1. Ad hoc Routing for Multilevel Power Saving Protocols Matthew J. Miller, Nitin H. Vaidya Ad Hoc Networks 2008 January University of Illinois at Urbana-Champaign, United States

2. Outline Introduction Introduction Relate Works Relate Works Protocol Design Protocol Design Simulation Simulation Conclusions Conclusions

3. Introduction The tradeoff between latency and energy consumption The tradeoff between latency and energy consumption

4. Introduction Goals Goals –To design a routing protocol Satisfy latency requirement Satisfy latency requirement Use k power saving levels Use k power saving levels Contribution Contribution –The ideal of heterogeneous power saving protocols to support multiple power save states

5. Related Works

6. GAF GAF –The node have location information and form virtual grids –The discovery process Most of the time one node remains active Most of the time one node remains active The rest enter low power mode The rest enter low power mode

7. Related Works Span Span –All node enter power saving mode except for elected coordinators.

8. Related Works All related works All related works –The node only be placed one or two power saving state –This paper placed the node in k power saving states

9. Protocol Design Multiple power saving level Multiple power saving level –To achieve an acceptable latency, while reducing the energy consumption k power level k power level –PS 0 …..PS k-1 –PS 0 means always power on –Provides different energy-latency tradeoff

10. Protocol Design Reference point

11. Protocol Design Assumptions Assumptions –Each node is initialized with the time of previous reference point –The node is added to the network, it can learn the time of the previous reference point

12. Protocol Design The node keeps track of its power state as follow The node keeps track of its power state as follow On every data and ACK packet a node send, it attaches its current power save state On every data and ACK packet a node send, it attaches its current power save state

13. Protocol Design PS 0 PS 1 PS 2 PS 3 A B C D Data arrival

14. Routing Protocol In Networks In Networks –(F 1,F 2 …..,F m ) m flow –(L 1,L 2 …..,L m ) Desired latency for flow –Finding routes that minimize the overall energy consumption is NP-Complete –Heuristics to address the problem Modify DSR (Dynamic Source Routing) Modify DSR (Dynamic Source Routing)

15. Routing Protocol Why DSR? Why DSR? –AODV The node have to collect the power saving state on the path The node have to collect the power saving state on the path –OLSR The flooding is needed The flooding is needed –Power save state change –Link break High overhead High overhead

16. Routing Protocol B A S E F H J D C G I K Z Y Represents a node that has received RREQ for D from S M N L

17. Routing Protocol B A S E F H J D C G I K Represents transmission of RREQ Z Y Broadcast transmission M N L node power_state S 1 E 2 node power_state S 1 B 3

18. Routing Protocol B A S E F H J D C G I K Z Y M N L node power_state S 1 B 3 A 0 node power_state S 1 E 2 F 4 node power_state S 1 B 3 H 0

19. Routing Protocol B A S E F H J D C G I K Z Y M N L node power_state S 1 E 2 F 4 J 0 Delay T delay

20. Routing Protocol B A S E F H J D C G I K Z Y M N L node power_state S 1 E 2 F 4 J 0 After T delay node power_state S 1 C 3 G 0 K 2 node power_state S 1 B 3 C 0 G 5 K 3 Pick a better path

21. Routing Protocol Input RREQ LIST Latency Output RREQ LIST Latency Send RREP Find the min cost in RREQ list

22. Routing Protocol Input RREQ LIST Latency do when latency not satisfy decrease power save state on the path The energy cost if decrease power save state

23. Routing Protocol

24. Route Reply B A S E F H J D C G I K Z Y Represents links on path taken by RREP M N L

25. Simulation Compare with Compare with –Always On –802.11 PSM –CS-ATIM ATIM Windows will be dynamically extended ATIM Windows will be dynamically extended –Multilevel PSM –Multilevel CS-ATIM

26. Simulation parameter Ns-2 Ns-2 ATIM windows 20ms ATIM windows 20ms BI 100ms BI 100ms 1000m X1000m 1000m X1000m CBR traffic CBR traffic

27. Simulation Proposed protocol

28. Simulation Data transmission

29. Simulation k=2 Proposed protocol

30. Simulation k=2 Proposed protocol

31. Simulation k=2

32. Simulation k=3

33. Simulation

34. Simulation

35. Conclusions The contributions of this paper The contributions of this paper –Handle k level power save state –Latency aware routing protocol

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