Localized Minimum-energy Broadcasting in Ad-hoc Networks

1. Localized Minimum-energy Broadcasting in Ad-hoc Networks Julien Cartigny, David Simplot and Ivan Stojmenović IEEE INFOCOM 2003 Speaker: Chung-Hsien Hsu Presented at TKU Group Meeting Apr. 15, 2004

2. Outline • Introduction • Preliminaries • Related literature • Localized protocol • RNG Topology Control Protocol • RNG Broadcast Oriented Protocol • Performance Evaluation • Conclusion

3. Introduction • Minimum energy broadcasting problem • Each node can adjust transmission power to minimize total energy consumption. • A message originated from a source node needs to be forwarded to all the other nodes in the network.

4. Introduction • Existing broadcasting protocol • Topology control oriented protocols • To assign the transmission power for each node. • To preserve strong connectivity of the network. • All nodes can be a source of a broadcast. • Using pre-assigned transmission radii at each node to reach all nodes of the network. • Min(-total) assignment problem. • NP-hard for two- and three-dimensional space. • Broadcast oriented protocols • Considering the broadcast process form a given source node. • NP-complete.

5. Introduction • Communication models: • One-to-all • Omnidirectional antennas • Communication zone: disk • One-to-one • Directional antennas • Communication zone: small beam • Variable angular range • Node can choose direction. • Width beam that allows to target several neighbor with one transmission.

6. Preliminaries - Communication Model • Communication Model

7. Preliminaries - Energy Model • Energy Model

8. 900 S D S D S D Preliminaries - Energy Model (c=0, α=2) S D

9. Preliminaries - Energy Model (c=0, α≧2) S D S D

10. Preliminaries – Minimum energy broadcasting • Total power consumption:

11. Related Literature – topology control protocol • “Power consumption in packet radio networks” • Addressed the tree construction in wireless networks. • Globalized protocol. • NP-hard for three-dimensional space. • “The power range assignment problem in radio networks on the plane” • NP-hard for two-dimensional space.

12. Related Literature – topology control protocol • “On the construction of energy-efficient broadcast and multicast trees in wireless networks” • MST Topology Control Protocol (MTCP) • Based on minimum-power spanning tree. • Applying Prim’s algorithm. • Strongly connected (undirected). • Range adjustment:

13. 8 8 7 7 b b c c d d 4 4 9 9 2 2 14 14 11 11 4 4 a a i i e e 7 7 6 6 8 8 10 10 h h g g f f 1 1 2 2 8 8 7 7 b b c c d d 4 4 9 9 2 2 14 14 11 11 4 4 a a i i e e 7 7 6 6 8 8 10 10 h h g g f f 1 1 2 2 Related Literature – Prim’s algorithm

14. Related Literature – topology control protocol • “On the construction of energy-efficient broadcast and multicast trees in wireless networks” • MST Topology Control Protocol (MTCP) • Based on minimum-power spanning tree. • Applying Prim’s algorithm. • Strongly connected (undirected). • Range adjustment:

15. Related Literature – topology control protocol

16. Related Literature – broadcast oriented protocol • Two minimum-energy broadcast problem: • Globalized greedy heuristics. • BLU heuristic (Broadcast Least-Unicast-cost) • Applying the Dijkstra’s algorithm. • BIP (Broadcast Incremental Power) • A modified version of the Prim’s algorithm. • Consider additional cost in order to cover new node.

17. t t t t t t x x x x x x 1 1 1 1 1 1 4 4 4 4 - 4 - 5 5 5 - 5 4 4 4 4 4 4 9 9 9 9 9 9 2 2 2 2 2 2 3 3 3 3 3 3 s s s s s s 4 4 4 4 4 4 6 6 6 6 6 6 0 0 0 0 0 0 7 7 7 7 7 7 8 8 8 8 8 8 6 - 6 6 8 6 - 8 - 9 - 8 2 2 2 2 2 2 y y y y y y z z z z z z Related Literature – Dijkstra’s algorithm

18. Related Literature – broadcast oriented protocol • Two minimum-energy broadcast problem: • Globalized greedy heuristics. • BLU heuristic (Broadcast Least-Unicast-cost) • Applying the Dijkstra’s algorithm. • BIP (Broadcast Incremental Power) • A modified version of the Prim’s algorithm. • Consider additional cost in order to cover new node.

19. Related Literature – broadcast oriented protocol • The “sweep” operation: • To remove some unnecessary transmission.

20. Localized Protocols • Localized Protocol • Communication model: one-to-all • Two protocols • RTCP (RNG Topology Control Protocol) • RBOP (RNG Broadcast Oriented Protocol) • RNG (Relative Neighborhood Graph) • To minimize node degrees, hop-diameter, maximum transmission radius and the number of biconnected components. • Localized protocol

21. Localized Protocols - RTCP • RNS Topology Control Protocol (RTCP) w u v

22. Localized Protocols - RTCP • Range adjustment:

23. Localized Protocols - RTCP • The RNG can be deduced locally by each node by using only the distance with its neighbors. • With position system (GPS) • Need only 1-hop information. • Without position system • Determine distances • Signal strength or time delay information. • Need 2-hop distance information.

24. Localized Protocols - RBOP • RNG Broadcast Oriented Protocol (RBOP) • The adaptation and some improvements of RTCP.

25. Localized Protocols - RBOP

26. Performance Evaluation • Compared four protocols: • MTCP: MST Topology Control Protocol • BIP: Broadcast Incremental Power • RTCP: RNG Topology Control Protocol • RBOP: RNG Broadcast Oriented Protocol • Two energy models: • α= 2, c = 0 • α= 4, c = 108

27. Performance Evaluation • Parameters: • Number of nodes: 100 (static node) • The maximum communication radius: 250 meters • Ideal MAC layer • Density: 6 to 30 nodes per communication zone • 5000 broadcasts have been run for each measure.

28. Performance Evaluation

29. Performance Evaluation

30. Conclusion • Proposed two localized RNG based minimum energy broadcast protocol • RTCP (RNG Topology Control Protocol) • RBOP (RNG Broadcast Oriented Protocol)