title page
Abstract
Contents
Chapter I. Introduction 9
1.1. Thesis Organization 11
Chapter II. Related Works 13
2.1. NACK-based Hop-by-hop Error Recovery Protocols 13
2.1.1. PSFQ 14
2.1.2. RMST 15
2.1.3. GARUDA 15
2.2. Code Distribution Protocols 16
2.2.1. Trickle 16
2.2.2. MOAP 17
Chapter III. Design Considerations 18
3.1. Sink-to-sensors multicast for code distribution 18
3.2. Efficient reliability support in the presence of route changes 19
3.3. Avoiding unnecessary NACK events 21
3.4. Solve typical problems of pure-NACK approaches 21
Chapter IV. HRS 23
4.1. Terminologies 23
4.2. Hop-by-hop sequence numbering 24
4.3. First packet bit 25
4.4. Hybrid of hNACK and delayed hACK 27
4.4.1. Timeout value of hACK reply timer 29
4.5. An HRS implementation 30
4.5.1. An overview of HRS structure 31
4.5.2. Send Function 34
4.5.3. Recv Function 35
4.5.4. Forward Function 36
4.5.5. Receive a Data Packet 37
4.5.6. Receive an hACK Packet 38
4.5.7. Receive an hNACK Packet 39
4.5.8. Receive an hRepair packet 40
4.5.9. Timer Expiration Events 41
Chapter V. Evaluation 43
5.1. Simulation environment 43
5.2. Simulation results 44
Chapter VI. Conclusions 49
국문요약 51
References 52
Acknowledgements 55
Curriculum Vitae 56
Figure 1. Sink-to-sensors multicast in WSNs comprised of heterogeneous sensor devices 10
Figure 2. Propagation of a NACK event 14
Figure 3. PSFQ with a route change event 20
Figure 4. First few packet losses and multi-hop error recovery In RMST 20
Figure 5. Packet Delivery in HRS 25
Figure 6. Forwarding with a route change event 26
Figure 7. hACK Suppression 27
Figure 8. Recovery by hACK 28
Figure 9. hACK Piggybacking 28
Figure 10. hACK reply timer spectrum 29
Figure 11. HRS structure 31
Figure 12. Pseudo-codes of HRS core 31
Figure 13. Send 34
Figure 14. Recv 35
Figure 15. Forward 36
Figure 16. Receive a Data Packet 37
Figure 17. Receive an hACK Packet 38
Figure 18. Receive an hNACK Packet 39
Figure 19. Receive an hRepair Packet 40
Figure 20. Timer Expiration Events 41
Figure 21. Topologies for the Simulation 43
Figure 22. Packet Sequence Trace with a Route Change Event 45
Figure 23. Packet Sequence Trace without a Route Change Event 45
Figure 24. Numbers of Control Packets per One Data Packet 46
Figure 25. Completion Time 47
Figure 26. Buffer Requirements 48