Table Of ContentSPRINGER BRIEFS IN ELECTRICAL AND
COMPUTER ENGINEERING COOPERATING OBJECTS
Nouha Baccour · Anis Koubâa · Carlo Alberto Boano
Luca Mottola · Hossein Fotouhi · Mário Alves
Habib Youssef · Marco Antonio Zúñiga
Daniele Puccinelli · Thiemo Voigt
Kay Römer · Claro Noda
Radio Link
Quality Estimation
in Low-Power
Wireless Networks
SpringerBriefs in Electrical and Computer
Engineering
Cooperating Objects
Series Editor
Pedro José Marron
For furthervolumes:
http://www.springer.com/series/10208
Nouha Baccour Anis Koubâa
•
Carlo Alberto Boano Luca Mottola
•
Hossein Fotouhi Mário Alves
•
Habib Youssef Marco Antonio Zúñiga
•
Daniele Puccinelli Thiemo Voigt
•
Kay Römer Claro Noda
•
Radio Link Quality
Estimation in Low-Power
Wireless Networks
123
NouhaBaccour HabibYoussef
HosseinFotouhi UniversitydeSousse
ClaroNoda Sousse
InstitutoSuperiordeEngenhariadoPorto Tunisia
Porto
Portugal MarcoAntonioZúñiga
UniversitätDuisburg-Essen
AnisKoubâa Essen
MárioAlves Germany
InstitutoSuperiordeCISTERResearchCentre
Porto DanielePuccinelli
Portugal UniversityofAppliedSciencesandArts
ofSouthernSwitzerland
CarloAlbertoBoano Manno
KayRömer Switzerland
UniverstätLübeck
Lübeck ThiemoVoigt
Germany SwedishInstituteofComputerScienceAB
Kista
LucaMottola Sweden
DipartimentodiElettronicaed
Informazione,PolitecnicodiMilano
Milan
Italy
ISSN 2191-8112 ISSN 2191-8120 (electronic)
ISBN 978-3-319-00773-1 ISBN978-3-319-00774-8 (eBook)
DOI10.1007/978-3-319-00774-8
SpringerChamHeidelbergNewYorkDordrechtLondon
LibraryofCongressControlNumber:2013940082
(cid:2)TheAuthor(s)2013
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Preface
Stringent cost and energy constraints in low-power wireless networks (such as
wireless sensor networks) impose the use of low-cost radio transceivers that
transmitlow-powersignals(typically,0dBmasmaximumpower).Thisfactlimits
theradiochannel,makingitmorevulnerabletonoise,interference,andmultipath
distortion.
Moreover, these radio transceivers typically rely on inexpensive and size
constrained antennas. Often, infeasibility of prime antenna positioning further
compromises its performance. This applies to both, antenna positioning in certain
WSN node designs as well as node placement in deployments, leading to aniso-
tropic connectivity.
Consequently, low-power radio links are extremely unreliable and often
unpredictable. Theyexperience qualityfluctuation over timeandspace,andshow
asymmetric connectivity. The unreliability of links greatly affects the network
performance. This raised the need for link quality estimation as a fundamental
building block for network protocols and mechanisms (e.g., medium-access con-
trol (MAC), routing, mobility management, and topology control), in order to
mitigate link unreliability.
Link quality estimation in low-power wireless networks is a challenging
researchproblemduetothelossyanddynamicnatureofthelinks.Thisbookaims
at providing a good understanding of several aspects of link quality estimations,
which covers the design, evaluation, experimentation, and impact on higher layer
protocols.
Organization of the Book
Thisbookisorganizedintofivechapters.Chapter1outlinesthecharacteristicsof
low-power links. A vast array of research efforts tackled the empirical charac-
terization of low-power links through real-world measurements with different
platforms, under varying experimental conditions, assumptions, and scenarios.
This first chapter provides a comprehensive survey of the most relevant key
observations drawn from empirical studies on low-power links. Chapter 2
v
vi Preface
addresses the most important factors that affect low-power links, which is inter-
ference.This chapter discussesseveral aspects relatedtointerference problemsin
low-power wireless networks, namely experimentation, measurement, modeling,
and mitigationof externalradio interference. Chapter3 gives anoverview oflink
quality estimation in low-power wireless networks. It starts by presenting the
fundamentalconceptsrelatedtolinkqualityestimation.Forexample,itdefinesthe
link quality estimation process and decomposes it into different steps. It also
provides important requirements for the design of efficient link quality estimators
(LQEs). Then, a taxonomy of existing LQEs is given. Chapter 4 provides an
extensive comparative performance study of most well-known LQEs, based on
bothsimulationandrealexperimentation.Theevaluationmethodologyconsistsin
analysing the statistical properties of LQEs, independently of any external factor,
suchascollisionsandrouting.Thesestatisticalpropertiesimpacttheperformance
ofLQEs, interms ofreliabilityand stability. Chapter5 investigatesthe impact of
using reliable and efficient LQEs for improving higher layer protocols and
mechanisms, namely routing and mobility management.
This book is the result of several years of research work of the authors on the
link quality estimation and low-power radio links. To the best of our knowledge,
this is the first book tackling link quality estimation in low-power wireless net-
works (such as wireless sensor/actuator networks). Thus, we hope it will serve as
baselinereading materialforstudentsandasareference texttoorient researchers
and system designers.
Contents
1 Characteristics of Low-Power Links. . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Low-Power Wireless Hardware. . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Radios. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Link Quality Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Spatial Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 Temporal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.6 Link Asymmetry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.7 Interference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7.1 External Interference. . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.7.2 Internal Interference . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2 External Radio Interference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.2 Crowded Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.2.1 Coexistence Between IEEE 802.15.1/.15.4 Devices. . . . . 26
2.2.2 Coexistence Between IEEE 802.11/.15.4 Devices. . . . . . 26
2.2.3 Coexistence Between Microwave Ovens
and IEEE 802.15.4 Devices . . . . . . . . . . . . . . . . . . . . . 27
2.2.4 Coexistence Between IEEE 802.15.4 Devices
Operating in Adjacent Channels . . . . . . . . . . . . . . . . . . 28
2.3 Interference Measurement and Modeling . . . . . . . . . . . . . . . . . 29
2.3.1 Measuring Interference Using Sensor Nodes. . . . . . . . . . 30
2.3.2 Interferer Identification . . . . . . . . . . . . . . . . . . . . . . . . 33
2.3.3 Modeling Interference . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.4 Mitigating Interference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4.1 Frequency Diversity Solutions . . . . . . . . . . . . . . . . . . . 36
2.4.2 Space Diversity Solutions . . . . . . . . . . . . . . . . . . . . . . 38
2.4.3 Hardware Diversity Solutions. . . . . . . . . . . . . . . . . . . . 39
2.4.4 Solutions Based on Redundancy. . . . . . . . . . . . . . . . . . 40
vii
viii Contents
2.4.5 Time Diversity Solutions. . . . . . . . . . . . . . . . . . . . . . . 43
2.5 Experimenting with Interference . . . . . . . . . . . . . . . . . . . . . . . 44
2.5.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.5.2 Experimenting Using Simulators. . . . . . . . . . . . . . . . . . 46
2.5.3 Experimenting Using Real Hardware. . . . . . . . . . . . . . . 48
2.5.4 Observations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3 Overview of Link Quality Estimation. . . . . . . . . . . . . . . . . . . . . . 65
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.2 The Link Quality Estimation Process. . . . . . . . . . . . . . . . . . . . 66
3.2.1 Link Monitoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.2.2 Link Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.2.3 Metric Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3 Design Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3.1 Energy Efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3.2 Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3.3 Reactivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.3.4 Stability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.4 Hardware-Based LQEs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.5 Software-Based LQEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.5.1 PRR-Based. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.5.2 RNP-Based. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
3.5.3 Score-Based. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
4 Performance Evaluation of Link Quality Estimators. . . . . . . . . . . 87
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
4.2 Holistic Evaluation Methodology. . . . . . . . . . . . . . . . . . . . . . . 89
4.2.1 Links Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . 89
4.2.2 Link Measurements Collection. . . . . . . . . . . . . . . . . . . 90
4.2.3 Data Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
4.3 LQEs Under Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
4.4 Evaluation Platforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
4.4.1 TOSSIM 2 Simulator. . . . . . . . . . . . . . . . . . . . . . . . . . 92
4.4.2 RadiaLE Experimental Testbed. . . . . . . . . . . . . . . . . . . 95
4.5 Performance Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
4.5.1 Experimental Study. . . . . . . . . . . . . . . . . . . . . . . . . . . 102
4.5.2 Simulation Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4.6 Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Contents ix
5 On the Use of Link Quality Estimation for Improving Higher
Layer Protocols and Mechanisms. . . . . . . . . . . . . . . . . . . . . . . . . 117
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
5.2 On the Use of Link Quality Estimation for Routing. . . . . . . . . . 118
5.2.1 Link Quality Based Routing Metrics. . . . . . . . . . . . . . . 118
5.2.2 Overview of CTP (Collection Tree Protocol) . . . . . . . . . 120
5.2.3 Integration of FLQE-RM in CTP . . . . . . . . . . . . . . . . . 122
5.2.4 Impact of FLQE-RM on CTP Performance . . . . . . . . . . 124
5.2.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
5.3 On the Use of Link Quality Estimation for Mobility
Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
5.3.1 Link Quality Estimation for Mobile Applications . . . . . . 134
5.3.2 Overview of Handoff Process. . . . . . . . . . . . . . . . . . . . 135
5.3.3 Soft Handoff in Low-Power Wireless Networks . . . . . . . 138
5.3.4 Hard Handoff in Low-Power Wireless Networks . . . . . . 139
5.3.5 Smart-HOP Design . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
5.3.6 Smart-HOP Observations. . . . . . . . . . . . . . . . . . . . . . . 141
5.3.7 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
6 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Acronyms
AC Supply line
ACK Acknowledgement
AFH Adaptive Frequency Hopping
ALQI Average LQI
AP Access Point
ARQ Automatic Repeat reQuest
ARR Acknowledgment Reception Ratio
ASK Amplitude Shift Keying
ASL Link Asymmetry Level
ASNR Average Signal to Noise Ratio
AWGN Additive White Gaussian Noise
BPM Burst Position Modulation
BPSK Binary Phase-Shift Keying
CCA Clear Channel Assessment
CDF Cumulative Distribution Function
CPDF Conditional Probability Distribution Function
CPM Closest-fit Pattern Matching
CRC Cyclic Redundancy Check
CSI Channel State Information
CSMA-CA Carrier Sense Multiple Access with Collision Avoidance
CSS Chirp Spread Spectrum
CTP Collection Tree Protocol
CV Coefficient of Variation
DataAnlApp Data Analysis Matlab application
DCF Distributed Coordination Function
DIFS Distributed Inter-Frame Space
DQCSK Differential Quadrature Chirp-Shift Keying
DSSS Direct Sequence Spread Spectrum
DUCHY DoUble Cost Field HYbrid
ETX Expected Transmission Count
EWMA Exponentially Weighted Moving Average
ExpCtrApp Experiment Control java application
FEC Forward Error Correction
xi
