Detailed Responses to “Reasons and Cures” Comments on MCS Set

Detailed Responses to “Reasons and Cures” Comments on MCS Set
May 2005 doc.: IEEE /0410r0 May 2005 Detailed Responses to “Reasons and Cures” Comments on MCS Set Date: Authors: Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) 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 Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures < ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 Abstract This presentation addresses issues raised in “reasons and cures” comments addressing issues related to the MCS set in theTGn Sync proposal John Ketchum, Qualcomm John Ketchum, Qualcomm

Comments on MCS Set (1) May 2005 May 2005 doc.: IEEE 802.11-05/0410r0
John Ketchum, Qualcomm John Ketchum, Qualcomm

Summary of MCS Set Comments (1)
May 2005 doc.: IEEE /0410r0 May 2005 Summary of MCS Set Comments (1) MCS set is too large Too many duplicate rates. Get rid of duplicate rates Large number of rates/duplicate rates make MCS selection too difficult No PER results for many of the MCSs Excessive number of modes causes problems with verification and interoperability testing 256 QAM is not realistic or practical Requires substantially better impairment performance Requires substantially better stream separation (orthogonality) Show PER curves to justify its inclusion Get rid of it Remove modes with one spatial stream in 20 MHz Use legacy modes instead John Ketchum, Qualcomm John Ketchum, Qualcomm

Responses to Comments on MCS Set (1)
May 2005 doc.: IEEE /0410r0 May 2005 Responses to Comments on MCS Set (1) MCS set is too large Set of 127 MCSs includes 33 Basic MCSs and 94 extended MCSs. Of the 33 Basic MCSs only 16 are mandatory. This is a minimal set of mandatory MCSs required to support High Throughput operation in Basic MIMO Mode with one or two spatial streams. This set provides for best rate vs range performance in Basic MIMO mode with one or two spatial streams 16 additional, optional MCSs in the Basic MCS set extend the per stream rates provided in the mandatory MCSs to 3 and four spatial streams The 94 extended MCSs are necessary to support advanced beamforming. Provide flexibility to match rates to per-stream SNR in beamforming mode. John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 Responses to Comments on MCS Set (2) Too many duplicate rates. Get rid of duplicate rates Duplicate rates are a result of the need to match modulation and code rate to channel conditions for beamforming and spatial spreading SNR profile in beamforming mode is very dependent on MIMO channel conditions. Further simplification and reduction of MCSs is under consideration Large number of rates/duplicate rates make MCS selection too difficult Simple ad hoc rate selection algorithms have been used in throughput vs range simulation results that we have provided Rate selection will not have an impact on device complexity. No PER results for many of the MCSs We are providing PER curves for all MCSs in 20 MHz John Ketchum, Qualcomm John Ketchum, Qualcomm

Duplicate Basic Rate Comparison with SS
May 2005 doc.: IEEE /0410r0 May 2005 Duplicate Basic Rate Comparison with SS John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 Throughput Simulations Comparing Basic MCS set with Basic + Extended With Beamforming 52 data subcarriers, 4 tracking pilots, full GI All impairments Channel models B, D, E HT-LTF (double) PPDU length: 1000 bytes 100 channel realizations per SNR point 50 packets per channel realization John Ketchum, Qualcomm John Ketchum, Qualcomm

Channel Model B May 2005 May 2005 doc.: IEEE 802.11-05/0410r0

Channel Model D May 2005 May 2005 doc.: IEEE 802.11-05/0410r0

Channel Model E May 2005 May 2005 doc.: IEEE 802.11-05/0410r0

May 2005 doc.: IEEE /0410r0 May 2005 Responses to Comments on MCS Set (3) Excessive number of modes causes problems with verification and interoperability testing There are only 16 mandatory MCSs. This should not pose a problem for testing and verification. Verification of the 16 mandatory MCSs is sufficient to verify the implementation of all the code rates and modulations used in the remaining non-mandatory MCSs, with the exception of 256-QAM. Remove modes with one spatial stream in 20 MHz and use legacy modes instead It is critical to include single-stream modes for high throughput operation to ensure the best rate vs range performance John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 Responses to Comments on MCS Set (4) 256 QAM is not realistic or practical Requires substantially better impairment performance Simulation results show that MCSs that include 256 QAM achieve 1% PER at below 20 dB (MCS 51, channel model B, advanced beamforming, all impairments) Requires substantially better stream separation (orthogonality) All our simulation results of beamforming included degradation due to mismatches between channel and Tx steering and Rx channel estimation errors Show PER curves to justify its inclusion Several examples follow Get rid of it 256-QAM will make a substantial contribution to throughput without imposing unreasonable implementation hurdles All MCSs that include 256-QAM are optional John Ketchum, Qualcomm John Ketchum, Qualcomm

Some Comparative 256-QAM Results
May 2005 doc.: IEEE /0410r0 May 2005 Some Comparative 256-QAM Results 2x2, 4x4 TGnSync ABF-MIMO Original double HT-LTF MIMO training 802.11n Channel B All impairments PPDU length: 1000 bytes 500 packet errors per point 2-stream, 3-stream, and 4-stream MCS’s (39 vs 40, 59 vs 63, 61 vs 65, 83 vs 90) John Ketchum, Qualcomm John Ketchum, Qualcomm

2×2 Two-stream example (97.5 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 2×2 Two-stream example (97.5 Mbps) MCS 39: 2 streams; R=3/4, 64-QAM, 16-QAM MCS 40: 2 streams; R=3/4, 256-QAM, QPSK John Ketchum, Qualcomm John Ketchum, Qualcomm

4×4 Three-stream example (136.5 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×4 Three-stream example (136.5 Mbps) MCS 59: 3 streams; R=3/4, 64-QAM, 16-QAM, 16-QAM MCS 63: 3 streams; R=3/4, 256-QAM, 16-QAM, QPSK John Ketchum, Qualcomm John Ketchum, Qualcomm

4×4 Three-stream example (156 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×4 Three-stream example (156 Mbps) MCS 61: 3 streams; R=3/4, 64-QAM, 64-QAM, 16-QAM MCS 65: 3 streams; R=3/4, 256-QAM, 64-QAM, QPSK John Ketchum, Qualcomm John Ketchum, Qualcomm

4×4 Four-stream example (143 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×4 Four-stream example (143 Mbps) MCS 83: 4 streams; R=1/2, 64-QAM, 64-QAM, 64-QAM, 16-QAM MCS 90: 4 streams; R=1/2, 256-QAM, 64-QAM, 16-QAM, 16-QAM John Ketchum, Qualcomm John Ketchum, Qualcomm

Effect of OBO on 256-QAM with Beamforming
May 2005 doc.: IEEE /0410r0 May 2005 Effect of OBO on 256-QAM with Beamforming 2x2, 4x4, 4x2 system configurations 802.11n Channel model B 5.25 GHz All impairments (PA nonlinearity, phase noise, frequency offset, timing offset) Channel estimation and acquisition per packet 7.2 us HT-LTF MIMO training PPDU length: 1000 bytes MCS’s from Extended MCS set 52 data subcarriers, 4 tracking pilots, full GI John Ketchum, Qualcomm John Ketchum, Qualcomm

2×2 Single Stream R=3/4, 256-QAM, (78 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 2×2 Single Stream R=3/4, 256-QAM, (78 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

2×2 Two Streams: R=3/4, 256-QAM, QPSK (97.5 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 2×2 Two Streams: R=3/4, 256-QAM, QPSK (97.5 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

4×2 Single Stream R=3/4, 256-QAM (78 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×2 Single Stream R=3/4, 256-QAM (78 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

4×2 Two Streams: R=3/4, 256-QAM, QPSK (97.5 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×2 Two Streams: R=3/4, 256-QAM, QPSK (97.5 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

4×2 Two Streams: R=3/4, 256-QAM, 16-QAM (117 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×2 Two Streams: R=3/4, 256-QAM, 16-QAM (117 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

4×4 Four Streams: R=1/2, 256-QAM, 16-QAM, QPSK, QPSK (104 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×4 Four Streams: R=1/2, 256-QAM, 16-QAM, QPSK, QPSK (104 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

4×4 Four Streams: R=3/4, 256-QAM, 256-QAM, QPSK, QPSK (195 Mbps)
May 2005 doc.: IEEE /0410r0 May 2005 4×4 Four Streams: R=3/4, 256-QAM, 256-QAM, QPSK, QPSK (195 Mbps) John Ketchum, Qualcomm John Ketchum, Qualcomm

TX EVM requirements for 256-QAM used in Beamforming
May 2005 doc.: IEEE /0410r0 May 2005 TX EVM requirements for 256-QAM used in Beamforming Tx EVM for 256-QAM for SISO application is ~-31 dB Beamforming gains complicate the extension of this value to beamforming MIMO application Because beamforming allows us to operate at lower SNRs, EVMs will be a lower percentage of total noise + interference than in SISO cases. This conclusion is supported by PER curves on previous slides. Conservative value for 2-Tx device is -31 dB Conservative value for 4-Tx device is -28 dB John Ketchum, Qualcomm John Ketchum, Qualcomm

Simulated EVM as a Function of OBO SISO 256-QAM R=3/4 No Phase Noise
May 2005 doc.: IEEE /0410r0 May 2005 Simulated EVM as a Function of OBO SISO 256-QAM R=3/4 No Phase Noise John Ketchum, Qualcomm John Ketchum, Qualcomm

PER VS SNR for Basic and Extended MCS
May 2005 doc.: IEEE /0410r0 May 2005 PER VS SNR for Basic and Extended MCS 2x2, 4x4, 4x2 system configurations 802.11n Channel model B 5.25 GHz All impairments (PA nonlinearity, phase noise, frequency offset, timing offset) Channel estimation and acquisition per packet 7.2 us HT-LTF MIMO training PPDU length: 1000 bytes Basic + Extended MCS 52 data subcarriers, 4 tracking pilots, full GI John Ketchum, Qualcomm John Ketchum, Qualcomm

Single-Stream Basic MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Single-Stream Basic MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

PERs for Basic MCS: 1 Spatial Stream, 2×2
May 2005 doc.: IEEE /0410r0 May 2005 PERs for Basic MCS: 1 Spatial Stream, 2×2 John Ketchum, Qualcomm John Ketchum, Qualcomm

Two-Stream Basic MCSs May 2005 May 2005 doc.: IEEE 802.11-05/0410r0

PERs for Basic MCS: 2 Spatial Streams, 2×2
May 2005 doc.: IEEE /0410r0 May 2005 PERs for Basic MCS: 2 Spatial Streams, 2×2 John Ketchum, Qualcomm John Ketchum, Qualcomm

One- and Two-Stream Extended MCSs
May 2005 doc.: IEEE /0410r0 May 2005 One- and Two-Stream Extended MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

PERs for Extended MCS: 1&2 Spatial Streams, 2×2
May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 1&2 Spatial Streams, 2×2 Use 256-QAM with R-3/4 John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 1&2 Spatial Streams, 4×2 John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 1&2 Spatial Streams, 4×4 Use 256-QAM with R=3/4 John Ketchum, Qualcomm John Ketchum, Qualcomm

Three-Stream Basic MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Three-Stream Basic MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

Four-Stream Basic MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Four-Stream Basic MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

Three-Stream R=1/2 Extended MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Three-Stream R=1/2 Extended MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

PERs for Extended MCS: 3 Spatial Streams, R=1/2, 4×4
May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 3 Spatial Streams, R=1/2, 4×4 Use 256-QAM with R=1/2 John Ketchum, Qualcomm John Ketchum, Qualcomm

Three-Stream R=3/4 Extended MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Three-Stream R=3/4 Extended MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 3 Spatial Streams, R=3/4, 4×4 Use 256-QAM with R=3/4 John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 3 Spatial Streams, R=3/4, 4×4 All use 256-QAM with R=3/4 John Ketchum, Qualcomm John Ketchum, Qualcomm

Four-Stream R=1/2 Extended MCSs
May 2005 doc.: IEEE /0410r0 May 2005 Four-Stream R=1/2 Extended MCSs John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 4 Spatial Streams, R=1/2, 4×4 None use 256-QAM John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 PERs for Extended MCS: 4 Spatial Streams, R=3/4, 4×4 None use 256-QAM John Ketchum, Qualcomm John Ketchum, Qualcomm

May 2005 doc.: IEEE /0410r0 May 2005 Conclusions Issues related to the size and practicality of the MCS sets proposed by TGn Sync have been addressed A full set of PER curves for channel model B and all 126 MCSs in 2x2, 4x2 and 4x4 channels (where applicable) have been presented TGn Sync is proposing a simple, stripped-down set of 16 mandatory MCSs that provide high performance basic spatial multiplexing functionality Additional optional MCSs provide substantially increased performance and throughput John Ketchum, Qualcomm John Ketchum, Qualcomm

Detailed Responses to “Reasons and Cures” Comments on MCS Set

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Detailed Responses to “Reasons and Cures” Comments on MCS Set

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