1NATO UNCLASSIFIED
The NATO Post-2000The NATO Post-2000Narrow Band Voice Coder: Narrow Band Voice Coder:
Test and Selection of Test and Selection of STANAG 4591STANAG 4591
The NATO Post-2000The NATO Post-2000Narrow Band Voice Coder: Narrow Band Voice Coder:
Test and Selection of Test and Selection of STANAG 4591STANAG 4591
CIS Division, NATO C3 AgencyCIS Division, NATO C3 AgencyCIS Division, NATO C3 AgencyCIS Division, NATO C3 Agency
Technical Presentation-001Technical Presentation-001Technical Presentation-001Technical Presentation-001
2 NATO UNCLASSIFIED
Abstract and Conditions of ReleaseAbstract and Conditions of ReleaseAbstract and Conditions of ReleaseAbstract and Conditions of Release
AbstractAbstract The work described in this presentation was carried out under customer
funded projects 25.12.00 and N.25.12.00, conducted by NC3A on behalf of AC322(SC/6-AHWG/3).
This presentation gives a general introduction to the work, which is documented in NC3A Technical Note-881 and NC3A Technical Memorandum-946.
This presentation is a working paper that may not be cited as representing formally approved NC3A opinions, conclusions or recommendations.
AbstractAbstract The work described in this presentation was carried out under customer
funded projects 25.12.00 and N.25.12.00, conducted by NC3A on behalf of AC322(SC/6-AHWG/3).
This presentation gives a general introduction to the work, which is documented in NC3A Technical Note-881 and NC3A Technical Memorandum-946.
This presentation is a working paper that may not be cited as representing formally approved NC3A opinions, conclusions or recommendations.
3 NATO UNCLASSIFIED
NC3A-NL, The Hague NC3A-BE, BrusselsScientific staff Acquisition staff
Set up voice coding testbed Equipment AcquisitionProcess input data Contractual issuesBlind and deblind dataSupport to AHWG NBVC, test labs and coder developers
NATO InfrastructureCommittee
NATO Narrow Band Voice Coder Ad-Hoc Working Group
NBVC and NC3ANBVC and NC3ANBVC and NC3ANBVC and NC3A
Customers
Customerfunded
Voice coder developers
Host Nation
4 NATO UNCLASSIFIED
Introduction to STANAG 4591Introduction to STANAG 4591Introduction to STANAG 4591Introduction to STANAG 4591
5 NATO UNCLASSIFIED
BackgroundBackgroundBackgroundBackground
• Voice Coding technology is constantly improvingVoice Coding technology is constantly improving• driven by mobile telephonydriven by mobile telephony
–narrow bandnarrow band–wireless channelswireless channels
• new coders outperform existing NATO voice codersnew coders outperform existing NATO voice coders
• Voice Coding technology is constantly improvingVoice Coding technology is constantly improving• driven by mobile telephonydriven by mobile telephony
–narrow bandnarrow band–wireless channelswireless channels
• new coders outperform existing NATO voice codersnew coders outperform existing NATO voice coders
STANAG 4209 - CVSD+ good resilience to noise- poor speech quality in no noise- high rate (16 k)
STANAG 4198 - LPC10e + low rate (2.4k)- low speech quality- low resilience to noise
• AHWG NBVC tasked by NATO to select a future AHWG NBVC tasked by NATO to select a future Narrow Band Voice Coder for NATO use at Narrow Band Voice Coder for NATO use at 1.2kbps and 2.4kbps1.2kbps and 2.4kbps
• AHWG NBVC tasked by NATO to select a future AHWG NBVC tasked by NATO to select a future Narrow Band Voice Coder for NATO use at Narrow Band Voice Coder for NATO use at 1.2kbps and 2.4kbps1.2kbps and 2.4kbps
6 NATO UNCLASSIFIED
Voice Coders TestedVoice Coders TestedVoice Coders TestedVoice Coders Tested• NATO requested candidates to be submitted by member NATO requested candidates to be submitted by member
nationsnations
• Three candidates submittedThree candidates submitted
• NATO requested candidates to be submitted by member NATO requested candidates to be submitted by member nationsnations
• Three candidates submittedThree candidates submitted
• FranceFrance• HSX (Harmonic Stochastic eXcitation)HSX (Harmonic Stochastic eXcitation)• FranceFrance• HSX (Harmonic Stochastic eXcitation)HSX (Harmonic Stochastic eXcitation)
• TurkeyTurkey• SB-PLC (Split-Band Linear Predictive Coding)SB-PLC (Split-Band Linear Predictive Coding) • TurkeyTurkey
• SB-PLC (Split-Band Linear Predictive Coding)SB-PLC (Split-Band Linear Predictive Coding)
• USAUSA• MELP (Mixed Excitation Linear Prediction)MELP (Mixed Excitation Linear Prediction)
• USAUSA• MELP (Mixed Excitation Linear Prediction)MELP (Mixed Excitation Linear Prediction)
(each candidate operates at (each candidate operates at both 1.2k & 2.4k)both 1.2k & 2.4k)
• plus LPC-10e (2.4k) CELP (4.8k) CVSD (16k) plus LPC-10e (2.4k) CELP (4.8k) CVSD (16k) as as known reference codersknown reference coders
(each candidate operates at (each candidate operates at both 1.2k & 2.4k)both 1.2k & 2.4k)
• plus LPC-10e (2.4k) CELP (4.8k) CVSD (16k) plus LPC-10e (2.4k) CELP (4.8k) CVSD (16k) as as known reference codersknown reference coders
7 NATO UNCLASSIFIED
Test Resources and ResponsibilitiesTest Resources and ResponsibilitiesTest Resources and ResponsibilitiesTest Resources and Responsibilities
• NC3A ran raw audio data through coders NC3A ran raw audio data through coders and ‘blinded’ all outputand ‘blinded’ all output
• National test labs analysed raw audio from National test labs analysed raw audio from NC3A. Test labs were:NC3A. Test labs were:• TNO, NLTNO, NL• CELAR, FRCELAR, FR• Arcon, USArcon, US
• NC3A impartially collated resultsNC3A impartially collated results
• NC3A ran raw audio data through coders NC3A ran raw audio data through coders and ‘blinded’ all outputand ‘blinded’ all output
• National test labs analysed raw audio from National test labs analysed raw audio from NC3A. Test labs were:NC3A. Test labs were:• TNO, NLTNO, NL• CELAR, FRCELAR, FR• Arcon, USArcon, US
• NC3A impartially collated resultsNC3A impartially collated results
• Project was ‘customer funded’ by Project was ‘customer funded’ by NATO Infrastructure Committee and NATO Infrastructure Committee and nations submitting codersnations submitting coders
• NC3A host nation, but worked with NC3A host nation, but worked with specialist speech processing labsspecialist speech processing labs
• Project was ‘customer funded’ by Project was ‘customer funded’ by NATO Infrastructure Committee and NATO Infrastructure Committee and nations submitting codersnations submitting coders
• NC3A host nation, but worked with NC3A host nation, but worked with specialist speech processing labsspecialist speech processing labs
The TNO test laboratory at Soesterberg, NL
NATO data being analysed at TNO
8 NATO UNCLASSIFIED
NATO NBVC testsNATO NBVC testsPhase 1Phase 1
NATO NBVC testsNATO NBVC testsPhase 1Phase 1
• Floating Point vocoder implementationsFloating Point vocoder implementations
• PerformancePerformance• IntelligibilityIntelligibility• QualityQuality
• Noise ConditionsNoise Conditions• QuietQuiet• Modern officeModern office• Acoustic noise, (6 dB, 12 dB)Acoustic noise, (6 dB, 12 dB)
• 5488 Mb of processed audio in 5848 files5488 Mb of processed audio in 5848 files
• Floating Point vocoder implementationsFloating Point vocoder implementations
• PerformancePerformance• IntelligibilityIntelligibility• QualityQuality
• Noise ConditionsNoise Conditions• QuietQuiet• Modern officeModern office• Acoustic noise, (6 dB, 12 dB)Acoustic noise, (6 dB, 12 dB)
• 5488 Mb of processed audio in 5848 files5488 Mb of processed audio in 5848 filesA typical test booth where subjects
listen to speech for analysis
9 NATO UNCLASSIFIED
Processing by NC3AProcessing by NC3AProcessing by NC3AProcessing by NC3A
Nine raw
audio output files
Sent to test labs for analysis
Encode Decode
CELP
FR1200
FR2400
CVSD
LPC10e
TU1200
TU2400
US1200
US2400
CELP
FR1200
FR2400
CVSD
LPC10e
TU1200
TU2400
US1200
US2400
BITSTREAM
CELP
FR1200
FR2400
CVSD
LPC10e
TU1200
TU2400
US1200
US2400
CELP
FR1200
FR2400
CVSD
LPC10e
TU1200
TU2400
US1200
US2400
123456789
Raw audio file
8kHz sample rate,
16 bit samples
10 NATO UNCLASSIFIED
Double blinding processDouble blinding processDouble blinding processDouble blinding process
CELP
FR1200
FR2400
CVSD
LPC10e
TU1200
TU2400
US1200
US2400
To test lab
Nine audio output files
Vocoder3
Vocoder4
Vocoder5
Vocoder2
Vocoder1
Vocoder6
Vocoder7
Vocoder8
Vocoder9
Decoded output
files
Double blinded
files
B
L
I
N
D
Coder3
Coder4
Coder5
Coder2
Coder1
Coder6
Coder7
Coder8
Coder9
Single blinded
files
B
L
I
N
D
Blinded by NC3A
Blinded by DSTL
LPC10e
Coder7
Vocoder9
11 NATO UNCLASSIFIED
17
Modulated Noise Reference UnitModulated Noise Reference UnitModulated Noise Reference UnitModulated Noise Reference Unit
CELPFR1200FR2400
CVSDLPC10e
TU1200TU2400US1200US2400
One raw audio file
Nine raw audio output files
CELPFR1200FR2400
CVSDLPC10e
TU1200TU2400US1200US2400
BITSTREAM
MNRU 15dB
MNRU 20dB
MNRU 25dB
MNRU 10dB
MNRU 5db
MNRU 30dB
MNRU 35dB
MNRU 40dB
•MNRU is a standard method to apply known levels of noise. It provides known references against which
listeners can compare vocoder outputs
MNRU 15dB
MNRU 20dB
MNRU 25dB
MNRU 10dB
MNRU 5db
MNRU 30dB
MNRU 35dB
MNRU 40dB
161514131211171017 raw audio output files.
MNRU files to test labs as references for analysing speech quality
12 NATO UNCLASSIFIED
NATO NBVC testsNATO NBVC testsPhase IIPhase II
NATO NBVC testsNATO NBVC testsPhase IIPhase II
• Fixed point implementationFixed point implementation
•CC plus ETSI libraries plus ETSI libraries
• Performance MeasurementsPerformance Measurements
• Intelligibility, QualityIntelligibility, Quality
• Speaker recognitionSpeaker recognition
• Language dependency Language dependency
–English, French, German, English, French, German, Dutch, Polish, TurkishDutch, Polish, Turkish
• Fixed point implementationFixed point implementation
•CC plus ETSI libraries plus ETSI libraries
• Performance MeasurementsPerformance Measurements
• Intelligibility, QualityIntelligibility, Quality
• Speaker recognitionSpeaker recognition
• Language dependency Language dependency
–English, French, German, English, French, German, Dutch, Polish, TurkishDutch, Polish, Turkish
• 10 acoustic noise 10 acoustic noise environmentsenvironments
• Transmission channelTransmission channel• 1% BER1% BER
• TandemTandem• 16 kbps CVSD - vocoder16 kbps CVSD - vocoder
• Whispered speechWhispered speech
• 10 acoustic noise 10 acoustic noise environmentsenvironments
• Transmission channelTransmission channel• 1% BER1% BER
• TandemTandem• 16 kbps CVSD - vocoder16 kbps CVSD - vocoder
• Whispered speechWhispered speech
13 NATO UNCLASSIFIED
Phase 2 additional test conditionsPhase 2 additional test conditionsPhase 2 additional test conditionsPhase 2 additional test conditions
Coder nAudio input file
Audio output file
Decoder nBitstream
1% random bit errors
Audio input file
CVSDCoder
Audio output file
Decoder nCoder nCVSDDecoder
Test configuration: 1% Bit error rate
Test configuration: Voice coder tandem
B i t s
B i t s
Audio
14 NATO UNCLASSIFIED
NATO NBVC tests - Phase 2NATO NBVC tests - Phase 2
Noise Conditions
Phase 1 plus ……..
NATO NBVC tests - Phase 2NATO NBVC tests - Phase 2
Noise Conditions
Phase 1 plus ……..
HMMWV Bradley Fighting Vehicle Le Clerc Tank Volvo (staff car)
MCE field shelter
Blackhawk helicopter Mirage 2000 F-15
15 NATO UNCLASSIFIED
NATO NBVC Phase 2NATO NBVC Phase 2NATO NBVC Phase 2NATO NBVC Phase 2
• Over 36,000 filesOver 36,000 files
• Over 30 GB of processed speech dataOver 30 GB of processed speech data
• 500 hours of speech 500 hours of speech
–Some voice coders ran approx 10 times real timeSome voice coders ran approx 10 times real time
• Over 36,000 filesOver 36,000 files
• Over 30 GB of processed speech dataOver 30 GB of processed speech data
• 500 hours of speech 500 hours of speech
–Some voice coders ran approx 10 times real timeSome voice coders ran approx 10 times real time
3 test labs
x 5 tests x 12 noise conditions
x 9 coders (+ 8 MNRU levels)
x 88 files per test
16 NATO UNCLASSIFIED
Need for Precision Weighted RankingNeed for Precision Weighted RankingNeed for Precision Weighted RankingNeed for Precision Weighted Ranking
• Graphs show variation Graphs show variation between intelligibility tests between intelligibility tests performed by the 3 test performed by the 3 test labslabs• General trends are the General trends are the
samesame• Absolute scores varyAbsolute scores vary
• Need to combine all Need to combine all results accurately and results accurately and fairlyfairly• Simple scaling is not Simple scaling is not
sufficientsufficient
• Graphs show variation Graphs show variation between intelligibility tests between intelligibility tests performed by the 3 test performed by the 3 test labslabs• General trends are the General trends are the
samesame• Absolute scores varyAbsolute scores vary
• Need to combine all Need to combine all results accurately and results accurately and fairlyfairly• Simple scaling is not Simple scaling is not
sufficientsufficient
Quiet
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
90.0
95.0
100.0
1 2 3 4 5 6 7 8 9
Arcon
CELAR
TNO
BlackHawk
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
1 2 3 4 5 6 7 8 9
Arcon
CELAR
TNO
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
17 NATO UNCLASSIFIED
Score vs Interval
y = 0.0341x + 0.1949
0.18
0.22
0.26
0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
cc
• Range of test results divided into Range of test results divided into segments or segments or binsbins
• Range of test results divided into Range of test results divided into segments or segments or binsbins
Precision Weighted RankingPrecision Weighted RankingPrecision Weighted RankingPrecision Weighted Ranking
• Coders in subsequent intervals Coders in subsequent intervals score score bin numberbin number
• Coders in subsequent intervals Coders in subsequent intervals score score bin numberbin number
1 2 3 4 5 6 70.2238 0.4263 0.6357 0.8522 1.0762 1.3077 1.54720.4263 0.6357 0.8522 1.0762 1.3077 1.5472 1.7948
V7V8V6V9
V3V1
V4V5V2
Bin 1 Bin 3 Bin 4 Bin 5 Bin 7
• Coder scores are determined by Coder scores are determined by which bin their test result falls which bin their test result falls intointo
• Coder scores are determined by Coder scores are determined by which bin their test result falls which bin their test result falls intointo
Confidence interval of test
Confidence interval of test
• The resolution (or The resolution (or 95% 95% confidence interval) confidence interval) of the test of the test determines determines bin bin sizesize
• The resolution (or The resolution (or 95% 95% confidence interval) confidence interval) of the test of the test determines determines bin bin sizesize
• Worst coder always scores 1. In Worst coder always scores 1. In this test Vocoder 7 came lastthis test Vocoder 7 came last
• Worst coder always scores 1. In Worst coder always scores 1. In this test Vocoder 7 came lastthis test Vocoder 7 came last
• Scores for vocoders 6, 8 and 9 Scores for vocoders 6, 8 and 9 were 4 - 5 confidence intervals were 4 - 5 confidence intervals above that of V7. They all score 5above that of V7. They all score 5
• Scores for vocoders 6, 8 and 9 Scores for vocoders 6, 8 and 9 were 4 - 5 confidence intervals were 4 - 5 confidence intervals above that of V7. They all score 5above that of V7. They all score 5
Score = 1
Score = 7
18 NATO UNCLASSIFIED
Combined Performance IndexCombined Performance IndexCombined Performance IndexCombined Performance IndexCoder Wgt.
Performance
Characteristic
Wgt.Test
MethodWgt.
Type Conditio
nWgt.
Condition
Wgt.Cond. by
Type
Cond. by Type by
Char.
Cond. by Type by Char. by
2.4 Coder
Cond. by Type by Char. by
1.2 Coder
2400bps 60% Intelligibility 41.8% DRT(US) NA Baseline 27.4% Quiet 100.0% 27.4% 11.44% 6.86% 4.58%
1200bps 40% CVC(NL) NA TOTAL 100.0%Inteltrans(FR) NA Acoustic Noise56.8% SNR(12) 11.1% 6.3% 2.64% 1.58% 1.06%
SNR(6) 11.1% 6.3% 2.64% 1.58% 1.06%Office 11.1% 6.3% 2.64% 1.58% 1.06%MCE Field
Shelter11.1% 6.3% 2.64% 1.58% 1.06%
HMMMWV or P4
11.1% 6.3% 2.64% 1.58% 1.06%
M2A2 Bradley or
Leclerc11.1% 6.3% 2.64% 1.58% 1.06%
UH60 Black Hawk
11.1% 6.3% 2.64% 1.58% 1.06%
F15 or Mirage-
200011.1% 6.3% 2.64% 1.58% 1.06%
Volvo 11.1% 6.3% 2.64% 1.58% 1.06%TOTAL 100.0%
Transmission.
Channel7.4%
Random Bit Errors
(1%)100.0% 7.4% 3.08% 1.85% 1.23%
TOTAL 100.0%Tandem 8.4% CVSD=>Coder100.0% 8.4% 3.52% 2.11% 1.41%
TOTAL 100.0%
TOTAL 100.0% CHECK 800.0% 100.0% 41.80% 25.08% 16.72%
Whispered Speech2.2% SRT(NL) NA Special 100.0%Whispered Speech
100.0% 100.0% 2.20% 1.32% 0.88%
TOTAL 100.0%
TOTAL 100.0% CHECK 200.0% 100.0% 2.20% 1.32% 0.88%Quality 34.2% MOS(US) NA Baseline 42.1% Quiet 100.0% 42.1% 14.40% 8.64% 5.76%
MOS(NL) NA TOTAL 100.0%Acoustic Noise52.6% SNR(12) 14.0% 7.4% 2.52% 1.51% 1.01%
SNR(6) 10.0% 5.3% 1.80% 1.08% 0.72%Office 20.0% 10.5% 3.60% 2.16% 1.44%MCE Field
Shelter16.0% 8.4% 2.88% 1.73% 1.15%
HMMMWV
10.0% 5.3% 1.80% 1.08% 0.72%
F15 10.0% 5.3% 1.80% 1.08% 0.72%Volvo 20.0% 10.5% 3.60% 2.16% 1.44%
TOTAL 100.0%Tandem 5.3% CVSD=>Coder100.0% 5.3% 1.80% 1.08% 0.72%
TOTAL 100.0%
TOTAL 100.0% CHECK 600.0% 100.0% 34.20% 20.52% 13.68%
Quality BER 1.8% MOS(NL) NATransmis
sion. Channel
100.0%Transmis
sion. Channel
100.0% 100.0% 1.80% 1.08% 0.72%
TOTAL 100.0%
TOTAL 100.0% CHECK 200.0% 100.0% 1.80% 1.08% 0.72%
19 NATO UNCLASSIFIED
Phase 2 Combined Performance IndexPhase 2 Combined Performance IndexPhase 2 Combined Performance IndexPhase 2 Combined Performance Index
0
1
2
3
4
5
6
7
8
9
US
FR
TU
0
1
2
3
4
5
6
7
8
9
US
FR
TU
• Selection made on combined scores at 2400 and 1200 bps
• 60% - 2400 bps score
• 40% - 1200 bps score
20 NATO UNCLASSIFIED
Phase 2 Combined Performance IndexPhase 2 Combined Performance IndexPhase 2 Combined Performance IndexPhase 2 Combined Performance Index
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
7
8
9
10
21 NATO UNCLASSIFIED
Specific Results - Intelligibility Specific Results - Intelligibility Specific Results - Intelligibility Specific Results - Intelligibility
• Results of all Results of all coders in all noise coders in all noise conditions (CVC conditions (CVC test) test)
• Results of all Results of all coders in all noise coders in all noise conditions (CVC conditions (CVC test) test)
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
In
telli
gib
ility
sco
re (
%)
I
nte
llig
ibili
ty s
core
(%
)
22 NATO UNCLASSIFIED
Specific Results - Speech Quality Specific Results - Speech Quality Specific Results - Speech Quality Specific Results - Speech Quality
• Range of Mean Range of Mean Opinion Score test Opinion Score test • 1 (Bad) 1 (Bad) • 2 (Poor)2 (Poor)• 3 (Fair)3 (Fair)• 4 (Good)4 (Good)• 5 (Excellent)5 (Excellent)
• Results of all Results of all coders in all noise coders in all noise conditions (MOS conditions (MOS test) test)
• Range of Mean Range of Mean Opinion Score test Opinion Score test • 1 (Bad) 1 (Bad) • 2 (Poor)2 (Poor)• 3 (Fair)3 (Fair)• 4 (Good)4 (Good)• 5 (Excellent)5 (Excellent)
• Results of all Results of all coders in all noise coders in all noise conditions (MOS conditions (MOS test) test)
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
US24 CELP FR24 CVSD TU24 US12 LPC TU12 FR12
M
ea
n O
pin
ion
Sco
re
Me
an
Op
inio
n S
core
23 NATO UNCLASSIFIED
Specific Results - Language DependencySpecific Results - Language DependencySpecific Results - Language DependencySpecific Results - Language Dependency
French-English
R2 = 0.71
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
-1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0
French SRT (dB SNR)
En
gli
sh S
RT
(d
B S
NR
)• Language Language dependency of all dependency of all tested coderstested coders
• The closer a point The closer a point lies to the lies to the xx==yy diagonal, the less diagonal, the less language language dependant the dependant the voice codervoice coder
• Language Language dependency of all dependency of all tested coderstested coders
• The closer a point The closer a point lies to the lies to the xx==yy diagonal, the less diagonal, the less language language dependant the dependant the voice codervoice coder
24 NATO UNCLASSIFIED
Current positionCurrent positionCurrent positionCurrent position
• Phase 1Phase 1• CompletedCompleted• Results available in NC3A Technical Note-881Results available in NC3A Technical Note-881
• Phase 2Phase 2• All material processed and analysedAll material processed and analysed• Results collated Results collated • Results analysed and blind removed Results analysed and blind removed • Coder selected on 24 October 2001Coder selected on 24 October 2001
• Stanag 4591 knownStanag 4591 known•MELPeMELPe
• Phase 1Phase 1• CompletedCompleted• Results available in NC3A Technical Note-881Results available in NC3A Technical Note-881
• Phase 2Phase 2• All material processed and analysedAll material processed and analysed• Results collated Results collated • Results analysed and blind removed Results analysed and blind removed • Coder selected on 24 October 2001Coder selected on 24 October 2001
• Stanag 4591 knownStanag 4591 known•MELPeMELPe
25 NATO UNCLASSIFIED
NC3A - Current activityNC3A - Current activityNC3A - Current activityNC3A - Current activity
• Test Process Phase 3Test Process Phase 3• Real-time Implementation of Phase 2 winnerReal-time Implementation of Phase 2 winner• Communicability testsCommunicability tests
–real-life communication problemreal-life communication problem–end-to-end delay effectsend-to-end delay effects
• Assist in drafting STANAG 4591Assist in drafting STANAG 4591• Advise on the use and implementation of STANAG 4591Advise on the use and implementation of STANAG 4591
• Test Process Phase 3Test Process Phase 3• Real-time Implementation of Phase 2 winnerReal-time Implementation of Phase 2 winner• Communicability testsCommunicability tests
–real-life communication problemreal-life communication problem–end-to-end delay effectsend-to-end delay effects
• Assist in drafting STANAG 4591Assist in drafting STANAG 4591• Advise on the use and implementation of STANAG 4591Advise on the use and implementation of STANAG 4591
26 NATO UNCLASSIFIED
0
10
20
30
40
50
60
70
80
CO
TS
X
CO
TS
Y
CO
TS
Z
ME
LP
e
CO
TS
X
CO
TS
Y
CO
TS
Z
ME
LP
e
6 dB SNR
12 dB SNR
Quiet
0
10
20
30
40
50
60
70
80
CO
TS
X
CO
TS
Y
CO
TS
Z
ME
LP
e
CO
TS
X
CO
TS
Y
CO
TS
Z
ME
LP
e
6 dB SNR
12 dB SNR
Quiet
Stanag 4591 vs COTS voice codersStanag 4591 vs COTS voice codersStanag 4591 vs COTS voice codersStanag 4591 vs COTS voice coders
Male speaker Female speaker
COTS X = 6 kbps
COTS Y = 4.56 kbps
COTS X = 4.56 kbps
MELPe = 2.4 kbps
27 NATO UNCLASSIFIED
ConclusionConclusionConclusionConclusion
• STANAG 4591 providesSTANAG 4591 provides
• substantially improved performancesubstantially improved performance– speech qualityspeech quality– intelligibilityintelligibility– noise immunity noise immunity
• reduced throughput requirementsreduced throughput requirements
• interoperabilityinteroperability
• STANAG 4591 providesSTANAG 4591 provides
• substantially improved performancesubstantially improved performance– speech qualityspeech quality– intelligibilityintelligibility– noise immunity noise immunity
• reduced throughput requirementsreduced throughput requirements
• interoperabilityinteroperability
28 NATO UNCLASSIFIED
Further informationFurther informationFurther informationFurther informationStanag 4591 test and selection processStreet MD, “Future NATO narrow band voice coder selection: Stanag 4591”, NC3A Technical Note 881, The Hague, December 2001
http://nc3a.info/Voice
Street MD and Collura JS, “Interoperable Voice Communications: test and selection of STANAG 4591”, RTA IST Symposium - NATO Research and Technology Agency (Information Systems and Technology panel) Tactical Military Communications symposium, Warsaw, October 2001
http://www.rta.nato.int/IST.htm
Street MD and Collura JS, “The test and selection of the future NATO narrow band voice coder”, RCMCIS - NATO Regional Conference on Military CIS, Warsaw, Zegrze, October 2001.
http://www.wil.waw.pl/ses3.htm
MELPe: the selected voice coderCollura JS and Rahikka DJ, “Interoperable secure voice communications in tactical systems, IEE coll. on Speech coding algorithms for radio channels, London, February 2000.
An overview of the MELP voice coder and its use in military environments http://www.iee.org/OnComms/pn/communications
Collura JS, Rahikka DJ, Fuja TE, Sridhara D and Fazel T, “Error coding strategies for MELP vocoder in wireless and ATM environments”, IEE coll. on Speech coding algorithms for radio channels, London, February 2000.
Performance of MELP with a variety of different error correction mechanismshttp://www.iee.org/OnComms/pn/communications
29 NATO UNCLASSIFIED
Information and Source Code available from:Information and Source Code available from:Information and Source Code available from:Information and Source Code available from:
http://elayne.nc3a.nato.int/S4591/http://elayne.nc3a.nato.int/S4591/
Applied Communication Technologies Branch
CIS Division
NATO C3 Agency
PO Box 174
2501 CD , The Hague
The Netherlands
Tel: +31 70 374 3043
Fax: +31 70 374 3049
Email: [email protected]
http://elayne.nc3a.nato.int/S4591/http://elayne.nc3a.nato.int/S4591/
Applied Communication Technologies Branch
CIS Division
NATO C3 Agency
PO Box 174
2501 CD , The Hague
The Netherlands
Tel: +31 70 374 3043
Fax: +31 70 374 3049
Email: [email protected]
Top Related