1. New Bit-Selection Method Suitable for Adaptive HARQ IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-09/0999 Date Submitted: 2009-04-27 Source: Chiwoo Lim, Seunghoon Choi, Sung-Eun Park, Songnam Hong, Jaeweon Cho, Jaehee Cho, Heewon Kang, Hokyu Choi E-mail: {chiwoo.lim, seunghoon.choi, se.park, sn7955.hong, jaeweon.cho, jaehee1.cho, hkang, choihk} @samsung.com Samsung Electronics, Co., Ltd. 416 Maetan-3, Suwon, 443-770, Korea Venue: Category: AWD comments / Area: Chapter 15.3.12 (Channel coding HARQ-PHY) “Comments on AWD 15.3.12 Channel coding HARQ-PHY” Base Contribution: None Purpose: To be discussed and adopted by TGm for 802.16m amendment 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. Instruction Adaptive HARQ is mandatory in the downlink of IEEE 802.16m. IEEE 802.16e’s bit selection method results in the serious problem in adaptive HARQ It is very hard to get IR gain if the amount of retransmissions is too small compared with that of initial transmission Starting positions should be determined as maximizing IR gain as possible under adaptive HARQ.

3. Proposed Bit Selection The benefits of the design is as follows:  SPID = 0 ensure systematic bits are transmitted  SPID = 1 minimizes the code rate if used in conjunction with SPID = 0  SPID = 2 and SPID = 3 are placed such that 4 SPIDs are equally placed in the buffer to ensure equal opportunity for all coded bits to be transmitted

4. Proposed Bit Selection

5. Simulation Parameters ParametersAssumption Channel codeCTC ModulationQPSK for each transmission HARQ modeAdaptive Channel modelAWGN Code Length480 bits # of coded bits for each transmission960bits Number of retransmission1 SamsungSPID=0 for initial transmission SPID=2 for first retransmission ZTESPID=0 for initial transmission SPID=1 for first retransmission

6. Simulation Result

7. Conclusion We suggest this new bit selection method to be adopted for CTC IR HARQ in 16m.