1. A Coverage-Preserving Node Scheduling Scheme for Large Wireless Sensor Networks Di Tian, Nicolas D. Georganas First ACM international workshop on Wireless sensor networks and applications (WSNA),2002,pp.32-41 Speaker : 陳希維

2. Outline  Introduction  Node self-scheduling algorithm  Performance evaluation and simulation  Conclusions

3. Introduction  Increasing system lifetime, by turning off some redundant nodes.  Guarantees that the original sensing coverage is maintained.  Extension of the LEACH protocol  Goal: Minimizing energy consumption and Maximizing the system lifetime

4. Node self-scheduling algorithm  Coverage-based off- duty eligibility rule  Sponsored sector:(b) 陰 影部分 :

5. Node self-scheduling algorithm  Node Scheduling Scheme Based On Eligibility Rule Two setps: 1. Neighbor Information Obtaining Step. 利用 position AdvertisementMessage(PAM )

6. Node self-scheduling algorithm  2. Back-off Based Self-scheduling Step Broadcast a Status Advertisement Message (SAM) to announce its status.

7. Node self-scheduling algorithm  流程圖

8. Performance evaluation and simulation  Comparison with probing-based off-duty eligibility rule.

9. Performance evaluation and simulation  On-duty node number vs. node density

10. Performance evaluation and simulation  Sensing Coverage vs. node density

11. Performance evaluation and simulation

16. Conclusions  reduce energy consumption,increase system lifetime coverage-based off-duty eligibility rule is better than the LEACH protocol.