 Introduction. 13
5.1.1 Setup for terminals . 14
5.1.1.0 Introduction . 14
5.1.1.1 Desktop operated handsfree terminal . 14
5.1.1.2 Handheld handsfree terminal . 15
5.1.1.3 Softphone (computer-based terminals) . 16
5.1.1.4 Group audio terminal (GAT). 19
5.1.1.5 Teleconference systems . 21
5.1.1.6 Void. 21
5.1.2 Test signals . 21
5.1.3 Test signal levels . 21
5.1.3.0 General . 21
5.1.3.1 Send. 21
5.1.3.2 Receive . 22
5.1.4 Setup of background noise simulation . 22
5.1.5 Acoustic environment . 23
5.1.5.1 Measurement environment . 23
5.1.5.2 Acoustic environment for the rooms where systems are implemented . 23
5.1.6 Influence of terminal delay issue on measurements . 23
5.2 Environmental conditions for tests . 24
5.3 Accuracy of measurements and test signal generation . 24
5.4 Specific test considerations . 25
5.4.0 Introduction. 25
5.4.1 Loudness Rating and Loudness . 25
5.4.1.1 Loudness Rating . 25
5.4.1.2 Loudness . 25
5.4.2 Binaural listening . 26
5.4.3 Subjective considerations . 26
5.4.4 Setup of variable echo path . 26
5.5 Network impairment simulation . 27
5.6 Verification of the environmental conditions . 28
6 Requirements and associated measurement methodologies . 28
ETSI
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4 ETSI TS 102 925 V1.2.1 (2018-10)
6.0 Considerations . 28
6.1 Send . 28
6.1.0 Introduction. 28
6.1.1 Frequency response. 28
6.1.2 Send Loudness rating (SLR) . 30
6.1.3 Void . 31
6.1.4 Send Noise . 31
6.1.5 Send Distortion . 31
6.1.5.1 Signal to harmonic distortion versus frequency . 31
6.1.5.2 Signal to harmonic distortion for higher input level . 33
6.1.6 Microphone mute . 33
6.2 Receive . 33
6.2.0 Introduction. 33
6.2.1 Equalization . 33
6.2.2 Frequency response. 34
6.2.2.0 General . 34
6.2.2.1 Handheld terminal . 34
6.2.2.2 Desktop terminal . 36
6.2.2.3 Terminals intended to be used simultaneously by several users . 37
6.2.3 Receive Loudness Rating (RLR) and Loudness . 38
6.2.3.1 Receive Loudness Rating . 38
6.2.3.2 Loudness . 39
6.2.4 Receive Noise . 39
6.2.5 Receive Distortion . 40
6.3 Other parameters . 41
6.3.0 Introduction. 41
6.3.1 Round-trip Delay . 41
6.3.1.1 Round-trip Delay for VoIP terminals . 41
6.3.1.2 Quality of jitter buffer adjustment . 43
6.3.2 Terminal Echo Loss (TCL) . 44
6.3.3 Objective listening quality . 44
6.3.4 Double talk performance . 45
6.3.4.1 General . 45
6.3.4.2 Attenuation range in send direction during double talk A . 45
H,S,dt
6.3.4.3 Attenuation range in receive direction during double talk A . 47
H,R,dt
6.3.4.4 Detection of echo components during double talk . 47
6.3.4.5 Minimum activation level and sensitivity of double talk detection . 49
6.3.5 Speech and audio quality in presence of noise. 50
6.3.5.1 Performance in send in the presence of background noise . 50
6.3.5.2 Speech quality in the presence of background noise . 50
6.3.5.3 Quality of background noise transmission (with far end speech). 51
6.3.6 Potential other quality features . 52
6.3.6.1 Sound localization and binaural performance . 52
6.3.6.2 Dereverberation performance . 52
6.3.6.3 Switching characteristics between transducers . 52
6.3.7 Quality of echo cancellation . 52
6.3.7.1 Temporal echo effects . 52
6.3.7.2 Spectral echo attenuation . 53
6.3.7.3 Occurrence of artefacts . 53
6.3.7.4 Variable echo path. 53
6.3.8 Switching characteristics . 54
6.3.8.1 Note . 54
6.3.8.2 Activation in send direction . 54
6.3.8.3 Silence suppression and comfort noise generation . 54
Annex A (normative): Room acoustics and electro acoustic equipment positioning . 55
Annex B (informative): Bibliography . 56
History . 57
ETSI
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5 ETSI TS 102 925 V1.2.1 (2018-10)
Intellectual Property Rights
Essential patents
IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly 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 Web
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 become, essential to the present document.
Trademarks
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ETSI claims no ownership of these except for any which are indicated as being the property of ETSI, and conveys no
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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 Speech and multimedia
Transmission Quality (STQ).
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 for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
Introduction
Speech terminals are currently implementing narrowband and wideband bandwidth. Nowadays, terminal equipment
may offer wider bandwidth, due to features already available in these terminals. Such equipment may implement
conversational features that may be to the benefit of the electro acoustic equipment's already available in the terminal
and may provide wider quality for the end users. High quality conferencing systems may also implement wider
bandwidth in order to reach quality and behaviour close to normal face to face conditions.
The present document is intended to provide initial requirements and test methods for such equipment. The present
document also provides materials for a further update of ETSI SR 002 959 [i.2]: Electronic Working Tools; Roadmap
including recommendations for the deployment and usage of electronic working tools in the ETSI standardization
process.
The present document complements the ETSI TS 102 924 [17] Handset and Headset mode specifications.
ETSI
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6 ETSI TS 102 925 V1.2.1 (2018-10)
1 Scope
The present document provides speech & audio transmission performance requirements and measurement methods for
handsfree functions of super-wideband/fullband terminals, including conferencing terminals. The present document
provides requirements in order to optimize the end to end quality perceived by users.
Users become more sensitive to voice and music quality (for music used in conversational services) when using
ICT/terminal equipment and so are more demanding for further enhancement especially further extension of the audio
coded bandwidth.
For instance, this is the case for high quality conferencing services with music on hold, better background environment
rendering and longer duration than normal point to point calls.
Standardized super-wideband and fullband codecs are now available, some being also compatible with wideband
codecs.
The present document will consider only conversational services (that may be mixed with other services) and does not
cover the streaming-only services.
Such applications include:
• Speech and audio communication including conferencing using high quality handsfree systems.
• Bandwidth extension which may allow usage for some mixed content applications.
• Super-wideband enhancement coupled with stereo/dichotic/multichannel.
In the send path the signal may combine speech, music and environmental signals. The signal may be:
• acoustically captured by a microphone; or
• directly inserted through a digital or analog connection.
In the receive path, the signal may combine:
• communication signals such as described for send path, including environmental signals; and
• signals coming from distributed applications (e.g. advertisement, music on hold, etc.).
2 References
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 amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
https://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.
The following referenced documents are necessary for the application of the present document.
[1] Recommendation ITU-T P.501: "Test signals for use in telephonometry".
[2] Recommendation ITU-T P.10/G.100: "Vocabulary for performance and quality of service".
[3] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".
ETSI
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7 ETSI TS 102 925 V1.2.1 (2018-10)
[4] Recommendation ITU-T P.581: "Use of head and torso simulator (HATS) for hands-free and
handset terminal testing".
[5] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".
[6] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[7] Recommendation ITU-T G.722.1 (Annex C): "Low-complexity coding at 24 and 32 kbit/s for
hands-free operation in systems with low frame loss".
[8] Recommendation ITU-T G.729.1 (Annex E): "G.729-based embedded variable bit-rate coder: An
8-32 kbit/s scalable wideband coder bitstream interoperable with G.729".
[9] Recommendation ITU-T G.718 (Annex B): "Frame error robust narrow-band and wideband
embedded variable bit-rate coding of speech and audio from 8-32 kbit/s".
[10] Recommendation ITU-T G.719: "Low-complexity, full-band audio coding for high-quality,
conversational applications".
[11] ETSI ES 202 740: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for wideband VoIP loudspeaking and handsfree terminals from a QoS perspective as
perceived by the user".
[12] ETSI TS 103 740: "Speech and multimedia Transmission Quality (STQ);Transmission
requirements for wideband wireless terminals (handsfree) from a QoS perspective as perceived by
the user".
[13] ETSI ETS 300 807: "Integrated Services Digital Network (ISDN); Audio characteristics of
terminals designed to support conference services in the ISDN".
[14] Recommendation ITU-T P.863: "Perceptual objective listening quality assessment".
[15] Recommendation ITU-T G.711.1: "Wideband embedded extension for G.711 pulse code
modulation".
[16] Recommendation ITU-T P.1301: "Subjective quality evaluation of audio and audiovisual
multiparty telemeetings".
[17] ETSI TS 102 924: "Speech and multimedia Transmission Quality (STQ); Transmission
requirements for Super-Wideband / Fullband handset and headset terminals from a QoS
perspective as perceived by the user".
[18] Void.
[19] Void.
[20] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
[21] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[22] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:
Specifications".
[23] ISO 3745: "Acoustics -- Determination of sound power levels and sound energy levels of noise
sources using sound pressure -- Precision methods for anechoic rooms and hemi-anechoic rooms".
[24] Void.
[25] ETSI TS 126 441: "Universal Mobile Telecommunications System (UMTS); LTE; Codec for
Enhanced Voice Services (EVS); General overview (3GPP TS 26.441)".
[26] ETSI TS 103 281: "Speech and multimedia Transmission Quality (STQ); Speech quality in the
presence of background noise: Objective test methods for super-wideband and fullband terminals".
[27] Recommendation ITU-T P.863.1: "Application Guide for Recommendation ITU-T P.863".
ETSI
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8 ETSI TS 102 925 V1.2.1 (2018-10)
[28] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field
reproduction method for terminal testing including a background noise database".
[29] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in
international connections".
[30] IETF RFC 6716: "Definition of the Opus Audio Codec".
[31] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using
complex test signals".
[32] Recommendation ITU-T P.1010: "Objective test methods for speech communication systems
using complex test signals".
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 version 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.
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.
...