Clarification on ACK of Bandwidth Request IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-09/0180r4 Date Submitted: 2009-1-15 Source: Gang Shen, Kaibin Zhang, Jimin Liu, Xiaobing Leng E-mail: gang.a.shen@alcatel-sbell.com.cn Alcatel Shanghai Bell Kelvin Chou, Yih-Shen Chen, I-Kang Fu, Paul Cheng Email: kelvin.chou@mediatek.com MediaTek Heejeong Cho, Jinyoung Chun, Sukwoo Lee, Kiseon Ryu E-mail: hj77cho@lge.com LG Electronics Venue: Re: Call for Comments on Project 802.16m System Description Document (SDD) Base Contribution: N/A Purpose: To be discussed and adopted by TGm for the 802.16m SDD 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: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.

Acknowledgement of bandwidth request in 16m SDD 16m SDD allows acknowledgement of the reception of bandwidth request In SDD it states “In step 2 and step 4, ABS may send message to acknowledge the reception Status” (line 20 of page 110) Acknowledge of BR enables MS to restart BR to recover quickly from a BR failure However, it is not necessary for ABS to response every BR with ACK considering the extra overhead

ACK of Bandwidth Request It is also not necessary for extra ACK together with UL grant in Step 2 and Step 4 If AMS receives the UL grant, thus it knows ABS has correctly received the BR. So extra ACK together with UL grant is not necessary ACK should follow the procedure step 1 or step 3 to let AMS be informed early If ABS allocates UL grant immediately, it is not necessary to send ACK of BR The ABS should respond by the acknowledgement only when needed ACK is useful when BS receives BR indicator (step 1) but can not respond by UL grant for BW REQ message immediately when BS receives BW REQ (step 3) but can not allocate the bandwidth request immediately

AMS Activities SDD has not mentioned AMS activities to restart BR AMS should restart the BR retransmission quickly If AMS does not receive UL grant or ACK within a pre-defined period (e.g. next frame), it then restarts the bandwidth request

Suggested Remedy [Change the following texts in line 20 of page 110 as indicated]