1. 1 Modification on random sequence generation scheme in DL/UL PHY (AWD – 15.3.5.3.3) IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16m-09/1593r2 Date Submitted: 2009-07-13 Source: Yu-Tao Hsieh, Chia-Lung Tsai, Pang-An TingE-mail: ythsieh@itri.org.twythsieh@itri.org.tw ITRI Venue: IEEE Session #62, San Francisco Base Contributions: None Re: Call for Contribution on 80216m-09_0028r1 Purpose: Discussion and Approval 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. 2 Introduction Problem formulation Proposed modification Simulation results Proposed text

3. 3 Problem formulation This contribution serves to reply the comment #424 and #675 with emphasis on random sequence generation function of 5.3.5.3.3 In current AWD, the subcarrier/tile permutation is composed of two steps  (1) Random sequence generation function PermSeg( )  (2) Randomizer function g( ) It is found that in some cases the permutation output does not actually randomize the input sequence

4. 4 Problem formulation (cont.) An example  UL tile permutation with L DRU =6, IDcell=1 The output of PermSeq() contains a segment with sequential input elements,. i.e., Applying the permuted output to the randomizer which in UL is defined as Inputoutput

5. 5 Problem formulation (cont.) The frequency diversity gain is reduced when a user burst uses long TTI with multiple subframes The artifact of the AWD randomization output can be solved by  Modifying PermSeq ()  Modifying g ()  Modifying both We propose to modify PermSeq () to improve the system performance

6. 6 Proposed modification Increase randomness of the AWD random sequence generation function by three modifications  Step 1.a. Modify d 2 as d 2 = SEED mod 2 5 + 227  Step 2.b. Increment x by i once and for all without iteration index j  Step 2.c. Modify calculation of y = d 1 *x+d 2 as y=d 1 +d 2 *x Advantages of the proposed algorithm  For a certain user burst: improve the frequency diversity for consecutive UL subframes or DL symbols  For interfering bursts: Reduce the DL/UL hit rate among different IDcell’s  Maintain average SNR distribution  Complexity is reduced No need to iterate 2.c with max. number N.

7. 7 Random sequence output comparison (M=8) AWD Proposed algorithm

8. 8 Random sequence output comparison (M=12) AWD Proposed algorithm

9. 9 Random sequence output comparison (M=16) AWDProposed algorithm

10. 10 Statistics of non-permuted segments Cell id = 0~511 Non-permuted segment length 34~78~M AWDM = 6144540 M = 81681200 M = 1013515120 M = 1216418927 M = 1618717446 M = 1815623237 ProposedM = 675170 M = 869220 M = 1060270 M = 126240 M = 166460 M = 184630

11. 11 Simulation for UL Tile permutation Channel model: PB-3 2x2 MIMO uncorrelated channel Cellid = 0~511 Channel estimator: 2D-MMSE Permutation parameter: N1 = 4, N2 = 1

12. 12 Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP12412 FP22412 FP32412 FP42412 Scenario1 (Mixed Reuse 1&3 – equal size) Scenario 2 (Mixed Reuse 1&3 – unequal size) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP14824 FP2088 FP3088 FP4088 Scenario 3 (Reuse 1) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP162448 FP2000 FP3000 FP4000 Scenario 4 (Reuse 3) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP1000 FP22816 FP32816 FP42816 BW = 10 MHz, N PRU = 48 (N 1 = 4, N 2 = 1) UL Evaluation Scenarios

13. 13 UL SNR distribution comparison: Scenarios 1, 2

14. 14 UL SNR distribution comparison: Scenarios 3, 4

15. 15 UL Hit rate comparison Select (512,2) = 130816 Cell_ID pairs  The hit rate of 3 collisions is reduced # COLLISION0 COLLISION1 COLLISION2 COLLISIONs3 COLLISIONs AWD6 DRU0.59610.31890.07390.0111 8 DRU0.68100.26940.04330.0064 10 DRU0.73570.23130.03010.0028 12 DRU0.77790.19680.02270.0026 16 DRU0.82900.15630.01310.0017 24 DRU0.88490.10640.00740.0012 Proposed algorithm 6 DRU0.59340.32230.07500.0092 8 DRU0.67630.27590.04430.0035 10 DRU0.73230.23680.02950.0014 12 DRU0.77220.20650.02050.0008 16 DRU0.82480.16320.01170.0003 24 DRU0.88040.11430.00520.0001

16. 16 DL Simulation for DL subcarrier permutation Channel model: PB-3 2x2 MIMO uncorrelated channel Cellid = 0~511 Channel estimator: 2D-MMSE Permutation parameter: N1 = 4, N2 = 1

17. 17 Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP12412 FP22412 FP32412 FP42412 Scenario1 (Mixed Reuse 1&3 – equal size) Scenario 2 (Mixed Reuse 1&3 – unequal size) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP14824 FP2088 FP3088 FP4088 Scenario 3 (Reuse 1) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP162448 FP2000 FP3000 FP4000 Scenario 4 (Reuse 3) Freq. Partition # of subbands (K SB,FP,i ) # of minibands (K MB,FPi ) # of PRUs in FP i FP1000 FP22816 FP32816 FP42816 BW = 10 MHz, N PRU = 48 (N 1 = 4, N 2 = 1) DL Evaluation Scenarios

18. 18 DL SNR distribution comparison: scenario 1, 2

19. 19 DL SNR distribution comparison: scenario 3, 4

20. 20 ProposalL DRU = 6L DRU = 8L DRU = 10L DRU = 12L DRU = 16L DRU = 24 AWD0.08680.02840.01100.00690.00150.0007 Proposed algorithm 0.08470.02060.00430.001600 DL Hit Number Comparison ProposalL DRU = 6L DRU = 8L DRU = 10L DRU = 12L DRU = 16L DRU = 24 AWD0.26850.25970.11450.09830.03700.0134 Proposed algorithm 0.26340.26090.10520.08940.02470.0027 Hits counted for 12 to 48 hits Hits counted for 24 to 48 hits The hit rate reduction is more prominent for heavy collision cases

21. 21 Summary The proposed modified random sequence generation scheme has the following advantage  Largely reduce the non-permuted segments of random sequence generation output  Simply the computation procedure (N is not needed)  Better Hit rate and similar SNR distribution

22. 22 Proposed text 1)Initialization a) Initialize the variables of the first order polynomial equation with the 10- bit seed, SEED. Set d 1 = floor(SEED/2 5 ) + 1 and d 2 = SEED mod 2 5 + 227. b) Initialize the maximum iteration number, N=4. Initialize an array A with size M with the numbers 0, 1, …, M-1 (i.e. A[0]=0, A[1]=1, …, A[M-1]=M-1). c) Initialize the counter i to M-1. d) Initialize x to -1. 2)Repeat the following steps if i > 0 a) Initialize the counter j to 0. a) Increment x and j by 1. by i. b) Calculate the output variable of y = {(d 1 *x + d 2 ) (d 1 + d 2 *x) mod 1031} mod M. c) Repeat the above steps 2.b and 2.c if y ≥ i and j<N. c) If y ≥ i, set y = y mod i. d) Swap A[i] and A[y]. e) Decrement i by 1. 3)PermSeq[i] = A[i], where 0 ≤ i < M. Replace the AWD text in 15.3.5.3.5 by