Table Of ContentT-Labs Series in Telecommunication Services
Błażej Lewcio
Management of
Speech and Video
Telephony Quality
in Heterogeneous
Wireless Networks
T-Labs Series in Telecommunication Services
Series Editors
SebastianMöller,TUBerlinandTelekomInnovationLaboratories,Berlin,Germany
AxelKüpper,TUBerlinandTelekomInnovationLaboratories,Berlin,Germany
AlexanderRaake,TUBerlinandTelekomInnovationLaboratories,Berlin,Germany
For furthervolumes:
http://www.springer.com/series/10013
Błaz_ej Lewcio
Management of Speech
and Video Telephony
Quality in Heterogeneous
Wireless Networks
123
Błaz_ej Lewcio
Quality andUsability Lab
Telekom InnovationLaboratories
TU Berlin
Berlin
Germany
ISSN 2192-2810 ISSN 2192-2829 (electronic)
ISBN 978-3-319-02101-0 ISBN 978-3-319-02102-7 (eBook)
DOI 10.1007/978-3-319-02102-7
SpringerChamHeidelbergNewYorkDordrechtLondon
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Preface
This book shows how networking research and quality engineering can be com-
bined to successfully manage the transmission quality when speech and video
telephony is delivered in heterogeneous wireless networks. Nomadic use of ser-
vices requires intelligent management of ongoing transmission, and to make the
best of available resources many fundamental trade-offs must be considered.
Network coverage versus throughput and reliability of a connection is one key
aspect,efficiencyversusrobustnessofsignalcompressionisanother.However,to
successfully manage services, user-perceived Quality of Experience (QoE) in
heterogeneous networks must be known, and the perception of quality changes
mustbeunderstood.Theseissuesareaddressedinthisbook,inparticularfocusing
on the perception of quality changes due to switching between diverse networks,
speech and video codecs, and encoding bit rates during active calls.
To tackle the addressed issues, the related work is reviewed first in this book.
Afterwardstheresearchtestbedthatwascreatedinscopeofthisworkisdescribed,
and the results of numerous experiments are evaluated. During the analysis two
primary goals are pursued for both speech and video telephony. First, user per-
ception of the addressed transmission phenomena is studied and guidelines for
perception-aware management of quality are derived. Second, a number of
existing speech and video quality prediction models is validated in the context of
heterogeneous wireless networks. The strengths and weaknesses of the individual
methodsarediscussed,andsomenewqualitymodellingapproachesareproposed.
It must be noted that this book is a result of myö doctoral research that would
nothavebeenpossiblewithoutthesupportofnumerouspeople.Foremost,Iwould
like to thank Prof. Dr. -Ing. Sebastian Möller for his excellent guidance and
immeasurable effort in supervising my research. I want to thank him for all the
constructive comments and suggestions that helped me to improve the quality of
my research. Also, I would like to thank him for providing excellent working
conditions, and for countless opportunities to exchange my knowledge with top
researchers from all over the world.
IwouldalsoliketothankDr.PabloVidales,whointroducedmetothetopicof
perception-based mobility management, and who provided me with excellent
guidance when I made my first step in the international research community.
Last but not least, I would like to collectively thank all the people who made
this research such an enjoyable and memorable experience. I would like to thank
v
vi Preface
all the members of the Mobisense project, as well as all my colleagues from the
QualityandUsabilityLab(Q&ULab)atTechnischeUniversitätBerlin.Finally,I
wouldliketothankthemanagementofTelekomInnovationLaboratories(T-Labs)
for supporting this research.
Berlin, April 2013 Błaz_ej Lewcio
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Motivation and Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Book Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Experience of Wireless Telephony . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Technology Heterogeneity . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.1 Networking Trade-Offs . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.2 Coding Trade-Offs . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Quality of Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.1 Subjective Measurement . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.2 Instrumental Measurement. . . . . . . . . . . . . . . . . . . . . . 15
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3 Heterogeneous Testbed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1 Network Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 Speech and Video Telephony Client . . . . . . . . . . . . . . . . . . . . 23
3.2.1 Raw Signal Processing . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2.2 Speech and Video Coding . . . . . . . . . . . . . . . . . . . . . . 26
3.2.3 Packetization and Buffering. . . . . . . . . . . . . . . . . . . . . 27
3.3 Codec Changeover Technique. . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.1 Requirement Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.3.2 Implementation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3.3 Qualitative Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . 32
3.4 Testbed Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.5 Demonstrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.6 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4 Experience of Speech Telephony. . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.1 Experimental Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.1.1 Subjective Tests of Listening-Only Quality . . . . . . . . . . 42
4.1.2 Subjective Test of Conversational Quality . . . . . . . . . . . 46
vii
viii Contents
4.2 Quality Perception. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.2.1 Quality of Emulated Calls . . . . . . . . . . . . . . . . . . . . . . 48
4.2.2 Quality of Short Samples. . . . . . . . . . . . . . . . . . . . . . . 53
4.2.3 Quality of Conversational Calls . . . . . . . . . . . . . . . . . . 59
4.3 Instrumental Quality Prediction. . . . . . . . . . . . . . . . . . . . . . . . 62
4.3.1 Accuracy of Sample Quality Models. . . . . . . . . . . . . . . 63
4.3.2 Extension of ITU-T Rec. G.107.1. . . . . . . . . . . . . . . . . 67
4.3.3 Accuracy of Call Quality Models . . . . . . . . . . . . . . . . . 71
4.3.4 Instrumental Call Quality Modeling . . . . . . . . . . . . . . . 74
4.4 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
5 Experience of Video Telephony . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.1 Experimental Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.2 Quality Perception. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.2.1 Quality of Short Video-Only Samples. . . . . . . . . . . . . . 88
5.2.2 Quality of Short Audiovisual Samples. . . . . . . . . . . . . . 93
5.2.3 Quality of Emulated Video Calls . . . . . . . . . . . . . . . . . 99
5.3 Instrumental Quality Prediction. . . . . . . . . . . . . . . . . . . . . . . . 103
5.3.1 Accuracy of Sample Quality Models. . . . . . . . . . . . . . . 103
5.3.2 Accuracy of Call Quality Models . . . . . . . . . . . . . . . . . 112
5.3.3 Instrumental Modeling of Video Call Quality. . . . . . . . . 114
5.4 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
6 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
6.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
6.2 Future Work. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Abbreviation List
4G Fourth generation of mobile communication standards
ACR Absolute Category Rating
ADPCM Adaptive Differential Pulse Code Modulation
AMR Adaptive Multi Rate
AMR-WB AMR wideband
ANOVA Analysis of Variance
API Application Programming Interface
ARQ Automatic Repeat-reQuest
CELP Code Excited Linear Prediction
CETVSQ Continuous Evaluation of Time Varying Speech Quality
CI Confidence Interval
CN Correspondent Node
CoA Care-of Address
DCR Degradation Category Rating
DHCP Dynamic Host Configuration Protocol
E-model Synonym for ITU-T Rec. G.107
EDGE Enhanced Data for GSM Evolution
ETSI European Telecommunications Standard Institute
FEC Forward Error Correction
GoP Group of Pictures
GPRS General Radio Packet System
GSM Global System for Mobile Communication
HA Home Agent
HSDPA High-Speed Downlink Packet Access
HSPA? Evolved High Speed Packet Access
HSUPA High-Speed Uplink Packet Access
IEEE Institute of Electrical and Electronics Engineers
IETF Internet Engineering Task Force
iLBC Internet Low Bitrate Codec
IP Internet Protocol
ITU International Telecommunication Union
ITU-T ITU Telecommunication Standardization Sector
LTE Long Term Evolution
MIH Media Independent Handover
ix
x AbbreviationList
MN Mobile Node
MOS MOS audio, measured in an audiovisual stimulus
ajav
MOS MOS audiovisual
av
MOS MOS audio
a
MOS MOS integrated of MOSMOS and MOS
intjav ajav vjav
MOS MOS video, measured in an audiovisual stimulus
vjav
MOS MOS video
v
MOS Mean Opinion Score
a
MPEG Moving Picture Experts Group
MSE Mean Squared Error
NB Narrowband
PC Paired Comparison
PCM Pulse Code Modulation
PESQ Synonym for ITU-T Rec. P.862
PLC Packet Loss Concealment
POLQA Synonym for ITU-T Rec. P.863
PSNR Peak Signal to Noise Ratio
QoE Quality of Experience
QoS Quality of Service
RMSE Root Mean Square Error
RTCP RTP Control Protocol
RTP Real-time Transport Protocol
SIP Session Initiation Protocol
SNR Signal to Noise Ratio
SSCQE Single Stimulus Continuous Quality Evaluation
SSIM Structural Similarity Index
SWB Super wideband
UMTS Universal Mobile Telecommunications System
VAD Voice Activity Detection
VoIP Voice over IP
VQM Synonym for ITU-T Rec. J.144
VQUAD Synonym for ITU-T Rec. J.341
WB Wideband
WB-PESQ Wideband PESQ, synonym for ITU-T Rec. P.862.2
WiFi Wireless Fidelity, synonym for WLAN
WLAN Wireless Local Area Network
XML Extensible Markup Language
