A Better Choice for Sensor Sleeping

1. A Better Choice for Sensor Sleeping Ou Yang and Wendi Heinzelman 1-28-2009

2. Outline • Motivation and Goal • Methodology- Sleep at single layer individually- Sleep at multiple layers simultaneously • Simulation Results- Performance of single layer sleeping- Comparisons of single layer sleeping- Comparisons of multi-layer sleeping • Conclusions

3. Motivation • Wireless sensors are energy constrained • Save energy to extend network lifetime • Make sensors sleep when they are not used

4. Application Layer Routing Layer MAC Layer Motivation • How to make sensors sleep? Source node selection e.g. target tracking [1] Topology control e.g. GAF [2] Routing protocol e.g. [3] Duty-cycled MAC protocol e.g. SMAC [4]

5. Source node selection e.g. target tracking [1] Application Layer Topology control e.g. GAF [2] Routing Layer Routing protocol e.g. [3] Duty-cycled MAC protocol e.g. SMAC [4] MAC Layer Goal • Which is better?- Given application requirements- Given network scenario • Is there a single layer providing most benefit? • Multi-layer better than individual layer? • Need cross-layer coordination?

6. Source node selection e.g. target tracking [1] Application Layer Topology control e.g. GAF [2] Routing Layer Routing protocol e.g. [3] MAC Layer Duty-cycled MAC protocol e.g. SMAC [4] Methodology • Focus on the routing and MAC protocol

7. Methodology • All combinations of sleeping schemes Non-sleeping Sleeping Sleeping Directed Diffusion Directed Diffusion [5] Routing Protocol IEEE 802.11 [6] SMAC [4] MAC Protocol

8. Non-sleeping Routing Protocol -Directed Diffusion [5] • Data-centric- Data is named in attribute-value pairs • Exploratory phase - Discover source nodes- Low data rate flooding • Reinforcement phase- “Pull down” data from selected source node- High data rate unicast

9. Sink Source INTEREST (periodic flooding) exploratory DATA (periodic flooding) positive REINFORCEMENT (unicast) high rate DATA (unicast) Directed Diffusion

10. Directed Diffusion Data Data Interest Put them to sleep! Interest (low rate) exploratory data (low rate) Pos reinforcement (high rate) Data (high rate)

11. INTEREST (periodic flooding) INTEREST timer gap exploratory DATA (periodic flooding) DATA timer gap positive REINFORCEMENT (unicast) high rate DATA (unicast) Sleeping Routing Protocol - Sleeping Directed Diffusion Node

12. Sleeping MAC – SMAC [4] • Duty-cycled MAC- Fixed awake time in a cycle • Synchronization- Periodic SYNC packets • Similar to IEEE 802.11- CSMA- RTS/CTS

13. Sleep at both layers Coordination? How to coordinate? Sleeping Sleeping Directed Diffusion Routing Protocol SMAC MAC Protocol

14. Sleep at both layers • Problem - When sleeping at routing layer, no need to wake up at MAC layer • Coordination- Routing protocol has higher priority to put sensor to sleep

15. Sleep at both layers • Problem- MAC updates topology according to periodic SYNC packets- MAC cannot differentiate routing layer sleeping and energy depletion • Coordination- Add energy info into SYNC packets

16. Performance: single layer sleeping Lower data deliver ratio QoS pause

17. Comparisons: single layer sleeping Higher density Higher contention Higher density Higher redundancy • Change node density Lower delivery ratio Lower throughput Higher throughput Lower delivery ratio due to more QoS pauses

18. Comparisons: single layer sleeping Larger network More hops to sink • Change network scale Larger network Same redundancy Similar delivery ratio Lower delivery ratio Lower throughput Similar throughput

19. Comparisons: single layer sleeping • Change number of source nodes More source nodes, fewer hops to sink More source nodes, more redundancy Higher throughput Higher delivery ratio Higher throughput Lower delivery ratio due to more QoS pauses

20. Comparisons: single layer sleeping • Change application data rate Higher data rate, higher contention Higher data rate, same redundancy Similar delivery ratio Lower delivery ratio Similar throughput/rate Lower throughput/rate

21. Comparisons: multi-layer sleeping • Change node density Need coordination in lower contention scenarios No coordination no gain Sacrifice delivery ratio

22. Discussions • Other routing protocols?- Sensors sleep when not routing data- e.g., Geographic routing • Other MAC protocols?- Duty-cycled MAC- e.g., T-MAC, B-MAC

23. Conclusion and Future Work • MAC layer sleeping is better when- Low contention- Small network scale • Routing layer sleeping is better when- Higher redundancy- Larger network scale • Multi-layer sleeping is better when- Proper coordination- Low contention

24. References • [1] Zoghi, M.R., Kahaei, M.H.: Sensor Selection forTarget Tracking in WSN Using Modified INS Algorithm. In: 3rdInternatioanl Conference on Information and CommunicationTechnologies: From Theory to Applications, pp. 1-6. 2008 • [2] Xu, Y, Heidemann, J., Estrin, D.: Geography-informed Energy Conservation for Ad HocRouting. In: 7th Annual International Conference on Mobile Computingand Networking, pp. 70-84. 2001 • [3] Zheng, R., Kravets, R.: On-demand PowerManagement for Ad Hoc Networks. In: 22nd Annual Joint Conference ofthe IEEE Computer and Communications Societies, vol.1, pp. 481-491. 2003 • [4] Ye, W., Heidemann, J., Estrin, D.: Medium Access Control with Coordinated Adaptive Sleeping for WirelessSensor Networks. IEEE/ACM Trans. on Networking, vol. 12,issue 3, pp. 493-506. 2004 • [5] Intanagonwiwat, C. Govindan, R. Estrin, D. Heidemann,J.: Directed Diffusion for Wireless Sensor Networking. IEEE/ACM Trans. on Networking, vol. 11, issue 1, pp. 2-16. 2003 • [6] LAN MAN Standards Committee of the IEEE Computer Society: Wireless LAN medium access control (MAC) and physical layer (PHY) specification, IEEE, New York, NY, USA, IEEE Std 802.11-1997 edition, 1997

25. Thank you Q & A