1. Proposal for differentiating bandwidth request based on Proposal for differentiating bandwidth request based in service class and retry attempts Document Number: IEEE S802.16m-09/1321r5 Date Submitted: 2009-07-14 Source: Abhay Karandikar E-mail : karandi@ieee.org B. Srinadh Prateek Kapadia Harshad Maral Telecom Center of Excellence, Indian Institute of Technology (Bombay) Kiran Kuchi J. Klutto MillethCeWiT Shatidev Mohanty Yang XiangyingIntel Ming-Hung TaoITRI Yih-Shen Chen MediaTek Re:Call for Comments on IEEE 802.16m-09/0010r2 IEEE 802.16m Amendment text/Area: Chapter 15.2.11.1.1. (Bandwidth Request) Purpose: To provide the details of the C802.16m-09/1321 : Proposal for differentiating bandwidth request based on service class and retry attempts 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.http://standards.ieee.org/guides/bylaws/sect6-7.html#6http://standards.ieee.org/guides/opman/sect6.html#6.3 Further information is located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat

2. Differentiation & Prioritization in Contention-based Random Access for Bandwidth Request (BR) Our proposal: Method for Differentiation & Prioritization in Content-based BR Present status of standardization: –Sections: AWD 80216m-09_0010r2 Section 15.2.2 Bandwidth Request Procedure AWD 80216m-09_0010r2 Section 15.2.11.1.1 Contention-based random access bandwidth request AWD 80216m-09_0010r2 Section 15.3.9.2.5 Bandwidth request channel –Need for Differentiation by Service Class & Priority is identified, but Method for Differentiation & Prioritization is TBD

3. Goals for BR Contention Differentiation & Prioritization Lower UL Grant Delay ==>> Smaller Contention Window sizes for Flows on Higher Service Class Lower Average UL Grant Delay ==>> Smaller Contention Window sizes for Flows with more BR retry attempts Values for Contention Window need to be varied depending on Load – More Load ==>> Higher window sizes reduce Contention – Less Load ==>> Lower window sizes reduce UL Grant Delay

4. Key Elements of Proposal Define Connection Priority (CP) for each contending Service Flow CP is a function of Service Class & Number of Retries (BR collisions) so far CP initialization parameters sent on DSA-REQ or DSC-REQ CP parameters:  Service Class  Initial / Maximum Window Size  Window Scaling Factor

5. Example 1: Truncated Binary Exponential Backoff Service Class0 (High)123 (Low) Initial Window1244 Max Window16128256512 Scaling Factor2222 Window Size (Retry #1)2488 Window Size (Retry #2)4816 Window Size (Retry #4)163264 Window Size (Retry #8)16128256 Window Size (Retry #12)16128256512 Window Size (Retry #16)16128256512

6. Example 2: No Backoff with Priority Service Class0 (High)123 (Low) Initial Window16244864 Max Window16244864 Scaling Factor1111 Window Size (Retry #1)16244864 Window Size (Retry #2)16244864 Window Size (Retry #4)16244864 Window Size (Retry #8)16244864 Window Size (Retry #12)16244864 Window Size (Retry #16)16244864

7. Connection Priority Data in DSx-REQ Service Class: 4 bit Initial Window Size: 8 bit Maximum Window Size: 11 bit Window Scaling Factor: 4 bit

8. ---------------------------------Start of the Text (page 64 line 38)------------------------------------- 15.2.11.1.1 Contention-based random access bandwidth request AMS considers the BR was failed and may restart the BR procedure upon one of the following conditions: 1)received a Negative-ACK; or 2)the BR timer expires. When AMS restarts BR procedure, the AMS shall randomly select a number within its backoff window specified by the connection priority. This random value indicates the number of contention transmission opportunities that the AMS shall defer before transmitting. The connection priority is defined by the tuple of contention window parameters and the number of retries. The ABS transmits initial connection priority parameters - initial and maximum window sizes and backoff window scaling factor - in DSx-REQ and/or DSx-RSP messages. Corresponding DSx-REQ and DSx-RSP message parameters: Connection priority/Service class: TBD bits, Initial window size: TBD bits, Maximum window size: TBD bits, Contention window scaling factor: TBD bits