1. uSense: A Unified Asymmetric Sensing Architecture for Wireless Sensor Networks Yu Gu, Joengmin Hwang, Tian He and David Du Minnesota Embedded Sensor System (MESS) Department of Computer Science & Engineering http://mess.cs.umn.edu

2. Outline Motivation Overview of uSense Architecture Global Scheduling Algorithms System Implementation and Evaluation Conclusion

3. Motivation (Different Services) Coverage Life Time Detection Delay Stealth Distance A Flexsible Solution? … C. Gui et al., Mobicom’04 S. Ren et al., MC2R 2005 X. Wang et al. Sensys’03 Q. Cao et al. IPSN’05 C. Chiasserini et al. Infocom’04 T. Yan et al., Sensys‘03 M. Cardei et al., Infocom’05 S. Kumar et al. Mobicom’04 S. Slijepcevic et al., ICC’01 D. Tian et al., Wireless Communications and Mobile Computing Journal 2003

4. New Design Philosophy Sensor Functions Essential functionsNon-Essential functions uSense Asymmetric Architecture

5. Connectivity Parameters

6. Generic Switching Algorithm  Scheduling Bits  Switching Rate 10110101 On 0.5HZ  16s round time

7. Algorithm2Algorithm1 Algorithm2Algorithm1 Algorithm2 Algorithm1 Have We Solved Some Problems?  Flexibility issue of existing protocols? Before: Algorithm1 Complete code for Algorithm2

8. Parameters2 Generic Switching Have We Solved Some Problems?  Flexibility issue of existing protocols? uSense: Parameters1 Schedule Bits Switching Rate Only need to disseminate two parameters Generic Switching unaffected

9. Outline

10. Sensor Network Sensor i Sensor j Generic Switching Algorithm Parameter Translating CCP … uScan Virtual Patrol Computational Entity DiffSurv Algorithm n Algorithm 1 Algorithm 2 Algorithm 3 Connectivity Parameters uScan Overview

11. Sensor Network Sensor i Sensor j Generic Switching Algorithm Parameter Translating CCP … uScan Virtual Patrol Computational Entity DiffSurv Connectivity Parameters Tile Level Scheduling Line Scanning Systolic Scanning Node Level Scheduling Parameter Translating CCP … uScan Virtual Patrol Computational Entity DiffSurv uScan Overview

12. Tile Level Scheduling  Tessellations  Line Scan  Energy saving  Systolic Scan  Minimal Worst-case Breach (10000 )* (00100 )* (00001 )*

13. Node Scheduling {N1,N5} {N2,N3} {N1,N4} N2 N1 N3 N5 N4 T1 T2 T3 T4 T5 Schedule(N1)=(00100 00000 00100)* Schedule(N2)=(00000 00100 00000)* Schedule(N3)=(00000 00100 00000)* Schedule(N4)=(00000 00000 00100)* Schedule(N5)=(00100 00000 00000)* (00100)*

14. Polynomial solution for set- cover Physical Coverage Bipartite GraphSet Cover

15. Outline

16. System Implementation

17. Life Time under Full Coverage At Node Density of 4, uSense outperforms DiffSurv 1.6 times DiffSurv: T. Yan et al. “Differentiated Surveillance service for sensor networks”, Sensys 2003

18. Life Time under Partial Coverage At Node Density of 10, uSense outperforms Virtual Patrol 27 times Virtual Patrol: C. Gui and P. Mohapatra, “Virtual Patrol: a new power conservation design for surveillance using sensor networks”, IPSN 2005

19. Future Work Incorporating more sensing protocols to further strengthen the flexibility of uSense Consider communication issues in uScan scenarios Resilience to node failures

20. Conclusion (1) uSense, provides a unified sensing architecture Simple generic switching algorithm in sensor nodes Allows changing sensing algorithms with only two parameters

21. Conclusion (2) uScan, a two-level global scheduling algorithm Seamlessly supported by the uSense Generic node scheduling for different sensing coverage requirements Significantly more energy efficient than the localized algorithms