1. Guinian Feng, Pingyi Fan Dept. of Electronic Engineerin Tsinghua University Beijing, China Soung Chang Liew Dept. of Information Engineering Chinese University of Hong Kong Hong Kong, China IEEE ICC 2008

2. outline Introduction Network graph model and notation Interference condition and definition The MIA algorithm Evaluation of MIA performance Conclusion

3. Introduction Ad hoc network The battery life of nodes is limited Energy is a precious resource To conserve energy To investigate minimizing mutual interference Topology control has been proposed to reduce transmit powers

4. Network graph model and notation n nodes randomly and uniformly distributed G=(V, E), |V|=n, |E|=m All node The same maximum transmission power P max The same maximum transmission range r max The same received power threshold P th

5. Network graph model and notation a → b:the directional link from node a to node b d ab : the distance between a and b p a → b =f ‧ p a /d ab α e i =(u i,v i ), i=1,2,…,m : the ith edge in the graph

6. Interference condition-(1) Consider simultaneous transmissions on two directional links a → b and c → d No collision at receiver b uiui vivi ujuj vjvj

7. Interference condition-(2) The minimum-power strategy

8. Interference condition-(3) The equal-power power strategy

9. Interference definition-(1) The distance d ij between two edges e i =(u i,v i ) and e j =(u j,v j )

10. Interference definition-(2) Consider e i =(u i,v i ) The area around e i is divided into three regions uiui vivi c

11. Interference definition-(2) Consider e i =(u i,v i ) The area around e i is divided into three regions uiui vivi c

12. Interference definition-(2) Consider e i =(u i,v i ) The area around e i is divided into three regions uiui vivi c

13. Interference definition-(2) I h (e i ) : the interference coefficient of node h with respect to e i q h : the number of edges having an interference relationship with e i among the p h p h : the number of edges incident to node h

14. Interference definition-(3) The mean partial interference coefficient K(e i ) of e i

15. Interference definition-(4) The interference of e i

16. Interference definition-(5) The network interference of G=(V, E)

17. The MIA algorithm

18. It aims at reducing energy cost while maintaining network connectivity a b c

19. Evaluation of MIA performance

22. Conclusion To considered one such particular algorithm Minimum Interference Algorithm(MIA) Conserving energy Maintaining good spanner property

23. Conclusion To establish the “pair-wise” interference condition between two links To consider the interference of a link with respect to all its surrounding links

24. Conclusion Have tackled the topology control problem with the goal of minimizing network interference To establish the “pair-wise” interference condition between two links To consider the interference of a link with respect to all its surrounding links

25. uiui vivi ujuj vjvj uiui vivi ujuj vjvj

26. Interference definition-(2) Consider e i =(u i,v i ) The area around e i is divided into three regions uiui vivi

27. The value of K