1. Resolution to CIDs on 21.3.12.3 Date: 2006-08-10 Authors: August 2006
doc.: IEEE /1310r0
August 2006
Resolution to CIDs on
Date:
Authors:
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John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

2. August 2006
doc.: IEEE /1310r0
August 2006
Abstract
This document contains proposed changes to the IEEE P802.11n Draft to address the following LB84 comments:
263, 5073, 5074, 5075, 5076, 5077, 970
Resolution also effects 969
The changes marked in this document are based on TGn Draft version D1.02.
Text that resolves these comments is proposed in:
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John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

3. August 2006
doc.: IEEE /1310r0
August 2006
Comment Summary
263
Comment: “The equation Nsts,max = min(Ntx,Nrx) is not correct. For example, if Nrx = 1, then the min(Ntx,Nrx) = 1, which would imply that Nsts,max = 1 according to the previous equation. But we know that we can transmit STBC encode payloads using a single receive chain.”
Proposed change:” Update equation as follows: Nss,max = min(Ntx, Nrx)”
5073
Comment: “Incorrect statement, can support more than min(Ntx,Nrx) space-time streams. For example Ntx=2, Nrx=1, Nss=1, Nsts=2 with STBC”
Proposed change: “Replace "N_STS,max" with "N_SS, max", replace "space time streams" with "spatial streams"”
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

4. Comment Summary 5074 5075 5076 Comment: “Missing information”
August 2006
doc.: IEEE /1310r0
August 2006
Comment Summary
5074
Comment: “Missing information”
Proposed change: “Include: "The maximum number of space time streams, N_STS,max, may be determined from N_SS,max and the STBC field of the HT-SIG, as shown in Table n70."”
5075
Comment: “Staggered HT-LTFs are not defined”
Proposed change: “Replace "staggered" with "extension" or use "staggered preamble" instead”
5076
Comment: “Incorrect use”
Proposed change: “Replace "segmented" with "staggered preamble"”
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

5. Comment Summary 5077 970 Comment: “Incorrect equation”
August 2006
doc.: IEEE /1310r0
August 2006
Comment Summary
5077
Comment: “Incorrect equation”
Proposed change: “Replace "Nss=Nsts,max" with "Nss,max=Nsts,max"”
970
Comment: “Change "orthonormal steering matrix" to "orthonormal spatial mapping matrix"”
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

6. Summary of Issues Raised
August 2006
doc.: IEEE /1310r0
August 2006
Summary of Issues Raised
Improper terminology
Segmented PPDU is undefined
Staggered HT-LTF is undefined
The above two issues are addressed but not properly resolved in D1.02
Generalize “orthonormal steering” to “orthonormal spatial mapping”
Relationship between MIMO dimensionality and supportable number of space time streams is incorrectly characterized.
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

7. August 2006
doc.: IEEE /1310r0
August 2006
Summary of Sounding Requirements Channel Quality Assessment (MFB Determination)
Simplest case is when responding STA does MCS calculation just for the number of spatial streams in the current PPDU
In this case, the number of HT-LTFs is determined by the number of space time streams in the data portion, as for a non-sounding PPDU
General case is when responding STA does MCS calculation for all available spatial streams
This may require transmission of more HT-LTFs than are required for demodulation of data portion
This can be accomplished using extension HT-LTFs in a sounding PPDU with a data portion, or it can be accomplished with a ZLF
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

8. Determining Number of HT-LTFs for full dimensionality MCS Calculation
August 2006
doc.: IEEE /1310r0
August 2006
Determining Number of HT-LTFs for full dimensionality MCS Calculation
Depends on whether spatial mapping matrix is used or direct mapping is used
In the case of direct mapping, full sounding requires that HT-LTFs to sound NTX spatial dimensions be transmitted. This allows an estimate of the full channel matrix to be made.
When spatial mapping is used, without STBC, the maximum useful number of space time streams is determined by the minimum of NTX and NRX.
When STBC is used, with or without spatial mapping, the maximum useful number of space time streams is NTX.
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated

9. References 11-06-1309-00-000n-text-21-3-12-3.doc August 2006
doc.: IEEE /1310r0
August 2006
References
n-text doc
John Ketchum, Qualcomm
John Ketchum, Qualcomm Incorporated