1. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 1 11ac Explicit Sounding and Feedback Authors: Date: 2010-09-14

2. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 2 Outline Overview Explicit Sounding Exchange NDP Sounding Compressed Feedback Format Summary Appendix: –Compressed V FB Simulations –Compressed V FB Angle extensions –CSI and Compressed V size comparisons Straw Polls

3. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 3 1. Overview MU-MIMO is an important optional feature of 11ac –This generally requires the channel feedback for beamformer to communicate with multiple STAs simultaneously. –The feedback format for SU-beamforming is well defined in 11n It is preferred to have common sounding and feedback mechanism for MU-MIMO and SU-BF. –Multiple options to implement a feature creates interoperability issues. Propose a sounding and feedback mechanism based on IEEE 802.11n SU-BF sounding and feedback –TGac PAR is for 5GHz only, dual band devices may support IEEE 802.11n SU-BF sounding and feedback for 2.4GHz –Desirable to have similar implementation for operation in TGac mode.

4. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 4 Background: Multiple Options in 11n TxBF Multiple Modes for 11n TxBF, including: –Implicit BF, + CSI FB for calibration. –Explicit feedback format: CSI, compressed V, Non-compressed V. –Implicit BF, explicit BF, and calibration with either Staggered sounding, or NDP. –NDP announcement frame: regular data packet, QoS null frame, management frame, control wrapper. –Immediate-SIFS feedback, Immediate-Aggregated feedback, and delayed feedback. It is highly desirable to trim down to only one option for TGac SU-BF and MU-MIMO.

5. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 5 2. Explicit Sounding Exchange 11n SU-BF has multiple options: –Implicit Beamforming. –Explicit Beamforming (Immediate Feedback). TRQ BFMer BFMee Sounding Data … (Steered) Sounding BFMer BFMee IFB Data (Steered)

6. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 6 Issues with Implicit Sounding in 11ac Sounding feedback cannot be collected from a BFee that has less TX antennas than RX antennas. Implicit sounding requires calibration exchange in each channel: –It is desirable to define only one sounding exchange in 11ac, but the calibration responder still needs to support explicit FB according to 11n calibration process.

7. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 7 Calibration Issues—cont’d Imperfect calibration at the transmitter is less tolerable in MU than in SU-BF: lead to interference leakage that may not be completely cancelled by the Rx. Uncalibrated clients is less tolerable in MU than in SU-BF. –Refer to Appendix I for the simulation of imperfect calibrations. –In 11n Implicit BF, BFMee is not required to do calibration. –For MU, uncalibrated RF imbalance at the clients may also introduce larger interference leakage for some MU precoder designs. –May require calibration supports at both AP and clients. Example for a 2-client case:

8. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 8 Propose Explicit Sounding Exchange as the Only 11ac Sounding Protocol Provides the best possible channel estimation quality for accurate MU precoder design. A unified SU/MU sounding protocol. Also propose to define one type of explicit feedback format, and only allow immediate-SIFS feedback, to further unify among the multiple choices of 11n. –Recall: 11n defines three explicit feedbacks: CSI, Noncomp V, Compressed V. –Recall: 11n defines three types feedback timing: immediate-SIFS, immediate- aggregated, and delayed. –Immediate-SIFS FB is also important for MU overhead reduction. Explicit sounding sequence and feedback format refer to the subsequent slides.

9. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 9 3. NDP Sounding 11n defines two types of sounding format: Staggered and NDP. NDP is more “friendly” for immediate FB at the receiver side. –NDP Announcement preceding NDP contains RA, STA information, and all other necessary information for preparing the feedback. Rx knows exactly what to do (or whether need to do anything) before the NDP comes. –NDP does not require ACK. A “clean” immediate FB frame SIFS following NDP is possible, and no frame aggregation is needed. May not need multiple possibilities of immediate feedbacks (i.e. immediate SIFS, and immediate aggregated) like in 11n BF. NDP is also more “friendly” for the Tx side: –AP/BFMer expects a single “clean” immediate SIFS feedback. –Q matrix for the sounding packet could always be set to identity matrix without power loss. Not require complex number matrix multiplication to determine the final steering matrices. NDP simplifies preamble design: –No additional N ESS bits required in VHTSIG –No special VHTLTF design and handling (same as VHTLTF for normal multi-stream data packet).

10. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 10 NDP PPDU Format NDP PPDU format should be the same as the VHT preamble. –VHTSIGA subfields are defined as a SU Packet. The SU-Nsts field implies the number of VHTLTFs –VHTSIGB has fixed bit pattern (TBD). To reduce PAPR VHT- SIGB should not have large number of zeros. VHT-STFVHT-LTF1 VHT-LTFN … L-LTFL-SIG VHT-SIG-A (Symbol 1) VHT-SIG-A (Symbol 2) L-STF VHT-SIG-B

11. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 11 L-LENGTH in NDP No “Non-Sounding” bit required in VHTSIGA. To indicate an NDP packet (Sounding indication). Rx: Assert NDP, if

12. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 12 NDP Sounding Sequence—Single User Not allow the 11n delayed or aggregated feedbacks. Detailed sequence refer to [1].

13. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 13 NDP Sounding Sequence—MU Feedback happens SIFS after NDP, or SIFS after polling frames. Detailed sequence refer to [1].

14. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 14 4. Compressed Feedback Compressed V matrix FB is a good candidate for both SU and MU. –Unified format between SU and MU. –Unified format between 11ac in 5GHz and 11n in 2.4GHz and 5GHz. Reduced overhead (important for MU) compared with CSI feedback, by using quantized angles in V to replace raw I/Q values in H. –Overhead reduction from compressed V FB was largely discussed back in 11n—refer to [2]. –Refer to Appendix III for size comparisons. Enables feeding back partial rank, in LOS or ill-conditioned channels. Feeding back V matrix in MU performs similarly as feeding back CSI matrix, for a wide range of precoder designs. –Refer to the Appendix I for simulations.

15. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 15 Other Compressed FB Options Regarding the time domain compressed CSI FB proposed in [3][4]. –It introduces a new feedback approach different from 11n, one more feedback mode for devices supporting both TGac feedback and 11n feedback(s). –Higher complexity, memory size and power consumption by using FFT engine to generate and decode the feedback, especially for immediate feedback. –Feeding back time domain CSI doesn’t allow reduced-rank feedbacks, which is definitely sufficient in SU, and somewhat sufficient in MU (e.g. in LOS or ill-conditioned channels).

16. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 16 Compressed V FB Proposal—1 Propose to define compressed V matrix FB, which is based on the 802.11n subclause 20.3.12.2.5 and 7.3.1.29, with appropriate changes for 11ac : –Extend the table of angles up to 8 streams (refer to Appendix II) –Define the feedback reports for 80 and 160MHz –Tone-grouping, and tone mapping are TBD (recall: pilots are introduced in VHTLTF) –Number of bits used to quantize the angles is TBD. MU is more sensitive to the angle quantization than SU-BF, so more simulations need to be run to determine this. –A SU or MU feedback request is signaled in the NDP sequence. –Whether MU feedback requires additional information compared with SU feedback is TBD. Example, per-tone SNR may be needed for MU.

17. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 17 Compressed V FB Proposal—2 Propose to define the 11ac compressed V FB frame for SU and MU be the Action-No-ACK format based on 7.4.10.8, with appropriate extensions: –Category: VHT –Action: Compressed Beamforming –Define VHT MIMO Control Field, with TBD subfields. Need a 1-byte sounding sequence number (refer to [1]) Other subfield examples: Nc, Nr, BW, Ng, Codebook Info, SU/MU FB Indication, etc OrderInformation 1Category (VHT) 2Action (Compressed Beamforming) 3VHT MIMO Control (TBD) 4Compressed Beamforming Report (TBD-see the previous slide)

18. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 18 5. Summary Propose to define explicit sounding and feedback as the only sounding exchange protocol for 11ac SU and MU. Propose to define NDP as the only sounding format in 11ac. Propose the NDP sequence with SIFS feedback after NDP and/or Polling frames, and no aggregated or delayed feedbacks are allowed. Propose to define compressed V matrix feedback as the only feedback format for 11ac SU and MU.

19. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 19 Appendix I: Simulations

20. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 20 Simulation Settings SU-BF: –Ntx=4, Nrx=2, DNLOS 80MHz, MCS15, Compressed V FB with b_phi=4, b_psi=2, Ng=1,2. DL-MU: –AP-Ntx=4, 2 Clients, each Nrx=2  (4,2,2) –40MHz, DNLOS channels, equal path loss for two clients. –Nss=1 per user (MCS7), full-rank feedbacks. –In CV FB, b_phi = 8, b_psi = 6. –Precoding with Channel Nulling. –PER of user 1 is measured, each receiver conducts full multiuser interference cancellation. –Focus only on high SNR regime (20~35dB).

21. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 21 SU-BF: DNLOS 80MHz, MCS15, 4x2, b_phi=4, b_psi=2

22. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 22 MU: DNLOS 40MHz, (4,2,2) Nss=1 per user, b_phi=8, b_psi=6

23. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 23 MU System Simulation: 8Tx AP, 3Rx Client Throughput Loss in % of CV with tone grouping relative to perfect feedback 40MHz, 8x3, 4STA, 11ac Chan D 10dB13dB16dB19dB22dB25dB28dB31dB Perfect H Avg. Tput - Mbps 32542053764982196810661166 CV Ng=1 00.1 0.20.30.40.20.4 CV Ng=4 0000.10.20.40.30.7 Tables below show throughput comparison of compressed V with tone grouping of one and four and with angle quantization relative to perfect channel feedback Further overhead reduction can be achieved with rank one feedback

24. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 24 MU System Simulation: 4Tx AP, 2Rx Client Throughput Loss in % of CV with tone grouping relative to perfect feedback 40MHz, 4x2, 4STA, 11ac Chan D 10dB13dB16dB19dB22dB25dB28dB31dB Perfect H Avg. Tput - Mbps 175237303388479540612702 CV Ng=1 0.10. 0.1 0.0.30.2 CV Ng=4 0.20.1 0.20.40.21.01.1

25. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 25 Explicit vs Implicit FB Same MU scenario, comparing explicit CV FB, and implicit sounding with perfect channel estimation, but imperfectly calibrated AP and uncalibrated clients. –At AP, assume a +-0.5dB gain uncertainty, and +-5 degree phase uncertainty. –At clients, assume +-1dB gain uncertainty, and arbitrary phase uncertainty. –Input SINR (@10% outage) of user 1 is compared.

26. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 26 MU SINR: DNLOS 40MHz, (4,2,2) Nss=1 per user

27. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 27 Appendix II: Compressed V FB Angle extensions for Nr>4

28. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 28 Angle Table—Nr=5 Extended table of the order of angles in the compressed beamforming report field: Size of V (Nr × Nc) Number of angles (Na) The order of angles in the Quantized Beamforming Feedback Matrices Information field 5×18φ11, φ21, φ31, φ41, ψ21, ψ31, ψ41, ψ51 5×214φ11, φ21, φ31, φ41, ψ21, ψ31, ψ41, ψ51, φ22, φ32, φ42, ψ32, ψ42, ψ52 5×318 φ11, φ21, φ31, φ41, ψ21, ψ31, ψ41, ψ51, φ22, φ32, φ42, ψ32, ψ42, ψ52, φ33, φ43, ψ43, ψ53 5×420 φ11, φ21, φ31, φ41, ψ21, ψ31, ψ41, ψ51, φ22, φ32, φ42, ψ32, ψ42, ψ52, φ33, φ43, ψ43, ψ53, φ44, ψ54 5×520 φ11, φ21, φ31, φ41, ψ21, ψ31, ψ41, ψ51, φ22, φ32, φ42, ψ32, ψ42, ψ52, φ33, φ43, ψ43, ψ53, φ44, ψ54

29. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 29 Angle Table—Nr=6 Extended table of the order of angles in the compressed beamforming report field: Size of V (Nr × Nc) Number of angles (Na) The order of angles in the Quantized Beamforming Feedback Matrices Information field 6×110φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61 6×218 φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61, φ22, φ32, φ42, φ52, ψ32, ψ42, ψ52, ψ62 6×324 φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61, φ22, φ32, φ42, φ52, ψ32, ψ42, ψ52, ψ62, φ33, φ43, φ53, ψ43, ψ53, ψ63 6×428 φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61, φ22, φ32, φ42, φ52, ψ32, ψ42, ψ52, ψ62, φ33, φ43, φ53, ψ43, ψ53, ψ63, φ44, φ54, ψ54, ψ64 6×530 φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61, φ22, φ32, φ42, φ52, ψ32, ψ42, ψ52, ψ62, φ33, φ43, φ53, ψ43, ψ53, ψ63, φ44, φ54, ψ54, ψ64, φ55, ψ65 6×630 φ11, φ21, φ31, φ41, φ51, ψ21, ψ31, ψ41, ψ51, ψ61, φ22, φ32, φ42, φ52, ψ32, ψ42, ψ52, ψ62, φ33, φ43, φ53, ψ43, ψ53, ψ63, φ44, φ54, ψ54, ψ64, φ55, ψ65

30. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 30 Angle Table—Nr=7 Extended table of the order of angles in the compressed beamforming report field: Size of V (Nr × Nc) Number of angles (Na) The order of angles in the Quantized Beamforming Feedback Matrices Information field 7×112φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71 7×222 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72 7×330 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72, φ33, φ43, φ53, φ63, ψ43, ψ53, ψ63, ψ73 7×436 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72, φ33, φ43, φ53, φ63, ψ43, ψ53, ψ63, ψ73, φ44, φ54, φ64, ψ54, ψ64, ψ74 7×540 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72, φ33, φ43, φ53, φ63, ψ43, ψ53, ψ63, ψ73, φ44, φ54, φ64, ψ54, ψ64, ψ74, φ55, φ65, ψ65, ψ75 7×642 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72, φ33, φ43, φ53, φ63, ψ43, ψ53, ψ63, ψ73, φ44, φ54, φ64, ψ54, ψ64, ψ74, φ55, φ65, ψ65, ψ75, φ66, ψ76 7×742 φ11, φ21, φ31, φ41, φ51, φ61, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, φ22, φ32, φ42, φ52, φ62, ψ32, ψ42, ψ52, ψ62, ψ72, φ33, φ43, φ53, φ63, ψ43, ψ53, ψ63, ψ73, φ44, φ54, φ64, ψ54, ψ64, ψ74, φ55, φ65, ψ65, ψ75, φ66, ψ76

31. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 31 Angle Table—Nr=8 Extended table of the order of angles in the compressed beamforming report field: Size of V (Nr × Nc) Number of angles (Na) The order of angles in the Quantized Beamforming Feedback Matrices Information field 8×114φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81 8×226 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82 8×336 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83 8×444 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83,φ44, φ54, φ64, φ74, ψ54, ψ64, ψ74, ψ84 8×550 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83,φ44, φ54, φ64, φ74, ψ54, ψ64, ψ74, ψ84, φ55, φ65, φ75, ψ65, ψ75, ψ85 8×654 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83,φ44, φ54, φ64, φ74, ψ54, ψ64, ψ74, ψ84, φ55, φ65, φ75, ψ65, ψ75, ψ85, φ66, φ76, ψ76, ψ86 8×756 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83,φ44, φ54, φ64, φ74, ψ54, ψ64, ψ74, ψ84, φ55, φ65, φ75, ψ65, ψ75, ψ85, φ66, φ76, ψ76, ψ86, φ77, ψ87 8×856 φ11, φ21, φ31, φ41, φ51, φ61, φ71, ψ21, ψ31, ψ41, ψ51, ψ61, ψ71, ψ81, φ22, φ32, φ42, φ52, φ62, φ72, ψ32, ψ42, ψ52, ψ62, ψ72, ψ82, φ33, φ43, φ53, φ63, φ73, ψ43, ψ53, ψ63, ψ73, ψ83,φ44, φ54, φ64, φ74, ψ54, ψ64, ψ74, ψ84, φ55, φ65, φ75, ψ65, ψ75, ψ85, φ66, φ76, ψ76, ψ86, φ77, ψ87

32. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 32 Appendix III: Comparing Sizes of CSI and CV Feedbacks

33. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 33 CSI Feedback Size (Bytes) 2345678 1 4736899051121 133715531769 2 905133717692201 263330653497 3 198526333281 392945775225 4 34974361 522560896953 Follow 11n CSI FB Definition. 40MHz, Ng=1, Nb=8 Nc Nr

34. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 34 Compressed V Feedback Size (Bytes) 2345678 1 189378567756 94511341323 2 1895679451323 170120792457 3 56711341701 226828353402 4 11341890 264634024158 Follow 11n CV FB Definition, extend to Nr>4 in Appendix II. 40MHz, Ng=1, b_phi=8, b_psi=6 Nr Nc

35. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 35 Discussions The tables are mainly for MU FB (high bit-width required). Overhead savings are big, e.g. –4x2: %47 reduction –4x4: %68 reduction –8x4: %41 reduction Overhead saving for SU-BF is more (see [2]). With reduced rank CV feedback, the saving could be more.

36. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 36 Straw Poll #1 Do you support updating the spec framework to require that only explicit sounding and feedback be supported for VHT SU beamforming and DL MU- MIMO? –Yes –No –Abstain

37. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 37 Straw Poll #2 Do you support updating the spec framework to require that NDP be the only VHT sounding format? –Yes –No –Abstain

38. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 38 Straw Poll #3 Do you support updating the spec framework to define the VHT NDP format as follows: –Same format as the VHT PPDU but with no data portion –VHT-SIG-A indicates SU packet –VHT-SIG-B carries a fixed TBD bit pattern and adding the following figure? –Yes –No –Abstain VHT-STFVHT-LTF1 VHT-LTFN … L-LTFL-SIG VHT-SIG-A (Symbol 1) VHT-SIG-A (Symbol 2) L-STF VHT-SIG-B

39. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 39 Straw Poll #4 Do you support updating the spec framework to require that the explicit sounding feedback be sent SIFS after the NDP or Polling frame with no option for the delayed or aggregated feedback as defined in 11n? –Yes –No –Abstain

40. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 40 Straw Poll #5 Do you support updating the spec framework to require that compressed V matrix feedback, as defined in subclause 20.3.12.2.5, be the only feedback format for both VHT SU beamforming and DL MU-MIMO? –Yes –No –Abstain

41. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 41 Straw Poll #6 Do you support updating the spec framework to define the VHT compressed V feedback frame as an Action No ACK format with –Category = VHT –Action = Compressed Beamforming –Containing a VHT MIMO Control field with 1-byte Sounding sequence number, and other TBD subfields –Containing a Compressed Beamforming Report field and adding the following figure? –Yes –No –Abstain OrderInformation 1Category (VHT) 2Action (Compressed Beamforming) 3VHT MIMO Control (TBD) 4Compressed Beamforming Report (TBD)

42. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 42 Straw Poll #7 Do you support updating the spec framework to define Compressed Beamforming Report Field as shown in the next slide ? –Yes –No –Abstain

43. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 43 SP7—Proposed Spec Framework Text Insert a new section 6.x describing the Compressed Beamforming Report Field, b y adopting the 11n subclause 7.3.1.29, and: With extending Table 7-25i to the angle ordering to up to 8 streams (refer to Appendix II) With TBD extensions to 80MHz and 160MHz With TBD extensions or modifications of 7-25f, on tone-grouping, and tone mapping. With TBD extensions or modifications of Table 7-25j, on the number of bits used to quantize the angles.

44. doc.:IEEE 802.11-10/1105r0 Submission Sept 14, 2010 Hongyuan Zhang, et al Slide 44 References [1] 11-10-1091-00-00ac-Protocol-for-SU-and-MU-Sounding-Feedback [2] 11-07-0666-00-000n-BEAM-LB97-CID2969 [3] 11-10-0332-00-00ac-csi-report-for-explicit-feedback-beamforming-in- downlink-mu-mimo [4] 11-10-0586-01-00ac-time-domain-csi-report-for-explicit-feedback