1. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 1 Multicast Issues for Multimedia Application 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: 2006-11-10 NameCompayAddressPhoneE-mail Jiyoung HuhLG Electronicsjyhuh@lge.com Yongho SeokLG Electronics Jaeyoung LeeLG Electronics Donghee ShimLG Electronicsdhshim@lge.com

2. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 2 Agenda Overview Issue1 – Reliability Issue2 – Fairness Issue3 – Rate Adaptation Issue4 – Multicast Group Management Conclusion Straw Poll

3. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 3 Overview High quality multimedia is being key application for high data rate 802.11 technology, e.g. 802.11n Use of multicast for various home network environments seems to be one of key applications with high data rate 802.11 Home Server AV Streaming

4. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 4 Issue 1 - Reliability Unreliable Multicast –No ACK mechanism and retransmission mechanism –No mechanism like RTS/CTS to solve the hidden node problem For the use of 802.11 multicast for multimedia data transfer, reliability becomes more important

5. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 5 Issue 2 - Fairness No Backoff procedure –Always fixed contention window size –On each collision Unicast packet: binary exponential back-off Multicast packet: no back-off Contention for a unicast flow and a multicast flow

6. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 6 Issue 3 – Rate Adaptation The lowest PHY data rate –Channel access probability of all hosts is equal –Strong influence of a slow host on overall WLAN performance 1 Mb/s rate A LAN Access Point server B WLAN 802.11b 11 Mb/s rate A Need any PHY rate adaptation mechanism for multicast

7. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 7 Issue 4 – Multicast Group Management No mechanism for multicast group management –No discrimination between Multicast packet and Broadcast packet –Inefficiency of the use of DTIM for all broadcast and multicast packet All STAs shall wake up every DTIM AP TIM DTIM DTIM Count (0) DTIM Period (3) Bitmap Control (Bit 0: 1) Partial Virtual Bitmap DTIM Count (0) DTIM Period (3) Bitmap Control (Bit 0: 1) Partial Virtual Bitmap AP buffers multicast frame for Multicast Group1 AP buffers multicast frame for Multicast Group2

8. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 8 Conclusion IEEE 802.11 is working on high data rate e.g. in TGn. One of killer applications for the use of available high data rate is high quality multimedia, e.g. AV streaming with MEPG 2 In addition to unicast AV streaming, multicast use cases are feasible in Home Network environments However, multicast in 802.11 is not enough as well as have several problems for supporting various user scenarios, especially high quality multimedia use case Currently 802.11 doesn’t have any TG/SG to focus on multicast investigating multicast problems and possible solutions

9. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 9 Straw Poll Require mechanisms that solve the multicast-related problems and new study group to discuss these Good idea: Bad idea:

10. doc.: IEEE 802.11-06/1687 Submission Nov 2006 Jiyoung et al.Slide 10 Reference IEEE Std802.11, 1999 edition (R2003) M. Heusse, F. Rousseau, G. Berger-Sabbatel, and A. Duda, “Performance Anomaly of 802.11b,” in Proc. of IEEE INFOCOM, April 2003