1. Performance Comparison of CDM and FDM for Sounding Channel of 802.16m AWD IEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE C80216m-0850 Date Submitted: 2009-04-27 Source: KeunChul Hwang, Jing Li, Inseok Hwang, Soon Young Yoon keunchul.hwang@samsung.comkeunchul.hwang@samsung.com Samsung Electronics Venue: IEEE 802.16m Session#61, Cairo, Egypt Base Contributions: N/A Re:Call for Contributions on Project 802.16m Amendment Working Document (AWD) Content Purpose: To discuss and adopt in TGm 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. Motivation There are Two Options for sounding multiplexing in the current UL CTRL AWD text (80216m-09_0010r1a), –Option 1: decimation separation (FDM) or cyclic shift separation (CDM) –Option 2: decimation separation (FDM) Link-level and system-level simulation results are provided to compare the performance of decimation separation (FDM) and cyclic shift separation (CDM).

3. Performance of CDM and FDM depends on the number of MS per sector, the channel estimation scheme and interference level Option 1 is needed for 16m Sounding due to different performance of CDM and FDM Summary Preferred Scheme K=1 MS/sectorK=6 MS/sector LSLS+MMSELSLS+MMSE Noise limitedCDM CDM  FDM CDMFDM Interference limited CDM CDM  FDM

4. Performance at low SINR ( less than 0dB) should be paid more attention The following simulations focus on performance at SINR [-10, 10]dB UL SINR distribution (57 sectors)

5. Simulation parameters OFDM parameters10 MHz (1024 subcarriers, 864 used subcarriers) Sounding sequence CDM cyclic shift (P): 6, 18 cyclic shift index: 0,1,2,…,K for both serving and interference cell FDM decimation value (D): 6, 18 subcarrier offset (g=0,1…D) for both serving and interference cell Loading size72 tones (one band) # of sectors 1 for noise limited case 2 for interference limited case # of MS per sector (K)1 or 6 Channel modelITU modified Ped.-B (3km/h, 2.4GHz) Channel estimation -LS -LS+MMSE: perform LS over each P tones, then MMSE over 18 tones Performance MetricMSE

6. LLS results (K=1,P=D=18) In noise limited case, using LS+MMSE, CDM and FDM have similar performance In the other cases, CDM performs better than FDM

7. LLS results (K=1,P=D=6) In noise limited case, using LS+MMSE, CDM and FDM have similar performance In the other cases, CDM performs better than FDM

8. LLS results (K=6,P=D=18) In noise limited case, using LS+MMSE, FDM performs better In the other cases, CDM performs better than FDM

9. LLS results (K=6,P=D=6) CDM and FDM have similar performance when P=D=6 and K=6

10. SLS results (P=D=6) SLS results (57 sectors) are provided with LS+MMSE channel estimation CDM is obviously better than FDM when K=1/Sector, and CDM is slightly better than FDM when K=6/Secoter

11. Proposed Remedy Modify the text in lines 65, page 118 (section 15.3.9.2.3.2. in 80216m- 09_0010r1a) 15.3.9.2.3.2 Multiplexing for multi-antenna and multi-AMS AMS and multiple antennas per AMS can be multiplexed through [Option 1: decimation separation or cyclic shift separation][Option2: decimation separation] in each sounding allocation. Also, in case of multiple UL subframes for sounding, time division separation can be applied by assigning different AMS to different UL subframe. For cyclic shift separation each AMS occupies all subcarriers within sounding allocation and uses the different sounding waveform [Editor's note: remove this sentence if Option 2 will be adopted]. For frequency decimation separation each AMS uses decimated subcarrier subset from the sounding allocation set with different frequency offset. For antenna switching capable AMS, ABS can command the AMS to switch the physical transmit antenna(s) for sounding transmission. The details for supporting antenna switching on sounding is TBD.

12. Appendix. Channel estimation methods System model LS LS+MMSE

13. Appendix. Impact of power difference Power difference has little impact on MSE performance of both FDM and CDM Simulation condition –Power difference between center and edge users : 10dB –Relative power difference at SNR = -10, -5, 0 (low geometry) [desired user#0, interf#1, interf#2,…interf#5] = [0dB 0dB 0dB 10dB 10dB 10dB] – Relative power difference at SNR = 5, 10 (high geometry) [desired user#0, interf#1, interf#2,…interf#5] = [0dB 0dB 0dB -10dB -10dB -10dB]