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

The present document provides speech transmission performance requirements for 8 kHz wideband 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 širokopasovne zvočniške in prostoročne terminale VoIP glede na kakovost storitev (QoS), kot jo dojema uporabnik

General Information

Status
Published
Publication Date
25-May-2020
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-May-2020
Due Date
30-Jul-2020
Completion Date
26-May-2020

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ETSI ES 202 740 V1.8.1 (2020-05)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for wideband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 1 ----------------------
2 ETSI ES 202 740 V1.8.1 (2020-05)
Reference
RES/STQ-277
Keywords
handsfree, loudspeaking, quality, speech,
terminal, VoIP, wideband
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
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
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 2020.
All rights reserved.

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.
ETSI
---------------------- Page: 2 ----------------------
3 ETSI ES 202 740 V1.8.1 (2020-05)
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 ........................................................................................................................................ 7

3 Definition of terms, symbols and abbreviations ....................................................................................... 8

3.1 Terms .................................................................................................................................................................. 8

3.2 Symbols .............................................................................................................................................................. 9

3.3 Abbreviations ..................................................................................................................................................... 9

4 General considerations ........................................................................................................................... 10

4.1 Coding algorithm .............................................................................................................................................. 10

4.2 End-to-end considerations ................................................................................................................................ 10

5 Test equipment ....................................................................................................................................... 11

5.1 IP half channel measurement adaptor ............................................................................................................... 11

5.2 Environmental conditions for tests ................................................................................................................... 11

5.3 Accuracy of measurements and test signal generation ..................................................................................... 11

5.4 Network impairment simulation ....................................................................................................................... 12

5.5 Acoustic environment ....................................................................................................................................... 12

5.6 Influence of terminal delay on measurements .................................................................................................. 12

6 Requirements and associated measurement methodologies ................................................................... 12

6.1 Notes ................................................................................................................................................................ 12

6.2 Test setup.......................................................................................................................................................... 13

6.2.1 General ........................................................................................................................................................ 13

6.2.2 Setup for terminals ...................................................................................................................................... 13

6.2.2.1 Hands-free measurements ..................................................................................................................... 13

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 18

6.2.3 Test signal levels ......................................................................................................................................... 18

6.2.3.1 Send....................................................................................................................................................... 18

6.2.3.2 Receive .................................................................................................................................................. 19

6.2.4 Setup of background noise simulation ........................................................................................................ 19

6.2.5 Setup for variable echo path ....................................................................................................................... 20

6.3 Coding independent parameters ....................................................................................................................... 20

6.3.1 Send sensitivity/frequency response ........................................................................................................... 20

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 21

6.3.3 Mic mute ..................................................................................................................................................... 22

6.3.4 Send distortion ............................................................................................................................................ 22

6.3.5 Out-of-band signals in send direction ......................................................................................................... 23

6.3.6 Send noise ................................................................................................................................................... 23

6.3.7 Terminal Coupling Loss (TCL) .................................................................................................................. 24

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

6.3.9 Receive frequency response ........................................................................................................................ 25

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 27

6.3.11 Receive distortion ....................................................................................................................................... 28

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 29

6.3.13 Receive noise .............................................................................................................................................. 29

6.3.14 Double talk performance ............................................................................................................................ 30

6.3.14.1 General .................................................................................................................................................. 30

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 30

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 31

H,R,dt
ETSI
---------------------- Page: 3 ----------------------
4 ETSI ES 202 740 V1.8.1 (2020-05)

6.3.14.4 Detection of echo components during double talk ................................................................................ 32

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 33

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 ................................................................................ 34

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 ............................................................................. 35

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 36

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

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

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 37

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 38

6.3.17.4 Variable echo path................................................................................................................................. 38

6.3.18 Variant impairments ................................................................................................................................... 38

6.3.18.1 Clock accuracy send .............................................................................................................................. 38

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

6.3.18.3 Send packet delay variation................................................................................................................... 39

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

6.4 Codec specific requirements............................................................................................................................. 41

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 41

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 42

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 44

Annex A (informative): Processing delays in VoIP terminals ............................................................ 46

Annex B (informative): Bibliography ................................................................................................... 49

History .............................................................................................................................................................. 50

ETSI
---------------------- Page: 4 ----------------------
5 ETSI ES 202 740 V1.8.1 (2020-05)
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

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.

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, wideband terminals providing higher audio-bandwidth and directly interfacing packet-switched

networks (VoIP) are being rapidly introduced. Such IP network edge devices may include gateways, specifically

designed IP phones, soft phones or other devices connected to the IP based networks and providing telephony service.

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.

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.

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

hands-free terminals.

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

ETSI
---------------------- Page: 5 ----------------------
6 ETSI ES 202 740 V1.8.1 (2020-05)
1 Scope

The present document provides speech transmission performance requirements for 8 kHz wideband 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 300 245-6: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 6: Wideband (7 kHz), loudspeaking and hands free telephony".

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

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

[4] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[5] Recommendation ITU-T G.722.1: "Low-complexity coding at 24 and 32 kbit/s for hands-free

operation in systems with low frame loss".

[6] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[7] 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".
[8] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[9] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

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

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

headset telephones".

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

hands-free terminals".
ETSI
---------------------- Page: 6 ----------------------
7 ETSI ES 202 740 V1.8.1 (2020-05)

[13] Recommendation ITU-T P.341: "Transmission characteristics for wideband digital loudspeaking

and hands-free telephony terminals".
[14] Recommendation ITU-T P.501: "Test signals for use in telephonometry".

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

complex test signals".

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

terminal testing".

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

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

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

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

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

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

[22] 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".

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

and gateways".
[24] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".

[25] TIA-920.130: "Telecommunications Communications Products Transmission Requirements for

Digital Interface Communications Devices with Headsets".

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

international connections".
[27] IETF RFC 5481: "Packet Delay Variation Applicability Statement".

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

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

code-excited linear prediction (CS-ACELP)".

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

transmitting at 5.3 and 6.3 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.

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".
ETSI
---------------------- Page: 7 ----------------------
8 ETSI ES 202 740 V1.8.1 (2020-05)

[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): reference point "n" from Recommendation ITU-T P.58 [9] "n" is

one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T P.58 [9], (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.

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
ETSI
---------------------- Page: 8 ----------------------
9 ETSI ES 202 740 V1.8.1 (2020-05)

loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a

telephone receiver

Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator

nominal setting of the volume control: setting which is closest to the nominal RLR

reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.

RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR-WB Adaptative Multi Rate - Wideband
CS Composite Source
CSS Composite Source Signal
DRP ear-Drum Reference Point
DUT Devise Under Test
EC Echo Canceller
EL Echo Loss
ERP Ear Reference Point
FFT Fast Fourrier Transform
G-MOS-LQOw Overall transmission quality wideband
GSM Global System for Mobile communications
HATS Head And Torso Simulator
HFRP Hands Free Reference Point
HFT Hands Free Terminal
IEC International Electrotechnical Commission
IP Internet Protocol
IPDV IP Packet Delay Variation

ITU-T International Telecommunication Union -Telecommunication standardization sector

LE Earphone coupling Loss
MOS Mean Opinion Score
MOS-LQOy Mean Opinion Score - Listening Quality Objective

NOTE: y being N for narrowband, M for mixed, S for super-wideband and F for fullband. See Recommendation

ITU-T P.800.1 [18].
MRP Mouth Reference Point
N-MOS-LQOw Transmission quality of the background noise wideband
NLP Non Linear Processor
PBX Private Branch eXchange
PC Personal Computer
PCM Pulse Code Modulation
PDA Personal Digital Assistant
PMRP Sound Pressure at the Mouth Reference Point
PN Pseudo Noise
POI Point Of Interconnection
QoS Quality of Service
RLR Receive Loudness Rating
RMS Root Mean Square
RTP Real-Time Transport Protocol
S-MOS-LQOw Transmission quality of the speech wideband
ETSI
---------------------- Page: 9 ----------------------
10 ETSI ES 202 740 V1.8.1 (2020-05)
SLR Send Loudness Rating
TCL Terminal Coupling Loss
TDM Time Division Multiplex
TELR Talker Echo Loudness Rating
TOSQA Telecommunications Objective Speech Quality Assessment
VAD Voice Activity Detection
VoIP Voice over Internet Protocol
4 General considerations
4.1 Coding algorithm
The coding algorithm assumed in the pr
...

Final draft ETSI ES 202 740 V1.8.1 (2020-03)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for wideband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 1 ----------------------
2 Final draft ETSI ES 202 740 V1.8.1 (2020-03)
Reference
RES/STQ-277
Keywords
handsfree, loudspeaking, quality, speech,
terminal, VoIP, wideband
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE
Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88
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
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 2020.
All rights reserved.

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.
ETSI
---------------------- Page: 2 ----------------------
3 Final draft ETSI ES 202 740 V1.8.1 (2020-03)
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 ........................................................................................................................................ 7

3 Definition of terms, symbols and abbreviations ....................................................................................... 8

3.1 Terms .................................................................................................................................................................. 8

3.2 Symbols .............................................................................................................................................................. 9

3.3 Abbreviations ..................................................................................................................................................... 9

4 General considerations ........................................................................................................................... 10

4.1 Coding algorithm .............................................................................................................................................. 10

4.2 End-to-end considerations ................................................................................................................................ 10

5 Test equipment ....................................................................................................................................... 11

5.1 IP half channel measurement adaptor ............................................................................................................... 11

5.2 Environmental conditions for tests ................................................................................................................... 11

5.3 Accuracy of measurements and test signal generation ..................................................................................... 11

5.4 Network impairment simulation ....................................................................................................................... 11

5.5 Acoustic environment ....................................................................................................................................... 12

5.6 Influence of terminal delay on measurements .................................................................................................. 12

6 Requirements and associated measurement methodologies ................................................................... 12

6.1 Notes ................................................................................................................................................................ 12

6.2 Test setup.......................................................................................................................................................... 13

6.2.1 General ........................................................................................................................................................ 13

6.2.2 Setup for terminals ...................................................................................................................................... 13

6.2.2.1 Hands-free measurements ..................................................................................................................... 13

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 18

6.2.3 Test signal levels ......................................................................................................................................... 18

6.2.3.1 Send....................................................................................................................................................... 18

6.2.3.2 Receive .................................................................................................................................................. 19

6.2.4 Setup of background noise simulation ........................................................................................................ 19

6.2.5 Setup for variable echo path ....................................................................................................................... 20

6.3 Coding independent parameters ....................................................................................................................... 20

6.3.1 Send sensitivity/frequency response ........................................................................................................... 20

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 21

6.3.3 Mic mute ..................................................................................................................................................... 22

6.3.4 Send distortion ............................................................................................................................................ 22

6.3.5 Out-of-band signals in send direction ......................................................................................................... 23

6.3.6 Send noise ................................................................................................................................................... 23

6.3.7 Terminal Coupling Loss (TCL) .................................................................................................................. 24

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

6.3.9 Receive frequency response ........................................................................................................................ 25

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 27

6.3.11 Receive distortion ....................................................................................................................................... 28

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 29

6.3.13 Receive noise .............................................................................................................................................. 29

6.3.14 Double talk performance ............................................................................................................................ 30

6.3.14.1 General .................................................................................................................................................. 30

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 30

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 31

H,R,dt
ETSI
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4 Final draft ETSI ES 202 740 V1.8.1 (2020-03)

6.3.14.4 Detection of echo components during double talk ................................................................................ 32

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 33

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 ................................................................................ 34

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 ............................................................................. 35

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 36

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

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

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 37

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 38

6.3.17.4 Variable echo path................................................................................................................................. 38

6.3.18 Variant impairments ................................................................................................................................... 38

6.3.18.1 Clock accuracy send .............................................................................................................................. 38

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

6.3.18.3 Send packet delay variation................................................................................................................... 39

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

6.4 Codec specific requirements............................................................................................................................. 41

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 41

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 42

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 44

Annex A (informative): Processing delays in VoIP terminals ............................................................ 46

Annex B (informative): Bibliography ................................................................................................... 49

History .............................................................................................................................................................. 50

ETSI
---------------------- Page: 4 ----------------------
5 Final draft ETSI ES 202 740 V1.8.1 (2020-03)
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

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.

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, wideband terminals providing higher audio-bandwidth and directly interfacing packet-switched

networks (VoIP) are being rapidly introduced. Such IP network edge devices may include gateways, specifically

designed IP phones, soft phones or other devices connected to the IP based networks and providing telephony service.

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.

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.

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

hands-free terminals.

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

ETSI
---------------------- Page: 5 ----------------------
6 Final draft ETSI ES 202 740 V1.8.1 (2020-03)
1 Scope

The present document provides speech transmission performance requirements for 8 kHz wideband 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 300 245-6: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 6: Wideband (7 kHz), loudspeaking and hands free telephony".

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

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

[4] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[5] Recommendation ITU-T G.722.1: "Low-complexity coding at 24 and 32 kbit/s for hands-free

operation in systems with low frame loss".

[6] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[7] 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".
[8] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[9] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

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

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

headset telephones".

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

hands-free terminals".
ETSI
---------------------- Page: 6 ----------------------
7 Final draft ETSI ES 202 740 V1.8.1 (2020-03)

[13] Recommendation ITU-T P.341: "Transmission characteristics for wideband digital loudspeaking

and hands-free telephony terminals".
[14] Recommendation ITU-T P.501: "Test signals for use in telephonometry".

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

complex test signals".

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

terminal testing".

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

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

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

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

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

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

[22] 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".

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

and gateways".
[24] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".

[25] TIA-920.130: "Telecommunications Communications Products Transmission Requirements for

Digital Interface Communications Devices with Headsets".

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

international connections".
[27] IETF RFC 5481: "Packet Delay Variation Applicability Statement".

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

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

code-excited linear prediction (CS-ACELP)".

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

transmitting at 5.3 and 6.3 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.

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".
ETSI
---------------------- Page: 7 ----------------------
8 Final draft ETSI ES 202 740 V1.8.1 (2020-03)

[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): reference point "n" from Recommendation ITU-T P.58 [9] "n" is

one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T P.58 [9], (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.

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
ETSI
---------------------- Page: 8 ----------------------
9 Final draft ETSI ES 202 740 V1.8.1 (2020-03)

loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a

telephone receiver

Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator

nominal setting of the volume control: setting which is closest to the nominal RLR

reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.

RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR-WB Adaptative Multi Rate - Wideband
CS Composite Source
CSS Composite Source Signal
DRP ear-Drum Reference Point
DUT Devise Under Test
EC Echo Canceller
EL Echo Loss
ERP Ear Reference Point
FFT Fast Fourrier Transform
G-MOS-LQOw Overall transmission quality wideband
GSM Global System for Mobile communications
HATS Head And Torso Simulator
HFRP Hands Free Reference Point
HFT Hands Free Terminal
IEC International Electrotechnical Commission
IP Internet Protocol
IPDV IP Packet Delay Variation

ITU-T International Telecommunication Union -Telecommunication standardization sector

LE Earphone coupling Loss
MOS Mean Opinion Score
MOS-LQOy Mean Opinion Score - Listening Quality Objective

NOTE: y being N for narrowband, M for mixed, S for super-wideband and F for fullband. See Recommendation

ITU-T P.800.1 [18].
MRP Mouth Reference Point
N-MOS-LQOw Transmission quality of the background noise wideband
NLP Non Linear Processor
PBX Private Branch eXchange
PC Personal Computer
PCM Pulse Code Modulation
PDA Personal Digital Assistant
PMRP Sound Pressure at the Mouth Reference Point
PN Pseudo Noise
POI Point Of Interconnection
QoS Quality of Service
RLR Receive Loudness Rating
RMS Root Mean Square
RTP Real-Time Transport Protocol
S-MOS-LQOw Transmission quality of the speech wideband
ETSI
---------------------- Page: 9 ----------------------
10 Final draft ETSI ES 202 740 V1.8.1 (2020-03)
SLR Send Loudness Rating
TCL Terminal Coupling Loss
TDM Time Division Multiplex
TELR Talker Echo Loudness Rating
TOSQA Telecomm
...

SLOVENSKI STANDARD
SIST ES 202 740 V1.8.1:2020
01-julij-2020
Kakovost prenosa govora in večpredstavnih vsebin (STQ) - Prenosne zahteve za
širokopasovne zvočniške in prostoročne terminale VoIP glede na kakovost
storitev (QoS), kot jo dojema uporabnik
Speech and multimedia Transmission Quality (STQ) - Transmission requirements for
wideband VoIP loudspeaking and handsfree terminals from a QoS perspective as
perceived by the user
Ta slovenski standard je istoveten z: ETSI ES 202 740 V1.8.1 (2020-05)
ICS:
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
SIST ES 202 740 V1.8.1:2020 en

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

---------------------- Page: 1 ----------------------
SIST ES 202 740 V1.8.1:2020
---------------------- Page: 2 ----------------------
SIST ES 202 740 V1.8.1:2020
ETSI ES 202 740 V1.8.1 (2020-05)
ETSI STANDARD
Speech and multimedia Transmission Quality (STQ);
Transmission requirements for wideband
VoIP loudspeaking and handsfree terminals
from a QoS perspective as perceived by the user
---------------------- Page: 3 ----------------------
SIST ES 202 740 V1.8.1:2020
2 ETSI ES 202 740 V1.8.1 (2020-05)
Reference
RES/STQ-277
Keywords
handsfree, loudspeaking, quality, speech,
terminal, VoIP, wideband
ETSI
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© ETSI 2020.
All rights reserved.

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

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GSM and the GSM logo are trademarks registered and owned by the GSM Association.
ETSI
---------------------- Page: 4 ----------------------
SIST ES 202 740 V1.8.1:2020
3 ETSI ES 202 740 V1.8.1 (2020-05)
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 ........................................................................................................................................ 7

3 Definition of terms, symbols and abbreviations ....................................................................................... 8

3.1 Terms .................................................................................................................................................................. 8

3.2 Symbols .............................................................................................................................................................. 9

3.3 Abbreviations ..................................................................................................................................................... 9

4 General considerations ........................................................................................................................... 10

4.1 Coding algorithm .............................................................................................................................................. 10

4.2 End-to-end considerations ................................................................................................................................ 10

5 Test equipment ....................................................................................................................................... 11

5.1 IP half channel measurement adaptor ............................................................................................................... 11

5.2 Environmental conditions for tests ................................................................................................................... 11

5.3 Accuracy of measurements and test signal generation ..................................................................................... 11

5.4 Network impairment simulation ....................................................................................................................... 12

5.5 Acoustic environment ....................................................................................................................................... 12

5.6 Influence of terminal delay on measurements .................................................................................................. 12

6 Requirements and associated measurement methodologies ................................................................... 12

6.1 Notes ................................................................................................................................................................ 12

6.2 Test setup.......................................................................................................................................................... 13

6.2.1 General ........................................................................................................................................................ 13

6.2.2 Setup for terminals ...................................................................................................................................... 13

6.2.2.1 Hands-free measurements ..................................................................................................................... 13

6.2.2.2 Measurements in loudspeaking mode ................................................................................................... 18

6.2.3 Test signal levels ......................................................................................................................................... 18

6.2.3.1 Send....................................................................................................................................................... 18

6.2.3.2 Receive .................................................................................................................................................. 19

6.2.4 Setup of background noise simulation ........................................................................................................ 19

6.2.5 Setup for variable echo path ....................................................................................................................... 20

6.3 Coding independent parameters ....................................................................................................................... 20

6.3.1 Send sensitivity/frequency response ........................................................................................................... 20

6.3.2 Send Loudness Rating (SLR)...................................................................................................................... 21

6.3.3 Mic mute ..................................................................................................................................................... 22

6.3.4 Send distortion ............................................................................................................................................ 22

6.3.5 Out-of-band signals in send direction ......................................................................................................... 23

6.3.6 Send noise ................................................................................................................................................... 23

6.3.7 Terminal Coupling Loss (TCL) .................................................................................................................. 24

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

6.3.9 Receive frequency response ........................................................................................................................ 25

6.3.10 Receive Loudness Rating (RLR) ................................................................................................................ 27

6.3.11 Receive distortion ....................................................................................................................................... 28

6.3.12 Out-of-band signals in receive direction ..................................................................................................... 29

6.3.13 Receive noise .............................................................................................................................................. 29

6.3.14 Double talk performance ............................................................................................................................ 30

6.3.14.1 General .................................................................................................................................................. 30

6.3.14.2 Attenuation range in send direction during double talk A .............................................................. 30

H,S,dt

6.3.14.3 Attenuation range in receive direction during double talk A ......................................................... 31

H,R,dt
ETSI
---------------------- Page: 5 ----------------------
SIST ES 202 740 V1.8.1:2020
4 ETSI ES 202 740 V1.8.1 (2020-05)

6.3.14.4 Detection of echo components during double talk ................................................................................ 32

6.3.14.5 Minimum activation level and sensitivity of double talk detection ....................................................... 33

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 ................................................................................ 34

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 ............................................................................. 35

6.3.16.3 Quality of background noise transmission (with far end speech).......................................................... 36

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

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

6.3.17.2 Spectral echo attenuation ...................................................................................................................... 37

6.3.17.3 Occurrence of artefacts ......................................................................................................................... 38

6.3.17.4 Variable echo path................................................................................................................................. 38

6.3.18 Variant impairments ................................................................................................................................... 38

6.3.18.1 Clock accuracy send .............................................................................................................................. 38

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

6.3.18.3 Send packet delay variation................................................................................................................... 39

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

6.4 Codec specific requirements............................................................................................................................. 41

6.4.1 Objective listening speech quality MOS-LQO in send direction ................................................................ 41

6.4.2 Objective listening speech quality MOS-LQO in receive direction............................................................ 42

6.4.3 Quality of jitter buffer adjustment .............................................................................................................. 44

Annex A (informative): Processing delays in VoIP terminals ............................................................ 46

Annex B (informative): Bibliography ................................................................................................... 49

History .............................................................................................................................................................. 50

ETSI
---------------------- Page: 6 ----------------------
SIST ES 202 740 V1.8.1:2020
5 ETSI ES 202 740 V1.8.1 (2020-05)
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

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.

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, wideband terminals providing higher audio-bandwidth and directly interfacing packet-switched

networks (VoIP) are being rapidly introduced. Such IP network edge devices may include gateways, specifically

designed IP phones, soft phones or other devices connected to the IP based networks and providing telephony service.

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.

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.

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

hands-free terminals.

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

ETSI
---------------------- Page: 7 ----------------------
SIST ES 202 740 V1.8.1:2020
6 ETSI ES 202 740 V1.8.1 (2020-05)
1 Scope

The present document provides speech transmission performance requirements for 8 kHz wideband 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 300 245-6: "Integrated Services Digital Network (ISDN); Technical characteristics of

telephony terminals; Part 6: Wideband (7 kHz), loudspeaking and hands free telephony".

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

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

[4] Recommendation ITU-T G.722: "7 kHz audio-coding within 64 kbit/s".

[5] Recommendation ITU-T G.722.1: "Low-complexity coding at 24 and 32 kbit/s for hands-free

operation in systems with low frame loss".

[6] Recommendation ITU-T G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive

Multi-Rate Wideband (AMR-WB)".

[7] 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".
[8] Recommendation ITU-T P.56: "Objective measurement of active speech level".
[9] Recommendation ITU-T P.58: "Head and torso simulator for telephonometry".

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

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

headset telephones".

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

hands-free terminals".
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[13] Recommendation ITU-T P.341: "Transmission characteristics for wideband digital loudspeaking

and hands-free telephony terminals".
[14] Recommendation ITU-T P.501: "Test signals for use in telephonometry".

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

complex test signals".

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

terminal testing".

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

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

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

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

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

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

[22] 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".

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

and gateways".
[24] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".

[25] TIA-920.130: "Telecommunications Communications Products Transmission Requirements for

Digital Interface Communications Devices with Headsets".

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

international connections".
[27] IETF RFC 5481: "Packet Delay Variation Applicability Statement".

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

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

code-excited linear prediction (CS-ACELP)".

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

transmitting at 5.3 and 6.3 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.

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".
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[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): reference point "n" from Recommendation ITU-T P.58 [9] "n" is

one of the points numbered from 11 to 17 and defined in table 6a of Recommendation ITU-T P.58 [9], (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.

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
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loudspeaking function: function of a handset telephone using a loudspeaker associated with an amplifier as a

telephone receiver

Mouth Reference Point (MRP): point located on axis and 25 mm in front of the lip plane of a mouth simulator

nominal setting of the volume control: setting which is closest to the nominal RLR

reordering: packet order changes during transfer over the network [i.5], packets arrive out of order at the receiver (i.e.

RTP packets)
softphone: speech communication system based upon a computer
3.2 Symbols
Void.
3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AM-FM Amplitude Modulation - Frequency Modulation
AMR-WB Adaptative Multi Rate - Wideband
CS Composite Source
CSS Composite Source Signal
DRP ear-Drum Reference Point
DUT Devise Under Test
EC Echo Canceller
EL Echo Loss
ERP Ear Reference Point
FFT Fast Fourrier Transform
G-MOS-LQOw Overall transmission quality wideband
GSM Global System for Mobile communications
HATS Head And Torso Simulator
HFRP Hands Free Reference Point
HFT Hands Free Terminal
IEC International Electrotechnical Commission
IP Internet Protocol
IPDV IP Packet Delay Variation
ITU-T International Telecommunication Union -Telecommunication sta
...

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