1. http://www.IMPACT.asu.edu Wireless Sensor Networking for “Hot” Applications: Effects of Temperature on Signal Strength, Data Collection and Localization Kenneth Bannister, Gianni Giorgetti, Sandeep K.S. Gupta HotEmnets’08 – Charlottesville – 3 June 2008 IMPACT LAB http://IMPACT.ASU.EDU

2. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

3. http://www.IMPACT.asu.edu Environmental Monitoring Daily Variations in RSS The “SMART” Container “SMART” Container ProjectDaily Variations in RSS Botanical Garden, Phoenix, AZ

4. http://www.IMPACT.asu.edu Correlation With Temperature The “SMART” Container “SMART” Container Project Botanical Garden, Phoenix, AZ RSS TEMP RSS TEMP

5. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

6. http://www.IMPACT.asu.edu Experimental Setup & Results Temperature at the Transmitter/RSS Effects of temperature on the transmitter Attenuators Thermal Chamber POWER AMPLIFIER RX Section of the CC2420

7. http://www.IMPACT.asu.edu Temperature Effects on the Receiver Effects of temperature on the receiver RX Section of the CC2420 Amplifies the RF signal from the antenna LNA Measures RSS DEMODULATOR Attenuators Thermal Chamber

8. http://www.IMPACT.asu.edu Sensitivity ~ 3 dB

9. http://www.IMPACT.asu.edu Loss due to Temperature

10. -3.3 dB -3.7 dB -2.0 dB -1.6 dB TI CC2400 and CC2520 Datasheets Output Power vs Temperature Sensitivity vs Temperature Output Power vs Temperature Sensitivity vs Temperature Temperature (°C) Output Power (dBm) Sensitivity (dBm) CC2400 and CC2520 DATASHEETS CC2400 CC2520

11. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

12. http://www.IMPACT.asu.edu Link Budget Analysis P RX (d) = P 0 + 10n p log10(d 0 /d) 0255075100125150 -100 -90 -80 -70 -60 -50 -40 RSS [dBm] Distance [m] + L TX (T) + L RX (T) n p =2.3

13. http://www.IMPACT.asu.edu Communication Range Depending on the path loss model, losses due temperature cause reduction in range comprised between 40% and 60% the max. value

14. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

15. http://www.IMPACT.asu.edu Network Connectivity @ 25°C Avg. Connectivity = 8.94; Connected nodes = 100%; Avg. Path Length = 2.95. SINK NODE

16. http://www.IMPACT.asu.edu Network Connectivity @ 45°C Avg. Connectivity = 4.57; Connected nodes = 98%. Avg. Path Length = 4.93. Few nodes are disconnected. SINK NODE

17. http://www.IMPACT.asu.edu Network Connectivity @ 65°C Avg. Connectivity = 1.88; Connected nodes = 0%. The sink is disconnected from the rest of the network! SINK NODE

18. http://www.IMPACT.asu.edu Data Collection: Summary Temperature steadily decreases connectivity Failure of Critical Links can cause the sink to become disconnected

19. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

20. http://www.IMPACT.asu.edu Effect of Temperature on Localization Anchors (GPS) Blind Nodes Location awareness: Enable Context-Aware Apps Resource & Services Discovery Tracking (People, Equipment,...) Navigation Support Security ( Location-based access ) Two Approaches : Range-Based Localization (e.g. triangulation) Range-Free Localization (e.g connectivity) Both Range Estimates and Connectivity can be obtained from radio communication.

21. http://www.IMPACT.asu.edu Ranging Errors -90-85-80-75-70-65 0 0.1 0.2 RSS [dBm] pdf d = 10 m d*=11.6m Received power modeled by the log-normal shadowing model: PRX(d) = P LOG-D (d) + ∆;∆~N(0, σ dB ); Maximum Likelihood Estimate: Errors increase with the temperature d* = 21.5m -95 σ dB

22. http://www.IMPACT.asu.edu Ranging Errors Case 1Case 2 Temperature will cause to over- estimate the node distances

23. http://www.IMPACT.asu.edu Effect of Connectivity on Localization

24. http://www.IMPACT.asu.edu Effect of Connectivity on Localization As temperature reduces connectivity, the number of range estimates decreases The number of “connectivity” measurements does not change 1 1 1 1 1 1 13 2 2 3 4 2 2 http://www.IMPACT.asu.edu Range-BasedConnectivity-Based

25. http://www.IMPACT.asu.edu Outline Signal Strength Observations Lab Experiments Effect of Temperature on: Link Budget and Communication Range Network Connectivity and Data Collection Localization Conclusions and Future Work

26. http://www.IMPACT.asu.edu Conclusions and Future Work Actual measurements only available for the CC2420 radio. Simple model to account for temperature effects on RSS. Tests with other platforms in progress Importance of including temperature sensors in node design. Importance of proper insulation and placement.

27. http://www.IMPACT.asu.edu Impact of Temperature on WSN Design MCU OS / HAL Networking Services Applications Sensors Radio Battery Software Hardware WSN Architecture Link Budget RSS Energy Capacity Physical Models Connectivity Life-time Networking Models Design & Implementation Routing / Scheduling Data Collection Localization TEMPERATURE Radio Battery Source: CR2330 Datasheet Panasonic

28. http://www.IMPACT.asu.edu Don’t forget the sunscreen! Thanks