kSIST FprES 202 740 V1.8.2:2022

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

RES/STQ-303

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: Not Published
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 07-Mar-2022
• Due Date: 25-Apr-2022
• Ref Project: ETSI ES 202 740 V1.8.2 (2022-03) - Speech and multimedia Transmission Quality (STQ); Transmission requirements for wideband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

Standards Content (sample)

Final draft ETSI ES 202 740 V1.8.2 (2022-03)
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
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2 Final draft ETSI ES 202 740 V1.8.2 (2022-03)
Reference
RES/STQ-303
Keywords
handsfree, loudspeaking, quality, speech, terminal,
VoIP, wideband
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ETSI
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3 Final draft ETSI ES 202 740 V1.8.2 (2022-03)
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 ....................................................................................................................... 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) ................................................................................................................ 28

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

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

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

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 .............................................................. 31

H,S,dt

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

H,R,dt
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4 Final draft ETSI ES 202 740 V1.8.2 (2022-03)

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 ....................................................... 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).......................................................... 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 ................................................................................................................................... 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................................................................................................................... 39

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 .............................................................................................................. 44

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

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

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

ETSI
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5 Final draft ETSI ES 202 740 V1.8.2 (2022-03)
Intellectual Property Rights
Essential patents

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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
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6 Final draft ETSI ES 202 740 V1.8.2 (2022-03)
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
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7 Final draft ETSI ES 202 740 V1.8.2 (2022-03)

[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] Void.

[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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8 Final draft ETSI ES 202 740 V1.8.2 (2022-03)

[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
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9 Final draft ETSI ES 202 740 V1.8.2 (2022-03)

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 Cancell
...