1. ETH Zurich – Distributed Computing – www.disco.ethz.ch Sharing a Medium Between Concurrent Protocols Without Overhead Using the Capture Effect Michael König Roger Wattenhofer

2. Wireless Sensor Networks

3. ? ? Priority Traffic – CSMA

4. Priority Traffic – Scheduling

5. The Capture Effect

7. The Capture Effect – Power Difference

8. The Capture Effect – Packet Timing Preamble SFD Len Payload... Time Preamble SFD Len Payload... (weaker) (stronger)

9. The Capture Effect – Packet Timing Preamble SFD Len Payload... Time Preamble SFD Len Payload... 160 µs (weaker) (stronger)

10. The Capture Effect – Packet Timing

11. Priority Traffic – Using the Capture Effect

12. Halfway Summary MethodAlarm DelayRegular Operation Impairment CSMAArbitrarily largeNone SchedulingBoundedConstant fraction Capture EffectNone *

13. Network Heterogeneity vs

14. Testbed Example

15. Network Heterogeneity

17. Layer 4 Layer 3 Layer 2 Layer 1 -64 dBm -70 dBm -75 dBm -81 dBm “Layer” Abstraction: Receiving

18. “Layer” Abstraction: Sending Layer 4 Layer 3 Layer 2 Layer 1

19. “Layer” Abstraction Layer 4 Layer 3 Layer 2 Layer 1

20. “Layer” Abstraction: Caveat Layer 4 Layer 3 Layer 2 Layer 1

21. Feasible number of layers vs

22. Summary Layer 4 Layer 3 Layer 2 Layer 1

23. ETH Zurich – Distributed Computing – www.disco.ethz.ch Questions Michael König

24. Backup Slides

25. Layer 1 - Convergecast