1. Power-Balance Broadcast in Wireless Mobile Ad Hoc Networks Jang-Ping Sheu, Yu-Chia Chang, and Hsiu- Ping Tsai National Central University, Chung-Li, 32054,Taiwan Speaker ： Hsu-Jui Chang

2. Outline Introduction Related work Power-Balance Broadcast Algorithm  Algorithm 1  Algorithm 2 Simulation Conclusion

3. Introduction Broadcast  Support network routing protocol Two characteristics of broadcast problem  Spontaneous  Unreliable

4. Introduction Flooding problem  Redundancy 、 Contention 、 Collision Battery exhaustion Reduce the network lifetime Reduce redundant rebroadcast and solve the rebroadcast storm problem  Sender-based mechanism  Receiver-based mechanism

5. Related work [7] S.-Y. Ni, Y.-C. Tseng, Y.-S. Chen, and J. P. Sheu, ”The Broadcast Storm Problem in a Wireless Mobile Ad Hoc Network,” in Proceedings of the International Conference on Mobile Computing and Networking, pp. 151-162, Aug. 1999.  Probabilistic scheme The host will rebroadcast with a probability  Counter-based scheme Use counter C to keep track of number of times that the broadcast message is received C ≧ C-threshold, the rebroadcast is inhibited

6. Power-Balance Broadcast Algorithm Each host determines a rebroadcast probability  Its remaining energy  Number of neighbors  Average remaining energy of its neighbors Goal  Balance the residual battery energy of hosts  Prolong the network lifetime

7. Power-Balance Broadcast Algorithm

8. RE(i) > 70%, P i = 0.9 70% ≧ RE(i) > 40%, P i = 0.7 RE(i) ≦ 40%, P i = 0.5

9. Power-Balance Broadcast Algorithm The main goal  Balance the remaining battery energy of hosts  Keep high reachability

10. Power-Balance Broadcast Algorithm The rebroadcast probability of a host is high and its neighbors have higher remaining energy  High reachability  Broadcast storm problem and waste much energy

11. Power-Balance Broadcast Algorithm

12. The higher value of N_threshold is, the bigger chance of a host keeping the high rebroadcast probability is The value of N_threshold is set to 4

13. Power-Balance Broadcast Algorithm Definition  P i ： rebroadcast probability of host i  RE(i) ： the remaining energy of host i  Avg_NE(i) ： the average remaining energy of the neighbors of host i  Neighbor_No(i) ： the number of neighbors of host i

14. Power-Balance Broadcast Algorithm -Algorithm 1 First  Each host periodically collects the remaining energy of its neighbors Second  Determine the rebroadcast probability of each host

15. Power-Balance Broadcast Algorithm -Algorithm 1 Initial:  RE(i) > 70%, P i = 0.9  70% ≧ RE(i) > 40%, P i = 0.7  RE(i) ≦ 40%, P i = 0.5

16. Power-Balance Broadcast Algorithm -Algorithm 1 Step1:  Case 1: Avg_NE(i) ≦ 40% RE(i) > 70%, assign P i = 0.9 70% ≧ RE(i) > 40%, assign P i = 0.8 RE(i) ≦ 40%, assign P i = 0.7  Case 2: 40% < Avg_NE(i) ≦ 70% Keep Pi as the initial assigned rule  Case 3: Avg_NE(i) > 70% Neighbor_No(i) < N_threshold, P i is held as before. Neighbor_No(i) ≧ N_threshold, assign P i = P i *(3/Neighbor_No) 0.5

17. Power-Balance Broadcast Algorithm -Algorithm 1 Step2:  Generate a random number RN over [0, 1] RN ≦ P i, rebroadcast the received message Otherwise, drop it.

18. Power-Balance Broadcast Algorithm -Algorithm 2 Problem  Receive the same packets k times Algorithm 2  Combines the idea of Algorithm 1 Counter-based scheme  Goal Save the number of redundant rebroadcast

19. Power-Balance Broadcast Algorithm -Algorithm 2 Initial  The rebroadcast probability P i is calculated based on Algorithm 1

20. Power-Balance Broadcast Algorithm -Algorithm 2 Step 1:  Receive a broadcast message M in the first time go to Step 2  Otherwise, the host is inhibited from rebroadcasting M Step 2:  Generate a random number RN over [0, 1] RN ≦ P i, go to Step 3 otherwise drop the message Step 3:  The host will not rebroadcast M if Rec_No(i) > 3  Otherwise, rebroadcast the message

21. Simulation Use Glomosim 2.03 Environment  1000m x 1000m  Random way-point movement model  Transmission radius ： 250m  Transmission rate ： 11M bits/sec  Broadcast packet size ： 280 bytes  The maximum speed of a host is 5 m/sec  Pause time is 30 seconds  Transmission power is 3.63W  Receiving power is 2.54W  Each host broadcasts a 64 bytes beacon in every10 seconds

22. Simulation -Reachability

23. Simulation -Lifetime

25. Simulation -Saved Rebroadcast Ratio

27. Simulation -The standard deviation of remaining battery energy

28. Conclusion Propose two power-balance broadcast algorithms in wireless networks to extend the network lifetime Determine the rebroadcast probability  Remaining energy information  Network density Advantage  Balance the battery energy of hosts  Extend the network lifetime without scanting the reachability  Suit in the environment of high mobility and density