Introduction to Wireless Sensor Networks

Anna Förster is a Professor and Head of the Sustainable Communication Networks Group at the University of Bremen, Germany. She earned her MSc in Computer Science and Aerospace Engineering from the Free University of Berlin and her PhD from the University of Lugano, Switzerland. Her main research interests lie in the area of sustainable communication networks and their applications to sustainability. Her passion is teaching these topics, both to students and the general public.

• How to Use This Book xiii1 What are Wireless Sensor Networks? 11.1 Wireless Sensor Networks 11.2 Sample Applications Around the World 31.3 Types of Wireless Sensor Networks 7Summary 10Further Reading 102 Anatomy of a Sensor Node 112.1 Hardware Components 112.2 Power Consumption 132.3 Operating Systems and Concepts 152.3.1 Memory Management 172.3.2 Interrupts 232.3.3 Tasks Threads and Events 242.4 Simulators 262.5 Communication Stack 282.5.1 Sensor Network Communication Stack 282.5.2 Protocols and Algorithms 30Anatomy of a Sensor Node: Summary 30Further Reading 303 Radio Communications 333.1 Radio Waves and Modulation/Demodulation 333.2 Properties of Wireless Communications 363.2.1 Interference and Noise 373.2.2 Hidden Terminal Problem 383.2.3 Exposed Terminal Problem 393.3 Medium Access Protocols 393.3.1 Design Criteria for Medium Access Protocols 413.3.2 Time Division Multiple Access 423.3.3 Carrier Sense Multiple Access 453.3.4 Sensor MAC 483.3.5 Berkeley MAC 503.3.6 Optimizations of B-MAC 513.3.7 Other Protocols and Trends 51Radio Communications: Summary 53Questions and Exercises 53Further Reading 544 Link Management 574.1 Wireless Links Introduction 574.2 Properties of Wireless Links 594.2.1 Links and Geographic Distance 594.2.2 Asymmetric Links 604.2.3 Link Stability and Burstiness 614.3 Error Control 624.3.1 Backward Error Control 624.3.2 Forward Error Control 634.4 Naming and Addressing 644.4.1 Naming 644.4.2 Addressing 654.4.3 Assignment of Addresses and Names 654.4.4 Using Names and Addresses 664.5 Link Estimation Protocols 664.5.1 Design Criteria 664.5.2 Link Quality Based 674.5.3 Delivery Rate Based 684.5.4 Passive and Active Estimators 694.5.5 Collection Tree Protocol 694.6 Topology Control 714.6.1 Centralized Topology Control 714.6.2 Distributed Topology Control 72Link Management: Summary 73Questions and Exercises 73Further Reading 745 Multi-Hop Communications 775.1 Routing Basics 775.2 Routing Metrics 805.2.1 Location and Geographic Vicinity 805.2.2 Hops 815.2.3 Number of Retransmissions 825.2.4 Delivery Delay 835.3 Routing Protocols 845.3.1 Full-Network Broadcast 855.3.2 Location-Based Routing 875.3.3 Directed Diffusion 905.3.4 Collection Tree Protocol 925.3.5 Zigbee 94Multi-Hop Communications: Summary 95Questions and Exercises 96Further Reading 966 Data Aggregation and Clustering 996.1 Clustering Techniques 996.1.1 Random Clustering 1016.1.2 Nearest Sink 1026.1.3 Geographic Clustering 1036.1.4 Clustering Summary 1046.2 In-Network Processing and Data Aggregation 1046.2.1 Compression 1046.2.2 Statistical Techniques 1076.3 Compressive Sampling 109Data Aggregation and Clustering: Summary 110Questions and Exercises 111Further Reading 1117 Time Synchronization 1137.1 Clocks and Delay Sources 1137.2 Requirements and Challenges 1147.3 Time Synchronization Protocols 1177.3.1 Lightweight Tree Synchronization 1177.3.2 Reference Broadcast Synchronization 1187.3.3 NoTime Protocol 118Time Synchronization: Summary 120Questions and Exercises 121Further Reading 1218 Localization Techniques 1238.1 Localization Challenges and Properties 1238.1.1 Types of Location Information 1248.1.2 Precision Against Accuracy 1258.1.3 Costs 1258.2 Pre-Deployment Schemes 1268.3 Proximity Schemes 1268.4 Ranging Schemes 1288.4.1 Triangulation 1298.4.2 Trilateration 1298.5 Range-Based Localization 1298.6 Range-Free Localization 1308.6.1 Hop-Based Localization 1308.6.2 Point in Triangle (PIT) 131Localization: Summary 132Questions and Exercises 133Further Reading 1339 Sensing Techniques 1359.1 Types of Sensors 1359.2 Sensing Coverage 1369.3 High-Level Sensors 1379.4 Special Case: The Human As a Sensor 1389.5 Actuators 1389.6 Sensor Calibration 1399.7 Detecting Errors 140Sensing Techniques: Summary 141Questions and Exercises 14110 Designing and Deploying WSN Applications 14310.1 Early WSN Deployments 14310.1.1 Murphy Loves Potatoes 14410.1.2 Great Duck Island 14410.2 General Problems 14510.2.1 Node Problems 14610.2.2 Link/Path Problems 14710.2.3 Global Problems 14810.3 General Testing and Validation 14910.4 Requirements Analysis 15110.4.1 Analyzing the Environment 15110.4.2 Analyzing Lifetime and Energy Requirements 15310.4.3 Analyzing Required Data 15310.4.4 Analyzing User Expectations 15410.5 The Top-Down Design Process 15410.5.1 The Network 15410.5.2 The Node Neighborhood 15510.5.3 The Node 15610.5.4 Individual Components of the Node 15610.6 Bottom-Up Implementation Process 15710.6.1 Individual Node-Level Modules 15810.6.2 The Node As an Entity 15910.6.3 The Network As an Entity 159Designing and Deploying WSN Applications: Summary 160Further Reading 16011 Summary and Outlook 163Index 167