1. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 1 July 2009 W. Y. Lee et. al Topology Considerations on Contention- based Directional MAC Simulation Date: 2009-07-14 Authors:

2. doc.: IEEE 802.11-09/0797r2 Submission Impact of Topology on Simulation of Contention-based Directional MAC (1/2) Topology and Service Scenario of Directional MAC observes different behaviors in simulation. For example, CRTS and CRCM have been tested under different topology. Slide 2 July 2009 W. Y. Lee et. al Randomly distributed 100 Nodes in 1500x1500m CRTS proposed by T. Korakis, G. Jakllari, and L. Tassiulas, "A MAC protocol for full exploitation of directional antennas in ad-hoc wireless networks," Proc. ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc), pp.98–107, June 2003. CRCM proposed by G Jakllari, J Broustis, T Korakis,S V. Krishnamurthy, and L Tassiulas, "Handling Asymmetry in Gain in Directional Antenna Equipped Ad Hoc Networks," Proc. IEEE 16th International Symposium on PIMRC, pp.1284-1288, 2005 1234 M Takata, M Bandai and T Watanabe, "MAC Protocol with Directional Antennas for Deafness Avoidance in Ad Hoc Networks," Proc. IEEE Goblecom 2007, pp.620-625, 2007

3. doc.: IEEE 802.11-09/0797r2 Submission Impact of Topology on Simulation of Contention-based Directional MAC (1/2) We observe the throughput performance of the two is reversed with different topology => Hence, a standardized approach is necessary. Slide 3 July 2009 W. Y. Lee et. al CRCM CRTS

4. doc.: IEEE 802.11-09/0797r2 Submission Three Performance Indices need to be analyzed Deafness problem (e.g., deafness ratio) Hidden node problem (e.g., failure rate due to hidden nodes) Spatial reuse Slide 4 July 2009 W. Y. Lee et. al

5. doc.: IEEE 802.11-09/0797r2 Submission Deafness Problem Definition: deafness occurs if a device does not answer an RTS message addressed to it. Consequences: originator of the RTS will try more RTSs while increasing contention window, during which messages toward other devices are subject to be blocked. Two examples

6. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 6 July 2009 W. Y. Lee et. al Deafness Example #1 X 1 2 4 3 B 1 2 4 3 A 1 2 4 3 Assume 3 nodes.

7. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 7 July 2009 W. Y. Lee et. al Deafness Example #1 X 1 2 4 3 B 1 2 4 3 A 1 2 4 3 DRTS Node A has a data to send B. A sends DRTS.

8. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 8 July 2009 W. Y. Lee et. al Deafness Example #1 X 1 2 4 3 B 1 2 4 3 A 1 2 4 3 DCTS Node B responds with DCTS.

9. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 9 July 2009 W. Y. Lee et. al Deafness Example #1 X 1 2 4 3 B 1 2 4 3 A 1 2 4 3 In Communication Other beams except one in communication are blocked.

10. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 10 July 2009 W. Y. Lee et. al Deafness Example #1 X 1 2 4 3 B 1 2 4 3 A 1 2 4 3 DRTS Deafness Now, node X has a data to send A, it will send DRTS to A. (node A is deaf now.)

11. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 11 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 Four nodes. Now, node S has a data to send D.

12. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 12 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 DRTS Four nodes. Now, node S has a data to send D.

13. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 13 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 DRTS Nodes A and B overhear the DRTS from S. Nodes A and B block their beams 3 and 4, respectively.

14. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 14 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 DCTS Node D responds with DCTS. Node B overhears the DCTS and blocks beam 2.

15. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 15 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 In Communication Nodes S and D are in communication.

16. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 16 July 2009 W. Y. Lee et. al Deafness Example #2 A 1 2 4 3 B 1 2 4 3 S 1 2 4 3 D 1 2 4 3 DCTS DRTS Deafness Now, B has a data to A, so it sends DRTS to A. But, node A’s beam 3 is blocked (Another deafness problem).

17. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 17 July 2009 W. Y. Lee et. al Hidden Terminal

18. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Problem Definition: hidden terminal problem occurs if another device interfere on-going communication by causing collision. Consequences: throughput of on-going communication is degraded. Two examples

19. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Assume nodes sense carrier omni-directionally. DCBA Sensing Range Slide 19W. Y. Lee et. al

20. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Now, node B has a data to A DCBA Slide 20W. Y. Lee et. al

21. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Node B has a data to A DCBA DRTS Slide 21W. Y. Lee et. al

22. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Node B changes it receiving antenna mode to directional one. DCBA Slide 22W. Y. Lee et. al

23. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Node A sends back to B with DCTS. DCBA DCTS Slide 23W. Y. Lee et. al

24. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Node A turns its receiving antenna mode to directional one, and communication is going on. DCBA In Communication Slide 24W. Y. Lee et. al

25. doc.: IEEE 802.11-09/0797r2 Submission Hidden Terminal Example #1 Now, node D has a data to send C. But, D’s RTS accidentally reaches to node A’s receiving range due to some channel conditions. DCBA In Communication Collision Slide 25W. Y. Lee et. al

26. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 26 July 2009 W. Y. Lee et. al Hidden Terminal Example #2 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 S 1 2 4 3 4 nodes Node A has a data to B.

27. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 27 July 2009 W. Y. Lee et. al A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 DRTS S 1 2 4 3 Hidden Terminal Example #2 Node A sends DRTS to B.

28. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 28 July 2009 W. Y. Lee et. al A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 DCTS S 1 2 4 3 Hidden Terminal Example #2 Node B responds with DCTS.

29. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 29 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 In Communication Hidden Terminal Example #2 Nodes A and B are in communication.

30. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 30 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 In Communication DRTS Hidden Terminal Example #2 Now, node S has a data to send D, so it sends DRTS to D.

31. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 31 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 In Communication DCTS Hidden Terminal Example #2 Node D responds with DCTS.

32. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 32 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 In Communication Hidden Terminal Example #2 Nodes S and D are in communication.

33. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 33 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 Communication completed In Communication Hidden Terminal Example #2 Further, nodes A and B complete their communication.

34. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 34 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 Now, A has a data to D In Communication Hidden Terminal Example #2 Again, node A has a data to D.

35. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 35 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 DRTS In Communication Hidden Terminal Example #2 Node A sends DRTS to D since A did not hear previous DRTS from S nor DCTS from D.

36. doc.: IEEE 802.11-09/0797r2 Submission Collision Slide 36 July 2009 W. Y. Lee et. al S 1 2 4 3 A 1 2 4 3 B 1 2 4 3 D 1 2 4 3 DRTS In Communication Hidden Terminal Example #2 Collision due to unheard RTS/CTS.

37. doc.: IEEE 802.11-09/0797r2 Submission Spatial Reuse Benefit from directivity of directional antennas. Two examples

38. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 38 July 2009 W. Y. Lee et. al Spatial Reuse B 1 2 4 3 A 1 2 4 3 C 1 2 4 3 E 1 2 4 3 D 1 2 4 3 F 1 2 4 3

39. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 39 July 2009 W. Y. Lee et. al Spatial Reuse A 1 2 4 3 S 1 2 4 3 B 1 2 4 3 D 1 2 4 3

40. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 40 July 2009 W. Y. Lee et. al An Example of Topology in Simulation

41. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) July 2009 W. Y. Lee et. alSlide 41 Deafness Example#1

42. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) July 2009 W. Y. Lee et. alSlide 42 Antenna blocked Deafness Example #2

43. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) July 2009 W. Y. Lee et. alSlide 43 Hidden Terminal Problem Example#1

44. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) July 2009 W. Y. Lee et. alSlide 44 Hidden terminal example #2 Communication Completed

45. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) July 2009 W. Y. Lee et. alSlide 45 Spatial reuse

46. doc.: IEEE 802.11-09/0797r2 Submission Scenarios (Conference Room) Slide 46 July 2009 W. Y. Lee et. al

47. doc.: IEEE 802.11-09/0797r2 SubmissionSlide 47 July 2009 W. Y. Lee et. al References [1] R. R. Choudhury, X. Yang, R. Ramanathan and NH Vaidya, “On designing MAC protocols for wireless networks using directional antennas,” IEEE Trans. Mobile Computing, Volume 5, Issue 5, May 2006, pp.477 – 491 [2] R.R. Choudhury, X. Yang, N.H. Vaidya, and R. Ramanathan, “Using Directional Antennas for Medium Access Control in Ad Hoc Networks,” Proc. ACM MobiCom, June 2002 [3] M. Takata, M. Bandai and T. Watanabe, "MAC Protocol with Directional Antennas for Deafness Avoidance in Ad Hoc Networks," Proc. IEEE GLOBECOM, pp.620- 625, 2007 [4] G. Jakllari, J. Broustis, T. Korakis,S V. Krishnamurthy, and L. Tassiulas, "Handling Asymmetry in Gain in Directional Antenna Equipped Ad Hoc Networks," Proc. IEEE 16th International Symposium on PIMRC, pp.1284-1288 [5] T. Korakis, G. Jakllari, and L. Tassiulas, "A MAC protocol for full exploitation of directional antennas in ad-hoc wireless networks," Proc. ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc), pp.98–107, June 2003.