1. A Load-Balanced Guiding Navigation Protocol in Wireless Sensor Networks Wen-Tsuen Chen Department of Computer Science National Tsing Hua University Po-Yu Chen Institute of Communications Engineering National Tsing Hua University Cheng-Han Wu Department of Computer Science National Tsing Hua University Chi-Fu Huang Department of Computer Science National Chiao Tung University IEEE GlobeCom 2008

2. Outline  Introduction  The Proposed Distributed Navigation Protocol  Simulation Results  Conclusions

3. Introduction  Guiding navigation is one of the major applications in WSNs. Destination Static sensor Moving object

4. Introduction - Congestion Destination Static sensor Moving object A Congestion point

5. Introduction – Direction Oscillation Problem Destination Static sensor Moving object A B

6. Goal  The authors propose a distributed load- balanced guiding protocol guide people to a light-load path to avoid congestion and escape quickly solves the direction oscillation problem efficiently

7. Assumptions  Sensors are assumed to be deployed in 2D environment  Each sensor knows its own location  Each sensor is aware of its neighbors

8. Network initialization phase Destination 1 1 1 2 2 2 3 3 3 3 3 44 4 4 4 4 4 5 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 7 7 7 7 7 7 7 8 8 8 88 8 8 9 9 10

9. Potential management phase PiPi the real potential of S i aiai the amount people that S i senses na i the amount people sensed by S k, S k α, β, γ constant number

10. Potential management phase  Raise Packet from  Down Packet from

11. Potential management phase  If | P i – P i ’ |>Threshold and P i > P i ’, S i will broadcast a Raise Packet A ： 11 Sensing range a A =5 a A =10 A ： 13

12. Potential management phase  Raise Packet from Case 1 ： 10 ： 11 A：5A：5 ：6：6 ：8：8 ：3：3 ：6：6 ：6：6 ：6：6

13. Potential management phase  Raise Packet from Case 2 ： 10 ： 11 A：5A：5 ：3：3 ：8：8 ：2：2 ：4：4 ：4：4 ：3：3

14. Potential management phase  Raise Packet from ： 10 ： 11 A：5A：5 ：3：3 ：8：8 ：2：2 ：6：6 | P A – P A ’ |>Threshold and P A > P A ’ ？

15. Potential management phase  If | P i – P i ’ |>Threshold and P i < P i ’, S i will broadcast a Down Packet A ： 11 Sensing range a A =5 aA=2aA=2 A：8A：8

16. Potential management phase  Down Packet from Case 1 ： 10 ： 11 A：5A：5 ：6：6 ：8：8 ：4：4 ：2：2 | P A – P A ’ |>Threshold and P A < P A ’ ？

17. Potential management phase  Down Packet from Case 1 ： 10 ： 11 A：5A：5 ： 10 ：8：8 ：2：2 ：6：6 | P A – P A ’ |>Threshold and P A < P A ’ ？

18. Potential management phase  Down Packet from Case 2 ： 10 ： 11 A：5A：5 ： 10 ：8：8 ：4：4 ：3：3 ：4：4 ：3：3

19. Simulation Results  Number of sensor nodes ： 10 × 10  Field ： 100m × 100m  Communication range ： 20m

20. Simulation Results  Simulation environment

21. Simulation Results

23. Conclusions  The proposed load balancing guiding protocol avoids people congestion at some place to delay the time to escape solves the direction oscillation problem efficiently

24. Thank You ~