1. 2016-5-311/42 Does Wireless Sensor Network Scale? A Measure Study on GreenOrbs Yunhao Liu, Yuan He, Mo Li, Jiliang Wang,Kebin Liu, Lufeng Mo, Wei Dong, Zheng Yang, Min Xi, Jizhong Zhao, Xiang-Yang Li Presented by: 张 猜

2. 2016-5-312/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

3. 2016-5-313/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

4. 2016-5-314/42 What's wireless sensor networks? Components: A group of specialized transducers A communications infrastructure

5. 2016-5-315/42 Applications Environment monitoring Scientific observation Emergency detection Field surveillance Structure monitoring......

6. 2016-5-316/42 Existing Large-scale sensor networks VigilNet for military surveillance fig.1 The VigilNet system Architecture

7. 2016-5-317/42 Existing Large-scale sensor networks Motelab for indoor testbed fig.2 Component model of Motelab

8. 2016-5-318/42 Existing Large-scale sensor networks SensorScope for weather monitoring fig.3 Design of a sensing station.

9. 2016-5-319/42 Existing Large-scale sensor networks Trio based on solar-powered fig.4 The system hardware architecture consists of four tiers: mote, gateway, server, and client.

10. 2016-5-3110/42 Existing Large-scale sensor networks Drawbacks of these deployments Often highly optimized for Specific application needs Not fully leveraged as Platforms for consistently observing general network behaviors.

11. 2016-5-3111/42 An overlook on the sensor network deployment and the real topology

12. 2016-5-3112/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

13. 2016-5-3113/42 Tens of sensors A Macroscope in the Redwoods Fidelity and yield in a volcano monitoring sensor network SensorScope: Out-of-the-Box Environmental Monitoring

14. 2016-5-3114/42 Tens of sensors Drawbacks: Hardly reveal some network behaviors Routing dynamics and Topology evolution

15. 2016-5-3115/42 Sensor Networks at scale ExScal: elements of an extreme scale wireless sensor network Trio: Enabling Sustainable and Scalable Outdoor Wireless Sensor Network Deployments

16. 2016-5-3116/42 Sensor Networks at scale Not proper for Measure study Organized hierarchically Either Large-scale or long-lifetime,but not both

17. 2016-5-3117/42 Measurements of GreenObrs! Fairly Comprehensive Low-level –Radio signal Strength –Link quality High-level –Routing –Data traffic

18. 2016-5-3118/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

19. 2016-5-3119/42 GreenOrbs Overview System and Applications –Canopy closure estimate –Research on biodiversity –Carbon sequestration –Fire risk prediction

20. 2016-5-3120/42 GreenOrbs Overview

21. 2016-5-3121/42 TinyOS 2.1

22. 2016-5-3122/42 GreenOrbs Overview Data Set –In December 2009 –29 consecutive days –2 540 000 data packets

23. 2016-5-3123/42 Data Set GreenOrbs Overview

24. 2016-5-3124/42 GreenOrbs Overview Data Set –Back End Data Set Refers to the entire data set collected at the sink –Routing trace –Link trace –Node statistics trace –Overhearing –Beaconing –Local Logging

25. 2016-5-3125/42 Measure and Derivations –Yield –Packet Reception Ratio(PRR) / Loss Ratio(PRL) –Packet Delivery Ratio (PDR)

26. 2016-5-3126/42 GreenOrbs Overview Measure and Derivation –End-to-end delay –Correlation coefficient A statistical measure of association between two varialbe, e.g. ETX and PDR. Range: [-1,1]

27. 2016-5-3127/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

28. 2016-5-3128/42 Basic Observation Network Characteristics

29. 2016-5-3129/42 Basic Observation Network characteristics

30. 2016-5-3130/42 Basic Observation Network Characteristics To investigate cause of packets losses: –Three categories of packet losses Transmit_Timeout (61.08%) Receive_Pool_Overflow (38.92%) Send_Queue_Overflow (0%)

31. 2016-5-3131/42 Basic Observation Network Characteristics

32. 2016-5-3132/42 Basic Observation Investigating Critical Nodes/Links

33. 2016-5-3133/42 Basic Observation Investigating Critical Nodes/Links

34. 2016-5-3134/42 Basic Observation Looking into the Links

35. 2016-5-3135/42 Basic Observation Looking into the Links

36. 2016-5-3136/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

37. 2016-5-3137/42 Who moved Our Cheese The Last Straw that Breaks the Camel’s Back First Conjecture: The bottlenecks are intermediate nodes instead of those lying in the “hot area” around the sink.

38. 2016-5-3138/42 Who moved Our Cheese How Dynamic Is the Environment? Second Conjecture: Most of the wireless links used in sensor networks are physically stable.The dynamics mainly come from internal network operation.

39. 2016-5-3139/42 Who moved Our Cheese Adaptive Routing Design Third Conjecture: The environment: unpredictable impact on the sensor network system running under it. Current dynamic routing approach: Lack adaption to environment.

40. 2016-5-3140/42 Outline Introduction Related Work GreenOrbs Overview Basic Observation Who moved Our Cheese Conclusion

41. 2016-5-3141/42 Conclusion Conduct a long term and large-scale measurement study on an operating sensor network in the wild. Validate three conjectures for future sensor network design

42. 2016-5-3142/42 Thank you! Q & A