1. Proposed text on section 15.3.5.2.1 subband partitioning of 802.16m Amendment Document Number: IEEE C802.16m-09/0316r3 Date Submitted: 2009-01-07 Source: HanGyu Cho, Seunghyun Kang, Jinsoo Choi, Jin Sam Kwak Email: {hgcho, samji} @lge.com LG Electronics Taeyoung Kim, Jeongho Park, Jaeweon Cho, Heewon Kang Samsung Electronics Xin Qi, Shaohua Li, Chao Wei Nokia Siemens Networks Venue: IEEE C802.16m-08/053 “Call for Comments and Contributions on Project 802.16m Amendment Working Document ” Purpose: To provide details on subband partitioning to be approved by TGm and adopted in the Amendment Working Document 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 located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat

2. Motivation In the current IEEE 802.16m Amendment Working Document (IEEE 802.16m-08/050), the subband partitioning rule in the section 15.3.5.2.1 are TBD In the document C80216m-08_1508r1, there are many subband partitioning rules proposed by many companies This contribution reviews those subband partitioning rules and proposes one.

3. Subband partitioning To assign K SB subbands as PRU SB and K MB subbands as PRU MB

4. The issue is Is there any reason why we break the subband alignment when performing the subband partitioning? Our answer is “ No ” because Regarding CQI feedback, keeping the subband alignment is efficient Keeping the subband alignment is simple and intuitional

5. The issue is Is shortage of frequency diversity for distributed LRU critical when keeping the subband alignment? Our answer is “ No ” because Usually, K SB <=N sub /2, then, shortage of frequency diversity does not occur The shortage of frequency diversity of distributed LRU might occur only when the number of reserved subbands K SB is very large (i.e., the number of remaining subbands is very small) This case is very scarce Even if K SB is very large, some subbands out of the K SB reserved subbands can be used for DRU, so, the frequency diversity order of distributed LRU will increase Any company hasn ’ t shown the results that performance is reduced when keeping the subband alignment Based on the contribution IEEE C802.16m-09/0251proposed by Intel, we don’t see any performance shortage when keepting the subband alignment (Opositely, the case when keeping the subband alignment ourperforms the case when breaking the subband alighment)

6. Consideration on the corner case Refer to the excel file The corner case is only when selecting (N SB -1) subbands among total N SB subbands Firstly, this case is very scarce In reality, the only corner case is for 5MHz Even for the corner case, there might be no problem because Some subbands can be used for DRU, which increases the diversity order of DRU The remaining subband can be allocated to CRU, not DRU BS can handle the corner case by scheduling such that it does not happen

7. Consideration on signaling overhead and etc. In terms of signaling overhead, we don’t think there is difference between two cases Which signaling overhead? Since the size of SAC is designed for the largest BW 20MHz, we don’t need any change or restriction when considering the corner case Compared to the disadvantage (the corner case) of when keeping the subband alignment, the disadvantage (scheduling gain reduction) of when breaking the subband alignment can happen more frequently

8. Current status on subband partitioning There are four subband partitioning rules keeping the subband alignment proposed by companies Based on simulations, we found that Intel, LGE, and, ZTE ’ s rules show exactly the same subband partitioning even if their equations are different Samsung ’ s rule does not seem different technically

9. Conclusions Subband alignment should be kept when performing subband partitioning Three rules proposed by LGE, Intel, and ZTE are exactly the same and also technically similar with Samsung ’ s one We suggest to adopt the LGE ’ s equations proposed in C80216m-08_1508r1

10. Proposed Text on subband partitioning Adopt the following equation for PRU to PRU SB mapping in page 24 of IEEE 802.16m-08/050 where where GCD(x, y) is the greatest common divisor of x and y. Adopt the following equation for PRU to PRU MB mapping in page 24 of IEEE 802.16m-08/050 where