Alma Mater Studiorum - Università di Bologna Human-Centric Wireless Communication Networks ...

179 Pages·2016·3.38 MB·English

by  Riccardo Cavallari

Alma Mater Studiorum - Università di Bologna
DEI - Dipartimento di Ingegneria dell’Energia Elettrica e
dell’Informazione “Guglielmo Marconi”
Dottorato di Ricerca in Ingegneria Elettronica, delle Telecomunicazioni e
Tecnologie dell’Informazione
XXVIII Ciclo
Settore Concorsuale: 09/F2 - Telecomunicazioni
Settore Scientifico Disciplinare: ING-INF/03
Human-Centric Wireless Communication Networks
Tesi di:
Riccardo Cavallari
Coordinatore:
Chiar.mo Prof. Ing. Alessandro Vanelli-Coralli
Relatori:
Chiar.mo Prof. Ing. Roberto Verdone
Dott.ssa Ing. Chiara Buratti
Esame anno finale 2016

Abstract
This thesis covers two main topics: the design and performance evaluation
of Wireless Body Area Networks (WBANs), and the simulation and mathe-
matical modeling of Delay Tolerant Networks (DTNs).
Different Medium Access Control (MAC) protocols for WBANs are im-
plemented on dedicated hardware in order to evaluate, through extensive
measurement campaigns, the performance of the network in terms of packet
loss rate, delay and energy consumption. Novel solutions to cope with body
shadowing and to improve the coexistence with other wireless technologies,
are presented and evaluated. An analytic model for the CSMA/CA protocol
defined in the IEEE 802.15.6 standard is also presented.
The benefits of offloading part of the traffic carried by a wireless back-
bone to a DTN composed of mobile nodes in a urban environment, is also
investigated. A more analytic approach, mainly using tools from stochas-
tic geometry and Markov chains theory, is used to develop a mathematical
framework for the evaluation of the performance of routing rules for DTNs.
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Contents
Introduction 1
Human-Centric Wireless Communication Networks: Concept . . . . 1
Problem Statement and Approach . . . . . . . . . . . . . . . . . . . 2
Context: the WiserBAN Project . . . . . . . . . . . . . . . . . . . . 4
Structure and Contribution of the Thesis . . . . . . . . . . . . . . . 6
I Wireless Body Area Networks 9
1 Wireless Body Area Networks 11
1.1 Definition and Taxonomy . . . . . . . . . . . . . . . . . . . . . 11
1.1.1 Taxonomy . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2 Applications and Requirements . . . . . . . . . . . . . . . . . 16
1.2.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . 18
1.3 Wireless Technologies for WBANs . . . . . . . . . . . . . . . . 21
1.3.1 The IEEE 802.15.4 Standard . . . . . . . . . . . . . . . 21
1.3.2 IEEE 802.15.6 Standard . . . . . . . . . . . . . . . . . 24
1.3.3 Low Power Listening (LPL) . . . . . . . . . . . . . . . 28
1.4 Main Challenges in WBAN Design . . . . . . . . . . . . . . . 30
1.4.1 Radio Channel . . . . . . . . . . . . . . . . . . . . . . 30
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CONTENTS
1.4.2 Energy Consumption . . . . . . . . . . . . . . . . . . . 31
1.4.3 Coexistence . . . . . . . . . . . . . . . . . . . . . . . . 32
1.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2 Performance Evaluation of MAC Protocols for WBANs 35
2.1 Reference Architecture, Scenario and Performance Metrics . . 35
2.1.1 Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.1.2 Architecture . . . . . . . . . . . . . . . . . . . . . . . . 38
2.1.3 Performance Metrics . . . . . . . . . . . . . . . . . . . 41
2.2 Analytic Model for MAC Performance in WBANs . . . . . . . 44
2.2.1 CSMA/CA Analytic Model . . . . . . . . . . . . . . . 44
2.2.2 Numerical Results . . . . . . . . . . . . . . . . . . . . 52
2.3 Experimental Performance Evaluation . . . . . . . . . . . . . 55
2.3.1 Body Shadowing . . . . . . . . . . . . . . . . . . . . . 56
2.3.2 PLR, Delay and Throughput . . . . . . . . . . . . . . . 62
2.3.3 Energy consumption . . . . . . . . . . . . . . . . . . . 68
2.3.4 Coexistence . . . . . . . . . . . . . . . . . . . . . . . . 74
2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
II Delay Tolerant Networks 79
3 A Wireless Backbone with Delay-Tolerant Offload 81
3.1 Introduction to Delay-Tolerant Networks and their Applications 81
3.2 A Wireless Backbone with Delay Tolerant Offload . . . . . . . 84
3.2.1 Related Work . . . . . . . . . . . . . . . . . . . . . . . 86
3.2.2 Reference Scenario . . . . . . . . . . . . . . . . . . . . 86
3.2.3 Backbone MAC protocol . . . . . . . . . . . . . . . . . 88
3.2.4 Offloading Mechanism . . . . . . . . . . . . . . . . . . 89
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CONTENTS
3.2.5 Numerical Results . . . . . . . . . . . . . . . . . . . . 90
3.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
4 Cost/Speed Analysis of Mobile DTNs 97
4.1 Related work . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
4.2 Network Model and Routing Rules . . . . . . . . . . . . . . . 98
4.2.1 Network Model . . . . . . . . . . . . . . . . . . . . . . 98
4.2.2 Stages . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4.2.3 Performance Metrics . . . . . . . . . . . . . . . . . . . 102
4.2.4 Routing Rule . . . . . . . . . . . . . . . . . . . . . . . 104
4.3 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.3.1 The Continuous-Time Markov Chain . . . . . . . . . . 105
4.3.2 Limiting Distributions . . . . . . . . . . . . . . . . . . 108
4.3.3 Performance Metrics . . . . . . . . . . . . . . . . . . . 111
4.3.4 Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4.4 Analysis of Routing Rule 1 without Multihop . . . . . . . . . 115
4.4.1 Numerical and Simulation Results . . . . . . . . . . . . 120
4.5 Analysis of Routing Rule 1 with Multihop . . . . . . . . . . . 123
4.5.1 Calculation of E[C|θ ] . . . . . . . . . . . . . . . . . . . 127
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4.5.2 Calculation of E[X |θ ] . . . . . . . . . . . . . . . . . . 131
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4.5.3 Numerical and Simulation Results . . . . . . . . . . . . 134
4.6 Other Routing Rules . . . . . . . . . . . . . . . . . . . . . . . 137
4.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Appendix 4.A Calculation of rate µ(φ;θ) . . . . . . . . . . . . . . 139
Conclusions 149
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List of Figures
1 WiserBAN application use cases and protocol stack. Figure
taken from [1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Taxonomy of WBANs. . . . . . . . . . . . . . . . . . . . . . . 12
1.2 Some of the available RF bands for WBANs. . . . . . . . . . . 13
1.3 IEEE 802.15.4 Superframe structure. . . . . . . . . . . . . . . 22
1.4 IEEE 802.15.4 slotted CSMA/CA algorithm. . . . . . . . . . . 23
1.5 Example of IEEE 802.15.6 superframe. . . . . . . . . . . . . . 25
1.6 IEEE 802.15.6 CSMA/CA algorithm. . . . . . . . . . . . . . . 27
1.7 The LPL mechanism. . . . . . . . . . . . . . . . . . . . . . . . 29
2.1 The position of the nodes for the reference WBAN. . . . . . . 36
2.2 Traffic schemes used to evaluate the WBAN performance. . . . 37
2.3 ISO/OSI model of the reference WBAN design. . . . . . . . . 38
2.4 Screenshot of the WiserBAN testing application that runs on
Android devices. . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.5 Example of diagram for UP 4 and transmission time D = 3.
tx
CirclesdenoteBackoffstates,SquaredenoteTransmissionstates. 47
2.6 P (UP ) for for a network of 3 senders with the same UP values. 53
s i
2.7 P for N = 2,...,7 where EDs use the same UP values. . . . . 54
s
2.8 P when a new ED is added to the network. . . . . . . . . . . 54
s
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LIST OF FIGURES
2.9 E[D] for N = 3, UP=4 for different payload size. . . . . . . . . 55
2.10 Cumulative distribution function of the delay for different va-
lues of N and for a payload size of 100 Bytes. . . . . . . . . . 56
2.11 PLR for different links of Fig. 2.1. . . . . . . . . . . . . . . . . 58
2.12 Example of the data aggregation strategy. . . . . . . . . . . . 59
2.13 Optimal value of N . . . . . . . . . . . . . . . . . . . . . . . . 60
a
2.14 PLR and energy consumption for the data aggregation strategy. 61
2.15 Comparison of the PLR for three different contention access
algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
2.16 Comparison of the average delay for three different contention
access algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . 64
2.17 Network throughput (periodic traffic). . . . . . . . . . . . . . 65
2.18 Average delay for a three nodes-network, each one with diffe-
rent UP values: node 1-UP 3; node 2-UP 5; node 3-UP 7. . . . 66
2.19 Average delay for a three nodes-network, each one with the
same UP value. . . . . . . . . . . . . . . . . . . . . . . . . . . 67
2.20 PLRforathreenodes-networkwiththesameUPanddifferent
number of retransmissions. . . . . . . . . . . . . . . . . . . . . 68
2.21 ComparisonoftheenergyconsumptionofIEEE802.15.6CSMA/CA
and Slotted ALOHA as function of the CAP duration and for
different number of retransmissions. . . . . . . . . . . . . . . . 69
2.22 Distribution of the energy consumed in the different radio
states for IEEE 802.15.6 CSMA/CA and Slotted ALOHA for
different CAP durations. . . . . . . . . . . . . . . . . . . . . . 70
2.23 AverageenergyconsumptionperpacketforIEEE802.15.4and
LPL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
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