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 ) ( )

Time Domain VAD Energy BasedThresholdkky(n)>ky(n)=kSpeech Segmenty(n)

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