Evaluation and Proposed Text on UL Tile Permutation Document Number: IEEE C80216m-09_0628r3 Date Submitted: 2009-03-10 Source: HanGyu Cho, Seunghyun Kang, Jong Young Han, Sunam Kim, Email: {hgcho @lge.com} Jin Sam Kwak LG Electronics Yanfeng Guan ZTE Corporation Shaohua Li, Xin Qi Nokia Siemens Networks Yu-Tao Hsieh ITRI Luciano Sarperi Fujitsu Venue: “802.16m AWD”: IEEE 802.16m-09/0012. ”Call for Contribution on Project 802.16m Amendment Working Document (AWD) Content” Target topic: Call for Comments on Amendment Working Document Purpose: To provide proposed text on DL subcarrier permutation 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: <http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>. Further information located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.

Motivation In the current IEEE 802.16m Amendment Working Document (IEEE 802.16m-09/0010), the UL tile permutation formula in the section 15.3.8.3.3 is TBD So far, there have been many tile permutation formulas proposed by each company This contribution reviews those rules and suggests a UL tile permutation formula based on simulation results.

Evaluation Criteria for Tile Permutation Link level simulation To show the diversity gain for distributed LRU Hit ratio To check the interference averaging effect of distributed LRU

Tile Permutation Formulas Considered LGE’s proposed formula where where where

Tile Permutation Formulas Considered Intel (IEEE 802.16m-09/0265) where PermSeq(L;i) is the i-th entry of the permutation sequence of length L as defined by the following equation where

Tile Permutation Formulas Considered Samsung (IEEE 802.16m-09/0206r3 ) where PermSeq is the sequence of length LDRU,FPi and is determined by SEED = {(IDcell+1024*t)*1357351} mod 220. The IDcell is the cell identification. The specific permutation sequence generation algorithm with 20-bit SEED (Sn-20, Sn-19, … , Sn-1) and a permutation size of M is defined as below (refer to IEEE 802.16m-09/0206r3 ). where or

Subcarrier Permutation Formulas Considered Samsung (updated) (C802.16m-09/0582) PermSeq is the sequence of length LDRU, FPi and is determined by SEED = {IDcell*1367} mod 210 and the permutation sequence generation algorithm specified in C80216m-09_0582 where

Tile Permutation Formulas Considered NSN (IEEE 802.16m-09/0260r2 )

Simulation Environment: LLS (1/2) BW=10MHz (NPRU=48) – IEEE 802.16m-09/0251 Scenario1 (Mixed Reuse 1&3 – equal size) Scenario 3 (Reuse 1) Freq. Partition # of subbands (KSB,FP,i) # of minibands (KMB,FPi) # of PRUs in FPi FP1 2 4 12 FP2 FP3 FP4 Freq. Partition # of subbands (KSB,FP,i) # of minibands (KMB,FPi) # of PRUs in FPi FP1 6 24 48 FP2 FP3 FP4 Scenario 2 (Mixed Reuse 1&3 – unequal size) Scenario 4 (Reuse 3) Freq. Partition # of subbands (KSB,FP,i) # of minibands (KMB,FPi) # of PRUs in FPi FP1 4 8 24 FP2 FP3 FP4 Freq. Partition # of subbands (KSB,FP,i) # of minibands (KMB,FPi) # of PRUs in FPi FP1 FP2 2 8 16 FP3 FP4

Simulation Environment: LLS (2/2) Antenna configuration 2x2 SFBC MMSE MIMO Receiver Channel Scenario : MAND_MIXED Model : Veh A Perfect channel estimation QPSK, ½ code rate Averaged over cell ID 0 ~ 47

Simulation Results: LLS Scenario 1

Simulation Results: LLS Scenario 2

Simulation Results: LLS Scenario 3

Simulation Results: LLS Scenario 4

Conclusion on LLS results We evaluated UL tile permutations with varying scenarios. In terms of diversity gain, LGE, Intel, SS have the same performance in all cases

Simulation Environment: Hit ratio BW 10MHz #Cell ID 512 Distributed LRU 3 6by6 tiles NDRU varying For choose(512,2)=130816 cell pairs, For each cell pair, there are NDRU * NDRU sub-channel pairs, Hit Number: the number of same tiles for each sub-channel pair Average Hit Number: hit statistic over 130816 cell pairs % of total hits: (Average Hit Number) / (NDRU * NDRU) * 100%

Simulation Results: Hit ratio #. of DRUs # of Hits 1 2 3 4 LGE 43.70 % 40.52 12.88 2.91 Intel 49.95 31.31 12.52 6.21 Samsung 47.16 36.15 11.20 5.48 Samsung (updated) 48.87 33.27 11.84 6.02 8 66.91 28.95 3.88 0.27 71.84 21.14 4.70 2.32 69.23 25.02 4.76 0.99 68.39 26.43 4.47 0.71 12 76.92 21.27 1.71 0.10 80.19 15.42 3.59 0.80 77.49 20.21 2.11 0.19 77.98 19.35 2.35 0.31 24 87.95 11.61 0.41 0.02 88.66 10.39 0.74 0.21 88.19 11.16 0.60 0.05 88.53 10.58 0.76 0.13 48 93.87 0.008 94.15 5.49 0.30 0.050 93.96 5.85 0.18 0.016 94.06 5.66 0.23 0.04 Best cases were bolded for larger hits

Simulation Results: modified LLS Two cells: Home cell and Interfering cell Scenario 1 (4DRUs per FP) 25% partial loading Cell IDs averaged over 0 ~ 47

Simulation Environment: Hit ratio BW 10MHz #Cell ID 512 Distributed LRU 3 6by6 tiles NDRU varying For choose(512,2)=130816 cell pairs, For each cell pair, select contiguous N sub-channels from sub-channel number 0 for each cell Hit Number: the number of same tiles for each sub-channel pair (Hit number range is [0, 3N]) Average Hit Number: hit statistic over 130816 cell pairs % of total hits: (Average Hit Number) * 100% This hit ratio comparison is more realistic to see the effect of hit ratio on SLS performance

Simulation Environment: Hit ratio LGE’s UL tile permutation formula considered SS’s UL tile permutation formula considered For the purpose of comparison we use the same permutation sequence (SS’s sequence in C802.16m-09/0582) where where

Simulation Results: Hit ratio SS's equation LGE's equation #Hit % of Total Hits Num Hit 1.187164 1553 1.13136 1480 1 5.954929 7790 5.555131 7267 2 13.63748 17840 13.49606 17655 3 20.24447 26483 20.48144 26793 4 21.68924 28373 21.9996 28779 5 17.32968 22670 17.5422 22948 6 10.87329 14224 11.06669 14477 7 5.528376 7232 5.497034 7191 8 2.325404 3042 2.221441 2906 9 0.80189 1049 0.7415 970 10 0.268316 351 0.198752 260 11 0.092496 121 0.050453 66 12 0.03975 52 0.011466 15 13 0.01376 18 0.003822 14 0.006115 0.002293 0.003058 16 0.001529 0.000764 17 19 20 21 22 23 24 # DRU = 48 N=8 (1/6 loading)

Simulation Results: Hit ratio # DRU = 24 N=4 (1/6 loading) SS's equation LGE's equation #Hit % of Total Hits Num Hit 9.040943 11827 9.605094 12565 1 22.80837 29837 26.39815 34533 2 28.1938 36882 31.30733 40955 3 21.72441 28419 20.51355 26835 4 11.7822 15413 8.85595 11585 5 4.504801 5893 2.589897 3388 6 1.375978 1800 0.583262 763 7 0.37075 485 0.107785 141 8 0.103963 136 0.028284 37 9 0.059626 78 0.003822 10 0.016818 22 0.004587 11 0.009173 12 0.002293

Simulation Results: Hit ratio # DRU = 4 N=1 (1/4 loading) SS's equation LGE's equation #Hit % of Total Hits Num Hit 43.83562 57344 44.09017 57677 1 30.52838 39936 28.96511 37891 2 7.827789 10240 21.13427 27647 3 17.80822 23296 5.810451 7601

Conclusion on Hit ratio results In terms of hitting ratio, LGE has the best performance showing the smallest ‘larger hit ratios (2 or 3 hit cases)’ in most scenarios

Conclusions Different proposals show different conclusions In this contribution, LGE is the best in terms of hit ratio and modified LLS In C80216m-09_0551 (ITRI), ITRI and LGE is the best in terms of hit ratio In C80216m-09_0582r1 (Samsung), Samsung is the best in terms of SLS only when random_Permbase is assumed, but, the reason is unclear. Comparison with more proposals are necessary assuming the agreed decision criterion and simulation environment This contribution only compares LGE, Intel, SS in terms of modified LLS C80216m-09_0582r1 (Samsung) only compares SS and LGE, It is necessary to provide comparison with ITRI and NSN and some other proposals if any for fair comparison It is better to adopt the UL tile permutation formula in the next meeting based on the results enough to make a final decision

Proposed Text Please leave the equation (196) of page 42 of Amendment Working Document IEEE 802.16m-09/0010 as it is