ETSI ES 202 718 V1.1.1 (2011-10)

ETSI Standard
Speech and multimedia Transmission Quality (STQ);
Transmission Requirements for IP-based Narrowband and
Wideband Home Gateways and Other Media Gateways from a
QoS Perspective as Perceived by the User

2 ETSI ES 202 718 V1.1.1 (2011-10)

Reference
DES/STQ-00145
Keywords
QoS, speech
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ETSI
3 ETSI ES 202 718 V1.1.1 (2011-10)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 8
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 9
4 General considerations . 9
4.1 Default Coding Algorithm . 9
4.2 End-to-end considerations . 10
4.3 Parameters to be investigated . 10
4.3.1 Applicability of parameters to different MGWs . 10
5 Test equipment . 11
5.1 IP half channel measurement adaptor . 11
5.2 Environmental conditions for tests . 12
5.3 Accuracy of measurements and test signal generation . 12
5.4 Network impairment simulation . 12
6 Requirements and associated Measurement Methodologies . 13
6.1 Test setup. 13
6.1.1 Setup for Media Gateways with 4-wire interface . 14
6.1.2 Setup for Media Gateways with 2-wire interface . 14
6.1.3 Setup for Media Gateways with Wireless Access . 15
6.1.4 Setup for IP-to-IP Media Gateways . 15
6.1.5 Test Signal Levels . 16
6.1.6 Background noise simulation . 16
6.2 Coding independent parameters . 16
6.2.1 Send Frequency response . 16
6.2.2 Circuit Loudness Rating in Send . 17
6.2.3 Linearity Range for CLR (SND) . 18
6.2.4 Send Distortion . 19
6.2.5 Spurious Out-of-Band Signals in Send direction . 20
6.2.6 Send Noise . 20
6.2.7 Receive Frequency Response . 20
6.2.8 Circuit Loudness Rating in Receive . 21
6.2.9 Linearity Range for CLR (RCV) . 22
6.2.10 Receive Distortion . 23
6.2.11 Out-of-Band Signals Wideband to Narrowband Transcoding . 24
6.2.12 Spurious Out-of-band Signals Narrowband to Wideband Transcoding . 24
6.2.13 Minimum Activation Level and Sensitivity in Receive Direction . 25
6.2.14 Receive Noise . 25
6.2.15 Double Talk Performance . 26
6.2.15.1 Attenuation Range in Send Direction during Double Talk A . 26
H,S,dt
6.2.15.2 Attenuation Range in Receive Direction during Double Talk A . 28
H,R,dt
6.2.15.3 Detection of Echo Components during Double Talk . 29
6.2.15.4 Minimum Activation Level and Sensitivity of Double Talk Detection . 31
6.2.16 Switching Characteristics . 31
6.2.16.1 Activation in Send Direction . 31
6.2.16.2 Activation in Receive Direction . 32
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4 ETSI ES 202 718 V1.1.1 (2011-10)
6.2.16.3 Silence Suppression and Comfort Noise Generation . 33
6.2.17 Background Noise Performance . 33
6.2.17.1 Performance in Send Direction in the Presence of Background Noise . 33
6.2.17.2 Quality of Speech with Background Noise . 34
6.2.17.3 Quality of Background Noise Transmission (with Far End Speech) . 35
6.2.17.4 Quality of Background Noise Transmission (with Near End Speech) . 36
6.2.18 Quality of Echo Cancellation . 36
6.2.18.1 Echo paths . 36
6.2.18.2 Echo Performance According to ITU-T Recommendation G.168 . 37
6.2.18.3 Terminal Coupling Loss (TCLw) . 37
6.2.18.4 Temporal Echo Effects . 38
6.2.18.5 Spectral Echo Attenuation . 38
6.2.18.6 Occurrence of Artefacts . 39
6.2.19 Variant Impairments; Network dependant . 39
6.2.19.1 Clock Accuracy Send . 39
6.2.19.2 Clock Accuracy Receive . 39
6.2.19.3 Send Delay Variation . 40
6.2.19.4 Delay versus Time Receive . 40
6.2.19.5 Quality of Jitter buffer adjustment . 40
6.2.20 Immunity to DTMF False Detection in Send Direction . 40
6.3 Codec Specific Requirements. 41
6.3.1 Send Delay . 41
6.3.2 Receive delay . 42
6.3.3 Delay for IP-to-IP MGW . 44
6.3.4 Objective Listening Speech Quality MOS-LQO in Send direction . 44
6.3.5 Objective Listening Quality MOS-LQO in Receive direction . 45
6.3.5.1 Efficiency of Packet Loss Concealment (PLC) . 47
6.3.5.2 Efficiency of Delay Variation Removal . 47
Annex A (informative): Impulse Response of a Narrowband and Wideband DECT PP . 48
Annex B (normative): Test signal for immunity to DTMF false detection in send direction . 50
Annex C (informative): Bibliography . 51
History . 52

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5 ETSI ES 202 718 V1.1.1 (2011-10)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is 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 (http://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.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
Introduction
Traditionally, the analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the
fast growth of IP networks, packet-switched networks (VoIP) interfacing PSTN networks and mobile networks, as well
as different types of IP-terminals, are being rapidly introduced. Different types of gateways are used to interconnect to
such IP networks. Since the IP networks will be in many cases interworking with the traditional PSTN and private
networks, many of the basic transmission requirements have to be harmonized between these different types of network
from an end-to-end perspective, including specifications for the edge points.
The present document covers IP-based narrowband and wideband home gateways and other media gateways. It aims to
enhance the interoperability and end-to-end quality.
In contrast to other standards which define minimum performance requirements, it is the intention of the present
document to specify gateway equipment requirements which enable manufacturers and service providers to enable
end-to-end speech performance as perceived by the user. These requirements are absolutely necessary to ensure a good
quality, but they are not sufficient. They have to be combined with requirements (and associated relevant measurement
methods) for other elements in the transmission chain (core IP network, PSTN, terminals), as well as for the whole
mouth-to-ear transmission path.
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6 ETSI ES 202 718 V1.1.1 (2011-10)
1 Scope
The present document provides speech transmission performance requirements for narrowband and wideband media
gateways from a QoS perspective as perceived by the user. Media gateways can be network or home based, they may
include a transcoding function. The present document covers the following types of IP-based media gateways:
• ATA (Analogue Terminal Adapter), home gateway IP to POTS
• ITA (ISDN Terminal Adapter), home gateway IP to ISDN
• IAD (Integrated Access device), home router including ATA or ITA
• Network based ATA and ITA
• Carrier grade media gateway, network gateway IP to TDM
• IP-to-IP media gateway, network gateway with transcoding and/or other media processing
DECT interfaces of media gateways are excluded from the present document and should be measured according to the
relevant DECT standards.
Interfaces of media gateways used together with terminals as a system (i.e. connected via Ethernet or with a proprietary
interface) are excluded in the present document and should be measured according to the relevant terminal standard.
If a media gateway includes more than one interface type (e.g. POTS and ISDN), each interface has to be dealt with
differently.
The requirements available in the present document will ensure a high compatibility with IP-and TDM-based fixed and
wireless terminals and networks, including DECT and mobile terminals.
It is the aim to optimize interoperability, the listening and talking quality and the conversational performance. Related
requirements and test methods are defined in the present document.
The present document does not apply to media gateways with 4-wire analogue interfaces.
2 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
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full
Rate (EFR) speech transcoding (GSM 06.60)".
[2] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); AMR speech codec, wideband; General description
(3GPP TS 26.171 version 6.0.0 Release 6)".
[3] ITU-T Recommendation G.107: "The E-model, a computational model for use in transmission
planning".
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7 ETSI ES 202 718 V1.1.1 (2011-10)
[4] ITU-T Recommendation G.108: "Application of the E-model: A planning guide".
[5] ITU-T Recommendation G.109: "Definition of categories of speech transmission quality".
[6] ITU-T Recommendation G.100.1: "The use of the decibel and of relative levels in speechband
telecommunications".
[7] ITU-T Recommendation G.111: "Loudness Ratings (LRs) in an international connection".
[8] ITU-T Recommendation G.122: "Influence of national systems on stability and talker echo in
international connections".
[9] ITU-T Recommendation G.711: "Pulse code modulation (PCM) of voice frequencies".
[10] ITU-T Recommendation G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
[11] ITU-T Recommendation G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code
Modulation (ADPCM)".
[12] ITU-T Recommendation G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-
code-excited linear prediction (CS-ACELP)".
[13] ITU-T Recommendation G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s
scalable wideband coder bitstream interoperable with G.729".
[14] ITU-T Recommendation G.1020: "Performance parameter definitions for quality of speech and
other voiceband applications utilizing IP networks".
[15] ITU-T Recommendation P.50: "Artificial voices".
[16] ITU-T Recommendation P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[17] ITU-T Recommendation P.501: "Test signals for use in telephonometry".
[18] ITU-T Recommendation P.502: "Objective test methods for speech communication systems using
complex test signals".
[19] ITU-T Recommendation P.862: "Perceptual evaluation of speech quality (PESQ): An objective
method for end-to-end speech quality assessment of narrow-band telephone networks and speech
codecs".
[20] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".
[21] ITU-T Recommendation P.800.1: "Mean Opinion Score (MOS) terminology".
[22] ETSI TS 102 971: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics of a 2-wire analogue interface
for short line interface".
[23] ETSI ES 201 970: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics at a 2-wire analogue presented
Network Termination Point (NTP)".
[24] ITU-T Recommendation G.168: "Digital network echo cancellers".
[25] ITU-T Recommendation P.863: "Perceptual objective listening quality assessment".
[26] ITU-T Recommendation G.722: "7 kHz audio-coding within 64 kbit/s".
[27] ITU-T Recommendation G.722.1: "Low-complexity coding at 24 and 32 kbit/s for hands-free
operation in systems with low frame loss".
[28] ITU-T Recommendation G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive
Multi-Rate Wideband (AMR-WB)".
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[29] ITU-T Recommendation P.862.1: "Mapping function for transforming P.862 raw result scores to
MOS-LQO".
2.2 Informative references
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 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality
performance in the presence of background noise; Part 1: Background noise simulation technique
and background noise database".
[i.2] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and
implementation of VoIP reference point".
[i.3] 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.4] IETF RFC 2833: "RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals".
[i.5] IETF RFC 4733: "RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals".
[i.6] ETSI TR 102 927: "Speech and multimedia Transmission Quality (STQ); Packet Loss
Concealment (PLC) performance measurement setup for home networks".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
0dBr point: reference point always located at the digital side of the gateway, for IP-IP gateways located at the input of
the MGW under test
NOTE: See ITU-T Recommendation G.100.1 [6].
2-wire interface: in the context of the present document, the telephony analogue interface over 2-wires used in the
local loop
4-wire interface: in the context of the present document, a 4-wire digital interface with separate channels for both
directions, irrespective of the physical transmission technology
codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions
of transmission in the same equipment
Composite Source Signal (CSS): signal composed in time by various signal elements
MGW with 2-wire interface: MGW with an analogue 2-wire interface (ATA)
MGW with 4-wire interface: MGW with only 4-wire interfaces, e.g. ITA, IP-to-IP and wireless access points
nominal setting of the volume control: when a receive volume control is provided, the setting which is closest to the
nominal RLR of 2 dB
receive direction: the direction from packet switched interfaces towards a synchronous interface (e.g. ISDN, analogue)
or between two packet switched interfaces (for media gateways with packet switched transport on only one side)
NOTE: For media gateways with packet switched transport on both sides (IP-to-IP-MGW), the requirements of
the receive direction have to be applied in both directions.
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9 ETSI ES 202 718 V1.1.1 (2011-10)
receive interface: interface in the measurement setup, where a receive signal is injected and/or a send signal is
measured.
send direction: direction from a synchronous interface (e.g. ISDN, analogue) towards a packet switched interface (for
media gateways with packet switched interface on only one side)
NOTE: For media gateways with packet switched interfaces on both sides the requirements of the send direction
are not relevant.
send interface: interface in the measurement setup, where a send signal is injected and/or a receive signal is measured
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ATA Analogue Terminal Adapter
CLR Circuit Loudness Rating
CSS Composite Source Signal
DSL Digital Subscriber Line
DSLAM Digital Subscriber Line Access Multiplexer
DTMF Dual Tone Multi Frequency
EL Echo Loss
IAD Integrated Access device
IP Internet Protocol
ITA ISDN Terminal Adapter
JLR Junction Loudness Rating
MGW Media GateWay
MOS-LQOy Mean Opinion Score - Listening Quality Objective
NOTE: See ITU-T Recommendation P.800.1 [21].
NLP Non Linear Processor
PCM Pulse Code Modulation
PESQ™ Perceptional Evaluation of Speech Quality™
PLC Packet Loss Concealment
PN Pseudo-random Noise
POI Point Of Interconnect
POTS Plain Old Telephone Service
PSTN Public Switched Telephone Network
QoS Quality of Service
TCL Terminal Coupling Loss
TCN Trace Control for Netem™
TDM Time Division Multiplexing
VAD Voice Activity Detection
VoIP Voice over Internet Protocol
4 General considerations
4.1 Default Coding Algorithm
Narrowband VoIP gateways shall support the coding algorithm according to ITU-T Recommendation G.711 [9] (both
µ-law and A-law). VoIP gateways may support other coding algorithms.
Wideband VoIP gateways shall support the coding algorithm according to ITU-T Recommendation G.722 [26]. VoIP
gateways may support other coding algorithms.
NOTE: Associated Packet Loss Concealment (PLC) e.g. as defined in ITU-T Recommendation G.711 [9]
appendix I should be used.
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4.2 End-to-end considerations
In order to achieve a desired end-to-end speech transmission performance (mouth-to-ear) it is recommended that the
general rules of transmission planning are carried out with the E-model of ITU-T Recommendation G.107 [3]; this
includes the a-priori determination of the desired category of speech transmission quality as defined in ITU-T
Recommendation G.109 [5].
While, in general, the transmission characteristics of single circuit-oriented network elements, such as switches or
terminals can be assumed to have a single input value for the planning tasks of ITU-T Recommendation G.108 [4], this
approach is not applicable in packet based systems and thus there is a need for the transmission planner's specific
attention.
In particular the decision as to which delay measured according to the present document is acceptable or representative
for the specific configuration is the responsibility of the individual transmission planner.
ITU-T Recommendation G.108 with its amendments [4] provides further guidance on this important issue.
The following optimum parameters from a users' perspective need to be considered:
• Minimized delay in send and receive direction.
• Optimum loudness Rating (JLR).
• Compensation for network delay variation.
• Packet loss recovery performance.
• Maximized echo loss.
• Immunity to false detection of DTMF in speech signal.
4.3 Parameters to be investigated
4.3.1 Applicability of parameters to different MGWs
Table 1: Parameter applicability
2-wire home 4-wire MGW 4-wire MGW wireless home
and network (excl. IP-to-IP (IP-to-IP-MGW) MGW
MGW MGW)
6.2 Codec independent parameters

6.2.1 Send frequency response M M NA M
6.2.2 Circuit Loudness Rating in Send M M NA M
6.2.3 Linearity Range for CLR(SND) M M NA M
6.2.4 Send Distortion M M NA M
6.2.5 Spurious Out-of-Band Signals in M NA NA NA
Send direction
6.2.6 Send Noise M M NA M
6.2.7 Receive frequency response M M MM M
6.2.8 Circuit Loudness Rating in Receive
M M MM M
6.2.9 Linearity Range for CLR(RCV)
M M MM M
6.2.10 Receive Distortion M M MM M
6.2.11 Out-of-Band Signals in Wideband to NA M M M
Narrowband Transcoding
6.2.12 Spurious Out-of-band Signals NA M M M
Narrowband to Wideband Transcoding
6.2.13 Minimum activation level and
FFS FFS FFS FFS
sensitivity in Receive direction
6.2.14 Receive Noise M M MM M
6.2.15 Double Talk Performance

6.2.15.1 Attenuation Range in Send M M M M
Direction during Double Talk
6.2.15.2 Attenuation Range in Receive
M M M M
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11 ETSI ES 202 718 V1.1.1 (2011-10)
2-wire home 4-wire MGW 4-wire MGW wireless home
and network (excl. IP-to-IP (IP-to-IP-MGW) MGW
MGW MGW)
Direction during Double Talk
6.2.15.3 Detection of Echo Components
M M M M
during Double Talk
6.2.15.4 Minimum activation level and FFS FFS FFS FFS
sensitivity of double talk detection
6.2.16 Switching characteristics
6.2.16.1 Activation in Send Direction M M NA M
6.2.16.2 Activation in Receive Direction M M M M
6.2.16.3 Silence Suppression and Comfort
FFS FFS FFS FFS
Noise Generation
6.2.17 Background Noise Performance
6.2.17.1 Performance in send direction in
M M MM M
the presence of background noise
6.2.17.2 Quality of Speech with M M MM M
Background Noise
6.2.17.3 Quality of Background Noise M M MM M
Transmission (with Far End Speech)
6.2.17.4 Quality of Background Noise M M MM M
Transmission (with Near End Speech)
6.2.18 Quality of echo cancellation
6.2.18.2 Echo Performance acc. To G.168 M M NA M
6.2.18.3 TCLw M M NA M
6.2.18.4Temporal echo effects M M NA M
6.2.18.5 Spectral Echo Attenuation M M NA M
6.2.18.6 Occurrence of Artefacts
FFS FFS NA FFS
6.2.19 Variant Impairments; Network

dependant
6.2.19.1 Clock accuracy send
M M MM M
6.2.19.2 Clock accuracy receive
M M MM M
6.2.19.3 Send delay variation M M MM M
6.2.20 Immunity to DTMF false detection in M M MM M
send direction
6.3 Codec Specific Requirements
6.3.1 Send Delay M M NA M
6.3.2 Receive Delay M M NA M
6.3.3 Delay for IP-to-IP MGW NA NA MM NA
6.3.4 Objective Listening Speech Quality M M M M
MOS-LQO in Send direction
6.3.5 Objective Listening Speech Quality M M M M
MOS-LQO in Receive direction
6.3.5.1 Efficiency of Packet Loss FFS FFS FFS FFS
Concealment (PLC)
6.3.5.2 Efficiency of Delay Variation
FFS FFS FFS FFS
Removal
M: Mandatory
MM: Mandatory for both interfaces of the MGW
NA: Not applicable
FFS: For further study
5 Test equipment
5.1 IP half channel measurement adaptor
The IP half channel measurement adaptor is described in EG 202 425 [i.2]. Such an apparatus is required to code and
insert audio signals into IP packets send to the IP receive interface of the gateway under test, as well as to capture and
decode audio signals constituting the payload of IP packets received from the IP sending interface of the gateway under
test.
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5.2 Environmental conditions for tests
The following conditions shall apply for the testing environment:
a) Ambient temperature: 15 °C to 35 °C (inclusive);
b) Relative humidity: 5 % to 85 %;
c) Air pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar).
5.3 Accuracy of measurements and test signal generation
Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or better than:
Table 2: Measurement Accuracy
Item Accuracy
Electrical signal level
±0,2 dB for levels ≥ -50 dBV
±0,4 dB for levels < -50 dBV
Frequency ±0,2 %
Time ±0,2 %
Unless specified otherwise, the accuracy of the signals generated by the test equipment shall be better than:
Table 3: Accuracy of test signal generation
Quantity Accuracy
Electrical excitation levels ±0,4 dB across the whole frequency range.
Frequency generation ±2 % (see note)
Time ±0,2 %
Specified component values ±1 %
NOTE: This tolerance may be used to avoid measurements at critical frequencies, e.g. those
due to sampling operations within the terminal under test.

If the equipment is powered by other means and those means are not supplied as part of the apparatus, all tests shall be
carried out within the power supply limit declared by the supplier. If the power supply is a.c. the test shall be conducted
within ±4 % of the rated frequency.
5.4 Network impairment simulation
At least one set of requirements is based on the assumption of an error free packet network, and at least one other set of
requirements is based on a defined simulated malperformance of the packet network.
An appropriate network simulator has to be used, for example Netem™.
The key points of Netem™ can be summarized as follows:
• Netem™ is part of most Linux™ distributions, it only has to be switched on, when compiling a kernel. With
Netem™, there are the same possibilities as with Nistnet™, there can be generated loss, duplication, delay and
jitter (and the distribution can be chosen during runtime). Netem™ can be run on a Linux-PC™ running as a
bridge or a router (Nistnet™ only runs on routers).
• With an amendment of Netem™, TCN (Trace Control for Netem™) which was developed by ETH Zurich™,
it is even possible, to control the behaviour of single packets via a trace file. So it is for example possible to
generate a single packet loss, or a specific delay pattern. This amendment is planned to be included in new
Linux Kernels™, nowadays it is available as a patch to a specific kernel and to the iproute2 tool (iproute2
contains Netem™).
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13 ETSI ES 202 718 V1.1.1 (2011-10)
• It is not advised to define specific distortion patterns for testing in standards, because it will be easy to adapt
devices to these patterns (as it is already done for test signals). But if a pattern is unknown to a manufacturer,
the same pattern can be used by a test lab for different devices and gives comparable results. It is also possible
to take a trace of Nistnet™ distortions, generate a file out of this and playback the exact same distortions with
Netem™.
6 Requirements and associated Measurement
Methodologies
Differences between different media gateway types are dealt with in the respective requirements.
In the case of IP-IP MGW packet based interfaces are provided at both sides of the gateway. Therefore the receive
requirements apply, for both interfaces.
NOTE 1: In general the test methods as described in the present document apply. If alternative methods exist they
may be used if they have been proven to give the same result as the method described in the standard.
NOTE 2: Due to the time variant nature of IP connections delay variation may impair the measurements. In such
cases the measurement has to be repeated until a valid measurement result is achieved.
6.1 Test setup
The preferred way of testing a gateway is to connect its interfaces to network simulators with exact defined settings and
access points. The test sequences are fed in electrically, using a reference codec or using the direct signal processing
approach.
When VoIP runs on the gateway under test only in conjunction with a registration by an application server (e.g. SIP
proxy), the network simulator may need to provide also the registration functionality.
Alternatively, if for the IP-interfaces another technology than Ethernet is used (for instance DSL access, it may be
necessary to add additional equipment in the test setup for connecting the measurement equipment (e.g. a DSLAM, if
the IP-interface works over DSL). There should be no speech signal processing in this additional equipment (the media
payload has to be passed transparent through this equipment, while e.g. header manipulation is allowed). The influence
of this additional equipment (delay and eventually delay variation) has to be taken in account for the measurements.
NOTE 1: It is up to the testlab to identify potential time invariances or non linearities in the network used for
interconnection and to take those effects into account properly.
With this setup it is possible to measure the parameters listed in the present document over a whole network, if the
behaviour of the network is known.
In the present document, the terms "send" and "receive" can be found in the pictures of the relevant test setup.
When a coder with variable bit rate is used for testing the MGW parameters, the bit rate recognized giving the best
characteristics and/or the ones commonly used should be selected, e.g.:
• AMR-NB (TS 126 171 [2]): 12,2 kbit/s.
• AMR-WB (G. 722.2 [28]): 12,65 kbit/s.
• ITU-T Recommendation G.729.1 [13]: 32 kbit/s.
NOTE 2: Although packet capturing and network simulation in figures 1 to 4 are shown in one box they may be
separate devices.
ETSI
14 ETSI ES 202 718 V1.1.1 (2011-10)
6.1.1 Setup for Media Gateways with 4-wire interface

Figure 1: Half channel measurement for MGW with 4-wire interface
6.1.2 Setup for Media Gateways with 2-wire interface

Figure 2: Half channel measurement for MGW with 2-wire interface
ETSI
15 ETSI ES 202 718 V1.1.1 (2011-10)
6.1.3 Setup for Media Gateways with Wireless Access
Receive
IP-Half-Channel
Network
Measurement
simulator
MGW
Adapter (delay, jitter,
Path through Path through
(VoIP Reference Point)
under test
packet loss)
IP network IP network
Gateway
Packet capture
Simulation
Send
Wireless
reference point
Measurement system
(e.g. DECT reference PP)
Figure 3: Half channel measurement for MGW with wireless access
6.1.4 Setup for IP-to-IP Media Gateways
P
I
a
P
t
h
n
e
t
h
t
w r
o
o
u
r
g
k
h
Figure 4: Half channel measurement for IP-to-IP MGW
NOTE 1: For measuring both directions of an IP-to-IP MGW, the network simulator can be moved to the other side
of the MGW.
ETSI
16 ETSI ES 202 718 V1.1.1 (2011-10)
NOTE 2: If the network simulator is moved to the other side of the IP-to-IP MGW the measurements to be
conducted in receive are to be conducted in this scenario on the other channel (send in the precious
scenario).
6.1.5 Test Signal Levels
Unless specified otherwise, the applied test signal level at the digital inputs shall be -16 dBm0. For analogue inputs
(2-wire) the applied test signal level should be -16 dBm for home MGWs and -19 dBm for network MGWs at the media
gateway interface.
NOTE: For analogue inputs of network MGWs, an attenuation of 3 dB for the simulation of an access line is
taken into account for measurements with nominal levels.
6.1.6 Background noise simulation
Background noise signals used for testing should be recorded according to the description in EG 202 396-1 [i.1].
EG 202 396-1 [i.1] contains a description of the recording arrangement for realistic background noises, a description of
the setup for a loudspeaker arrangement suitable to simulate a background noise field in a lab-type environment and a
database of realistic background noises, which can be used for testing the terminal performance with a variety of
different background noises.
In order to create a representative electrical test signal for the MGW containing speech at a nominal level mixed with
the amount of background noise picked up by a terminal, the setup in EG 202 396-1 [i.1] is used. The terminal is
connected to a reference interface providing nominal properties for the electrical interface as used by the terminal. The
signal (speech plus noise) is recorded at this interface and inserted through the appropriate reference interfaces as
described in clauses 6.1.1 to 6.1.4 in such a way that the signal level and spectral content delivered to the MGW under
test is equivalent to the one it would have seen if the terminal was connected directly. Either terminals considered to be
representative for the type of terminal attached to the MGW are used or individual terminals are used.
NOTE: Due to terminal geometry, microphone technique and signal processing used in the phone the signals
acquired at the electrical interface may highly vary. As a consequence the performance of the MGW may
highly depend on the terminal connected.
The following noises of EG 202 396-1 [i.1] shall be used.
L: 77,8 dB(A)
Recording in pub Pub_Noise_binaural 30 s Binaural
R: 78,9 dB(A)
L: 68,4 dB(A)
Recording at sales counter Cafeteria_Noise_binaural 30 s Binaural
R: 67,3 dB(A)
L: 56,6 dB(A)
Recording in business office Work_Noise_Office_Callcener_binaural 30 s Binaural
R: 57,8 dB(A)
6.2 Coding independent parameters
6.2.1 Send Frequency response
Requirement
The frequency response for 4-wire MGW shall be according to tables 4 and 5:
Table 4: Send frequency response for 4-wire MGW
Frequency Upper Limit Lower Limit
100 Hz 1 dB
300 Hz 1 dB -1 dB
3 400 Hz 1 dB -1 dB
4 000 Hz 1 dB
ETSI
17 ETSI ES 202 718 V1.1.1 (2011-10)
Table 5: Send frequency response for wideband 4-wire MGW
Frequency Upper Limit Lower Limit
100 Hz 1 dB
200 Hz 1 dB 1 dB
7 000 Hz 1 dB 1 dB
8 000 Hz 1 dB
NOTE: The frequency response characteristics requirements apply to codecs having flat response characteristics.
If a codec with non-flat characteristics is used the requirement has to be corrected by the ideal response
characteristics of this codec.
The frequency response for 2-wire MGW shall be according to table 6 (see [22]) for both home and network MGWs:
Table 6: Send frequency response for narrowband 2-wire MGW
Frequency Upper Limit Lower Limit
0 Hz 1 dB
300 Hz 1 dB -1 dB
3 400 Hz 1 dB -1 dB
4 000 Hz 1 dB
Measurement Method
The test signal to be used for the measurements shall be the artificial voice according to ITU-T Recommendation
P.50 [15]. If the signal to noise ratio in the high frequency domain is not sufficient Composite Source Signal (CSS) as
defined in ITU-T Recommendation P.501 [17] shall be used. The test signal duration shall be 20 s (10 s female, 10 s
male voice). The test signal level is averaged over the complete test signal sequ
...

SLOVENSKI STANDARD
01-oktober-2014
.DNRYRVWSUHQRVDJRYRUDLQYHþSUHGVWDYQLKYVHELQ6743UHQRVQH]DKWHYH]D
R]NRSDVRYQHLQãLURNRSDVRYQHGRPDþHSUHKRGHLQGUXJHPHGLMVNHSUHKRGHSR
SURWRNROX,3JOHGHQDNDNRYRVWVWRULWHY4R6NRWMLKGRMHPDXSRUDEQLN
Speech and multimedia Transmission Quality (STQ) - Transmission Requirements for IP-
based Narrowband and Wideband Home Gateways and Other Media Gateways from a
QoS Perspective as Perceived by the User
Ta slovenski standard je istoveten z: ES 202 718 Version 1.1.1
ICS:
33.040.35 Telefonska omrežja Telephone networks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ETSI Standard
Speech and multimedia Transmission Quality (STQ);
Transmission Requirements for IP-based Narrowband and
Wideband Home Gateways and Other Media Gateways from a
QoS Perspective as Perceived by the User

2 ETSI ES 202 718 V1.1.1 (2011-10)

Reference
DES/STQ-00145
Keywords
QoS, speech
ETSI
650 Route des Lucioles
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Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

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Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

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The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2011.
All rights reserved.
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of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI ES 202 718 V1.1.1 (2011-10)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 8
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 9
4 General considerations . 9
4.1 Default Coding Algorithm . 9
4.2 End-to-end considerations . 10
4.3 Parameters to be investigated . 10
4.3.1 Applicability of parameters to different MGWs . 10
5 Test equipment . 11
5.1 IP half channel measurement adaptor . 11
5.2 Environmental conditions for tests . 12
5.3 Accuracy of measurements and test signal generation . 12
5.4 Network impairment simulation . 12
6 Requirements and associated Measurement Methodologies . 13
6.1 Test setup. 13
6.1.1 Setup for Media Gateways with 4-wire interface . 14
6.1.2 Setup for Media Gateways with 2-wire interface . 14
6.1.3 Setup for Media Gateways with Wireless Access . 15
6.1.4 Setup for IP-to-IP Media Gateways . 15
6.1.5 Test Signal Levels . 16
6.1.6 Background noise simulation . 16
6.2 Coding independent parameters . 16
6.2.1 Send Frequency response . 16
6.2.2 Circuit Loudness Rating in Send . 17
6.2.3 Linearity Range for CLR (SND) . 18
6.2.4 Send Distortion . 19
6.2.5 Spurious Out-of-Band Signals in Send direction . 20
6.2.6 Send Noise . 20
6.2.7 Receive Frequency Response . 20
6.2.8 Circuit Loudness Rating in Receive . 21
6.2.9 Linearity Range for CLR (RCV) . 22
6.2.10 Receive Distortion . 23
6.2.11 Out-of-Band Signals Wideband to Narrowband Transcoding . 24
6.2.12 Spurious Out-of-band Signals Narrowband to Wideband Transcoding . 24
6.2.13 Minimum Activation Level and Sensitivity in Receive Direction . 25
6.2.14 Receive Noise . 25
6.2.15 Double Talk Performance . 26
6.2.15.1 Attenuation Range in Send Direction during Double Talk A . 26
H,S,dt
6.2.15.2 Attenuation Range in Receive Direction during Double Talk A . 28
H,R,dt
6.2.15.3 Detection of Echo Components during Double Talk . 29
6.2.15.4 Minimum Activation Level and Sensitivity of Double Talk Detection . 31
6.2.16 Switching Characteristics . 31
6.2.16.1 Activation in Send Direction . 31
6.2.16.2 Activation in Receive Direction . 32
ETSI
4 ETSI ES 202 718 V1.1.1 (2011-10)
6.2.16.3 Silence Suppression and Comfort Noise Generation . 33
6.2.17 Background Noise Performance . 33
6.2.17.1 Performance in Send Direction in the Presence of Background Noise . 33
6.2.17.2 Quality of Speech with Background Noise . 34
6.2.17.3 Quality of Background Noise Transmission (with Far End Speech) . 35
6.2.17.4 Quality of Background Noise Transmission (with Near End Speech) . 36
6.2.18 Quality of Echo Cancellation . 36
6.2.18.1 Echo paths . 36
6.2.18.2 Echo Performance According to ITU-T Recommendation G.168 . 37
6.2.18.3 Terminal Coupling Loss (TCLw) . 37
6.2.18.4 Temporal Echo Effects . 38
6.2.18.5 Spectral Echo Attenuation . 38
6.2.18.6 Occurrence of Artefacts . 39
6.2.19 Variant Impairments; Network dependant . 39
6.2.19.1 Clock Accuracy Send . 39
6.2.19.2 Clock Accuracy Receive . 39
6.2.19.3 Send Delay Variation . 40
6.2.19.4 Delay versus Time Receive . 40
6.2.19.5 Quality of Jitter buffer adjustment . 40
6.2.20 Immunity to DTMF False Detection in Send Direction . 40
6.3 Codec Specific Requirements. 41
6.3.1 Send Delay . 41
6.3.2 Receive delay . 42
6.3.3 Delay for IP-to-IP MGW . 44
6.3.4 Objective Listening Speech Quality MOS-LQO in Send direction . 44
6.3.5 Objective Listening Quality MOS-LQO in Receive direction . 45
6.3.5.1 Efficiency of Packet Loss Concealment (PLC) . 47
6.3.5.2 Efficiency of Delay Variation Removal . 47
Annex A (informative): Impulse Response of a Narrowband and Wideband DECT PP . 48
Annex B (normative): Test signal for immunity to DTMF false detection in send direction . 50
Annex C (informative): Bibliography . 51
History . 52

ETSI
5 ETSI ES 202 718 V1.1.1 (2011-10)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is 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 (http://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.
Foreword
This ETSI Standard (ES) has been produced by ETSI Technical Committee Speech and multimedia Transmission
Quality (STQ).
Introduction
Traditionally, the analogue and digital telephones were interfacing switched-circuit 64 kbit/s PCM networks. With the
fast growth of IP networks, packet-switched networks (VoIP) interfacing PSTN networks and mobile networks, as well
as different types of IP-terminals, are being rapidly introduced. Different types of gateways are used to interconnect to
such IP networks. Since the IP networks will be in many cases interworking with the traditional PSTN and private
networks, many of the basic transmission requirements have to be harmonized between these different types of network
from an end-to-end perspective, including specifications for the edge points.
The present document covers IP-based narrowband and wideband home gateways and other media gateways. It aims to
enhance the interoperability and end-to-end quality.
In contrast to other standards which define minimum performance requirements, it is the intention of the present
document to specify gateway equipment requirements which enable manufacturers and service providers to enable
end-to-end speech performance as perceived by the user. These requirements are absolutely necessary to ensure a good
quality, but they are not sufficient. They have to be combined with requirements (and associated relevant measurement
methods) for other elements in the transmission chain (core IP network, PSTN, terminals), as well as for the whole
mouth-to-ear transmission path.
ETSI
6 ETSI ES 202 718 V1.1.1 (2011-10)
1 Scope
The present document provides speech transmission performance requirements for narrowband and wideband media
gateways from a QoS perspective as perceived by the user. Media gateways can be network or home based, they may
include a transcoding function. The present document covers the following types of IP-based media gateways:
• ATA (Analogue Terminal Adapter), home gateway IP to POTS
• ITA (ISDN Terminal Adapter), home gateway IP to ISDN
• IAD (Integrated Access device), home router including ATA or ITA
• Network based ATA and ITA
• Carrier grade media gateway, network gateway IP to TDM
• IP-to-IP media gateway, network gateway with transcoding and/or other media processing
DECT interfaces of media gateways are excluded from the present document and should be measured according to the
relevant DECT standards.
Interfaces of media gateways used together with terminals as a system (i.e. connected via Ethernet or with a proprietary
interface) are excluded in the present document and should be measured according to the relevant terminal standard.
If a media gateway includes more than one interface type (e.g. POTS and ISDN), each interface has to be dealt with
differently.
The requirements available in the present document will ensure a high compatibility with IP-and TDM-based fixed and
wireless terminals and networks, including DECT and mobile terminals.
It is the aim to optimize interoperability, the listening and talking quality and the conversational performance. Related
requirements and test methods are defined in the present document.
The present document does not apply to media gateways with 4-wire analogue interfaces.
2 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
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] ETSI EN 300 726: "Digital cellular telecommunications system (Phase 2+) (GSM); Enhanced Full
Rate (EFR) speech transcoding (GSM 06.60)".
[2] ETSI TS 126 171: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); AMR speech codec, wideband; General description
(3GPP TS 26.171 version 6.0.0 Release 6)".
[3] ITU-T Recommendation G.107: "The E-model, a computational model for use in transmission
planning".
ETSI
7 ETSI ES 202 718 V1.1.1 (2011-10)
[4] ITU-T Recommendation G.108: "Application of the E-model: A planning guide".
[5] ITU-T Recommendation G.109: "Definition of categories of speech transmission quality".
[6] ITU-T Recommendation G.100.1: "The use of the decibel and of relative levels in speechband
telecommunications".
[7] ITU-T Recommendation G.111: "Loudness Ratings (LRs) in an international connection".
[8] ITU-T Recommendation G.122: "Influence of national systems on stability and talker echo in
international connections".
[9] ITU-T Recommendation G.711: "Pulse code modulation (PCM) of voice frequencies".
[10] ITU-T Recommendation G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
[11] ITU-T Recommendation G.726: "40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code
Modulation (ADPCM)".
[12] ITU-T Recommendation G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-
code-excited linear prediction (CS-ACELP)".
[13] ITU-T Recommendation G.729.1: "G.729-based embedded variable bit-rate coder: An 8-32 kbit/s
scalable wideband coder bitstream interoperable with G.729".
[14] ITU-T Recommendation G.1020: "Performance parameter definitions for quality of speech and
other voiceband applications utilizing IP networks".
[15] ITU-T Recommendation P.50: "Artificial voices".
[16] ITU-T Recommendation P.340: "Transmission characteristics and speech quality parameters of
hands-free terminals".
[17] ITU-T Recommendation P.501: "Test signals for use in telephonometry".
[18] ITU-T Recommendation P.502: "Objective test methods for speech communication systems using
complex test signals".
[19] ITU-T Recommendation P.862: "Perceptual evaluation of speech quality (PESQ): An objective
method for end-to-end speech quality assessment of narrow-band telephone networks and speech
codecs".
[20] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".
[21] ITU-T Recommendation P.800.1: "Mean Opinion Score (MOS) terminology".
[22] ETSI TS 102 971: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics of a 2-wire analogue interface
for short line interface".
[23] ETSI ES 201 970: "Access and Terminals (AT); Public Switched Telephone Network (PSTN);
Harmonized specification of physical and electrical characteristics at a 2-wire analogue presented
Network Termination Point (NTP)".
[24] ITU-T Recommendation G.168: "Digital network echo cancellers".
[25] ITU-T Recommendation P.863: "Perceptual objective listening quality assessment".
[26] ITU-T Recommendation G.722: "7 kHz audio-coding within 64 kbit/s".
[27] ITU-T Recommendation G.722.1: "Low-complexity coding at 24 and 32 kbit/s for hands-free
operation in systems with low frame loss".
[28] ITU-T Recommendation G.722.2: "Wideband coding of speech at around 16 kbit/s using Adaptive
Multi-Rate Wideband (AMR-WB)".
ETSI
8 ETSI ES 202 718 V1.1.1 (2011-10)
[29] ITU-T Recommendation P.862.1: "Mapping function for transforming P.862 raw result scores to
MOS-LQO".
2.2 Informative references
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 202 396-1: "Speech and multimedia Transmission Quality (STQ); Speech quality
performance in the presence of background noise; Part 1: Background noise simulation technique
and background noise database".
[i.2] ETSI EG 202 425: "Speech Processing, Transmission and Quality Aspects (STQ); Definition and
implementation of VoIP reference point".
[i.3] 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.4] IETF RFC 2833: "RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals".
[i.5] IETF RFC 4733: "RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals".
[i.6] ETSI TR 102 927: "Speech and multimedia Transmission Quality (STQ); Packet Loss
Concealment (PLC) performance measurement setup for home networks".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
0dBr point: reference point always located at the digital side of the gateway, for IP-IP gateways located at the input of
the MGW under test
NOTE: See ITU-T Recommendation G.100.1 [6].
2-wire interface: in the context of the present document, the telephony analogue interface over 2-wires used in the
local loop
4-wire interface: in the context of the present document, a 4-wire digital interface with separate channels for both
directions, irrespective of the physical transmission technology
codec: combination of an analogue-to-digital encoder and a digital-to-analogue decoder operating in opposite directions
of transmission in the same equipment
Composite Source Signal (CSS): signal composed in time by various signal elements
MGW with 2-wire interface: MGW with an analogue 2-wire interface (ATA)
MGW with 4-wire interface: MGW with only 4-wire interfaces, e.g. ITA, IP-to-IP and wireless access points
nominal setting of the volume control: when a receive volume control is provided, the setting which is closest to the
nominal RLR of 2 dB
receive direction: the direction from packet switched interfaces towards a synchronous interface (e.g. ISDN, analogue)
or between two packet switched interfaces (for media gateways with packet switched transport on only one side)
NOTE: For media gateways with packet switched transport on both sides (IP-to-IP-MGW), the requirements of
the receive direction have to be applied in both directions.
ETSI
9 ETSI ES 202 718 V1.1.1 (2011-10)
receive interface: interface in the measurement setup, where a receive signal is injected and/or a send signal is
measured.
send direction: direction from a synchronous interface (e.g. ISDN, analogue) towards a packet switched interface (for
media gateways with packet switched interface on only one side)
NOTE: For media gateways with packet switched interfaces on both sides the requirements of the send direction
are not relevant.
send interface: interface in the measurement setup, where a send signal is injected and/or a receive signal is measured
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ATA Analogue Terminal Adapter
CLR Circuit Loudness Rating
CSS Composite Source Signal
DSL Digital Subscriber Line
DSLAM Digital Subscriber Line Access Multiplexer
DTMF Dual Tone Multi Frequency
EL Echo Loss
IAD Integrated Access device
IP Internet Protocol
ITA ISDN Terminal Adapter
JLR Junction Loudness Rating
MGW Media GateWay
MOS-LQOy Mean Opinion Score - Listening Quality Objective
NOTE: See ITU-T Recommendation P.800.1 [21].
NLP Non Linear Processor
PCM Pulse Code Modulation
PESQ™ Perceptional Evaluation of Speech Quality™
PLC Packet Loss Concealment
PN Pseudo-random Noise
POI Point Of Interconnect
POTS Plain Old Telephone Service
PSTN Public Switched Telephone Network
QoS Quality of Service
TCL Terminal Coupling Loss
TCN Trace Control for Netem™
TDM Time Division Multiplexing
VAD Voice Activity Detection
VoIP Voice over Internet Protocol
4 General considerations
4.1 Default Coding Algorithm
Narrowband VoIP gateways shall support the coding algorithm according to ITU-T Recommendation G.711 [9] (both
µ-law and A-law). VoIP gateways may support other coding algorithms.
Wideband VoIP gateways shall support the coding algorithm according to ITU-T Recommendation G.722 [26]. VoIP
gateways may support other coding algorithms.
NOTE: Associated Packet Loss Concealment (PLC) e.g. as defined in ITU-T Recommendation G.711 [9]
appendix I should be used.
ETSI
10 ETSI ES 202 718 V1.1.1 (2011-10)
4.2 End-to-end considerations
In order to achieve a desired end-to-end speech transmission performance (mouth-to-ear) it is recommended that the
general rules of transmission planning are carried out with the E-model of ITU-T Recommendation G.107 [3]; this
includes the a-priori determination of the desired category of speech transmission quality as defined in ITU-T
Recommendation G.109 [5].
While, in general, the transmission characteristics of single circuit-oriented network elements, such as switches or
terminals can be assumed to have a single input value for the planning tasks of ITU-T Recommendation G.108 [4], this
approach is not applicable in packet based systems and thus there is a need for the transmission planner's specific
attention.
In particular the decision as to which delay measured according to the present document is acceptable or representative
for the specific configuration is the responsibility of the individual transmission planner.
ITU-T Recommendation G.108 with its amendments [4] provides further guidance on this important issue.
The following optimum parameters from a users' perspective need to be considered:
• Minimized delay in send and receive direction.
• Optimum loudness Rating (JLR).
• Compensation for network delay variation.
• Packet loss recovery performance.
• Maximized echo loss.
• Immunity to false detection of DTMF in speech signal.
4.3 Parameters to be investigated
4.3.1 Applicability of parameters to different MGWs
Table 1: Parameter applicability
2-wire home 4-wire MGW 4-wire MGW wireless home
and network (excl. IP-to-IP (IP-to-IP-MGW) MGW
MGW MGW)
6.2 Codec independent parameters

6.2.1 Send frequency response M M NA M
6.2.2 Circuit Loudness Rating in Send M M NA M
6.2.3 Linearity Range for CLR(SND) M M NA M
6.2.4 Send Distortion M M NA M
6.2.5 Spurious Out-of-Band Signals in M NA NA NA
Send direction
6.2.6 Send Noise M M NA M
6.2.7 Receive frequency response M M MM M
6.2.8 Circuit Loudness Rating in Receive
M M MM M
6.2.9 Linearity Range for CLR(RCV)
M M MM M
6.2.10 Receive Distortion M M MM M
6.2.11 Out-of-Band Signals in Wideband to NA M M M
Narrowband Transcoding
6.2.12 Spurious Out-of-band Signals NA M M M
Narrowband to Wideband Transcoding
6.2.13 Minimum activation level and
FFS FFS FFS FFS
sensitivity in Receive direction
6.2.14 Receive Noise M M MM M
6.2.15 Double Talk Performance

6.2.15.1 Attenuation Range in Send M M M M
Direction during Double Talk
6.2.15.2 Attenuation Range in Receive
M M M M
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11 ETSI ES 202 718 V1.1.1 (2011-10)
2-wire home 4-wire MGW 4-wire MGW wireless home
and network (excl. IP-to-IP (IP-to-IP-MGW) MGW
MGW MGW)
Direction during Double Talk
6.2.15.3 Detection of Echo Components
M M M M
during Double Talk
6.2.15.4 Minimum activation level and FFS FFS FFS FFS
sensitivity of double talk detection
6.2.16 Switching characteristics
6.2.16.1 Activation in Send Direction M M NA M
6.2.16.2 Activation in Receive Direction M M M M
6.2.16.3 Silence Suppression and Comfort
FFS FFS FFS FFS
Noise Generation
6.2.17 Background Noise Performance
6.2.17.1 Performance in send direction in
M M MM M
the presence of background noise
6.2.17.2 Quality of Speech with M M MM M
Background Noise
6.2.17.3 Quality of Background Noise M M MM M
Transmission (with Far End Speech)
6.2.17.4 Quality of Background Noise M M MM M
Transmission (with Near End Speech)
6.2.18 Quality of echo cancellation
6.2.18.2 Echo Performance acc. To G.168 M M NA M
6.2.18.3 TCLw M M NA M
6.2.18.4Temporal echo effects M M NA M
6.2.18.5 Spectral Echo Attenuation M M NA M
6.2.18.6 Occurrence of Artefacts
FFS FFS NA FFS
6.2.19 Variant Impairments; Network

dependant
6.2.19.1 Clock accuracy send
M M MM M
6.2.19.2 Clock accuracy receive
M M MM M
6.2.19.3 Send delay variation M M MM M
6.2.20 Immunity to DTMF false detection in M M MM M
send direction
6.3 Codec Specific Requirements
6.3.1 Send Delay M M NA M
6.3.2 Receive Delay M M NA M
6.3.3 Delay for IP-to-IP MGW NA NA MM NA
6.3.4 Objective Listening Speech Quality M M M M
MOS-LQO in Send direction
6.3.5 Objective Listening Speech Quality M M M M
MOS-LQO in Receive direction
6.3.5.1 Efficiency of Packet Loss FFS FFS FFS FFS
Concealment (PLC)
6.3.5.2 Efficiency of Delay Variation
FFS FFS FFS FFS
Removal
M: Mandatory
MM: Mandatory for both interfaces of the MGW
NA: Not applicable
FFS: For further study
5 Test equipment
5.1 IP half channel measurement adaptor
The IP half channel measurement adaptor is described in EG 202 425 [i.2]. Such an apparatus is required to code and
insert audio signals into IP packets send to the IP receive interface of the gateway under test, as well as to capture and
decode audio signals constituting the payload of IP packets received from the IP sending interface of the gateway under
test.
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12 ETSI ES 202 718 V1.1.1 (2011-10)
5.2 Environmental conditions for tests
The following conditions shall apply for the testing environment:
a) Ambient temperature: 15 °C to 35 °C (inclusive);
b) Relative humidity: 5 % to 85 %;
c) Air pressure: 86 kPa to 106 kPa (860 mbar to 1 060 mbar).
5.3 Accuracy of measurements and test signal generation
Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or better than:
Table 2: Measurement Accuracy
Item Accuracy
Electrical signal level
±0,2 dB for levels ≥ -50 dBV
±0,4 dB for levels < -50 dBV
Frequency ±0,2 %
Time ±0,2 %
Unless specified otherwise, the accuracy of the signals generated by the test equipment shall be better than:
Table 3: Accuracy of test signal generation
Quantity Accuracy
Electrical excitation levels ±0,4 dB across the whole frequency range.
Frequency generation ±2 % (see note)
Time ±0,2 %
Specified component values ±1 %
NOTE: This tolerance may be used to avoid measurements at critical frequencies, e.g. those
due to sampling operations within the terminal under test.

If the equipment is powered by other means and those means are not supplied as part of the apparatus, all tests shall be
carried out within the power supply limit declared by the supplier. If the power supply is a.c. the test shall be conducted
within ±4 % of the rated frequency.
5.4 Network impairment simulation
At least one set of requirements is based on the assumption of an error free packet network, and at least one other set of
requirements is based on a defined simulated malperformance of the packet network.
An appropriate network simulator has to be used, for example Netem™.
The key points of Netem™ can be summarized as follows:
• Netem™ is part of most Linux™ distributions, it only has to be switched on, when compiling a kernel. With
Netem™, there are the same possibilities as with Nistnet™, there can be generated loss, duplication, delay and
jitter (and the distribution can be chosen during runtime). Netem™ can be run on a Linux-PC™ running as a
bridge or a router (Nistnet™ only runs on routers).
• With an amendment of Netem™, TCN (Trace Control for Netem™) which was developed by ETH Zurich™,
it is even possible, to control the behaviour of single packets via a trace file. So it is for example possible to
generate a single packet loss, or a specific delay pattern. This amendment is planned to be included in new
Linux Kernels™, nowadays it is available as a patch to a specific kernel and to the iproute2 tool (iproute2
contains Netem™).
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13 ETSI ES 202 718 V1.1.1 (2011-10)
• It is not advised to define specific distortion patterns for testing in standards, because it will be easy to adapt
devices to these patterns (as it is already done for test signals). But if a pattern is unknown to a manufacturer,
the same pattern can be used by a test lab for different devices and gives comparable results. It is also possible
to take a trace of Nistnet™ distortions, generate a file out of this and playback the exact same distortions with
Netem™.
6 Requirements and associated Measurement
Methodologies
Differences between different media gateway types are dealt with in the respective requirements.
In the case of IP-IP MGW packet based interfaces are provided at both sides of the gateway. Therefore the receive
requirements apply, for both interfaces.
NOTE 1: In general the test methods as described in the present document apply. If alternative methods exist they
may be used if they have been proven to give the same result as the method described in the standard.
NOTE 2: Due to the time variant nature of IP connections delay variation may impair the measurements. In such
cases the measurement has to be repeated until a valid measurement result is achieved.
6.1 Test setup
The preferred way of testing a gateway is to connect its interfaces to network simulators with exact defined settings and
access points. The test sequences are fed in electrically, using a reference codec or using the direct signal processing
approach.
When VoIP runs on the gateway under test only in conjunction with a registration by an application server (e.g. SIP
proxy), the network simulator may need to provide also the registration functionality.
Alternatively, if for the IP-interfaces another technology than Ethernet is used (for instance DSL access, it may be
necessary to add additional equipment in the test setup for connecting the measurement equipment (e.g. a DSLAM, if
the IP-interface works over DSL). There should be no speech signal processing in this additional equipment (the media
payload has to be passed transparent through this equipment, while e.g. header manipulation is allowed). The influence
of this additional equipment (delay and eventually delay variation) has to be taken in account for the measurements.
NOTE 1: It is up to the testlab to identify potential time invariances or non linearities in the network used for
interconnection and to take those effects into account properly.
With this setup it is possible to measure the parameters listed in the present document over a whole network, if the
behaviour of the network is known.
In the present document, the terms "send" and "receive" can be found in the pictures of the relevant test setup.
When a coder with variable bit rate is used for testing the MGW parameters, the bit rate recognized giving the best
characteristics and/or the ones commonly used should be selected, e.g.:
• AMR-NB (TS 126 171 [2]): 12,2 kbit/s.
• AMR-WB (G. 722.2 [28]): 12,65 kbit/s.
• ITU-T Recommendation G.729.1 [13]: 32 kbit/s.
NOTE 2: Although packet capturing and network simulation in figures 1 to 4 are shown in one box they may be
separate devices.
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14 ETSI ES 202 718 V1.1.1 (2011-10)
6.1.1 Setup for Media Gateways with 4-wire interface

Figure 1: Half channel measurement for MGW with 4-wire interface
6.1.2 Setup for Media Gateways with 2-wire interface

Figure 2: Half channel measurement for MGW with 2-wire interface
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15 ETSI ES 202 718 V1.1.1 (2011-10)
6.1.3 Setup for Media Gateways with Wireless Access
Receive
IP-Half-Channel
Network
Measurement
simulator
MGW
Adapter (delay, jitter,
Path through Path through
(VoIP Reference Point)
under test
packet loss)
IP network IP network
Gateway
Packet capture
Simulation
Send
Wireless
reference point
Measurement system
(e.g. DECT reference PP)
Figure 3: Half channel measurement for MGW with wireless access
6.1.4 Setup for IP-to-IP Media Gateways
P
I
a
P
t
h
n
e
t
h
t
w r
o
o
u
r
g
k
h
Figure 4: Half channel measurement for IP-to-IP MGW
NOTE 1: For measuring both directions of an IP-to-IP MGW, the network simulator can be moved to the other side
of the MGW.
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16 ETSI ES 202 718 V1.1.1 (2011-10)
NOTE 2: If the network simulator is moved to the other side of the IP-to-IP MGW the measurements to be
conducted in receive are to be conducted in this scenario on the other channel (send in the precious
scenario).
6.1.5 Test Signal Levels
Unless specified otherwise, the applied test signal level at the digital inputs shall be -16 dBm0. For analogue inputs
(2-wire) the applied test signal level should be -16 dBm for home MGWs and -19 dBm for network MGWs at the media
gateway interface.
NOTE: For analogue inputs of network MGWs, an attenuation of 3 dB for the simulation of an access line is
taken into account for measurements with nominal levels.
6.1.6 Background noise simulation
Background noise signals used for testing should be recorded according to the description in EG 202 396-1 [i.1].
EG 202 396-1 [i.1] contains a description of the recording arrangement for realistic background noises, a description of
the setup for a loudspeaker arrangement suitable to simulate a background noise field in a lab-type environment and a
database of realistic background noises, which can be used for testing the terminal performance with a variety of
different background noises.
In order to create a representative electrical test signal for the MGW containing speech at a nominal level mixed with
the amount of background noise picked up by a terminal, the setup in EG 202 396-1 [i.1] is used. The terminal is
connected to a reference interface providing nominal properties for the electrical interface as used by the terminal. The
signal (speech plus noise) is recorded at this interface and inserted through the appropriate reference interfaces as
described in clauses 6.1.1 to 6.1.4 in such a way that the signal level and spectral content delivered to the MGW under
test is equivalent to the one it would have seen if the terminal was connected directly. Either terminals considered to be
representative for the type of terminal attached to the MGW are used or individual terminals are used.
NOTE: Due to terminal geometry, microphone technique and signal processing used in the phone the signals
acquired at the electrical interface may highly vary. As a consequence the performance of the MGW may
highly depend on the terminal connected.
The following noises of EG 202 396-1 [i.1] shall be used.
L: 77,8 dB(A)
Recording in pub Pub_Noise_binaural 30 s Binaural
R: 78,9 dB(A)
L: 68,4 dB(A)
Recording at sales counter Cafeteria_Noise_binaural 30 s Binaural
R: 67,3 dB(A)
L: 56,6 dB(A)
Recording in business office Work_Noise_Office_Callcener_binaural 30 s Binaural
R: 57,8 dB(A)
6.2 Coding independent parameters
6.2.1 Send Frequency response
Requirement
The frequency response for 4-wire MGW shall be according to tables 4 and 5:
T
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