1. Energy-Efficient Shortest Path Self-Stabilizing Multicast Protocol for Mobile Ad Hoc Networks Ganesh Sridharan Ganesh.Sridharan@asu.edu

2. Outline Introduction Goals System Model Cost metric Simulation & Implementation Conclusion

3. Introduction Mobile Ad Hoc Networks (MANETs) No infrastructure Limited transmission range Energy constrained Multicasting in MANETs Why multicast as opposed to multiple unicast? Less number of messages Less energy spent

4. Introduction Issues in MANET Multicasting Dynamic Topology Energy constrained Possible solution – flooding Suffers from redundant rebroadcast Increase in collision and contention Energy inefficient Tree or Mesh Structure Examples: MAODV, ODMRP etc.

5. Shortest Path Self-Stabilizing Protocol SS-SPST Shortest path spanning tree from root Pro active tree construction Tree includes both multicast group and non-group nodes Faults Change in topology caused by mobility SS-SPST is self-stabilizing Converge to a global legitimate state from an illegitimate state Fault-tolerant solution SS-SPST is distributed Uses only local knowledge

6. Self-Stabilization Properties Convergence Closure Inter-communication Share memory Message passing Beaconing Time complexity Rounds Round definition in a lossy medium A round is defined to be the time period in which each node in the system receives at least one beacon message from each of its neighbors and performs computation based on the information it has received.

7. SS-SPST Cost metric Multicast tree is constructed to optimize the cost metric Currently hop count is the cost metric Goal: To optimize energy An energy-efficient cost metric is required to minimize total energy consumption

8. Wireless Multicast Advantage X Y Z P XZ P XY P XZ > P XY

9. Motivation - example R 1 2 NG X Total discard energy = 3 * Reception energy

10. Problem Statement Propose energy-efficient cost metric Simulation based performance comparison with MAODV and ODMRP Comparison of different cost metrics

11. MAODV & ODMRP MAODV properties Tree based On-demand Route request and route reply phase ODMRP properties Mesh based On-demand Many routes to the receivers

12. System Model - Assumptions Unique identification Periodic beaconing Soft-state neighbors Cost metric computation Dynamic transmission range Active mode Single source multicasting

13. Energy Model E Tx = E elec. K + E amp. K. d 2 E Rx = E elec. K E elec = Fixed energy E amp = Amplification energy K = Number of bits d = distance

14. SS-SPST - Algorithm If (root) Dist-to-root = 0 Parent = -1 else Dist-to-root = Shortest distance to root through any neighbor node ‘ i ’ Parent = i

15. R 1 2 NG X SS-SPST An Example

16. R 1 2 NG X Round 1 Round 2 Round 3

17. Motivation - example R 1 2 NG X Total discard energy = 3 * Reception energy

18. Cost metric Hop count C ij = 1 Transmission Energy C ij = T ij Transmission Energy based on farthest node C ij = (T ij + R) if j is the farthest node from i = R otherwise

19. Cost metric Transmission Energy based on farthest node with discard energy C ij = (T ij +R+L i ) if j is the farthest node from i = R otherwise L i = R * (#neighbors i - #tree children i )

20. An Example 0162345 789 120.1 120.02 75.27 75.37 120.36 120.04 120.56 120.06 200.03 120.45120.34 75.48 75.49

21. Hop count metric – SS-SPST Stabilization time = 3 rounds Energy consumed / bit = 5.95 micro J 0162345 789 1 1 1 1 1 1 1 1 1 Round 1 Round 2 Round 3

22. Transmission Energy metric – SS-SPST-T Stabilization time = 4 rounds Energy consumed / bit = 4.72 micro J 0162345 789 1.492 1.49 0.617 1.4909 1.491 4.051 1.5 0.619 0.6199 Round 1 Round 2 Round 3 0.618 Round 4

23. Max Transmission Energy metric – SS-SPST-F Stabilization time = 5 rounds Energy consumed / bit = 3.392 micro J 0162345 789 0.05 0.617 0.05 4.101 1.55 0.05 Round 1 Round 2 Round 3 Round 4 0.05 Round 5 1.542

24. Max Transmission Energy + Discard Energy metric – SS-SPST-E Stabilization time = 5 rounds Energy consumed / bit = 3.29 micro J 0162345 789 0.05 0.657 0.05 4.101 1.55 0.05 Round 1 Round 2 Round 3 Round 4 0.05 Round 5 1.542

25. Summary Metric# roundsEnergy in micro J SS-SPST35.9512 SS-SPST-T44.7279 SS-SPST-F53.3922 SS-SPST-E53.2959

26. Simulation Environment Simulator - NS-2 Simulation area - 750 x 750 Simulation time - 1800 seconds # nodes- 50 Traffic rate – 64 Kbps # group nodes - 20

27. Performance Metrics Packet delivery ratio #pkts received/#pkts transmitted Energy consumed per packet delivered Total energy consumption/pkts received End-to-end delay Total delay per packet/#received nodes Unavailability ratio Service interrupt time/simulation time

28. Energy Spent – Different cost metrics

29. Packet Delivery Ratio – Different cost metrics

30. Unavailability Ratio – Different cost metrics

31. Packet Delivery Ratio – Different protocols

32. Energy Spent – Different protocols

33. Control Byte Overhead – Different protocols

34. Delay – Different protocols

35. Implementation To check the correctness of the protocols Implementation testing with 3 laptops working in ad hoc mode Emulation – mobility, energy and bit error rate

36. Implementation Utility Classes Packet Listener Event Handler SS-SPST Packet Handler SendReceive

37. Conclusion & Future work Energy saving using proposed cost metric Cost of saving energy Nodes operating in sleep mode Testing real implementation with many nodes

38. Questions? Thank you!