1. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Leader based Multicast Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfstuart.kerry@philips.compatcom@ieee.org Date: 2007-1-18

2. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Abstract This document describes an example of leader-based multicast mechanism. First, we introduce the problems of the current 802.11 multicast mechanism. Second, we describe a specific leader-based multicast mechanism Third, we evaluate its benefits with experimental results. At the end of the presentation, there will be a motion to include normative text of this proposal in 802.11v draft.

3. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Introduction Increasing quantity of WiFi enabled portable devices Growing availability of multimedia streaming Increasing WiFi coverage on public places The best option: Multicast

4. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Problem Current implementation of Multicast: Open Loop Transmission -No CW adaptation -No rate adaptation -No retransmission Multicast transmission starts

5. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Proposed solution Leader-based Multicast: [Kuri and Kasera] -Choose one receiver as the Leader -Send back ACK to the AP STA3 STA5[Leader] STA4 STA2 STA1 ACK

6. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Proposed solution Leader Election Protocol -Leader is elected using three Action frames Leader Selection Algorithm -It is possible to utilize IEEE 802.11v multicast diagnostic capability -E.g.: The station with the highest PER may be selected as the Leader of the group (a) Leader Request Action(b) Leader Response Action(b) Leader Release Action New LeaderOld LeaderNew LeaderOld LeaderNew LeaderOld Leader

7. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Experimentation: Platform 5 Probes for data acquisition and traffic generation 1 Software-based Access Point Uniform Wireless Hardware (Atheros-based Proxim cards) Wireless Probe

8. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Experimentation: Controlled conditions 4 Experiments: 5 tests of 5 minutes of VBR video streaming Legacy Multicast without background traffic Legacy Multicast with TCP background traffic Leader based without background traffic. Leader based with TCP background traffic

9. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Results Video Goodput for both mechanisms Leader based Legacy Multicast

10. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Conclusion Leader based solution: -Better throughput than Legacy multicast -Can follow the VBR test video requirements -Increases throughput with retransmissions on a loaded network -Low complexity to be implemented -Compatible with legacy 802.11 station

11. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK Motion Move to include normative text in document 11-07- 0144-02-000v-normative-text-leader-based- multicast.doc into the TGv draft. Mover: Seconder: Result:

12. doc.: IEEE 802.11-07/0115r1 Submission Jan 2007 Yongho SEOK References J. Kuri and S.K. Kasera, “ Reliable Multicast in Multi-access Wireless LANs, ” ACM Wireless Networks, 2001. D. Dujovne and T. Turletti, “ Multicast in 802.11 WLANs: An Experimental Study, ” in ACM MSWiM 2006. J. Villalon, P. Cuenca, L. Orozco-Barbosa, Y. Seok and T. Turletti, “ Cross-Layer Architecture for Adaptive Video Multicast Streaming over Multirate Wireless LANs, ” to appear in JSAC, 2007. Y. Seok and T. Turletti, “ Practical Rate-Adaptive Multicast Schemes for Multimedia over IEEE 802.11 WLANs, ” INRIA Report, http://hal.inria.fr/inria-00104699.http://hal.inria.fr/inria-00104699 *the one from MSWiM where the figures are from