1. A novel gossip-based sensing coverage algorithm for dense wireless sensor networks Vinh Tran-Quang a, Takumi Miyoshi a,b a Graduate School of Engineering, Shibaura Institute of Technology, Saitama 337-8570, Japan b College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan Computer Networks Volume 53, Issue 13, 28 August 2009, Pages 2275-2287

2. Outline Introduction Definitions and MSCR problem formulation Application of the MSCR algorithm Maximum sensing coverage region algorithm Performance evaluation Conclusion 2

3. Introduction In wireless sensor networks Once deployed, however, most applications of sensor networks expect a long system lifetime. The energy expenditure of sensors has to be wisely managed by their architectures and protocols to prolong the overall network lifetime. 3

4. Introduction In a dense network The sensing areas of different nodes may be similar and overlap with those of neighboring nodes. It is important to place or select them so that the monitored area is covered as much as possible without diminishing the overall system coverage. 4

5. Introduction We propose a new architecture for routing in large distributed WSNs Removing redundant sensor nodes Permits configurable QoS coverage parameters Low communication overhead 5

6. Definitions and MSCR problem formulation Definition 1. The neighbor set of a sensor node s i Communication Range Sensing Range Neighbor Overlapping neighbor SiSi SjSj RsRs 2R s 6

7. Definition 2. The sensing region of a sensor s i located at (x i, y i ), denoted by S i region, is a set of all points within s i ’s sensing range. A point p is said to be k-covered if it is within at least k sensors’ sensing regions. SiSi SjSj 1-covered 2-covered Definitions and MSCR problem formulation 7

8. Definition 3. Boundary arc The arc created by two overlapped sensor nodes s i and s j is the arc created by two intersection points between two sensing region boundaries. Definitions and MSCR problem formulation 0o0o 90 o 180 o 270 o 8

9. Definition 4. MSRC (Maximum sensing coverage region) Given a set of m sensors S=s 1, s 2,..., s m deployed in a desired area and a natural number k The MSCR problem is the problem of finding a subset S ’ guarantees that the whole area is k-covered Achieves a maximum sensing region Definitions and MSCR problem formulation 9

10. Application of the MSCR algorithm Send sleep_msg. or Send active_msg. Setup phase Steady phase 10

11. Maximum sensing coverage region algorithm 11 SiSi S3S3 S4S4 S5S5 S1S1 S2S2 k times

12. Maximum sensing coverage region algorithm S3S3 S4S4 S5S5 S1S1 S2S2 Redundant Node 12 SiSi Send sleep_msg S3S3 S3S3 S3S3 k=1

13. Performance evaluation ParameterValue Initial energy (E initial )2 J Data packet size500 byte Broadcast packet size25 byte Packet header size25 byte Data frames30 Energy of transceiver electron (E elec )50 nJ/bit Energy for transmission in free space model (E fs )10 pJ/bit/m 2 Energy for transmission in multi-path model (E mp )0.0013 pJ/bit/m 4 Threshold distance (d 0 )75 m 13

14. Performance evaluation MSCR-LEACHG k=2 Cluster Head Redundant Node Active Node 14

15. Performance evaluation 15

16. Performance evaluation 16

17. Performance evaluation 17

18. Conclusion We have defined the maximum sensing coverage region problem for randomly distributed WSNs and proposed a gossip-based sensing-coverage- aware algorithm to solve this problem. Simulation results confirmed Reduced total energy consumption Significantly increased network lifetime 18

19. 19 SiSi S3S3 S4S4 S5S5 S1S1 S2S2 SiSi S3S3 S1S1 S2S2