PREFACE 1 INTRODUCTION 1.1 Wireless Sensor Networks 1.2 Time Synchronization 1.3 Importance of Time Synchronization 1.4 History of Clock Synchronization 1.5 Outline 2 SIGNAL MODELS FOR TIME SYNCHRONIZATION 2.1 Definition of Clock 2.2 Design Considerations 2.3 Delay Components in Timing Message Delivery 3 TIME SYNCHRONIZATION PROTOCOLS 3.1 Pairwise Synchronization 3.1.1 Timing-Sync Protocol for Sensor Networks(TPSN) 3.1.2 Tiny-Sync and Mini-Sync 3.1.3 Reference Broadcast Synchronization(RBS) 3.1.4 Flooding Time Synchronization Protocol(FTSP) 3.2 Network-Wide Synchronization 3.2.1 Extension of TPSN 3.2.2 Lightweight Time Synchronization(LTS) 3.2.3 Extension of RBS 3.2.4 Extension of FTSP 3.2.5 Pairwise Broadcast Synchronization(PBS) 3.2.6 Time Diffusion Protocol(TDP) 3.2.7 Synchronous and Asynchronous Diffusion Algorithms 3.2.8 Protocols Based on Pulse Transmissions 3.3 Adaptive Time Synchronization 3.3.1 Rate-Adaptive Time Synchronization(RATS) 3.3.2 RBS-based Adaptive Clock Synchronization 3.3.3 Adaptive Multi-Hop Time Synchronization(AMTS) 4 FUNDAMENTAL APPROACHES TO TIME SYNCHRONIZATION 4.1 Sender-Receiver Synchronization(SRS) 4.2 Receiver-Only Synchronization(ROS) 4.3 Receiver-Receiver Synchronization(RRS) 4.4 COmparisons 5 MINIMUM VARIANCE UNBIASED ESTIMATION(MVUE)OF CLOCK OFFSET 5.1 The System Architecture 5.2 Best Linear Unbiased Estimation Using Order Statistics(BLUE-OS) 5.2.1 Symmetric Link Delays 5.2.2 Asymmetric Link Delays 5.3 Minimum Variance Unbiased Estimation(MVUE) 5.3.1 Asymmetric Link Delays 5.3.2 Symmetric Link Delays 5.4 Explanatory Remarks 6 CLOCK OFFSET AND SKEW ESTIMATION 6.1 Gaussian Delay Model 6.1.1 Maximum Likelihood(ML) Clock Offset Estimation 6.1.2 Cramer-Rao Lower Bound(CRLB) for Clock Offset 6.1.3 Joint Maximum Likelihood Estimation(JMLE) of Clock Offset and Skew 6.1.4 Cramer-Rao Lower Bound(CRLB) for Clock Offset and Skew 6.2 Exponential Delay Model 6.2.1 Cramer-Rao Lower Bound(CRLB) for Clock Offset 6.2.2 Joint Maximum Likelihood Estimation(JMLE) of Clock Offsetand Skew 7 COMPUTATIONALLY SIMPLIFIED ScHEMEs FOR ESTIMATION OF CLOCK OFFSET AND SKEW 7.1 Using the First and the Last Data Sample 7.1.1 Gaussian Delay Model 7.1.2 Exponential Delay Model 7.1.3 Combination of Clock Offset and Skew Estimation 7.1.4 Simulation Results 7.2 Fitting the Line Between Two Points at Minimum Distance Apart 7.2.1 Simulation Results 7.2.2 Computational Complexity Comparison 8 PAIRWISE BROADCAST SYNCHRONIZATION(PBS) 8.1 Synchronization for Single-Cluster Networks 8.2 Comparisons and Analysis 8.3 Synchronization for Multi-Cluster Networks 8.3.1 Network-Wide Pair Selection Algorithm(NPA) 8.3.2 Group-Wise Pair Selection Algorithm(GPA) 8.4 Comparisons and Analysis 9 ENERGY-EFFICIENT ESTIMATION OF CLOCK OFFSET FOR INACTIVE NODES 9.1 Problem Formulation 9.2 Maximum Likelihood Estimation(MLE) 9.3 Cramer-Rao Lower Bound(CRLB) 9.3.1 CRLB for the Clock Offset of Inactive Node * 9.3.2 CRLB for the Clock Offset of Active Node * 9.4 Simulation Results 10 SOME IMPROVED AND GENERALIZED ESTIMATION SCHEMES FOR CLOCK SYNCHRONIZATION OF INACTIVE NODES 10.1 Asymmetric Exponential Link Delays 10.1.1 Best Linear Unbiased Estimation Using Order Statistics(BLUE-OS) 10.1.2 MINIMUMV ARIANCUEN BIASEEDS TIMATIO(MN VUE) 10.1.3 Minimum Mean Square Error(MMSE) Estimation 10.2 Symmetric Exponential Link Delays 10.2.1 Best Linear Unbiased Estimation Using Order Statistics(BLUE-OS) 10.2.2 Minimum Variance Unbiased Estimation(MVUE) 10.2.3 Minimum Mean Square Error(MMSE) Estimation 11 ADAPTIVE MULTI-HOP TIME SYNCHRONIZATION(AMTS) 11.1 Main Ideas 11.2 Level Discovery Phase 11.3 Synchronization Phase 11.4 Network Evaluation Phase 11.4.1 Synchronization Mode Selection 11.4.2 Determination of Synchronization Period 11.4.3 Determination of the Number of Beacons 11.4.4 Sequential Multi-Hop Synchronization Algorithm(SMA) 11.5 Simulation Results 12 CLOCK DRIFT ESTIMATION FOR ACHIEVING LONG-TERM SYNCHRONIZATION 12.1 Problem Formulation 12.2 The Estimation Procedure 13 JOINT SYNCHRONIZATION OF CLOCK OFFSET AND SKEW IN a RECEIVER-REcEIVER PROTOCOL 13.1 Modeling Assumptions 13.2 Joint Maximum Likelihood Estimation(JMLE)of the Offset and Skew 13.3 Application of the Gibbs Sampler 13.4 Performance Bounds and Simulations 14 ROBUST ESTIMATION OF CLOCK OFFSET 14.1 Problem Modeling and Objectives 14.2 Gaussian Mixture Kalman Particle Filter(GMKPF) 14.3 Testing the Performance of GMKPF 14.4 Composite Particle Filtering(CPF) with Bootstrap Sampling(BS) 14.5 Testing the Performance of CPF and CPF with BS 15 CONCLUSIONS AND FUTURE DIRECTIONS ACRONYMS REFERENCES INDEX
京公网安备 11010102004214号