TD 70 (PLEN/16)

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Contact:

Harald Kullmann

Deutsche Telekom AG

Germany

Tel: +49 6151 628 2296

Fax: +49 521 921 00 678 (PC
-
Fax)

Email:
Harald.Kullmann@telekom.de


Attention:

This is not a publication made available to the public, but
an internal ITU
-
T Document

intended only for use by the
Member States of ITU, by ITU
-
T Sector Members and Associa
tes, and their respective staff and collaborators in their ITU related
work. It shall not be made available to, and used by, any other persons or entities without the prior written consent of ITU
-
T.


INTERNATIONAL TELECOMMUNICATION UNION

STUDY

GROUP

16

TELECOMMUNICATION

STANDARDIZATION SECTOR

STUDY PERIOD
2009
-
2012

TD 70 (PLEN/16)

English only

Original: English

Question(s):

14,

15,

16,

18
/16

Geneva, 27 January
-

6 February 2009

TEMPORARY DOCUMENT

Source:

Chair WP1/16

Title:

Draft report of Working Party 1/16 (Network Signal Processing and Voiceband
Terminals)


1

INTRODUCTION

................................
................................
................................
......................

3

2

ORGANISATION OF WORK

................................
................................
................................
.

3

2.1

D
OCUMENTATION

................................
................................
................................
.................

3

2.2

A
LLOCATION OF WORK

................................
................................
................................
.........

3

3

RESULTS

................................
................................
................................
................................
...

3

3.1

S
UMMARY

................................
................................
................................
.............................

3

3.1.1

Recommendations for Approval

................................
................................
...................

3

3.1.2

Recommendations proposed for Consent in accordance with Rec. A.8.

......................

3

3.1.3

Other documents for Approval

................................
................................
.....................

4

3.1.4

Ques
tion
14/16
Summary

................................
................................
.............................

4

3.1.5

Question 15/16 Summary

................................
................................
.............................

4

3.1.6

Question 16/16 Summary

................................
................................
.............................

4

3.1.7

Question 18/16 Summary

................................
................................
.............................

4

3.2

G
ENERAL
W
ORKING
P
ARTY
1/16

MATTERS

................................
................................
..........

5

3.2.1

Reports on interim activities

................................
................................
........................

5

3.2.2

Liaison Statements considered by WP 1/16

................................
................................
.

5

3.2.3

Summary of discussion results on

ITU
-
T mark as described in Resolution 7
6

............

5

3.2.4

Promotion activities

................................
................................
................................
.....

5

3.2.5

Future interim activities

................................
................................
...............................

6

3.3

Q
UESTION
14/16



V
OICEBAND MODEMS AND
FACSIMILE TERMINALS
PROTOCOLS
:

SPECIFICATION
,

PERFORMANCE EVALUATI
ON AND INTERWORKING
WITH
NGN

................................

6

3.3.1

Documentation

................................
................................
................................
.............

6

3.3.2

Report of Interim Activities

................................
................................
..........................

6

3.3.3

Discussions
................................
................................
................................
...................

6

3.3.4

Intellectual Property Stateme
nts

................................
................................
..................

8

3.3.5

Outgoing Liaison statements

................................
................................
........................

8

3.3.6

Work programme

................................
................................
................................
.........

8

-

2

-

TD 70 (PLEN/16)

3.4

Q
UESTION
15/16



V
OICE GATEWAY SIGNAL
PROCESSING FUNCTIONS

AND CIRCUIT
MULTIPLICATION EQUIP
MENT

/

SYSTEMS

................................
................................
...........................

8

3.4.1

Documentation

................................
................................
................................
.............

9

3.4.2

Report of Interim Activities

................................
................................
..........................

9

3.4.3

Discussions
................................
................................
................................
...................

9

3.4.4

Intellectual Property Statements

................................
................................
................

10

3.4.5

Outgoing Liaison statements

................................
................................
......................

11

3.4.6

Work programme

................................
................................
................................
.......

11

3.5

Q
UESTION
16/16



S
PEE
CH ENHANCEMENT FUNCT
IONS IN SIGNAL PROCE
SSING NETWORK
EQUIPMENT

................................
................................
................................
................................
.....

11

3.5.1

Documentation

................................
................................
................................
...........

12

3.5.2

Report of Interim Activities

................................
................................
........................

12

3.5.3

Discussions
................................
................................
................................
.................

12

3.5.4

Intellectual Property Statements

................................
................................
................

16

3
.5.5

Outgoing Liaison statements

................................
................................
......................

16

3.5.6

Work programme

................................
................................
................................
.......

17

3.6

Q
UESTION
18/16



I
NTERACTION ASPECTS O
F SIGNAL PROCESSING
NETWOR
K EQUIPMENT

.

17

3.6.1

Documentation

................................
................................
................................
...........

18

3.6.2

Report of interim activities

................................
................................
.........................

18

3.6.3

Discussions
................................
................................
................................
.................

18

3.6.4

Intellectual property statements

................................
................................
.................

20

3.6.5

Outgoing Liaison Statements

................................
................................
.....................

20

3.6.6

Work Programme

................................
................................
................................
.......

20

4

SUMMARY OF LIAISON A
CTIVITY

................................
................................
.................

21

5

WORKPLAN

................................
................................
................................
............................

21

6

SUMMARY OF INTERIM R
APPORTEUR MEETINGS

................................
.................

21

ANNEX
Q16.
A UPDATED TEXT FOR
RECOMMENDATION ITU
-
T
G.160

.......................

23


-

3

-

TD 70 (PLEN/16)

1

Introduction

Working Party 1/16 (
Network Signal Processing and Voiceband Terminals
) held its first meeting of
the 2009
-

2012
Study P
eriod from 27 January
-
06 February

2009, in Geneva, under the
chairmanship of Mr Harald Kullmann (Deutsche Telekom, Germany)
.

The results of the last meeting of WP1/16 are contained in COM 16


R 26.

The Questions
currently
allocated to WP 1/16 (and respective Rapporteurs) are:

Q14/16

Voiceband modems and facsimile terminals protocols: specification,
performance evaluation and
interworking with NGN
(
Mr Keith Chu,
Teridian
/USA
)

Q15/16

Voice gateway signal processing functions and circuit multiplication
equipment

/ systems
(Mr
Dominic Ho, Nortel Network
/Canada
)

Q16/16

Speech enhancement functions in signal processing network equ
ipment
(Mr
Bob Reeves, BT/United Kingdom)

Q18/16

Interaction aspects of signal processing network equipment (Mr Harald
Kullmann, Deutsche Telekom/Germany)

2

Organisation of Work

2.1

Documentation

WP1 examined the following documents:



Reports:

COM 16
-
R
26



Contr
ibutions:
COM16
-
C1
, C2



TD/Plen:
1, 2,
3
,
6,
7
,
8, 10,
11
, 12, 13, 14



TD
/Gen
:
10
,
15, 16, 1
7,
15
, 60



TD/WP
1
:
1,
6, 7
,
9

2.2

Allocation of work

WP 1/16 adopted the agenda and
i
nitial work schedule
provided in
TD

1
/WP1.

3

Results

3.1

Summary

3.1.1

Recommendations for Approva
l

N
o documents were considered under TAP
A
pproval at this meeting
.

3.1.2

Recommendations proposed for Consent in accordance with Rec. A.8.

The following Recommendation
s
,
Corrigendum
and
Annexes
were

proposed
by WP 1/16
for
Co
nsent:

-

4

-

TD 70 (PLEN/16)

Description

Documents

Question

ITU
-
T Rec.

V.152

Amendment 1
: New Annex B on use of data signal
detection and silence insertion in voiceband data and Annex C on use of
V.21 preamble for echo canceller control in a V.152 Gateway

(New)

TD

51
/P
LEN

14

ITU
-
T Rec.
ITU
-
T
I.733 “
Voice on ATM
Circuit Multiplication
Equipment


(New)

TD

49
/P
LEN

1
5

ITU
-
T Rec.
G.763 (1
9
98)

Corrigendum
1 “
Digital circuit multiplication
equipment using G.726 ADPCM and digital speech interpolation:
Corrections”

(New)

TD

48
/P
LEN

15

ITU
-
T Rec.
G.168 “Digital network e
cho cancellers”
(Rev.)

TD 45
/P
LEN

16

3.1.3

Other documents for Approval

No Appendices, Supplements, Implementors’ Guides or Technical Papers were proposed by
WP1/16 for approval at this meeting.

3.1.4

Question
14
/16

Summary

The goal of Question 14/16 at this meeting w
as to continue the development of Recommendations
V.150.1, V.151, V.152 and V.IP2IP
-
VxF and complete the Draft for new Recommendation
V.AMAT. The group made good progress on V.152 and V.IP2IP
-
VxF but unfortunately no
contributions or updated editor drafts
were available on V.151 and V.AMAT, so the goals set for
consent of these

Recommendations were not met.
The Rapporteur will encourage renewed effort to
complete these Recommendations for the next meeting of SG16
.

3.1.5

Question 15/16 Summary

Two contributions an
d eighteen temporary documents were received in this meeting. One
contribution proposes additions/changes to I.733

and the proposal was adopted.
Q.15 has the
consensus in putting
Recommendation ITU
-
T
I.733 forward for consent. A Corrigendum was
created f
or G.763 based on the G.763
Implementors’
Guide. The Corrigendum is going to put
forward for consent at this meeting. Some up
dates were made in G.IP2IP.
One interim meeting is
proposed.

3.1.6

Question 16/16 Summary

Further progress was made
in Question 16/16
on

drafting text for revised Rec. ITU
-
T G.168
(Digital network echo cancellers), revised Rec. ITU
-
T G.160 (Voice enhancement devices) and
revised Rec. ITU
-
T G.169 (Automatic level control devices). Work on revised Appendix II to
G.160 covering objective meas
ures for characterizing noise reduction functions was also
progressed. G.168 was put forward for consent at this meeting. One interim meeting is proposed.

3.1.7

Question 18/16 Summary

At this meeting, Question 18/16
advanced the work on drafting
new Recommendati
on
G.MDCSPNE

“Mechanism for dynamic coordination of SPNE”, revised Recommendation
ITU
-
T
G.161 "Interaction aspects of signal processing network equipment" and new Recommendation
G.
SPNE
“Signal Processing Network Equipment”.

One Liaison Statement was sent t
o
IETF,
SG

11

and

the
FG
-
FITCAR II
. The Question plans to hold one interim meeting
.

-

5

-

TD 70 (PLEN/16)

3.2

General Working Party 1/16
m
atters

3.2.1

Reports on interim activities

After the
sixth

meeting of

SG

16 (Geneva,
22 April


2 May 2008
)
one

joint
Rapporteur
s

meeting
for Question
s
15, 16
, 17

and 1
8
/16

w
as

held in
Stockholm
/
Sweden
,
24
-
30 September 2008
, under
the kind invitation of
Erics
son
. The meeting report
s

can be

found in
TD

6, 7

and
9
/WP
1
, which
w
er
e

reviewed by each of the Questions and approved by WP

1
/16.

More information
is provided in
the reports of the individual Questions.

3.2.2

Liaison Statements considered by WP 1/16

WP 1/16 took note of the Liaison Statements received from other
Study G
roups
or other
standardi
z
ation bodies.
Some of the Liaison Statements had already been r
eviewed at the
Rapporteur
s
meeting
in Stockholm/Sweden
,
24
-
30 September 2008

and
i
t

was decided to sent
one
Liaison Statement
(COM 16
-

LS 354
-

E )
to 3GPP2,
3GPP SA4

and
the
FG
-
FITCAR II. The list
of Liaison Statements
agreed at this meeting
is contained

in Section

4.


3.2.3

Summary of
discussion results on

ITU
-
T mark as described in Resolution 76

WP

1
/16

discussed
TD

3
/
PLEN with regard to Resolution 76
during the meetings of
WP1/16
. The
following points were noted:


1)

Conformance testing are applicable to R
ecommendations developed by the Questions Q14,

Q15, Q16 and Q18 since they all contain requirements that need to be passed for the relevant

device or function to "conform"

to the Recommendation.

2)

Interoperability testing is very difficult to define fo
r the Recommendations developed by the

Questions Q14, Q15, Q
16 and Q18 because some of them
apply to stand
-
alone functions or

devices only and needs some more investigations.

3)

The idea of an ITU Mark or Logo was considered a good one in theory, but me
mbers had lots of

questions about how this would be implemented in practice.



The following list includes some of the questions:



-


will there be different ITU
-
T logos available for Conformance and Interoperability



-


should appropriate testing proc
edures be developed for existing Recommendations



-


guidelines for providing the testability, conformance and interoperability in






Recommendations are necessary



-


who can provide the test laboratory (independent test laboratory) and requirements

on test




laboratories



-


can independent, accredited bodies be found and who pays the expenditures of the tests



-


who can provide the definitions on testing, accreditation and certification fields (test report,




evaluation of the test results,
etc.)



-


how can the different regional network environment criteria for

Conformance






and

Interoperability testing be provided

4)

The Questions in WP1/16 would like to see more information on how the ITU Mark program



will be implemented in pract
ice before committing any of its Recommendations to take part



in trials.

3.2.4

Promotion activities

No specific promotion activity is planned by WP

1
/16
.

-

6

-

TD 70 (PLEN/16)

3.2.5

Future
i
nterim
a
ctivities

The W
orking
P
arty

plans to hold
one joint
Rapporteur
s

meeting

for Q
uestions
15,

16 and 18
/16
.


3.3

Question 1
4
/16


Voiceband modems and facsimile terminals protocols: specification,
performance evaluation and interworking with NGN

Working Party 1/16 addressed Questions 14/16 at this meeting under the chairmanship of Mr. Keith
Chu (UK).

The agenda for these joint sessions is contained in TD
-
02 (WP1). The Agenda and work plan for
WP1/16 meetings is contained in TD
-
01 (WP1).

The group adopted the agenda in TD
-
02 (WP1). The following section describes the results of the
work by Q14 for this

session of SG16

3.3.1

Documentation

The following documents were considered by Q14 at this meeting:



Contributions: 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 37, 101 and 102



TD/Gen:
57



TD/WP1: 02, 08, 13, 14, 15, 16, 17, 18, 21, 22 and 32



TD/PLEN: 51

3.3.2

Report of Interim Activities

There were no interim meeting between this and previous Study Group meeting for Q14.

3.3.3

Discussions

3.3.3.1

Incoming Liaison Statements

TD
-
57 (GEN) “LS on new versions of the Access Network Transport (ANT) Stand
ardization Plan
and Work P
lan”
was reviewed. The documents located at the URL
http://www.itu.int/ITU
-
T/studygroups/com15/ant/

were reviewed for any potential updates. No
modification to the tables or content as approp
riate to the T and V
-
series recommendations under
the perview of Question 14 were noticed.

3.3.3.2

V.150.1 (V.MoIP)

There were no contributions on this work item. The V.MOIP Issues List TD
-
14 (WP1) was
presented for information with no updates made to the Issues l
ist at this meeting. There is still an
intention of including elements that were developed for V.151 that appropriately belong in V.150.1
the group agreed to work on this in the interim period and have text prepared for the next meeting
of SG16.

3.3.3.3


V.152 (V.
VBD)

There were two contributions on this work item for consideration at this meeting (C
-
37 and 101).
The V.152 Consensus List TD
-
16

(WP1) as approved at the last meeting was presented. As a
-

7

-

TD 70 (PLEN/16)

consequence of presentation and discussions on the two contribut
ions agreements and updates were
recorded in the Consensus list at this meeting (TD
-
16R1 (WP1)).

The work on the proposed new Annexes on Data Signal Detection and embedded echo canceller
enable control on facsimile detection were concluded at this meeting,

It was agreed to submit the
text presented in TD
-
21 and 22 (WP1) for consent. These texts are provided in TD
-
51 (PLEN)
.

3.3.3.4

V.151 (V.ToIP)

No contributions on this work item were submitted at this meeting. The Consensus List
TD
-
15

(WP1) as approved at the las
t meeting was presented for information with no updates made
at this meeting. The work on the completion of new Annex F for interoperation of V.151 gateways
with devices that support RFC 4103 has not progressed. No input was provided to resolve the
outsta
nding issues and questions contained in the Consensus List (TD
-
15 (WP1)). The Rapporteur
will encourage the group for contributions on this topic so that Annex F/V.151 can be completed.

3.3.3.5

V.AMAT

Baseline text as agreed at the last meeting of SG16 along with
comments on how it is to be changed
to fit the agreed scope was provided in TD
-
18 (WP1). There were no contributions or any
modifications made to the baseline text at this meeting. The Rapporteur undertook the effort to
implement the changes in the baselin
e text as agreed in previous meetings. During the editing of the
text several issues arose. The latest version (although incomplete) of the text is provided in
TD
-
18R1 (WP1) along with comments on the issues discovered during the review. It is hoped that
t
his text will encourage new text for missing commands and feedback from early implementers of
these commands.

3.3.3.6

T.38

Two Contributions were submitted on revisions to Recommendation ITU
-
T T.38. These
contributions considered several issues that arose from imp
lementation and interoperability of
ITU
-
T T.38 equipped devices. It was agreed to revise this Recommendation but not at this meeting.
The intent is to allow at least a one meeting cycle to allow for comments to the proposed changes.
The various proposals c
ontained in Contributions 24 and 102 were agreed.

It was also agreed to create a Consensus list for ITU
-
T T.38 to facilitate the capture of the issues
and recording of agreements and proposed draft text. The ITU
-
T T.38 Consensus List was
published as TD
-
08

(WP1).

3.3.3.7

V.IP2IP
-
VxF

There were twelve contributions presented on the topic of V.IP2IP
-
VxF. These contributions
contain proposed text for the baseline of the draft Recommendation. TD
-
13 (WP1) contains the
baseline text and was modified upon the basis of the

twelve contributions. This revised text is
provided in TD
-
13R1. TD
-
17 (WP1) contains the incoming Consensus List for this work item. TD
-
17R1 (WP1) contains the updated outgoing document that was approved by the group.

3.3.3.8

Revisions of Existing V
-
series and T
-
series Recommendations

There were no proposals for Revisions of existing Modem Recommendations at this meeting.

-

8

-

TD 70 (PLEN/16)

3.3.3.9

Other

The concept of an ITU
-
T mark as described in Resolution 76 was presented. It was agreed to save
the discussion to the Working Party Plenar
y to allow for a much wider consideration.

3.3.4

Intellectual Property Statements

The committee was advised on the ITU
-
T Patent Declaration policy and was asked if the group was
aware of any IP related to the work of Question 14. No IPR statements were received
or indicated at
this meeting.

3.3.5

Outgoing Liaison statements

A single outgoing liaison is to be sent to ETSI TISPAN from Q14 at this meeting (TD
-
32/WP1).
This LS makes a request for information that ETSI TISPAN may have on issues regarding
interoperability of

ITU
-
T V.152 equipment.

3.3.6

Work programme

3.3.6.1

Future work

E
-
mail correspondences pertaining to the activities of this group are routinely conducted using the
e
-
mail reflector currently hosted by the ITU. Those wishing to subscribe or unsubscribe to this
email ref
lector should visit the ITU web page at:


http://www.itu.int/ITU
-
T/services/

E
-
mails to all subscribed Q14/16 Experts should be sent to
t09sg16q14@list.itu.in
t
.

The currently open work items are as follows:

Recommendation

Editor

Consent

Reference

New Recommendation V.25x


AT
commands for control of mobile devices by
assistive controllers

Gunnar
Helström

2009

TD
-
18R1 (WP1)

New Annex F for V.151

TBD

2009

TD
-
1
5 (WP1)

Amendment 1 to V.152
-

New Annex B:

Use of data signal detection
and silence
insertion in
voiceband data

and New Annex
C:
Use of
V.21 preamble for echo canceller
control in a V.152 Gateway

Jun Zhang

2009

TD
-
51 (PLEN), TD
-
16R1
(WP1)

New V.IP2IP


VxF

Albrecht
Schwartz

TBD

TD
-
17R1 (WP1)

Revised V.150.1

Keith Chu

2009

TD
-
14 (WP1)

Revised T.38

TBD

2009

TD
-
08 (WP1)

3.3.6.2

Future meetings

No interim meetings are planned for Q14/16
.


-

9

-

TD 70 (PLEN/16)

3.4

Question 15/16


Voice gateway signal processing functions and circuit mu
ltiplication
equipment

/ systems

Question 15/16 was addressed in two sessions during the SG 16 meeting under the chairmanship of
Mr. Dominic Ho (Nortel Networks, Canada). The group adopted the agenda in TD 3/WP1.

The objectives for this meeting were:



Progr
ess in drafting of
ITU
-
T
I.733, and prepare it for consent



Progress work on new Recommendation G.IP2IP



Progress work on revised Recommendation
ITU
-
T
G.799.1/Y.1451.1

3.4.1

Documentation

The following documents were examined:



Contributions: COM16
-
C1, C90



TD/Plen:

R26, 2, 3, 8



TD/Gen: 7, 9, 10, 15, 16, 17, 28



TD/WP1: 1, 3, 6, 28, 29, 30, 31

3.4.2

Report of Interim Activities

Since the last SG 16 plenary meeting, Question 15/16 held a Rapporteur meeting in Stockholm,
Sweden, from 24 September t
o 30 September 2008. The rep
ort

of this Rapporteur meeting
(TD

6/WP1) was approved at this SG 16 meeting.

The work also progressed by correspondence using the Question e
-
mail reflector (t09sg16q15@
lists.itu.int). Documentation is found in the SG 16 IFA for Q15/16 at:

http://ifa.it
u.int/t/2009/sg16/exchange/wp1/q15

3.4.3

Discussions

3.4.3.1

Incoming Liaison Statements

The following liaisons were presented for information:



TD 7/GEN from ITU
-
T SG4 on LS on SG 4 Report and Request in its role as Lead SG on
Telecommunication Management






TD 9/GEN f
rom ITU
-
T SG4 on LS on Joint Coordination Activity on Management (JCA
-
Mgt)



TD 10/GEN from ITU
-
T SG12 on LS on SG Restructuring: Results and proposals from Study
Group 12



TD 15/GEN from TSAG on LS regarding handling of patent declarations



TD 16/GEN from TSA
G on LS on quality of ITU
-
T Recommendations



TD 17/GEN from TSAG on LS on improved Geographic Distribution and Coordination of ITU
-
T Seminars and Workshops



TD 28/GEN from ITU
-
T SG15 on LS on clock function for media gateway




-

10

-

TD 70 (PLEN/16)

3.4.3.2

Draft New Recommendation
ITU
-
T
I.733

Contribution C 90

proposes the text for clause 7.3 Local Alarm Interface, moving the text
currently in clause 7.3 to clause 14.1.4, and an editorial correction in the Contents. The proposed
changes from C 90 were agreed and I.733 was updated accor
dingly.

The latest draft of I.733 is in TD 49/PLEN, and it was agreed to put I.733 forward for consent at
this meeting.

3.4.3.3

Draft New Recommendation G.IP
-
to
-
IP

No contribution was received on G.IP
-
to
-
IP. The latest draft (v1.8) of G.IP
-
to
-
IP (TD 29/WP1) was
d
iscussed. During the discussion and review of the latest draft, the following changes were made in
G.IP
-
to
-
IP:



Sub
-
clause 3.2.1, the sentence “The term “voice” is indicating that the gateway is optimized for
narrowband services (like voice, voiceband data
, or 1x64 circuit
-
mode data), and that the level
of interworking may also be above the IP layer (e.g. similar to layer 5 (session) peering).” was
changed to “The term “voice” is indicating that the gateway is optimized for voice, voiceband
data, or 1x64 ci
rcuit
-
mode data
services
, and that the level of interworking may also be above
the IP layer (e.g. similar to layer 5 (session) peering).”



Sub
-
clause 7.1, the sentence “
Delay caused by voice coding should be kept to a minimum (see
Annex A of [ITU
-
T G.114]
for calculation of delay figures).
” was changed to “
Delay caused by
voice coding should be kept to a minimum (see Annex A
and in particular Annex A.3

of [ITU
-
T
G.114] for calculation of delay figures).


TD 28/GEN proposed to include Ethernet Synchronizatio
n as new synchronization source for media
gateway in G.799.1/ Y.1451.1. It was realized the proposal from TD28/GEN is also applicable to
G.IP
-
to
-
IP. An entry on Ethernet Synchronization was added to the living list of G.IP
-
to
-
IP.

The latest draft of G.IP
-
to
-
IP(ver1.9) is located in the stable text directory of the WP1/16 informal
FTP area at:

http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/GIP2IP/

3.4.3.4

Recommendation G.799.1

No contribution was received on the revision of G.799.1. The first draft of
revised G.799.1 (TD
28/WP1) was reviewed and discussed.

TD 28/GEN proposed to include Ethernet Synchronization as new synchronization source for media
gateway in G.799.1/ Y.1451.1. There was no agreement to include the Ethernet Synchronization in
G.7
99.1/
Y.1451.1 at this moment.
Further investigation on the implication when including Ethernet
Synchronization in G.
799.1/Y.1451.1 is needed.
An editor note was added to clause 8.4 of
G.799.1/Y.1451.1 about the possible inclusion of Ethernet Synchronization as
new synchronization
source.

The latest draft of G.799.1/Y.1451.1 is located in the stable text directory of the WP1/16 informal
FTP area at:

http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/G799.1(2010)/

-

11

-

TD 70 (PLEN/16)

3.4.3.5

G.763 Corrigendum 1

TD 8/PLEN indicates the
Implementors’
Guide of G.763 approved at 2000
-
04 is in force, but the
Implementors’
Guide is not available as ITU publication. It was decided to replace the
Implementors’
Guide by a Corrigendum with the same content as the
Implementors’
Guide.

The Corrige
ndum is in TD 48/PLEN, and it was submitted for consent at this meeting.

3.4.4

Intellectual Property Statements

No IPR statements were received at this meeting.

3.4.5

Outgoing Liaison statements

One LS was created to inform SG13 and SG15 that I.733 has been submitted
for consent through
the AAP process. The LS is in TD34/WP1.

3.4.6

Work programme

3.4.6.1

Future work

E
-
mail correspondences pertaining to the activities of this group are routinely conducted using the
e
-
mail reflector currently hosted by the ITU. Those wishing to subsc
ribe or unsubscribe to this
email reflector should visit the ITU web page at:

http://www.itu.int/ITU
-
T/studygroups/com16/edh/ifa
-
structure.html

E
-
mails to all subscribed Q15/16 Experts should be sent to t09sg16q15@ lists.itu.int

Those wishing to subscribe
or unsubscribe to e
-
mail reflectors hosted by ITU should follow the
instructions at
http://www.itu.int/ITU
-
T/edh/faqs
-
email.html

The currently open work items are as follows:

Recommendation

Edit
or

Consent /
Approval

Reference

G.IP2IP

TBD

2010

TD 29/WP1 and
http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/GIP2IP/


G.799.1/Y.1451

TBD

2010

TD 28/WP1 and
http://ifa.itu.int/t/2009/s
g16/exchange/wp1/Stabl
e_Text/G799.1(2010)/


G.769/Y.1242

TBD

2010

http://
ifa.itu.int/t/2009/s
g16/exchange/wp1/Stabl
e_Text/G769/

3.4.6.2

Future meetings

Q.16 and Q.18 are planning to hold a Rapporteur meeting before the next SG

16 meeting in October
2009. Q.15 is planning to meet jointly with them.


-

12

-

TD 70 (PLEN/16)

3.5

Question 16/16


Speech enhancemen
t functions in signal processing network equipment

Question 16/16 was addressed in four sessions during the SG 16 meeting under the chairmanship of
Bob Reeves (BT, UK). The group adopted the agenda in TD 4/WP1.

The objectives for this meeting were:



Continu
e work on revised Rec. ITU
-
T G.168 (Digital network echo cancellers) and prepare it
for consent at this meeting



Continue work on revised Rec. ITU
-
T G.160 (Voice enhancement devices)



Continue work on new Annex E to Rec. ITU
-
T G.168 (Embedded echo cancellers
)



Continue work on revised Rec. ITU
-
T G.169 (Automatic level control devices)

3.5.1

Documentation

The following documents were examined:



Contributions: COM16
-
R26, C1, C39, C51, C52, C58, C76;



TD/Plen: 2, 3, 8, 45;



TD/Gen: 1, 7, 9, 10, 15, 16, 17;



TD/WP1: 1, 4, 7
, 11, 12, 19, 20, 26

3.5.2

Report of Interim Activities

Since the last SG 16 plenary meeting, Question 16/16 held a Rapporteur meeting in September
2008. The report of this Rapporteur meeting (TD

7/WP1) was approved at this SG 16 meeting.

The work also progress
ed by correspondence using the Question e
-
mail reflector (t05sg16q16@
ties.itu.int). Documentation is found in the SG 16 IFA for Q16/16 at:
http://ties.itu.int/u/tsg16/sg16/xchange/wp1/q16

3.5.3

D
iscussions

3.5.3.1

Incoming Liaison Statements

The following liaisons were presented for information:



TD 7/GEN from SG 4 on its role as Lead SG on Telecommunication Management



TD 9/GEN from SG 4 on Joint Coordination Activity on Management (JCA
-
Mgt)



TD 10/GEN from

SG 12 on SG Restructuring: Results and proposals from Study Group 12



TD 15/GEN from TSAG on the handling of patent declarations



TD 16/GEN from TSAG on the quality of ITU
-
T Recommendations



TD 17/GEN from TSAG on improved Geographic Distribution and Coordin
ation of ITU
-
T
Seminars and Workshops



TD 57/GEN from SG15 on new versions of the Access Network Transport (ANT)
Standardization Plan and Work Plan


-

13

-

TD 70 (PLEN/16)

3.5.3.2

Revised Rec. ITU
-
T G.168 (Digital network echo cancellers)

Contribution C51

proposed restructuring new Tests

No. 16 and 17 of G.168 into a single test. This
proposal was agreed. In addition, following some discussion at the meeting, the following small
change was made to the text under the heading “Test method” in new section 6.4.2.1.7.2:

Test method

The echo ca
nceller is enabled. NLP is enabled. Once chosen, the echo path ( along with its
ERL as well as t
r
) remains the same throughout the test. The test is to be performed for all
values of ERL


6 dB. The CSS levels are to be within the range of [
-
15dBm0,
-
5dBm0
].
The DTMF levels and the timing are to be within the range specified in Table A
-
1/Q.24.
The timing of the CSS and DTMF tones has to be such that the first DTMF digit applied at
S
gen

has to be delayed with respect to the start of the CSS by T
ad

(T
ad

> 150
0 ms)


Figure
36. At least one digit (but not more than two digits) shall be applied following the time
when the CSS is removed.

Contribution C58

proposed some changes to Test No. 9 comfort noise test. After some discussion,
the specific proposal in C58 w
as not agreed due to concerns over the increased number of test cases
that it would introduce. Instead, it was agreed to increase the number of steps in Parts 2 and 3 from
the current one (10 dB) to two (5 and 10 dB). The following changes to the text of T
est No. 9 were
agreed:

6.4.2.10.2


Part 2 (adjustment down)

The following 8 steps should be performed in sequence for


dB and

10 dB:

1)

Lower L
Sgen

by


dB from the level in Part 1.

2)

Set L
Rin

to silence (<


60 dBm0) and hold for 10 s.

3)

L
Rin

t
o

10 dBm0.

4)

Measure L
RET

after 2 s.

Requirement

L
RET

should be within 2.0 dB of L
Sgen

when measured over a 700 ms window. Also, this
value should hold as long as noise level L
Sgen

remains constant, and sequential 700 ms
measurements should be made over
a minimum period of 7.7 s to check this.

6.4.2.10.3



Part 3 (adjustment up)

5)

Raise L
Sgen

by


dB from the level in Part 2.

6)

Set L
Rin

to silence (<


60 dBm0) and hold for 10 s.

7)

Set L
Rin

to

10 dBm0.

8)

Measure L
RET

after 2 s.

Requirement

L
RET

should be within 2.0 dB of L
Sgen

when measured over a 700 ms window. Also, this
value should hold as
long as noise level L
Sgen

remains constant, and sequential 700 ms
measurements should be made over a minimum period of 7.7 s to check this.

Document TD 26/WP1

was presented by the Rapporteur as a summary of interim work that had
taken place on the subject
of Test No. 14 (Data modem test). The specific proposals in TD 26/WP1
were not agreed, but following some discussion, it was agreed to make the following changes to the
text under the heading “Test method” in Test No. 14:

-

14

-

TD 70 (PLEN/16)

The values of the settings should
be as follows:

R1, R2 = 6 dB to simulate access/egress loss.

T1 = 3 dB to 9 dB (3 dB is the nominal level, 9 dB simulates a 6 dB level offset).

T2 = 3 dB.

DR1, DR2 = echo path delay




ms.

N1, N2 = set to produce signal
-
to
-
noise ratios of not less than 25

dB, and, no noise.

D1, D2 = set to produce a round trip delay of up to 520 ms, with D1 = D2.

The transmit level at the 2
-
wire interface of a modem is determined by the regulations
applying to the particular country in which the modem is used. This level
is usually factory
pre
-
set and is not adjustable by the user. For Test 14, where it is desired to vary the levels
at the input to the network echo cancellers, this can be achieved by the use of different
lengths of artificial line (W1 and W2 in Figure 30)

together with the transmit attenuators
T1 and T2.

The Rapporteur will continue to work on the remaining action items relating to Test No. 14 and
identified in TD 7/WP1 over the interim period.

The remaining text of revised Rec. ITU
-
T G.168 was reviewed by

the group in preparation for
consent. As part of this review, the words “under study” were removed from the titles of Test Nos.
12 and 13 since these tests are now considered mature tests with complete test methods and
requirements. The Telecommunications

Accessibility Checklist (available here:
http://www.itu.int/ITU
-
T/studygroups/com16/accessibility/

) was also reviewed and it was noted
that this version of G.168 contains performance

measures for text telephones as part of Test No. 14.
The text of revised Rec. ITU
-
T G.168 that was put forward for consent is given in TD 45/Plen.

3.5.3.3

Revised Rec. ITU
-
T G.160 (Voice enhancement devices)

Contribution C52

proposed a change to the definition of

a VED in clause 3.1. This proposal was
agreed.

Contribution C39

proposed changes to the metrics given in Appendix II for the characterisation of
noise reduction functions. A similar contribution was introduced at the interim meeting of Q16 in
Stockholm. T
he specific changes proposed in contribution C39 were not agreed at this time, since
the group needed more time to evaluate the proposed changes. For the purpose of evaluation, the
proponent has made a toolkit available to anyone wishing to try out the met
rics in their own lab.
Access to the toolkit is as follows:

ftp url:

ftp://itu:ituG160@ftp.audience.com

username:

itu

password:

ituG160

The toolkit cont
ains the source code and a test signal corpus that can be used to evaluate the
proposed new metrics, as well as Word documents containing details of any changes to the
algorithm made as a result of discussions at this meeting.

There was much discussion of
Contribution C39 and the key points that emerged from that
discussion were as follows:



Consideration should be given to adding text to the introduction describing the motivation
for extending the accuracy of the metrics and their use for non
-
stationary sig
nals as well as a
cautionary note to warn users that the metrics do not measure speech quality or voice
-

15

-

TD 70 (PLEN/16)

distortion, which should be taken into account when assessing the overall performance of a
noise suppressor.



The proposed change to the calculation of S
NRI does not include the medium and low
power frames. To address these concerns it was agreed to keep the method that includes the
medium and low power frames as an alternative way of computing SNRI.



It was noted that the graph of SNRI measurement error gi
ven in Figure 6 of Contribution
C39 contained two lines (relating to SNRI+ pink noise and car noise) that were truncated for
values of True NR below about 16 and 20 dB respectively. The proponent was asked to
explain these apparent truncations.



Additional
text describing how to measure the active noise level in clause II.4.1 is required.



Concerns were raised that the TNLR equation needs some provision for the possibility of
comfort noise generated by network components. The agreed fix was to add a “comfort
noise level” component to the equation that will default to
-
66 dBov in the absence of any
comfort noise.

Following some discussion on the way forward, it was agreed that work should be continued at an
interim meeting of Q16, kindly hosted by the proponent
, with the view to approving revised text of
Appendix II at the next meeting of SG16 in October 2009. The revised draft text of G.160
Appendix II that addresses the concerns raised above can be found in Annex Q16.A to this report.
Members are encouraged to

evaluate the proposed changes using the toolkit provided and submit
contributions to the interim meeting of Q16.

An updated draft of revised Rec. ITU
-
T G.160 was prepared by the editor and posted in the iftp area
at:
http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/G160_2010/

3.5.3.4

Revised Rec. ITU
-
T G.169 (Automatic level control devices)

Contribution C76

contained proposals for modifications and additions to the tests co
ntained in
G.169. The following list of bullets summarises the agreements made in respect of this contribution:



Proposed enhancement to Test 7.3A (robustness to circuit noise)


not agreed. The proposed
additional values of circuit noise were not considere
d to be representative of true circuit
noise found in networks



Proposed enhancement to Test 7.3B (robustness to environmental noise)


agreed.



Proposed additional Test 7.3C (robustness to ITU
-
T environmental noise)


agreed. The
editor should add the speci
fic reference to ITU
-
T car, street and babble noise referred to in
the contribution.



Proposed additional Test 7.4A (ability to estimate the signal level correctly)


not agreed.
Although the specific proposals in this test were not agreed, there was consen
sus that
assessing the ability of an ALC device to estimate the signal level correctly was a valid thing
to do. Contributions are requested on how to address this.



Proposed additional Test 7.4B (ability to converge on short bursts of speech)


not agreed.
There were concerns that adopting this requirement may lead to incorrect adaptation of the
ALC to short words often muttered during a conversation. To move this forward, the
minimum duration of a short utterance needs to be defined. Contributions are reque
sted. The
editor agreed to modify the text in the current placeholder for this test to reflect the need for
a definition of a short utterance.

-

16

-

TD 70 (PLEN/16)



Proposed additional tests 7.5A and 7.5B refer to the operation of an Automatic Listener
Enhancement (ALE) functio
n. There was much discussion as to whether an ALE function
was a form of ALC or not. As a result of this discussion, it was agreed to move the existing
text in draft revised Rec. ITU
-
T G.169 (TD 20/WP1) clause 7.8 onwards into a new Annex
B called “Automat
ic Listener Enhancement”.



Proposed additional test 7.5A was not agreed to be included as part of new Annex B. There
was concern that the proposed requirements in this test would place unjustifiable restrictions
on the design of an ALE function.



Proposed te
st 7.5B was agreed. The following text should be added to new Annex B. In
addition, the editor agreed to add specific references to ITU
-
T car, street and babble noise,
as well as ITU
-
T speech utterances:


B.xx

Test to verify the robustness of an ALE functi
on to the presence of speech in
the opposite direction

The intent of this test is to verify that an ALE function does not react to the presence of
speech in the other direction but only to noise. The presence of speech along with noise
should not drastical
ly change the amount of gain applied by ALE.

The test signals in this test consist of sine tones defined in test 7.4B and ITU speech
utterances. The noise used in this test consists of ITU noise files car, street and babble. The
steps should be repeated fo
r all levels of noise for which the operation is defined.

1.

Connect the ALC device (or the equipment containing the ALC device) into an
appropriate test circuit, such that test signals can be applied to the input of the device,
and the level of the input and

output signals can be monitored.

2.

Set the ALC target level to be the same as that of the input signal level so that ALC is
applying a 0dB gain.

3.

Apply on/off modulated tone to A and the ITU noise of the test level to B for a duration
of 8 seconds. Refer to

Figure 2 for definition of A and B.

4.

Check the ALC device gain by measuring the level of the tone during its final on
-
duration of 1 second at the device output.

5.

Replace the noise in the other direction with noise mixed with ITU speech file at 10dB
SNR whil
e maintaining the on/off signal at A.

6.

Check the ALC gain by measuring the level of the tone during its final on
-
duration of 1
second at the device output.

Allowing for measurement inaccuracies, the gain of the ALC device at step 4 and the gain
of the devic
e at step 6 should be within 1dB of each other. If the gain is beyond these limits
then the ALC device should be considered to have failed the test.


An updated draft of revised Rec. ITU
-
T G.169 will be prepared by the editor and posted in the iftp
area at
:
http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/G169_2010/

Mr Mahesh Godavarti (Ditech Networks, USA) kindly volunteered to be editor of Rec. ITU
-
T
G.169.

-

17

-

TD 70 (PLEN/16)

3.5.3.5

New Ann
ex E to Rec. ITU
-
T G.168 (Embedded echo cancellers)

Document TD 19/WP1

was presented as the latest draft of new Annex E for information. No
contributions were received to this meeting on this topic.

3.5.4

Intellectual Property Statements

No IPR statements were r
eceived at this meeting.

3.5.5

Outgoing Liaison statements

No LSs were prepared at this meeting.

3.5.6

Work programme

3.5.6.1

Future work

E
-
mail correspondences pertaining to the activities of this group are routinely conducted using the
e
-
mail reflector currently hosted by t
he ITU. Those wishing to subscribe or unsubscribe to this
email reflector should visit the ITU web page at:


http://www.itu.int/ITU
-
T/services/

E
-
mails to all subscribed Q16/16 Experts should be sent to:
t09sg16q16@lists.itu.int

Those wishing to subscribe or unsubscribe to e
-
mail reflectors hosted by ITU should follow the
instructions at
http://www.i
tu.int/ITU
-
T/edh/edh
-
faqs.html


The currently open work items are as follows:


Recommendation

Editor

Consent /
Approval

Reference

Revised Rec. ITU
-
T G.160 (Voice
enhancement devices)

Dominic Ho

2010

http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/G160_2010/

Revised Appendix II to Rec. ITU
-
T
G.160 (Objective measures for NR)

Dominic Ho

2009

Annex
A to this report

Revised Rec. ITU
-
T G.169 (Automatic
level control d
evices)

Mahesh
Godavarti

2010

http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/G169_2010/

New Annex E to Rec. ITU
-
T G.168
(Embedded echo cancellers)

Bob Reeves

2010

http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/G168_Annex_E_(EEC
)/


Revised Rec. ITU
-
T G.168 (Digital
network echo cancellers)

Dominic Ho

2011

None avai
lable at
present

-

18

-

TD 70 (PLEN/16)

3.5.6.2

Future meetings

Q16 is planning to hold one Rapporteur meeting before the next SG

16 meeting in October 2009.
This meeting will be located in Mountain View, CA, USA and will be hosted by Audience Inc. Q15
and Q18 are planning to meet join
tly with Q16.


3.6

Question 18/16


Interaction aspects of signal processing network equipment

Question 18/16 was addressed in
three

sessions during the SG 16 meeting under the chairmanship
of
Mr

Harald Kullmann (Deutsche Telekom, Germany). The group adopted t
he agenda in
TD

5/WP1.

The objectives for this meeting were:



To progress work on new Recommendation
ITU
-
T
G.MDCSPNE “Mechanism for dynamic
coordination of SPNE” in preparation for the Consent date in
October
2009.



To progress work on revised Recommendation

ITU
-
T
G.161 "Interaction aspects of signal
processing network equipment" in preparation for the Consent date in
October
2009.



To progress work on new Recommendation
ITU
-
T
G.SPNE “Signal Processing Network
Equipment” in preparation for the Consent date in
October
2009.



To
coordinate the activities verifying the consistency of SPNE Recommendations

3.6.1

Documentation

The following documents were examined:



Contributions: COM 16
-

C.1, C.50,

C.52, C.76



TD/Plen:
2, 3, 8, 9



TD/Gen: 1,
7, 9, 10, 15, 16, 17, 28, 57, 60



T
D/WP1: 1, 5, 9,
10, 23, 24, 25, 27

3.6.2

Report of
i
nterim
a
ctivities

Since the last SG 1
6 plenary meeting, Q18/16 held
o
ne

Rapporteur meeting.

3.6.3

Discussions

3.6.3.1

Incoming Liaison Statements



TD 1 (GEN/16) (TSB)
“Outgoing LSs produced by the SG 16 management and at Rapp
orteurs
meetings during the interim period (May 2008 January 2009), Addendum 2”



TD 8 (PLEN/16) (TSB) “
List of Implementors’ Guides for Study Group 16




TD 7 (GEN/16) (ITU
-
T SG 4) “
LS on SG 4 Report and Request in its role as Lead SG on
Telecommunication Man
agement




TD 9 (GEN/16) (ITU
-
T SG 4) „
LS on Joint Coordination Activity on Management (JCA
-
Mgt)




TD 10 (GEN/16) (ITU
-
T SG 12) “
LS on SG Restructuring: Results and proposals from Study
Group 12


-

19

-

TD 70 (PLEN/16)



TD 15 (GEN/16) (TSB) “
LS regarding handling of patent declarati
ons




TD 16 (GEN/16) (TSB) “
LS on quality of ITU
-
T Recommendations




TD 17 (GEN/16) (TSB) “
LS on improved Geographic Distribution and Coordination of ITU
-
T
Seminars and Workshops




TD 57 (GEN/16) (ITU
-
T SG 15) “
LS on new versions of the Access Network Transpo
rt (ANT)
Standardization Plan and Work Plan”



TD 28 (GEN/16) (ITU
-
T SG 15)
“LS on clock function for media gateway”



TD 60 (GEN/16) (ITU
-
T FG
-
CarCom) „
Reply to LS on progress update on G.MDCSPNE




TD 3 (PLEN/16) (TSB) “
Summary of WTSA
-
08 decisions with impact

on SG 16 work”



TD 2 (PLEN/16) (TSB) “
Proposed SG 16 Structure and Chairmanship assignments


3.6.3.2

Summary of Results and Agreement
s



COM 16

R 26 with regard to the work of Q18/16 in the last SG 16 meeting in Geneva, 22 April


2 May 2008 was presented and discus
sed. The report was accepted.



TD 9 (WP 1/16
) “Report for former Q18/16 Rapporteurs Group Meeting (Stockholm, Sweden,

24
-
30 September 2008)”

was presented and agreed.



TD 2 (PLEN/16) (TSB) “
Proposed SG 16 Structure and Chairmanship assignments”

from the
TSB

was presented for information.



TD

1/GEN “
Outgoing LSs produced by the SG 16 management and at Rapporteurs meetings
during the interim period (May 2008 January 2009), Addendum 2
)” from the TSB was
presented and discussed. No action was required or taken at

this meeting.



TD 8 (PLEN/16) “
List of Implementors’ Guides for Study Group 16
” from the TSB was
presented and discussed. No action was required or taken at this meeting.



TD 7 (GEN/16) (ITU
-
T SG 4) “
LS on SG 4 Report and Request in its role as Lead SG on
T
elecommunication Management
” and TD 9 (GEN/16) (ITU
-
T SG 4) „
LS on Joint
Coordination Activity on Management (JCA
-
Mgt)
” were presented as background information
regarding management aspect of SPNE.



TD 10 (GEN/16) (ITU
-
T SG 12) “
LS on SG Restructuring: Resu
lts and proposals from Study
Group 12


was presented as background information regarding the structure of SG12 and the
Focus Group CarCom.



TD 15 (GEN/16) (TSB) “
LS regarding handling of patent declarations
” was presented and it
was agreed to keep it for in
formation.



TD 16 (GEN/16) (TSB) “
LS on quality of ITU
-
T Recommendations
” was presented and it was
agreed to keep it for information.



TD 17 (GEN/16) (TSB) “
LS on improved Geographic Distribution and Coordination of ITU
-
T
Seminars and Workshops
” was presente
d and it was agreed to keep it for information.



TD 28 (GEN/16) (ITU
-
T SG 15)
“LS on clock function for media gateway”

was presented and
it was agreed to keep it for information.

-

20

-

TD 70 (PLEN/16)



TD 57 (GEN/16) (ITU
-
T SG 15) “
LS on new versions of the Access Network Transpo
rt (ANT)
Standardization Plan and Work Plan”

was presented and it was agreed to keep it for
information for draft new Recommendation G.MDCSPNE.



TD 3 (PLEN/16) (TSB) “
Summary of WTSA
-
08 decisions with impact on SG 16 work”

was
presented and it was agreed to

coordinate the discussion on Resolution 76 in each Question of
WP1/16. The results are shown in section 3.2.3 of the WP1/16 report.



TD 60 (GEN/16) (ITU
-
T FG
-
CarCom) „
Reply to LS on progress update on G.MDCSPNE
“ and
COM 16


LS 354 “LS to 3GPP2 on progress

update on G.MDCSPNE” were presented and the
group informed that the LS 354 was sent by the TSB also to 3GPP SA4 after the Rapporteur`s
meeting in Stockholm/Sweden.



COM 16


C 1 “
Questions assigned to ITU
-
T Study Group 16 by WTSA
-
08
” on the current text
fo
r Q.18/16 was presented for information.



COM 16


C 50 “
Proposed Liaison to IETF AVT WG in Requesting Assistance on the Protocols
for G.MDCSPNE
” was presented and agreed to write this Liaison Statement to IETF and SG11
for action and to the FG CarCom for i
nformation. The text can be found in TD 35/PLEN.



COM 16


C 52 “
Definition of VED in G.160
” was presented and agreed to update the definition
in draft revised Rec. G.161 (TD 24 (WP1/16).



COM 16


C 76 “
Incorporation of additional tests to Automatic Level C
ontrol (ALC)
specification G.169
” was presented on interaction aspects on ALCs and no action was required
or taken at this meeting.



TD 10 (WP 1/16) on “
Updated draft of new Rec.
ITU
-
T
G.MDCSPNE
Mechanism for Dynamic
Coordination of Voice Enhancement SPNE

was presented and agreed.

The updated text of G.mdcspne, draft 8 is available on the ITU IFA, at:
http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/GMDCSPNE/




The Livi
ng List of Recommendation G.mdcspne contained in TD 27 (WP 1/16) was presented
for information and is available on the ITU IFA, at:
http://ifa.itu.int/t/2009/sg16/exchang
e/wp1/q18/LivingList_Gmdcspne/




TD 24 (WP 1/16) “
Draft revised Recommendation
ITU
-
T
G.161
”, with the updated Version 3.7
and the Living List of G.161 contained in TD 23 (WP 1/16) were presented and discussed and
no action was required or taken at this mee
ting. Contributions are requested.

The updated text is available on the ITU IFA, at:
http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/G161_2010/

. The Living List of

Recommendation G.161 is available in the stable text directory of WP 1/16 at:
http://ifa.itu.int/t/2009/sg16/exchange/wp1/q18/LivingList_G161/




TD 25 (WP 1/16) Draft new Re
commendation
ITU
-
T
G.SPNE “
Signal processing network
equipment
”, Version 2.1 was presented and discussed and no action was required or taken at this
meeting. Contributions are requested. The text is available on the ITU IFA, at:

http://ifa.itu.int/t/2009/sg16/exchange/wp1/Stable_Text/GSPNE/


The work programme (
http://www.itu.int/ITU
-
T/workpr
og/wp_search.aspx?isn_sp=545&isn_sg=554

) for the Question and the future work was
discussed and agreed with the modification of the new Consent date for G.SPNE and G.161
.

-

21

-

TD 70 (PLEN/16)

3.6.4

Intellectual
property statements

No i
ntellectual
property statements

were raised du
ring the meeting of Q18/16.

3.6.5

Outgoing Liaison Statements

One Liaison Statement to IETF AVT WG, SG11 and the FG CarCom in “
Requesting Assistance on
the Protocols for G.MDCSPNE
” was prepared at this meeting, see TD 35/WP1
.

3.6.6

Work Programme

3.6.6.1

Future work

E
-
mail co
rrespondences pertaining to the activities of this group are routinely conducted using the
e
-
mail reflector currently hosted by the ITU. Those wishing to subscribe or unsubscribe to this
email reflector should visit the ITU web page at:


http://www.itu.int/ITU
-
T/studygroups/com16/edh/ifa
-
structure.html


E
-
mails to all subscribed Q18/16 Experts should be sent
to
t09sg16q18@lists.i
tu.int
.

Those wishing to subscribe or unsubscribe to e
-
mail reflectors hosted by ITU should follow the
instructions at
http://www.itu.int/ITU
-
T/edh/faqs
-
email.html

The currently open work items

are as follows:

Recommendation

Editor

Consent

Reference

Revised Rec.
ITU
-
T
G.161

Harald Kullmann

2010

TD 24/WP1 and
http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext
/G161_2009/


New Rec. G.mdcspne

Dominic Ho

2009
-
10

TD 10/WP1 and
http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/GMDCSPNE/


New Rec. G.SPNE

Harald Kullmann

2010

T
D 35/WP1 and
http://ifa.itu.int/t/2009/sg1
6/exchange/wp1/Stable_T
ext/GSPNE/


3.6.6.2

Future Meetings

Qs 15, 16 and 18/16 are planning to hold a Rapporteurs meeting before the next SG

16 meeting in
October 2009. The host is Audience Inc. and the location is Mountain View
, CA,
USA. Q18
/16

is
planning to meet jointly with them if needed
.

4

Summary of Liaison Activity

Three

outgoing Liaison Statement
s

were

prepared by WP 1/16.
The

full text
s

are

contained in
TD

xx
/PLEN
.

-

22

-

TD 70 (PLEN/16)

Title

Destination

Purpose

Document

Source

LS to ETSI TISPAN on interoperability of
ITU
-
T V.152

ETSI TISPAN

Information

TD

32
/
WP1

Q1
4/16

LS to SG13 and SG15 about I.733

SG13 and SG15

Information

TD

34
/
WP1

Q1
5/16

Requesting A
ssistance on the Protocols for
G.MDCSPNE

SG11, IETF AVT
WG, FG CarCom

Action
,
deadline 31

May 2009;
FG Car
C
om

for
information

TD

35
/
WP1

Q18
/16

5

Workplan

The updated work programme for Recommendations that are the responsibility of WP

1
/16 is on the
SG 16 w
eb page at
http://www.itu.int/ITU
-
T/workprog/wp_search.aspx?isn_sp=545&isn_sg=554
.

6

Summary of Interim Rapporteur Meetings

The following is a summary of the interim Rapp
orteur’s meetings proposed by WP 1/16. Evolution
of the status of the meetings will be regularly updated in the SG 16 home page at

http://itu.int/ITU
-
T/studygroups/com16/meetings.html

Q
uestion

14/16

No interim meeting is being requested by Q14/16
.

However, TIA TR
-
30.1 will meet on the following dates to help progress the work on V.150.1
Version 2, V.151, V.152, V.IP2IP
-
VxF and T.38.

The subject matter experts of
Q14/16
and

Q.
26
/16

are in
vited to contribute to the technical discussions at these meetings.


Date (week of)

Location

30
March 2009

TIA, Arlington , VA

14
September 2009

TIA, Arlington , VA

7
December 2009

TBD


Questions 15, 16

and

18/16

Dates

Place

Host

Q

O
bjectives

10
-

16

June 2009

Mountain
View,
CA,
US
A

Audience
Inc.

15
/16



To address the comments received, if there are, about
ITU
-
T
I.733 during the AAP process



To co
ntinue work on new Rec.
ITU
-
T
G.IP2
IP



To continue work on revised Rec.
ITU
-
T
G.799.1/G.1451.1 (VoIP Gateway)

-

23

-

TD 70 (PLEN/16)

Dates

Place

Host

Q

O
bjectives




1
6
/16



Continue work on revised Rec. ITU
-
T G.160 (Voice
enhancement devices)



Continue work on revised Appendix II to Rec. ITU
-
T
G.160 (Voice enhancement devices) for approval at the
next SG16 meeting



Continue work on revised Rec. ITU
-
T G.169 (Automatic

level control devices)



Continue work on new Annex E to Rec. ITU
-
T G.168
(Embedded echo cancellers)



Continue work on revised Rec. ITU
-
T G.168 (Digital
network echo cancellers)




18/16



Pro
gress the work on revised
Rec. ITU
-
T
G.161



Progress the work on

dra
ft new Rec. ITU
-
T
G.mdcspne



Progress the work on

draft new Rec. ITU
-
T
G.SPNE

N
ote: The details of the
dates

and venue
above
are subjects to change and
a
final decision, once it has made,
will be notified to the experts through
e
-
mail reflectors of Q
uestio
ns 15, 16, 18
/16 and WP

1/16.


(Full text available only in the electronic version)


-

24

-

TD 70 (PLEN/16)

Annex
Q16.A

Updated

text for
Recommendation ITU
-
T
G.160

Appendix
II


Objective Measures for the Characterization of the Basic Functioning of Noise Reduction
Algorithms

(T
his appendix does not form an integral part of this Recommendation)

II.1

Introduction

This appendix presents an objective methodology for characterising the basic effect of noise
reduction (NR) methods. Three objective measures are specified for characteri
sing NR solutions.
Recommendation target value ranges in specified conditions are given for the measures to serve as
basic guidelines for proper functioning of NR methods.

The methodology monitors the basic functioning of an NR solution in terms of signal
-
to
-
noise ratio
improvement (
SNRI
) and total noise level reduction (
TNLR
). While
SNRI

is measured during speech
activity, focusing on the effect of NR on speech signal,
TNLR

estimates the overall level of noise
reduction, experienced both during speech and
speech pauses. In addition, a delta measurement
(
DSN
) is computed to reveal speech attenuation or undesired speech amplification caused by an NR
solution.

The proposed methodology is a further development of one included in the [b
-
ETSI TS 126 077]
and the
[b
-
TIA/EIA
-
IS
-
853]. A detailed description of the earlier methodology is incorporated in
the named specifications.

NOTE


“Noise suppression” in the named standard specifications refers to methods that reduce the
background noise impact in the desired spee
ch signal, with no limitation as to their capability of
reducing the noise level either only outside of or also during speech activity. The terms “Noise
suppression” and “noise reduction” are used interchangeably in this Appendix.

The measurement technique
s have been extended to improve the accuracy of measurement of high
noise reduction levels, and to permit nonstationary noise sources to be used, as required for modern
terminal noise suppressors, which may have multiple microphones. It should be noted t
hat these
objective measures of noise reduction performance do not measure speech quality or voice
distortion, which should be taken into account when assessing the overall performance of a noise
suppressor.

II.2

Notations

The following notations are used
in this Appendix:



The operator NR(

) corresponds to applying the NR algorithm on the input speech.



The clean speech original signals are referred to as
s
i
,
i

=

1

to

I, where I is the total
number of speech files used.



The noise original signals are referr
ed to as
n
j
,

j

=

1

to

J, where J is the total number of
noise files used.



The noisy speech test signals are referred to as
d
ij

=

s
i

+

ij
(SNR)
n
j
, i

=

1

to

I, j

=

1

to

J,
where
d
ij

is built by adding
s
i

and
n
j

with a pre
-
specified SNR as presented below.



The processed signal is referred to as
y
ij

=

NR

(
d
ij
).

-

25

-

TD 70 (PLEN/16)



The reference signal in the calculations shall be the noisy speech test signal
d
ij

itself.



The notation
Log
(

) indicates the decimal logarithm.




ij
(SNR) is the scaling factor to be applied to the backg
round noise signal
n
i

in order to
have a ratio
SNR

(in dB) between the clean speech signal
s
i

and

n
j
. The use of the
scaling factor is explained below in clause II.3 in conjunction with the generation of test
samples.



Frames are classified by their average

speech power (high, medium, low); these classes
are named {k
sph
}, {k
spm
}, {k
spl
}.



Frames containing only noise form a separate class, named {k
nse
}.



The determination of which frames contain active speech is to be carried out with
reference to [b
-
ITU
-
T P.5
6] “Objective measurement of active speech level”and is
related to the classification of the frames into the presented categories, or
speech power
classes

which is explained below.

II.3

Test signals

The test material should manifest at least the following

extent:



Clean speech utterance sequences: 6

utterances from 4

speakers
-

2

male and 2

female
-

totalling 24

utterances



Noise sequences:

-

Car interior noise, 120

km/h, fairly constant power level

-

Street noise, slowly varying power level

Special care should
be taken to ensure that the original samples fulfil the following requirements:



The clean speech signals are of a relatively constant average (within sample, where
‘sample’ refers to a file containing one or more utterances) power level



The noise signals a
re of a short
-
time stationary nature with no rapid changes in the
power level and no speech
-
like components

The test signals should cover the following background noise and SNR conditions:



Car noise at 6 dB, 12 dB and 18

dB SNR



Street noise at 6 dB, 12 dB
and 18 dB SNR

The samples should be digitally filtered before NR processing by an appropriate filter to become
representative of a real cellular system frequency response. This filtering should be carried out
before the scaling of the samples to be discuss
ed below.

NOTE
-

Appropriate digital filters to make the test material representative of a real cellular mobile
station frequency response, which are available as part of the G.191 Software Tool Library are the
following:



The modified IRS filter according
to the [ITU
-
T P.48]



The MSIN (mobile station in) filter. The transfer function of the MSIN filter has been
defined based on measurements by British Telecom. Even though the MSIN filter attempts
mainly to describe the spectral modifications of background no
ise, in the ETSI (European
Telecommunication Standardisation Institute) STC SMG11#8 Plenary (Jan 1999; Helsinki,
Finland), it has been discussed that this filter may also be applied to the speech signal.

-

26

-

TD 70 (PLEN/16)

The test samples corresponding to the named SNR cond
itions shall be generated according to the
following procedure:



The clean speech material shall be scaled to the active speech level

26 dBov with the
[b
-
ITU
-
T P.56] speech voltmeter, one file at a time, each file including a sequence of
one (to four) utte
rance(s) from one speaker.



A silence period of 2s is inserted in the beginning of each of the resulting files to make
up augmented clean speech files.



Within each noise type and SNR condition, a noise sequence is selected for every
augmented clean speech u
tterance file, each with the same length as the corresponding
speech file, and each noise sequence is stored in a separate file.



Each of the noise sequences is scaled to a dBov level leading to the SNR condition
corresponding to the

ij
(SNR) value in each
of the test cases by applying the RMS level
based scaling according to [b
-
ITU
-
T P.56].



Augmented clean speech and noise files are then added sample by sample (overload
values being clipped) to create the needed set of noisy speech files with predefined
SNR
, sample
-
rate, bits/sample, file
-
length.

II.4

Objective measures for characterisation of NR algorithm effect

II.4.1

Frame categorisation for speech and speech pause classes

The objective metric for measuring SNR improvement due to an NR algorithm, or
SNRI
,

that is
presented below, is calculated separately in three groups of speech signal frames that represent
power
-
gated constituents of active speech signal. These groups of frames are called
speech power
classes

or just
power classes

in the following. Hence
, the
SNRI

measure is calculated separately in
frames of high, medium and low power. These categories are used to characterise the effect of the
NR processing on speech, allowing the distinction of the effect on strong, medium and weak
speech. In addition
to calculating the SNR improvement separately on the three categories, they are
used to form an aggregate measure.

In addition to the division into three frame classes containing speech activity, a fourth frame class is
needed to be able to calculate the p
ower levels in the noise periods lying amongst speech activity.
These power levels are used both in the calculation of the
SNRI

metrics and in the calculation of the
overall change in noise power level (
TNLR
) due to NR processing.

A frame length of 10 ms,
i.e., 80 samples (for speech sampled at 8 kHz), is used in the analysis
since it has been found the most efficient to describe changes in the signal caused by NR
processing.

To determine which frames belong to high, medium and low power classes of active s
peech and
which present pauses in the speech activity (noise only), the active speech level (in dB) (sp_lvl) of
the noise free speech
s
i
(n) is first determined according to the [b
-
ITU
-
T P.56]. Thereafter, the
frames are classified into the four classes bas
ed upon a comparison of the power in each frame to
predefined threshold values relative to the active speech level. As a result, four number sequences
are obtained to represent the three speech classes and the speech pause class, respectively:


sph
k
,


spm
k
,


spl
k
,


nse
k
.

The threshold values to be related to the active speech level are presented in Table II.1. To be able
to apply the threshold values given here, the speech should be fir
st normalised at
-
26

dBov using the
-

27

-

TD 70 (PLEN/16)

[b
-
ITU
-
T P.56] speech voltmeter Figure II
-
1 presents an example of the classification of a clean
speech sample into power classes.

Table

II.1
-

Power threshold values for speech power classes

Threshold

Explanation

Value

th_h

Lower bound for high speech power class

-
1

dB

th_m

Lower bound for medium speech power class

-
10

dB

th_l

Lower bound for low speech power class

-
16

dB

th_nh

Higher bound for speech pause class

-
25

dB


Dlp_min

Minimum duration for long speech paus
e class

400 ms


The active noise level is determined by applying the ITU
-
T P.56 speech voltmeter to the long pause
frames of input signal (before noise suppression).


The following notes are made concerning the formulation of the speech power classes:



Al
l frames with power level lower than the higher bound for speech pause class, th_nh,
are used in the computation of
TNLR

as this should indicate the overall reduction in
noise level experienced both during short speech pauses amongst speech activity and
lo
ng speech pauses when no speech is immediately continuing. On the other hand, only
those frames in speech pauses of duration less than the minimum duration for long
speech pauses, Dlp_min, are applied to the computation of both
SNRI

and
DSN
. This
exclusion

of long pauses from the analysis makes
SNRI

and
DSN

concentrate on those
noise frames among or close to speech activity.




In low SNR conditions, the noise power level may occur to be higher than the lower
bound of some of the speech power classes. Howev
er, even in this case, the information
of the effect on the low power portions of speech may be informative.

-

28

-

TD 70 (PLEN/16)




1
2
3
4
5
6
7
8
-70
-60
-50
-40
-30
-20
-10
sp_lvl + th_h
sp_lvl + th_m
sp_lvl + th_l
sp_lvl + th_nh
Power (dBov)
Time (second)

Figure II
-
1


Power in frames of clean speech as a function of time.

Classification into power classes

II.4.2

Assessment of SNR improvement
-

SNRI

The SNR improvement measure,
SNRI
, measures the SNR improvement achieved by the NR
algorithm. As said above, SNR improvement is calculated in three
speech power classes

to obtain
an evaluation of the effect separately for strong, medium and weak spee
ch. An aggregate measure is
obtained in addition via weighted averaging.

The calculation is here presented for the high power speech class. A similar procedure is used to
obtain the respective figures for the medium and low power speech classes.

For each b
ackground noise condition j and for each speech sample i, construct a noisy speech input
signal d
ij

as follows:

d
ij
(n)

=


ij


n
j
(n)

+


s
i
(n),

where

ij

depends on the SNR condition according to the procedure described above. Now,
the noise suppressed outpu
t speech signal can be denoted as:

y
ij

=

NR

(
d
ij
)

-

29

-

TD 70 (PLEN/16)

In this way, the SNR of the output and input speech signals can be expressed as:


























































1
10
10
,
max
Log
10
out_h
1
2
1
2
)
(
,
max
Log
1
)
(
,
max
Log
1
ij
nse
K
m
n
ij
nse
sph
K
l
n
ij
sph
n
y
K
n
y
K
SNR





























































1
10
10
,
max
Log
10
in_h
1
2
1
2
)
(
,
max
Log
1
)
(
,
max
Log
1
ij
nse
K
m
n
ij
nse
sph
K
l
n
ij
sph
n
d
K
n
d
K
SNR




ij
ij
ij
SNRin_h
SNRout_h
SNRI_h


,


(3)


where


K
sph

is the total number of frames con
taining speech of high power;






K
nse

is the total number of frames containing noise during short speech
pauses;






0



is a constant that should be set at
8*10
-
8
;






0



is a constant that should be set at 0.
0631 (equivalent to
-
12 dB).



The summation with respect to indices
n

and

p

is carried out in frames of 80 samples.
SNRI_m
ij

and
SNRI_l
ij

are computed correspondingly for medium and low power frames.

Finally, the aggregate measure for signal
-
to
-
noise rati
o improvement is computed as below.

ij
ij
SNRI_h

SNRI


(4a)


As an alternate for evaluation purposes, the original aggregate measure for SNRI will also be
computed:



ij
ij
ij
ij
SNRI_l
SNRI_m
SNRI_h
1
spl
spm
sph
spl
spm
sph
K
K
K
K
K
K
SNRI








(
1
b)




I
i
SNRI
SNRI
1
ij
j
I
1

=



(5)



J
j
SNRI
SNRI
1
j
J
1

=


(6)

In addition, measures for the SNR improvement in the high, medium and low power speech classes
(SNRI_h, SNRI_m, SNRI_l, respectively) shall be recorded based on the following formulae:








J
j
I
i
ij
J
j
j
SNRI_h
I

J
=
SNRI_h
J
SNRI_h
1
1
1
1
1
1


(7)

-

30

-

TD 70 (PLEN/16)








J
j
I
i
ij
J
j
j
SNRI_m
I

J
=
SNRI_m
J
SNRI_m
1
1
1
1
1
1

(8)








J
j
I
i
ij
J
j
j
SNRI_l
I

J
=
SNRI_l
J
SNRI_l
1
1
1
1
1
1


(9)

It is, in addition, informative to record separately the noise type specific SNR improvement
measures, namely,
SNRI_hj, SNRI_lj, SNRI_mj

and
SNRIj

for each background noise condition j.

II.4.3

Assessment of

total noise level reduction
-

TNLR

The total noise level reduction measure, or
TNLR,

relates to the capability of the NR method to
attenuate the background noise level measured during both speech activity and speech pauses. As
the number of frames in the
speech pause class during speech activity is typically relatively small
compared to the number of frames during long speech pauses,
TNLR

mainly measures the capability
of an NR to reduce noise during long speech pauses.

The
TNLR

measure is calculated as fo
llows:

For each background noise condition j and for each speech sample i, construct a noisy input signal
d
ij

as follows:


d
ij
(n)

=


ij


n
j
(n)

+


s
i
(n),


where

ij

depends on the SNR condition according to the procedure described above. The
noise suppresse
d output speech signal can be denoted as:


y
ij

=

NR

(
d
ij
)

In this way, the total noise level reduction measure can be expressed as:




















































pse
K
m
q
ij
q
ij
pse
ij
q
m
y
q
m
d
K
TNLR
1
2
2
)
,
(
,
max
Log
)
,
(
,
max
Log
10
1


,

(10)

where



K
pse

is total number of noise frames during

speech pauses (frame power of
clean speec
h signal < sp_lvl + th_nh) with active noise (frame power of
noisy input signal > max(nse_lvl
-
20, cft_lvl))
;

0



is a constant that should be set at
8*10
-
8


cft_lvl is a comfort noise level constant that will default to
-
66dB




I
i
ij
j
TNLR
TNLR
1
I
1

=



(11)



J
j
j
TNLR
TNLR
1
J
1

=


(12)

The summation with respect to index

q

is carried out in noise frames of 80 samples. The index,
q
,
relates to noise frames with frame power less than the higher bound for speech pause class, th_nh
(see Tabl
e II.1).

Furthermore, it is informative to record separately the noise type specific
TNLR

measures, or
TNLR
j
, for each background noise condition j.

-

31

-

TD 70 (PLEN/16)

II.4.4


Assessment of Speech Level Difference
-

DSN

One of the targets in noise suppression is to maintain
the power level of the speech signal so as not
to attenuate the level of the speech signal together with the noise signal in the NR processing.
Furthermore, an improvement in the SNR of a noisy speech signal may be obtained in a simple
amplification of the

speech signal, the amplification being typically only applied to the high
-
energy
portions of the signal. As both the attenuation and amplification of speech are not desirable in NR,
they should be detected.

Both the attenuation and amplification of a spee
ch signal due to an NR can be measured by
studying the balance between the SNR improvement and the noise level reduction obtained during
speech activity. For this purpose, noise power level reduction, or
NPLR
, is measured during short
speech pauses lying a
mongst speech activity to study the capability of an NR to reduce noise from
speech. This measure is computed otherwise as
TNLR
, i.e., according to the equations of (10), (11)
and (12),
except that the computation is only carried out with frames classified

as short pause frame. Here a
frame of speech pause class is classified as a short pause frame if its duration is less than the minimum
duration of long pause, Dlp_min, which is set at 400 ms.
In this way,
NPLR

provides a counterpart for
SNRI
, these metric
s forming together the basis for the evaluation of the balance. As
NPLR

is used as
an internal variable, it is not reported.

SNRI
-
to
-
NPLR

difference

(
DSN
), comprising a comparison of the
SNRI

and
NPLR

measures, is
therefore proposed as a measure to acquire

an indication of possible speech attenuation or speech
amplification produced by the tested NR method and is formulated as:

NPLR
SNRI
DSN




(13)

Typically the
DSN

quantity should get values close to zero. If the
NPLR

parameter assumes clearly
hig
her values than
SNRI
, making
DSN

clearly negative, the NR solution turns out to produce speech
level attenuation. On the other hand, if
DSN

becomes clearly positive, it indicates the speech signal
has been amplified, which contributes to the SNR improvemen
t partially or wholly if no reduction
in noise level.

Note that DSN is affected by the choice of formula for computing SNRI (default is equation 4a,
with the toolkit supporting the option to use equation 4b).



It is informative to record separately the n
oise type specific
DSN

measures, or
DSN
j
, for
each

background noise condition j.

II.4.5

Block diagram presentation of proposed measures

A block diagram of the calculation for the proposed metrics is provided in Figure II.2. It should be
noted that an appro
priate pre
-
filtering method (see clause II.3) should be used in each studied case
to make the speech data representative of real network conditions.

If the measurement of the NR device (“Noise reduction”) is made in a network system
implementation, the int
erfaces for playing back the NR input signal (“
Playback

IF
”) and recording
(“
Record

IF
”) the NR output signal can be utilised. The rest of the processing and calculation stages
can be conducted off
-
line.

-

32

-

TD 70 (PLEN/16)

Frame
classification
(section 4)
SNRI
calculation
(Eqs. 3-9)
Prefiltered
clean speech
(section 3)
Prefiltered
noise
(section 3)

Noisy
speech
Test
condition
(section 3)
Noise
reduction
Noise
reduced
speech
Noisy
pause
class
NR'ed
pause
class
SNR in
calculation
(Eq. 2)
SNR out
calculation
(Eq. 1)
NPLR
calculation
(Eqs. 10-12)
DSN
calculation
(Eq. 13)
Noisy speech classes
NR'ed speech classes
Playback IF
Record IF
TNLR
calculation
(Eqs. 10-12)
Frame power < th_nh

Figure II
-
2
-

Block dia
gram of calculation of
SNRI
,
TNLR
,
NPLR

and

DSN

measures for noise reduction algorithms

II.4.6 Assessment of Noise Reduction Leakage
-

MNLR

Minimum Noise Level Reduction,

MNLR
, measures the level of noise reduction leakage. It is
calculated as a mean of t
he noise reduction of the 10 percent frames with the least noise
reduction during the long and short pauses.
MNLR

reflects the lowest noise reduction a noise
suppressor provides for the whole duration of speech pauses. Its purpose is to catch the noise
lea
ked out of a noise suppressor with no or less noise suppression even just for a fraction of
seconds. If
MNLR

is close to
TNLR
, then the noise leakage is negligible. If
MNLR

is far below
TNLR
, then the noise leakage is large and the fluctuation of the noise

level may become audible.
If
MNLR

is close to zero, then it indicates a portion of noise is leaked out of noise suppressor
without any reduction and it may cause annoying effect.


II.5

Recommendation values for
SNRI
,
TNLR and DSN

The objective measures of

signal
-
to
-
noise ratio improvement (
SNRI
), total noise level reduction
(
TNLR
), and
DSN

defined above are to be used to characterise the performance of the NR solution.
Objectives are defined for these measures in Table II.2. These measures can be used to p
rovide an
indication of the benefit produced by an NR solution but should be interpreted as informative.

It is noted that NR solutions may function in different ways in varying usage conditions in terms of
the objective metrics presented above. Therefore,
for

SNRI, TPLR

and
DSN

the performance
objectives are defined for average values of these measures over all test conditions.

-

33

-

TD 70 (PLEN/16)

Table

II.2
-

NR algorithm performance targets in
SNRI
,
TNLR

and
DSN

metrics

Objective quality measure/test condition

Performance ob
jective

SNRI

Assessment:
To be evaluated according to clause II.4
using a predefined set of material comprising speech
mixed with stationary car noise and street noise in the
SNR conditions defined in clause II.3.


SNRI ≥ 4

dB


as an average over all tes
t
conditions


TNLR

Assessment
: To be evaluated according to clause II.4
using a predefined set of material comprising speech
mixed with stationary car and street noise in the SNR
conditions defined in clause II.3.


TNLR ≥ 5 dB


as an average over all tes
t
conditions

DSN

Assessment:
To be evaluated according to clause II.4
using a predefined set of material comprising speech
mixed with stationary car noise and street noise in the
SNR conditions defined in clause II.3.




4dB ≤ DSN ≤ 3 dB

as an average over all test conditions


Meeting the presented performance objectives can be regarded as indicating that the NR method
under study is capable of producing significant benefit over not using noise reduction. On the other
h
and, different tuning of an NR algorithm design may be beneficial in different usage scenarios, e.g.
with regard to the number of speech transcoding and/or voice enhancement processing stages in the
speech path. Hence, no strict requirements on the NR perf
ormance in the specified metrics are set.


_________________________