1. AUTO-ADAPTIVE MAC FOR ENERGY-EFfiCIENT BURST TRANSMISSIONS IN WIRELESS SENSOR NETWORKS Romain Kuntz, Antoine Gallais and Thomas No¨el IEEE WCNC 2011 Speaker : Chuan-Heng, Chi

2. Outline Introduction Related works Problem statement Goal Environment assumption Proposed solution BOX-MAC Simulation Conclusion

3. Introduction WSNs are composed of small and cheap sensors that can sense, compute and communicate

4. Introduction How to design a MAC protocol Reduce energy consumption with LPL

5. Related works B-MAC Low Power Listening (LPL) Sender Receiver Long Preamble awake sleep DATA Target address in data header S R others Receive DATA

6. Related works X-MAC Sender Receiver awake sleep DATA Receive DATA S R PR R wake up A A Short preambles with target address information

7. Problem statement How the LPL can be configured on-the-fly, while the network is running In centralized solution Large control message In localized solution Node isolation

8. Goal To propose a simple mechanism that allows preamble-sampling MAC protocols to adapt their LPL Energy efficient

9. Environment assumption To establish energy-efficient communications over certain data collect paths toward the sink station Every node has the information of neighbors

10. Proposed solution BOX-MAC (Burst-Oriented X-MAC) Preamble Length (PL) T max, T min Sampling Period (SP) T max, T min S1 S2

11. BOX-MAC Sender side Receiver side

12. BOX-MAC Sender side

13. BOX-MAC Receiver side

14. BOX-MAC In order to correctly synchronizing for receiving the second data packet Upon reception of the first data packet from a sender, a forwarder(or receiver) sets SP=T min

15. BOX-MAC SenderForwarderReceiver Sender Forwarder Receiver Radio off Tx preamble Radio off time PL=T max Tx data Tx ack SP=T max Channel sampling Back offReception

16. BOX-MAC SenderForwarderReceiver Sender Forwarder Receiver Radio off Tx preamble Radio off Tx preamble Radio off time PL=T max Tx data Tx ack SP=T max Tx data Tx data Tx ack SP=T max PL=T max SP=T max Channel sampling Back offReception

17. BOX-MAC SenderForwarderReceiver Sender Forwarder Receiver Radio off Tx preamble Radio off Tx preamble Radio off time Tx preamble Radio off Radio off Radio off Radio off PL=T max Tx data Tx ack SP=T max PL=T min Tx data Tx data Tx ack SP=T max Tx data Tx ack PL=T max SP=T min SP=T max SP=T min Channel sampling Back offReception

18. Simulation Simulation environment

19. Simulation

21. Conclusion In this paper, we have shown that addressing a dynamic scenario with a homogenous LPL configuration over the network Energy efficient