1. An Efficient Real-Time Routing with Presence of Concave Voids in Wireless Sensor Networks Mohamed Aissani Abdelhamid Mellouk, Nadjib Badache, and Brahim Saidani University of Paris, USTHB University, Polytechnic School 1 ACM IWCMC 2009

2. Outline Introduction Problem Related Works Assumption Concave void avoidance scheme Simulation Results Conclusions 2

3. Introduction Wireless sensor network (WSN) is composed of several sensor nodes deployed and scattered over a specific monitoring region for collecting sensed data. Moreover, to bypass voids in sensor networks, most existing geographic routing protocols tend to route packets along the boundary nodes. 3

4. Problem 4 s d

5. Related Works T. He, J.A. Stankovic, C. Lu and T.F. Abdelzaher, “A Spatiotemporal Communication Protocol for Wireless Sensor Networks,” IEEE Transactions on Parallel and Distributed Systems 16(10): 995-1006, 2005. Soft Real-Time, QoS Routing and Congestion Management, Traffic Load Balancing, Void Avoidance 5 sd

6. Goal To prevent data packets from traveling along the boundaries of voids. To avoid them the concave zones of voids. 6 s d

7. Assumption Each node can get the location information of itself and of its one-hop neighbors Sender node marks packets with their destination’s location. 7

8. Concave void avoidance scheme Void Discovery Step Void Announce Step Packet Rerouting Step 8

9. Void Discovery Step 9 dw v S

10. 10

11. Void Discovery Step Initial phase – Node b i broadcasts a void-beacon packet to its one-hop neighbors 11 d b0b0 s

12. Void Discovery Step Initial phase 12 d b1b1 θ b0b0 s

13. Void Discovery Step Intermediate phase 13 d nknk ψ b0b0 b1b1

14. Void Discovery Step Final phase 14 d b0b0 b1b1 b2b2 b3b3 b4b4 b5b5 b6b6 b7b7

15. Void Discovery Step Final phase 15 d bibi bjbj v b0b0

16. Void Announce Step 16 bibi bjbj v r R SR ： average radio range of sensor nodes AA d b0b0

17. Located at n-hops far from borders of a void Packet Rerouting Step 17 v s AA d

18. Sender s node inside the announce area AA Packet Rerouting Step 18 v b1b1 d θ AA s

19. Void Announce Step Due to the dynamics of a sensor network 19 d v b0b0 b1b1 b2b2 b3b3 b4b4 b5b5 b6b6 b7b7

20. Simulation Results 20 Simulation parametersInitial values Bandwidth200 Kbps Payload32 bytes Terrain200m × 200m Number of nodes100 Node placementUniform Radio Range40 m MAC Layer802.11 Radio LayerRADIO-NONOISE Propagation modelTWO-RAY Radius of the void105 m Time of simulation200 sec

21. Simulation Results 21

22. Simulation Results 22

23. Simulation Results 23

24. Conclusions This paper proposed an efficient void avoidance scheme for real-time routing protocols. Proposed scheme prevents data packets from traveling along the boundaries of voids and avoids them the concave zones of voids. 24

25. Thank you 25