Title Page
Abstract
국문요약
Contents
Chapter 1. Introduction 18
1.1. Research Background 18
1.1.1. Wireless Sensor Networks 18
1.1.2. Localization in Wireless Sensor Networks 25
1.2. Research Objectives 26
1.3. Thesis Organization 28
Chapter 2. Overview of Localization in Wireless Sensor Networks 29
2.1. Introduction 29
2.2. Node Localization 31
2.2.1. Coarse-grained localization using minimal information 31
2.2.2. Fine-grained localization using detailed information 34
2.3. Network-wide Localization 36
2.3.1. Iterative (Recursive) Multilateration 37
2.3.2. Multi-hop Distance-estimation Approaches 38
2.3.3. Multi-dimensional Scaling 40
2.4. Remarks 41
Chapter 3. Recursive Localization in Large-Scale Sensor Networks 42
3.1. Introduction 42
3.2. Issues of Large-Scale Sensor Networks 44
3.3. Recursive Position Estimation 45
3.3.1. Reference Selection based on Residual Value 46
3.3.2. Position Estimation 46
3.3.3. Joining as a Reference Node 47
3.4. Remarks 47
Chapter 4. Recursive Localization with a Few Beacon Nodes in Large-Scale Sensor Networks 49
4.1. Introduction 49
4.2. Placement of Beacon Nodes 51
4.3. Recursive Localization 51
4.3.1. Reference Selection based on Hop Distance 52
4.3.2. Least Square Estimation of Sensor Position 54
4.3.3. Joining as a Reference Node 56
4.4. Improving Location Accuracy by Using a Sample Mean of Residual Value 56
4.5. Remarks 58
Chapter 5. Performance Evaluation of Localization Algorithms 63
5.1. Simulation Setups 63
5.2. Performance of RPE and the Proposed Localization 64
5.3. Conclusions 70
Chapter 6. Conclusions 76
6.1. Summary 76
6.2. Further Works 78
Abbreviations 80
References 81
Curriculum Vitae 87
Table 5.1. The simulation model 64
Figure 1.1. The architecture of the sensor node 19
Figure 1.2. Cooperative localization, measurements between any pairs of sensors. 27
Figure 2.1. Localization using intersection of geometric constraints 33
Figure 2.2. The approximate point-in-triangle (APIT) technique 34
Figure 2.3. Illustration of sequence of iterative multilateration steps 39
Figure 4.1. The placement of beacon nodes in wireless sensor networks. 52
Figure 4.2. Recursive localization of nodes with a few beacon nodes. 53
Figure 4.3. Position estimation using TDOA measurement 55
Figure 4.4. The observations in different nodes at the ith iteration 60
Figure 4.5. The Diagrams of recursive localization process. 61
Figure 4.6. The geographical distribution of reference set. 62
Figure 5.1. Location error performance depending on reference selection method (σ=... 65
Figure 5.2. The calculation iteration (σ=0.0005, γ=0.1) 66
Figure 5.3. The variance of location error (σ=0.0005, γ=0.1) 67
Figure 5.4. Location error performance depending on reference selection method (σ=... 68
Figure 5.5. The calculation iteration (σ=0.00075, γ=0.1) 69
Figure 5.6. The variance of location error (σ=0.00075, γ=0.1) 70
Figure 5.7. Location error performance depending on reference selection method (σ=... 71
Figure 5.8. The calculation iteration (σ=0.0005, γ=0.1, τ=0.8) 72
Figure 5.9. The variance of location error (σ=0.0005, γ=0.1, τ=0.8) 73
Figure 5.10. The comparison of location error performance (σ=0.0005, γ=0.1,... 74
Figure 5.11. The comparison of calculation iteration performance (σ=0.0005, γ=0.1,... 75