1. C80216m-08_214 ProjectIEEE 802.16 Broadband Wireless Access Working Group http://ieee802.org/16 Title16m Downlink Common Pilot Structure for TDM Control Structure Date Submitted 2008-03-10 Source(s)Zhigang Rong, Yunsong Yang Jung Woon Lee, Young Hoon Kwon Yang Tang, Anthony Soong Jianmin Lu Huawei E-mail: zrong@huawei.com Re:IEEE 802.16m-08/005: Call for Contributions on Project 802.16m System Description Document (SDD). Target topic: Pilot Structures as relevant to downlink MIMO. AbstractThis contribution proposes a common pilot structure supporting the enhanced TDM based control structure in a mini-frame. PurposeFor discussion and approval by 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. C80216m-08_214 2 Objectives In contribution IEEE C802.16m-08/211, we described an enhanced TDM based control structure in a mini-frame In this contribution, we describe a common pilot structure supporting this enhanced TDM based control structure in a mini-frame

3. C80216m-08_214 3 Proposed Control and Data Multiplexing Scheme within a Data Mini-frame Control zone occupies x subcarriers in the first 2 OFDM symbols –To gain the benefits of TDM based control structure Data zone occupies the remaining usable subcarriers in the first 2 OFDM symbols –To enhance bandwidth and power efficiency by adding FDM –The Control zone size (x) is modulated on Common Pilots in the control zone 3rd to 6th OFDM symbols are used for data zone –Cleaner design for the data zone and pilot structures

4. C80216m-08_214 4 Proposed Common Pilot Structures 1st and 2nd Tx Antenna Common Pilots always provided in the control zone (if BS supports at least 2 Tx antennas) –Modulated with Control zone size information –Used for channel measurement and coherent demodulation for both localized and diversity resource allocation 3rd and 4th Tx Antenna Common Pilots may be provided in the control zone based on demand –Absence or presence as indicated –The BS may group MSs that can benefit from the 3rd and 4th Tx antennas into some mini-frames so that the BS can turn off the 3rd and 4th Tx antenna common pilots in the other mini-frames No Common Pilots provided in the data zone –Optimized the common pilots on the first 2 antennas for average users and schemes –Use dedicated pilots to address user-specific needs –For MBS/SFN, use dedicated pilots as SFN common pilots

5. C80216m-08_214 5 Summary of Simulation Results (Details provided in the Appendix) Channel Estimation Loss @ 10% PER (dB) Mobile Speed Pilot Tones in First 2 OFDM Symbols (New Design) Pilot Tones in All OFDM Symbols (Band AMC) 3 km/h0.80.6 30 km/h0.80.7 120 km/h0.81 Comparison of channel estimation loss @ 10 -1 PER (with one transmission) relative to idealized channel estimation between the proposal and 16e Band AMC Ped. B, 3/30/120 kmph, 1x2 antennas Pilot overhead –16e Band AMC : 1/9 with 2.5 dB pilot boost –TDM Pilot: 2/(9*6)=1/27 with 3dB pilot boost Conclusion: with significant lower pilot density, TDM common pilot scheme achieves almost same performance as in 16e Band AMC

6. C80216m-08_214 6 Benefits of the Proposals Design of Common Pilots that is optimized for average users and without burdening these users with unnecessary pilot overhead –Additional dedicated pilots are provided per user on a needed base –Optimized pilot overhead design for every user Separating the Common Pilots from the data zone gives the system flexibility to implement advanced techniques such as various CL-MIMO/BF, various OL-MIMO, SFN for MBS and Paging, and schemes for high mobility or long delay spread

7. C80216m-08_214 7 Text Proposal Insert the following text in Chapter 11 (Physical Layer): 11.Z Downlink Pilot Structures 11.Z.1 Common Pilots For TDM-based downlink control/data multiplexing scheme: The common pilots for the 1st and 2nd transmit antennas are always provided (in a diversity fashion) in the control zone in a data mini- frame, if the BS supports at least 2 transmit antennas. The common pilots for additional transmit antennas are provided (in a diversity fashion) in the control zone in a data mini-frame based on needs, if the BS supports more than 2 transmit antennas. The absence or presence of the common pilots for the additional transmit antennas is indicated by the BS. There is no common pilots provided in the data zone. Instead, the dedicated pilots are provided based on needs in each specific resource block. For MBS/SFN transmission, dedicated pilots are used as SFN common pilots.

8. C80216m-08_214 8 Appendix - Simulation Results

9. C80216m-08_214 9 Carrier frequency: 2 GHz System BW: 10 MHz Ped B. with 3km/h, 30km/h and 120km/h Channel coding: Turbo code Antenna Configuration: 1x2 Packet size: 384 Modulation and coding: QPSK Resource Allocation: 4 symbols * 5 subchannel (1 subchannel = 18 subcarriers) Effective coding rate: 0.5333 Pilot tone is boosted with 3dB over data tone and located every 9th subcarrier on first 2 OFDMA symbol Channel estimation (MMSE-CE4) –MMSE-based CE on frequency domain with filter length 4 –MMSE-based CE on time domain with 4 OFDM symbols (2 in current + 2 in next) Simulation Parameters for the New Proposal

10. C80216m-08_214 10 Simulation Results

11. C80216m-08_214 11 Simulation Results

12. C80216m-08_214 12 Simulation Results

13. C80216m-08_214 13 Carrier frequency: 2 GHz System BW: 5 MHz Ped B. with 3km/h Channel coding: Turbo code Antenna Configuration: 1x2 Packet size: 384 Modulation and coding: QPSK Resource Allocation: 8 slots ( 4 symbols * 4 subchannel) Effective coding rate: 0.5 Pilot tone is boosted with 2.5dB over data tone Channel estimation –MMSE-based CE on frequency domain –MMSE on time domain (filter length is 6) Simulation Parameters for 16e Band AMC

14. C80216m-08_214 14 Simulation Results

15. C80216m-08_214 15 Simulation Results

16. C80216m-08_214 16 Simulation Results