1. Quorum-based Power-Saving Multicast Protocols in the Asynchronous Ad Hoc Network Yu-Chen Kuo Department of Computer Science and Information Management Soochow University Computer Networks, vol. 54, no. 11, August 2010, pp. 1911-1922

2. Outline Introduction Quorum concept Asynchronous multicast problem Quorum-based asynchronous power-saving protocols –Rotation m-closure property –Uniform k-arbiter quorum systems –CRT quorum systems Performance evaluation Conclusion

3. Introduction IEEE 802.11 wireless hosts –batteries to supply their limited power Critical issue –How to extend the lifetime of wireless hosts

4. Introduction IEEE 802.11 defines the power-saving (PS) mode for wireless hosts to reduce the usage of radio activity. –ATIM = Announcement Traffic Indication Map Station ATIM Window Beacon Interval 0 PS Mode Beacon DATA Window ATIM Window Beacon Interval 1 Active Mode Beacon DATA Window … ATIM Window Beacon Interval k Active Mode Beacon DATA Window Station A ATIM Window Beacon Interval Active Mode ATIM DATA Window Station B ACK Active Mode

5. Quorum Concept Quorum-based Power Saving protocols have been proposed for IEEE 802.11 ad hoc networks –increase energy efficiency –prolong the operational time of mobile stations Quorum Systems –Random selection –Intersection

6. Quorum systems –Random selection –Intersection Quorum Concept 123 456 789 123 456 789 Host A ATIM Window Beacon Intervals 3 and 4 Active Mode ATIM DATA Window Host B ACK Active Mode Host AHost B Quorum Interval (A): 1, 2, 3, 4, 7 Quorum Interval (B): 3, 4, 5, 6, 9 A B 234567891 Grid Quorum Systems

7. Quorum Concept Q1Q1 Q2Q2 Q3Q3 Q4Q4 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Q5Q5 Q6Q6 Q7Q7 Q8Q8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Cyclic Quorum Systems

8. Quorum Concept Cyclic Quorum Systems –Random selection –Intersection –Q 1 = {1, 2, 3}, Q 7 = {1, 7, 8}, Q 8 = {1, 2, 8} Q1Q1 1 2 3 4 5 6 7 8 Q7Q7 Q8Q8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

9. Asynchronous Multicast Problem However, how to apply the quorum-based power-saving protocol for –Asynchronous networks –Multicast Quorum systems U={0, 1, 2, 3} C={{0,1}, {0,2}, {0,3}} Q 1 ={0,2}, Q 2 ={0,1}, Q 3 ={0,3} Clock drift r 3 = 3

10. Asynchronous Multicast Problem However, how to apply the quorum-based power-saving protocol for –Asynchronous networks –Multicast B C D A B C D A t B CD

11. However, how to apply the quorum-based power-saving protocol for –Asynchronous networks –Multicast Asynchronous Multicast Problem Possible Solution: Busy Waiting Sender

12. Asynchronous Multicast Problem However, how to apply the quorum-based power-saving protocol for –Asynchronous networks –Multicast Possible Solution: Busy Waiting Sender

13. Goals To design quorum-based power-saving multicast protocols in the asynchronous –Quorum systems –Asynchronous –Multicast

14. Rotation m-Closure Property Quorum system C under U={0, 1, 2, …, N-1} Quorums Q  C Clock drift r Quorum systems U={0, 1, 2, 3} C={{0,1}, {0,2}, {0,3}} Q 1 ={0,2}, Q 2 ={0,1}, Q 3 ={0,3} Clock drift r 3 = 3

15. Rotation m-Closure Property Intersection Property Quorum systems U={0, 1, 2, 3} C={{0,1}, {0,2}, {0,3}} Q 1 ={0,2}, Q 2 ={0,1}, Q 3 ={0,3} Clock drift r 3 = 3

16. Rotation m-Closure Property Rotation Closure Property  

17. Rotation m-Closure Property To multicast for m hosts at the same time  

18. Uniform k-arbiter Quorum Systems Quorum system C under U={0, 1, 2, …, N-1} Quorums Q  C Clock drift r Uniform k-arbiter:

19. Uniform k-arbiter Quorum Systems, k: number of multicast members, N=|U| Quorum systems U ={0, 1, 2, 3, 4, 5, 6, 7, 8} Q 1 ={0, 1, 2, 4, 5, 7, 8} Q 2 ={0, 2, 3, 5, 6, 7, 8} Q 3 ={0, 1, 2, 3, 4, 5, 6} Clock drift r 2 = 1 Clock drift r 3 = 8 123456789 H1H1 H2H2 H3H3 Sender 1

20. Compare with Busy waiting Uniform k-arbiter Busy waiting

21. CRT Quorum Systems Chinese Reminder Theorem p i = wakeup frequency f i for host H i H 1 : p 1 =5, r 1 =0 H 2 : p 2 =3, r 2 =1 H 3 : p 3 =2, r 3 =8 H 1 ={0(+5) 5(+5)10(+5) } H 2 ={1(+3) 4(+3) 7(+3)10(+3)} H 3 ={8(+2) 10(+2) }

22. Performance Evaluation Simulator: NS2 –100 hosts in 200m*200m –Transmission range: 250m –Transmission rate: 2 Mbps –Battery power: 1000 J

23. Performance Evaluation

32. Conclusion This paper proposes a quorum-based power saving protocols –Asynchronous networks –For multicast TheEND Thanks for your attention !