Speech and multimedia Transmission Quality (STQ) - Transmission requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and
hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio
terminals.
DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].
In contrast to other standards which define minimum performance requirements it is the intention of the present
document to specify terminal equipment requirements which enable manufacturers and service providers to enable good
quality end-to-end speech performance as perceived by the user.
In addition to basic testing procedures, the present document describes advanced testing procedures taking into account
further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.

Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Prenosne zahteve za ozkopasovne zvočniške in prostoročne terminale VoIP glede na kakovost storitev (QoS), kot jo dojema uporabnik

V tem dokumentu so podane zahteve glede učinkovitosti prenosa govora za ozkopasovne zvočniške in prostoročne terminale VoIP; obravnava vse vrste terminalov na podlagi naslova IP, vključno z brezžičnimi in programskimi telefoni ter terminali za skupinske zvočne klice. Terminali digitalnih izboljšanih brezvrvičnih telekomunikacij (DECT) so zajeti v dokumentih ETSI EN 300 175-8 [i.6] in ETSI EN 300 176-2 [i.7]. V nasprotju z drugimi standardi, ki opredeljujejo minimalne zahteve glede učinkovitosti, je namen tega dokumenta določiti zahteve za terminalsko opremo, ki proizvajalcem in ponudnikom storitev omogočajo, da zagotavljajo dobro kakovost govora od začetka do konca, kot jo dojema uporabnik. Poleg osnovnih preskusnih postopkov ta dokument opisuje napredne preskusne postopke, ki upoštevajo tudi druge parametre kakovosti, kot jih dojema uporabnik. OPOMBA: Ta dokument se ne navezuje na naglavne terminale.

General Information

Status
Published
Publication Date
29-Jun-2022
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
23-Jun-2022
Due Date
28-Aug-2022
Completion Date
30-Jun-2022

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SLOVENSKI STANDARD
SIST ES 202 738 V1.8.2:2022
01-september-2022
Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Prenosne zahteve za
ozkopasovne zvočniške in prostoročne terminale VoIP glede na kakovost storitev
(QoS), kot jo dojema uporabnik
Speech and multimedia Transmission Quality (STQ) - Transmission requirements for
narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as
perceived by the user
Ta slovenski standard je istoveten z: ETSI ES 202 738 V1.8.2 (2022-05)
ICS:
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
SIST ES 202 738 V1.8.2:2022 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ES 202 738 V1.8.2:2022
---------------------- Page: 2 ----------------------
SIST ES 202 738 V1.8.2:2022
ETSI ES 202 738 V1.8.2 (2022-05)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 3 ----------------------
SIST ES 202 738 V1.8.2:2022
2 ETSI ES 202 738 V1.8.2 (2022-05)
Reference
RES/STQ-302
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP
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 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871
Important notice
The present document can be downloaded from:
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 perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI

deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.

Users of the present document should be aware that the document may be subject to revision 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/CommiteeSupportStaff.aspx

If you find a security vulnerability in the present document, please report it through our

Coordinated Vulnerability Disclosure Program:
https://www.etsi.org/standards/coordinated-vulnerability-disclosure
Notice of disclaimer & limitation of liability

The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of

experience to understand and interpret its content in accordance with generally accepted engineering or

other professional standard and applicable regulations.

No recommendation as to products and services or vendors is made or should be implied.

No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law

governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness

and/or

for any particular purpose or against infringement of intellectual property rights.

In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not

limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property

rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages

for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use

of or inability to use the software.
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 authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2022.
All rights reserved.
ETSI
---------------------- Page: 4 ----------------------
SIST ES 202 738 V1.8.2:2022
3 ETSI ES 202 738 V1.8.2 (2022-05)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

Introduction ........................................................................................................................................................ 5

1 Scope ........................................................................................................................................................ 7

2 References ................................................................................................................................................ 7

2.1 Normative references ......................................................................................................................................... 7

2.2 Informative references ........................................................................................................................................ 8

3 Definition of terms, symbols and abbreviations ....................................................................................... 9

3.1 Terms .................................................................................................................................................................. 9

3.2 Symbols ............................................................................................................................................................ 10

3.3 Abbreviations ................................................................................................................................................... 10

4 General considerations ........................................................................................................................... 11

4.1 Default Coding Algorithm ................................................................................................................................ 11

4.2 End-to-end considerations ................................................................................................................................ 11

5 Test equipment ....................................................................................................................................... 12

5.1 IP half channel measurement adaptor ............................................................................................................... 12

5.2 Environmental conditions for tests ................................................................................................................... 12

5.3 Accuracy of measurements and test signal generation ..................................................................................... 12

5.4 Network impairment simulation ....................................................................................................................... 13

5.5 Acoustic environment ....................................................................................................................................... 13

5.6 Influence of terminal delay on measurements .................................................................................................. 13

6 Requirements and associated measurement methodologies ................................................................... 14

6.1 Notes ................................................................................................................................................................ 14

6.2 Test setup.......................................................................................................................................................... 14

6.2.1 General ........................................................................................................................................................ 14

6.2.2 Setup for terminal ....................................................................................................................................... 15

6.2.2.1 Hands-free measurements ..................................................................................................................... 15

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 19

6.2.3 Test signal levels ......................................................................................................................................... 19

6.2.3.1 Send....................................................................................................................................................... 19

6.2.3.2 Receive .................................................................................................................................................. 20

6.2.4 Setup of background noise simulation ........................................................................................................ 20

6.2.5 Setup for variable echo path ....................................................................................................................... 21

6.3 Coding independent parameters ....................................................................................................................... 21

6.3.1 Send frequency response ............................................................................................................................ 21

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 22

6.3.3 Mic mute ..................................................................................................................................................... 23

6.3.4 Send distortion ............................................................................................................................................ 23

6.3.5 Out-of-band signals in send direction ......................................................................................................... 24

6.3.6 Send noise ................................................................................................................................................... 24

6.3.7 Terminal Coupling Loss weighted (TCLw) ................................................................................................ 25

6.3.8 Stability loss................................................................................................................................................ 25

6.3.9 Receive frequency response ........................................................................................................................ 26

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 28

6.3.11 Receive Distortion ...................................................................................................................................... 29

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 30

6.3.13 Receive noise .............................................................................................................................................. 30

6.3.14 Double talk performance ............................................................................................................................ 31

6.3.14.1 General .................................................................................................................................................. 31

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 31

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 32

H,R,dt
ETSI
---------------------- Page: 5 ----------------------
SIST ES 202 738 V1.8.2:2022
4 ETSI ES 202 738 V1.8.2 (2022-05)

6.3.14.4 Detection of echo components during double talk ................................................................................ 33

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 34

6.3.15 Switching characteristics ............................................................................................................................ 34

6.3.15.1 Note ....................................................................................................................................................... 34

6.3.15.2 Activation in send direction .................................................................................................................. 34

6.3.15.3 Silence suppression and comfort noise generation ................................................................................ 35

6.3.16 Background noise performance .................................................................................................................. 35

6.3.16.1 Performance in send direction in the presence of background noise ..................................................... 35

6.3.16.2 Speech quality in the presence of background noise ............................................................................. 36

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 37

6.3.17 Quality of echo cancellation ....................................................................................................................... 37

6.3.17.1 Temporal echo effects ........................................................................................................................... 37

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 38

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 39

6.3.17.4 Variable echo path................................................................................................................................. 39

6.3.18 Variant impairments ................................................................................................................................... 39

6.3.18.1 Clock accuracy send .............................................................................................................................. 39

6.3.18.2 Clock accuracy receive ......................................................................................................................... 39

6.3.18.3 Send packet delay variation................................................................................................................... 40

6.3.19 Send and receive delay - round trip delay ................................................................................................... 40

6.4 Codec specific requirements............................................................................................................................. 42

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 42

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 43

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 45

Annex A (informative): Processing delays in VoIP terminals ............................................................ 47

Annex B (informative): Bibliography ................................................................................................... 50

History .............................................................................................................................................................. 51

ETSI
---------------------- Page: 6 ----------------------
SIST ES 202 738 V1.8.2:2022
5 ETSI ES 202 738 V1.8.2 (2022-05)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations

pertaining to these essential IPRs, if any, are 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 Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,

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

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 or 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.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP

Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the

oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.

Foreword

This ETSI Standard (ES) 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

Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast

growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.

Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to

the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the

traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with

specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including

packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be

developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific

issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding

algorithms.

The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals

are used for testing in order to achieve mostly realistic test conditions and meaningful results.

ETSI
---------------------- Page: 7 ----------------------
SIST ES 202 738 V1.8.2:2022
6 ETSI ES 202 738 V1.8.2 (2022-05)

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals.

NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.

ETSI
---------------------- Page: 8 ----------------------
SIST ES 202 738 V1.8.2:2022
7 ETSI ES 202 738 V1.8.2 (2022-05)
1 Scope

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio

terminals.

DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].

In contrast to other standards which define minimum performance requirements it is the intention of the present

document to specify terminal equipment requirements which enable manufacturers and service providers to enable good

quality end-to-end speech performance as perceived by the user.

In addition to basic testing procedures, the present document describes advanced testing procedures taking into account

further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
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] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree

telephony".

[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full

Rate (EFR) speech transcoding (GSM 06.60)".

[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile

Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive

Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".

[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".

[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".

[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in

international connections".

[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".

[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications

transmitting at 5.3 and 6.3 kbit/s".

[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code

Modulation (ADPCM)".

[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-

code-excited linear prediction (CS-ACELP)".
ETSI
---------------------- Page: 9 ----------------------
SIST ES 202 738 V1.8.2:2022
8 ETSI ES 202 738 V1.8.2 (2022-05)

[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s

scalable wideband coder bitstream interoperable with G.729".

[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".

[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".

[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and

headset telephones".

[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of

hands-free terminals".

[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital

loudspeaking and hands-free telephony terminals".

[20] Recommendation ITU-T P.501: "Test signals for use in telephony and other speech-based

applications".

[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using

complex test signals".

[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset

terminal testing".

[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:

Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".

[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field

reproduction method for terminal testing including a background noise database".

[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".

[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".

[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission

requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as

perceived by the user".

[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals

and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
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.
ETSI
---------------------- Page: 10 ----------------------
SIST ES 202 738 V1.8.2:2022
9 ETSI ES 202 738 V1.8.2 (2022-05)

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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and

implementation of VoIP reference point".

[i.2] ETSI EG 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.3] Netem™.

NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.

[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and

measurement of speech transmission quality; Part 1: Introduction to objective comparison

measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".

[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common

Interface (CI); Part 8: Speech and audio coding and transmission".

[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test

specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:

artificial ear: device for the calibration of earphones 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

codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions

of transmission in the same equipment

ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position

freefield equalization: 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

freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating

in free air

NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head

present.
group audio terminal: handsfree terminal primarily designed fo
...

ETSI ES 202 738 V1.8.2 (2022-05)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 1 ----------------------
2 ETSI ES 202 738 V1.8.2 (2022-05)
Reference
RES/STQ-302
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP
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 - APE 7112B
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° w061004871
Important notice
The present document can be downloaded from:
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 perceived difference in contents between such versions and/or in print, the prevailing version of an ETSI

deliverable is the one made publicly available in PDF format at www.etsi.org/deliver.

Users of the present document should be aware that the document may be subject to revision 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/CommiteeSupportStaff.aspx

If you find a security vulnerability in the present document, please report it through our

Coordinated Vulnerability Disclosure Program:
https://www.etsi.org/standards/coordinated-vulnerability-disclosure
Notice of disclaimer & limitation of liability

The information provided in the present deliverable is directed solely to professionals who have the appropriate degree of

experience to understand and interpret its content in accordance with generally accepted engineering or

other professional standard and applicable regulations.

No recommendation as to products and services or vendors is made or should be implied.

No representation or warranty is made that this deliverable is technically accurate or sufficient or conforms to any law

governmental rule and/or regulation and further, no representation or warranty is made of merchantability or fitness

and/or

for any particular purpose or against infringement of intellectual property rights.

In no event shall ETSI be held liable for loss of profits or any other incidental or consequential damages.

Any software contained in this deliverable is provided "AS IS" with no warranties, express or implied, including but not

limited to, the warranties of merchantability, fitness for a particular purpose and non-infringement of intellectual property

rights and ETSI shall not be held liable in any event for any damages whatsoever (including, without limitation, damages

for loss of profits, business interruption, loss of information, or any other pecuniary loss) arising out of or related to the use

of or inability to use the software.
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 authorization of ETSI.

The copyright and the foregoing restriction extend to reproduction in all media.
© ETSI 2022.
All rights reserved.
ETSI
---------------------- Page: 2 ----------------------
3 ETSI ES 202 738 V1.8.2 (2022-05)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

Introduction ........................................................................................................................................................ 5

1 Scope ........................................................................................................................................................ 7

2 References ................................................................................................................................................ 7

2.1 Normative references ......................................................................................................................................... 7

2.2 Informative references ........................................................................................................................................ 8

3 Definition of terms, symbols and abbreviations ....................................................................................... 9

3.1 Terms .................................................................................................................................................................. 9

3.2 Symbols ............................................................................................................................................................ 10

3.3 Abbreviations ................................................................................................................................................... 10

4 General considerations ........................................................................................................................... 11

4.1 Default Coding Algorithm ................................................................................................................................ 11

4.2 End-to-end considerations ................................................................................................................................ 11

5 Test equipment ....................................................................................................................................... 12

5.1 IP half channel measurement adaptor ............................................................................................................... 12

5.2 Environmental conditions for tests ................................................................................................................... 12

5.3 Accuracy of measurements and test signal generation ..................................................................................... 12

5.4 Network impairment simulation ....................................................................................................................... 13

5.5 Acoustic environment ....................................................................................................................................... 13

5.6 Influence of terminal delay on measurements .................................................................................................. 13

6 Requirements and associated measurement methodologies ................................................................... 14

6.1 Notes ................................................................................................................................................................ 14

6.2 Test setup.......................................................................................................................................................... 14

6.2.1 General ........................................................................................................................................................ 14

6.2.2 Setup for terminal ....................................................................................................................................... 15

6.2.2.1 Hands-free measurements ..................................................................................................................... 15

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 19

6.2.3 Test signal levels ......................................................................................................................................... 19

6.2.3.1 Send....................................................................................................................................................... 19

6.2.3.2 Receive .................................................................................................................................................. 20

6.2.4 Setup of background noise simulation ........................................................................................................ 20

6.2.5 Setup for variable echo path ....................................................................................................................... 21

6.3 Coding independent parameters ....................................................................................................................... 21

6.3.1 Send frequency response ............................................................................................................................ 21

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 22

6.3.3 Mic mute ..................................................................................................................................................... 23

6.3.4 Send distortion ............................................................................................................................................ 23

6.3.5 Out-of-band signals in send direction ......................................................................................................... 24

6.3.6 Send noise ................................................................................................................................................... 24

6.3.7 Terminal Coupling Loss weighted (TCLw) ................................................................................................ 25

6.3.8 Stability loss................................................................................................................................................ 25

6.3.9 Receive frequency response ........................................................................................................................ 26

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 28

6.3.11 Receive Distortion ...................................................................................................................................... 29

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 30

6.3.13 Receive noise .............................................................................................................................................. 30

6.3.14 Double talk performance ............................................................................................................................ 31

6.3.14.1 General .................................................................................................................................................. 31

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 31

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 32

H,R,dt
ETSI
---------------------- Page: 3 ----------------------
4 ETSI ES 202 738 V1.8.2 (2022-05)

6.3.14.4 Detection of echo components during double talk ................................................................................ 33

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 34

6.3.15 Switching characteristics ............................................................................................................................ 34

6.3.15.1 Note ....................................................................................................................................................... 34

6.3.15.2 Activation in send direction .................................................................................................................. 34

6.3.15.3 Silence suppression and comfort noise generation ................................................................................ 35

6.3.16 Background noise performance .................................................................................................................. 35

6.3.16.1 Performance in send direction in the presence of background noise ..................................................... 35

6.3.16.2 Speech quality in the presence of background noise ............................................................................. 36

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 37

6.3.17 Quality of echo cancellation ....................................................................................................................... 37

6.3.17.1 Temporal echo effects ........................................................................................................................... 37

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 38

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 39

6.3.17.4 Variable echo path................................................................................................................................. 39

6.3.18 Variant impairments ................................................................................................................................... 39

6.3.18.1 Clock accuracy send .............................................................................................................................. 39

6.3.18.2 Clock accuracy receive ......................................................................................................................... 39

6.3.18.3 Send packet delay variation................................................................................................................... 40

6.3.19 Send and receive delay - round trip delay ................................................................................................... 40

6.4 Codec specific requirements............................................................................................................................. 42

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 42

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 43

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 45

Annex A (informative): Processing delays in VoIP terminals ............................................................ 47

Annex B (informative): Bibliography ................................................................................................... 50

History .............................................................................................................................................................. 51

ETSI
---------------------- Page: 4 ----------------------
5 ETSI ES 202 738 V1.8.2 (2022-05)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations

pertaining to these essential IPRs, if any, are 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 Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,

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

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 or 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.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP

Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the

oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.

Foreword

This ETSI Standard (ES) 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

Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast

growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.

Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to

the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the

traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with

specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including

packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be

developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific

issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding

algorithms.

The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals

are used for testing in order to achieve mostly realistic test conditions and meaningful results.

ETSI
---------------------- Page: 5 ----------------------
6 ETSI ES 202 738 V1.8.2 (2022-05)

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals.

NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.

ETSI
---------------------- Page: 6 ----------------------
7 ETSI ES 202 738 V1.8.2 (2022-05)
1 Scope

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio

terminals.

DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].

In contrast to other standards which define minimum performance requirements it is the intention of the present

document to specify terminal equipment requirements which enable manufacturers and service providers to enable good

quality end-to-end speech performance as perceived by the user.

In addition to basic testing procedures, the present document describes advanced testing procedures taking into account

further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
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] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree

telephony".

[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full

Rate (EFR) speech transcoding (GSM 06.60)".

[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile

Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive

Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".

[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".

[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".

[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in

international connections".

[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".

[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications

transmitting at 5.3 and 6.3 kbit/s".

[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code

Modulation (ADPCM)".

[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-

code-excited linear prediction (CS-ACELP)".
ETSI
---------------------- Page: 7 ----------------------
8 ETSI ES 202 738 V1.8.2 (2022-05)

[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s

scalable wideband coder bitstream interoperable with G.729".

[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".

[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".

[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and

headset telephones".

[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of

hands-free terminals".

[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital

loudspeaking and hands-free telephony terminals".

[20] Recommendation ITU-T P.501: "Test signals for use in telephony and other speech-based

applications".

[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using

complex test signals".

[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset

terminal testing".

[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:

Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".

[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field

reproduction method for terminal testing including a background noise database".

[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".

[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".

[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission

requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as

perceived by the user".

[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals

and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
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.
ETSI
---------------------- Page: 8 ----------------------
9 ETSI ES 202 738 V1.8.2 (2022-05)

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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and

implementation of VoIP reference point".

[i.2] ETSI EG 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.3] Netem™.

NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.

[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and

measurement of speech transmission quality; Part 1: Introduction to objective comparison

measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".

[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common

Interface (CI); Part 8: Speech and audio coding and transmission".

[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test

specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:

artificial ear: device for the calibration of earphones 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

codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions

of transmission in the same equipment

ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position

freefield equalization: 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

freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating

in free air

NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head

present.

group audio terminal: handsfree terminal primarily designed for use by several users which will not be equipped with

a handset

handsfree telephony terminal: telephony terminal using a loudspeaker associated with an amplifier as a telephone

receiver and which can be used without a handset

HATS Hands-Free Reference Point (HATS HFRP): corresponds to a reference point "n" from Recommendation

ITU-T P.58 [15]: "n" is one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T

P.58 [15] (coordinates of far field front point)

NOTE: The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the

appropriate axis lip-ring/HATS HFRP is to be as close as possible to the axis lip-ring/HFT microphone

under test.
ETSI
---------------------- Page: 9 ----------------------
10 ETSI ES 202 738 V1.8.2 (2022-05)

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
loudspeaking function: function of a handset telephone using a loud
...

Final draft ETSI ES 202 738 V1.8.2 (2022-03)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for narrowband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 1 ----------------------
2 Final draft ETSI ES 202 738 V1.8.2 (2022-03)
Reference
RES/STQ-302
Keywords
handsfree, loudspeaking, narrowband, quality,
speech, terminal, VoIP
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© ETSI 2022.
All rights reserved.
ETSI
---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 202 738 V1.8.2 (2022-03)
Contents

Intellectual Property Rights ................................................................................................................................ 5

Foreword ............................................................................................................................................................. 5

Modal verbs terminology .................................................................................................................................... 5

Introduction ........................................................................................................................................................ 5

1 Scope ........................................................................................................................................................ 7

2 References ................................................................................................................................................ 7

2.1 Normative references ......................................................................................................................................... 7

2.2 Informative references ........................................................................................................................................ 8

3 Definition of terms, symbols and abbreviations ....................................................................................... 9

3.1 Terms .................................................................................................................................................................. 9

3.2 Symbols ............................................................................................................................................................ 10

3.3 Abbreviations ................................................................................................................................................... 10

4 General considerations ........................................................................................................................... 11

4.1 Default Coding Algorithm ................................................................................................................................ 11

4.2 End-to-end considerations ................................................................................................................................ 11

5 Test equipment ....................................................................................................................................... 12

5.1 IP half channel measurement adaptor ............................................................................................................... 12

5.2 Environmental conditions for tests ................................................................................................................... 12

5.3 Accuracy of measurements and test signal generation ..................................................................................... 12

5.4 Network impairment simulation ....................................................................................................................... 13

5.5 Acoustic environment ....................................................................................................................................... 13

5.6 Influence of terminal delay on measurements .................................................................................................. 13

6 Requirements and associated measurement methodologies ................................................................... 14

6.1 Notes ................................................................................................................................................................ 14

6.2 Test setup.......................................................................................................................................................... 14

6.2.1 General ........................................................................................................................................................ 14

6.2.2 Setup for terminal ....................................................................................................................................... 15

6.2.2.1 Hands-free measurements ..................................................................................................................... 15

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 19

6.2.3 Test signal levels ......................................................................................................................................... 19

6.2.3.1 Send....................................................................................................................................................... 19

6.2.3.2 Receive .................................................................................................................................................. 20

6.2.4 Setup of background noise simulation ........................................................................................................ 20

6.2.5 Setup for variable echo path ....................................................................................................................... 21

6.3 Coding independent parameters ....................................................................................................................... 21

6.3.1 Send frequency response ............................................................................................................................ 21

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 22

6.3.3 Mic mute ..................................................................................................................................................... 23

6.3.4 Send distortion ............................................................................................................................................ 23

6.3.5 Out-of-band signals in send direction ......................................................................................................... 24

6.3.6 Send noise ................................................................................................................................................... 24

6.3.7 Terminal Coupling Loss weighted (TCLw) ................................................................................................ 25

6.3.8 Stability loss................................................................................................................................................ 25

6.3.9 Receive frequency response ........................................................................................................................ 26

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 28

6.3.11 Receive Distortion ...................................................................................................................................... 29

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 30

6.3.13 Receive noise .............................................................................................................................................. 30

6.3.14 Double talk performance ............................................................................................................................ 31

6.3.14.1 General .................................................................................................................................................. 31

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 31

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 32

H,R,dt
ETSI
---------------------- Page: 3 ----------------------
4 Final draft ETSI ES 202 738 V1.8.2 (2022-03)

6.3.14.4 Detection of echo components during double talk ................................................................................ 33

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 34

6.3.15 Switching characteristics ............................................................................................................................ 34

6.3.15.1 Note ....................................................................................................................................................... 34

6.3.15.2 Activation in send direction .................................................................................................................. 34

6.3.15.3 Silence suppression and comfort noise generation ................................................................................ 35

6.3.16 Background noise performance .................................................................................................................. 35

6.3.16.1 Performance in send direction in the presence of background noise ..................................................... 35

6.3.16.2 Speech quality in the presence of background noise ............................................................................. 36

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 37

6.3.17 Quality of echo cancellation ....................................................................................................................... 37

6.3.17.1 Temporal echo effects ........................................................................................................................... 37

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 38

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 39

6.3.17.4 Variable echo path................................................................................................................................. 39

6.3.18 Variant impairments ................................................................................................................................... 39

6.3.18.1 Clock accuracy send .............................................................................................................................. 39

6.3.18.2 Clock accuracy receive ......................................................................................................................... 39

6.3.18.3 Send packet delay variation................................................................................................................... 40

6.3.19 Send and receive delay - round trip delay ................................................................................................... 40

6.4 Codec specific requirements............................................................................................................................. 42

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 42

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 43

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 45

Annex A (informative): Processing delays in VoIP terminals ............................................................ 47

Annex B (informative): Bibliography ................................................................................................... 50

History .............................................................................................................................................................. 51

ETSI
---------------------- Page: 4 ----------------------
5 Final draft ETSI ES 202 738 V1.8.2 (2022-03)
Intellectual Property Rights
Essential patents

IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The declarations

pertaining to these essential IPRs, if any, are 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 Directives including the ETSI IPR Policy, no investigation regarding the essentiality of IPRs,

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

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 or 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.

DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its

Members. 3GPP™ and LTE™ are trademarks of ETSI registered for the benefit of its Members and of the 3GPP

Organizational Partners. oneM2M™ logo is a trademark of ETSI registered for the benefit of its Members and of the

oneM2M Partners. GSM and the GSM logo are trademarks registered and owned by the GSM Association.

Foreword

This final draft ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia

Transmission Quality (STQ), and is now submitted for the ETSI standards Membership Approval Procedure.

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

Traditionally, analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the fast

growth of IP networks, terminals directly interfacing packet-switched networks (VoIP) are being rapidly introduced.

Such IP network edge devices may include specifically designed IP phones, soft phones or other devices connected to

the IP based networks, providing telephony service. Since the IP networks will be in many cases interworking with the

traditional PSTN and private networks, many of the basic transmission requirements have to be harmonised with

specifications for traditional digital terminals. However, due to the unique characteristics of the IP networks including

packet loss, delay, etc. new performance specification, as well as appropriate measurement methods, will have to be

developed. Terminals are getting increasingly complex. Advanced signal processing is used to address the IP specific

issues. Also, the VoIP terminals may use other than 64 kbit/s PCM (Recommendation ITU-T G.711 [7]) speech coding

algorithms.

The advanced signal processing of terminals is targeted to speech signals. Therefore, wherever possible speech signals

are used for testing in order to achieve mostly realistic test conditions and meaningful results.

ETSI
---------------------- Page: 5 ----------------------
6 Final draft ETSI ES 202 738 V1.8.2 (2022-03)

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals.

NOTE: Requirement limits are given in tables, the associated curve when provided is given for illustration.

ETSI
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7 Final draft ETSI ES 202 738 V1.8.2 (2022-03)
1 Scope

The present document provides speech transmission performance requirements for narrowband VoIP loudspeaking and

hands-free terminals; it addresses all types of IP based terminals, including wireless, softphones and group audio

terminals.

DECT terminals are covered in ETSI EN 300 175-8 [i.6] and ETSI EN 300 176-2 [i.7].

In contrast to other standards which define minimum performance requirements it is the intention of the present

document to specify terminal equipment requirements which enable manufacturers and service providers to enable good

quality end-to-end speech performance as perceived by the user.

In addition to basic testing procedures, the present document describes advanced testing procedures taking into account

further quality parameters as perceived by the user.
NOTE: The present document does not concern headset terminals.
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] ETSI I-ETS 300 245-3: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 3: Pulse Code Modulation (PCM) A-law, loudspeaking and handsfree

telephony".

[2] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full

Rate (EFR) speech transcoding (GSM 06.60)".

[3] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile

Telecommunications System (UMTS); LTE; Speech codec speech processing functions; Adaptive

Multi-Rate - Wideband (AMR-WB) speech codec; General description (3GPP TS 26.171)".

[4] Recommendation ITU-T G.108: "Application of the E-model: A planning guide".

[5] Recommendation ITU-T G.109: "Definition of categories of speech transmission quality".

[6] Recommendation ITU-T G.122: "Influence of national systems on stability and talker echo in

international connections".

[7] Recommendation ITU-T G.711: "Pulse code modulation (PCM) of voice frequencies".

[8] Recommendation ITU-T G.723.1: "Dual rate speech coder for multimedia communications

transmitting at 5.3 and 6.3 kbit/s".

[9] Recommendation ITU-T G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code

Modulation (ADPCM)".

[10] Recommendation ITU-T G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-

code-excited linear prediction (CS-ACELP)".
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8 Final draft ETSI ES 202 738 V1.8.2 (2022-03)

[11] Recommendation ITU-T G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s

scalable wideband coder bitstream interoperable with G.729".

[12] Recommendation ITU-T O.41: "Psophometer for use on telephone-type circuits".

[13] Recommendation ITU-T P.50: "Artificial voices".
[14] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[15] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

[16] Recommendation ITU-T P.79: "Calculation of loudness ratings for telephone sets".

[17] Recommendation ITU-T P.310: "Transmission characteristics for narrow-band digital handset and

headset telephones".

[18] Recommendation ITU-T P.340: "Transmission characteristics and speech quality parameters of

hands-free terminals".

[19] Recommendation ITU-T P.342: "Transmission characteristics for narrow-band digital

loudspeaking and hands-free telephony terminals".

[20] Recommendation ITU-T P.501: "Test signals for use in telephony and other speech-based

applications".

[21] Recommendation ITU-T P.502: "Objective test methods for speech communication systems using

complex test signals".

[22] Recommendation ITU-T P.581: "Use of head and torso simulator for hands-free and handset

terminal testing".

[23] IEC 61260-1: "Electroacoustics - Octave-band and fractional-octave-band filters - Part 1:

Specifications".
[24] Recommendation ITU-T P.800.1: "Mean Opinion Score (MOS) terminology".

[25] ETSI TS 103 224: "Speech and multimedia Transmission Quality (STQ); A sound field

reproduction method for terminal testing including a background noise database".

[26] Recommendation ITU-T P.863.1: "Application guide for Recommendation ITU-T P.863".

[27] Recommendation ITU-T P.863: "Perceptual objective listening quality prediction".

[28] ETSI ES 202 737: "Speech and multimedia Transmission Quality (STQ); Transmission

requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as

perceived by the user".

[29] Recommendation ITU-T P.1010: "Fundamental voice transmission objectives for VoIP terminals

and gateways".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".
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.
ETSI
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9 Final draft ETSI ES 202 738 V1.8.2 (2022-03)

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] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and

implementation of VoIP reference point".

[i.2] ETSI EG 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.3] Netem™.

NOTE: Information available at https://wiki.linuxfoundation.org/networking/netem.

[i.4] ETSI EG 201 377-1: "Speech and multimedia Transmission Quality (STQ); Specification and

measurement of speech transmission quality; Part 1: Introduction to objective comparison

measurement methods for one-way speech quality across networks".
[i.5] IETF RFC 4737: "Packet Reordering Metrics".

[i.6] ETSI EN 300 175-8: "Digital Enhanced Cordless Telecommunications (DECT); Common

Interface (CI); Part 8: Speech and audio coding and transmission".

[i.7] ETSI EN 300 176-2: "Digital Enhanced Cordless Telecommunications (DECT); Test

specification; Part 2: Audio and speech".
3 Definition of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the following terms apply:

artificial ear: device for the calibration of earphones 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

codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions

of transmission in the same equipment

ear-Drum Reference Point (DRP): point located at the end of the ear canal, corresponding to the ear-drum position

freefield equalization: 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

freefield reference point: point located in the free sound field, at least in 1,5 m distance from a sound source radiating

in free air

NOTE: In case of a head and torso simulator (HATS) in the centre of the artificial head with no artificial head

present.

group audio terminal: handsfree terminal primarily designed for use by several users which will not be equipped with

a handset

handsfree telephony terminal: telephony terminal using a loudspeaker associated with an amplifier as a telephone

receiver and which can be used without a handset

HATS Hands-Free Reference Point (HATS HFRP): corresponds to a reference point "n" from Recommendation

ITU-T P.58 [15]: "n" is one of the points numbered from 11 to 17 and defined in table 6a of Recommendation

ITU-T P.58 [15] (coordinates of far field front point)

NOTE: The HATS HFRP depends on the location(s) of the microphones of the terminal under test: the

appropriate axis lip-ring/HATS HFRP is to be as close as possible to the axis lip-ring/HFT microphone

under test.
ETSI
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10 Final draft ETSI ES 202 738 V1.8.2 (2022-03)

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
loudspeaking function: function of a handset telephone using a loudspeaker ass
...

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