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整合性封包保護機制提升語音通訊之品質. Ren-Yuh Lu. Outline. Introduction MANET Motivation & Objective Problem Description Related Work Reliable Blast UDP Partial-Reliable TCP 整合性封包保護機制提升語音通訊之品質 分辨重要封包的方法 整合性封包保護技術 Evaluation & Performance Analysis. Introduction. - PowerPoint PPT Presentation
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Ren-Yuh Lu
OutlineIntroductionMANETMotivation & ObjectiveProblem DescriptionRelated WorkReliable Blast UDPPartial-Reliable TCPEvaluation & Performance Analysis
IntroductionVoIP ( Voice over IP ) VoIPVoIPHigh Loss RateVoIPHigh Loss RateMANET
MANETMANET MANET ( WiFi PDA ) Multi-Hop Ad-Hoc Wireless Intranet Wireless Intranet
Motivation & ObjectiveHigh Loss RateMANETServerVoIP
Problem DescriptionVoIPVoIPUDPUDPVoIPVoIP
Related WorkReliable Blast UDPPartial-Reliable UDP
Reliable Blast UDP
Partial-Reliable TCP
Partial-Reliable UDPVoIPVAD ( Voice Activity Detection )
VADTime Domain VADFrequency Domain VADVADVAD
Time Domain VADFrame
FrameDelay TimeFrameBuffer
Time Domain VAD ( SNR ) ( )
Frequency Domain VADFrequency DomainWhite Noise40Hz4000HzEntropyWhite Noise
Frequency Domain VAD Entropy-BasedAn Example of Entropy
The entropy of class A is bigger than the entropy of class B.Class 1Class 2
Frequency Domain VAD Entropy-Based
Frame
t (Sine Wave)Entropy
Frequency Domain VAD Entropy-BasedWhite NoiseEntropyNoiseEntropyThresholdSpeech Segmentnon-Speech SegmentSpeech Segmentnon-Speech SegmentSpeech SegmentOverhead
Frequency Domain VAD Entropy-BasedNoiseSNRSpeech Segmentnon-Speech SegmentVOIPDelayExWhite NoiseColored Noisenon-Speech SegmentSpeech SegmentEntropy
VADSNRNoiseColored NoiseEnergy-Based VADSNRNoiseWhite NoiseEntropy-Based VADNoiseNoiseVAD
VAD ( ) NoiseMethod 1Method 2
VAD Method 1NoiseNoise
VAD Method 2Voice CancellationNoiseClean & Background
Model1. ( msec / packet ) 20 ( ms/packet ) 30 ( ms / packet )2. Redundant Voice PacketsPacket Stream3. Voice Packets ( Codec )4. Packet Stream5. Packet StreamStream6. Packet StreamRedundant Stream7. Packet Stream PiggybackPacket Stream
Example 1 Redundancy OnlyTime ( msec )Voice Stream1231230204060801004564512076Time ( msec )Voice Stream 1Voice Stream 21231230204060801001204564567
Example 2 Different Codec & RedundancyTime ( msec )Voice Stream 1Voice Stream 21212020406080100120Voice Stream 31+2+34+5+6345634567
Example 2 Different Codec & Redundancy
Time ( msec )020406080100120121321+2+3435Voice Stream 1Voice Stream 2Voice Stream 34654+5+676
Example 3 VAD & RedundancyTime ( msec )Voice Stream1231230204060801004564512076Time ( msec )Voice Stream 1Voice Stream 21231230204060801001204564567
Partial-Reliable UDPReliable Blast UDPSenderReceiver
Evaluation & Performance AnalysisVoIP ( Total Harmonic Distortion, THD )VADRedundancyCost vs PacketP-R UDPHop Count vs Loss Rate vs Traffic Load vs
VoIP THDNonlinear Distortion ( ) ( harmonics )
VoIP THD 1000Hz 2kHz3kHz4kHz THD 1000Hz 1000Hz 1000Hz
VAD
Redundancy Cost vs
Chart2
2250
3178
3686
4991
6193
8695
9296
Aggregate Cost of Redundancy
Arrived Ratio of All Packets ( % )
Redundancy Frequency
Performance Analysis for Redundancy
Sheet1
Cost ( Redundancy Frquency )Arrived Ratio of All Packets ( % )Hop CountUDPP-R UDPError Rate ( % )Traffic Load
1508510
0225002358030
13178103267660
23686204197390
349913051471
461934061069
58695507868
69296608667
70
80
90
100
Sheet1
UDP
P-R UDP
Hop Count
Arrived Ratio of Important Packet ( % )
Performance Analysis for P-R UDP
Sheet2
Aggregate Cost of Redundancy
Arrived Ratio of All Packets ( % )
Redundancy Frequency
Performance Analysis for Redundancy
Sheet3
P-R UDP Hop Count
P-R UDP Loss Rate
P-R UDP Traffic Load
Evaluation & Performance Analysis
Conclusion
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