1. Notice: This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who 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 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and. Further information is located at and. IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-08/1022r1 Date Submitted: 2008-09-09 Source:Kelvin ChouKelvin.Chou@mediatek.com Yih-Shen ChenYihshen.Chen@mediatek.com I-Kang FuIK.Fu@mediatek.com Paul ChengPaul.Cheng@mediatek.com MediaTek Inc. No.1, Dusing Rd. 1, Hsinchu Science-Based Industrial Park, Hsinchu, Taiwan 300, R.O.C. Venue:MAC: Enhanced MBS; in response to the TGm Call for Contributions and Comments 802.16m-08/033 for Session 57 Base Contribution: This is the base contribution Purpose: To be discussed and adopted by TGm for the 802.16m SDD Enhanced MBS for IEEE 802.16m

2. 2 16e MBS Spectrum efficiency vs. Reliability MCS of MBS burst shall accommodate the MS with the weakest link Lack of feedback for MCS channel condition Lack of dynamic MCS adjustment mechanism For unicast service, adaptive modulation and coding can be used for different users to maximize the spectrum efficiency For MBS, the modulation and coding scheme shall accommodate the user with the weakest link. Therefore, spectrum efficiency is sacrificed for reliability and MBS coverage.

3. 3 MBS with Dynamic MCS BSs provide common feedback channel for subscriber MSs Enable dynamic MCS Enable dynamic HARQ parameters for time-diversity-enabled MBS Retransmission only when necessary Retransmission may not be helpful for delay-sensitive applications Example: Dynamic MCS adjustment according to the accumulated feedback measured per Superframe

4. 4 Example of Using Dynamic MCS Multi-layer coded video streaming QPSK MBS zone for base-layer data streaming Dynamic MCS MBS zone for enhanced-layer data streaming

5. 5 SDD Text Proposal Add the following text into Session 15 of the SDD (IEEE 802.16m-08/003r4) ----------------------- text begin ----------------------------------------------------------------------------- 10.15 Support for Enhanced Multicast Broadcast Service 10.15.x EMBS with dynamic MCS The BSs in an MBS zone may provide a common feedback channel to accumulate MBS feedback from subscriber MSs. The BSs in the MBS zone may perform dynamic MCS on the MBS channels according to the accumulated feedback. The selected MCS should be identical among BSs of the same MBS zone. ----------------------- text end -------------------------------------------------------------------------------