0. Finding and Mending Barrier Gaps in Wireless Sensor Networks
Anwar Saipulla Benyuan Liu Jie Wang
Department of Computer Science
University of Massachusetts Lowell
Lowell, MA 01854, USA
IEEE Globecom 2010

1. Outline Introduction Network model Two-phase algorithm Simulation
Finding
Mending
Simulation
Conclusion

2. Introduction
Barrier coverage has been studied intensively in recent years
Military operations
Homeland security
Hazardous area

3. Introduction
Barrier coverage using wireless sensor networks aims at detecting intruders that attempt to cross the network
Area A
Area B

4. Introduction-motivation
Barrier gap
Malfunctioning
Run out of power
Environmental factor
Barrier gap
Barrier gap

5. Introduction-goal Forming new barrier coverage Finding barrier gaps
Relocating mobile sensors to the desired locations

6. Network model

7. Network model ns stationary nm mobile sensors Sensing range = r
i-th sensor’s target landing point w l
Ex:
n = ns + nm 1 2 3 4 5 6 7 8 9 5 15 25 35 45
l = 50

8. Network model
P(any crossing path is covered) = 1 w l

9. Finding
Mending

10. Find barrier gaps
Finding
Mending s t

11. Find barrier gaps s t x x1 y y1 Gap (x,y) Gap (x1,y1) Finding Mending
Dist>2r s t
Dist>2r
Gap (x,y)
Gap (x1,y1)

12. Mend barrier gaps
Finding
Mending
Ex:
grid point = 4 x y g1 g2 g3 g4

13. Mend barrier gaps
Finding
Mending m1 m3 m4 x y m2 m5

14. Mend barrier gaps 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 S D Finding
Mending S 1 1 1 1 1 m1 m3 m2 m4 m5 1 1 1 1 1 1 1 1 1 1 1 1 1 D

15. Mend barrier gaps
Finding
Mending m1 m3 m4 x y m2 m5

16. Mend barrier gaps 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 S D Finding
Mending S 1 1 1 1 1 m1 m3 m2 m4 m5 1 1 1 1 1 1 1 1 1 1 1 1 1 D

17. Mend barrier gaps
Finding
Mending m1 m3 m4 x y m2 m5

18. Simulation

19. Simulation Parameter Value Filed size 1000*300 Sensing range 10
Stationary sensors
100
Offset variances
10, 30, 50

20. Simulation result

21. Simulation result

22. Conclusion The authors devise a two-phase algorithm
First finding barrier gaps in the network
Then relocating mobile sensors to desirable locations to fill the gaps
Simulation results show that our algorithm can effectively improve barrier coverage of a wireless sensor networks

23. Wireless Access and Networking Technology Lab (WANT Lab)
Thanks for your attention n t n u f r y n h o t