November 2007doc.: IEEE 802.11-07/2719r1doc.: IEEE 802.11-07/2719r0

IEEE P802.11
Wireless LANs

LB115 Beam Comment Resolutions: Link Adaptation
Date: 2007-11-05
Author(s):
Name / Company / Address / Phone / email
Bjorn A. Bjerke / Qualcomm, Inc. / 9 Damonmill Sq. Suite 2A
Concord, MA01742, USA / +1 781-276-0912 /
5513 / 73.31 / 7.3.2.52.5 / According to the resolution to CID 1876 of LB97, the text related to the value 3 in the MCS feedback field means that the station supports at least one of the MCS feedback policies described in section 9.16.1. If my interpretation is correct I would suggest to use a more explicit sentence. / Replace the text with: "Set to 3 if the STA supports at least one of the MCS feedback policies as described in clause 9.16.1" / EDITOR: 2007-10-31 12:50:49Z - Transferred to Beam. In my view the text is quiet clear, it is set to 3 when the STA supports *both* policies. The proposed change ends up with the equivalent of "at least one of the policies - but I won't tell you which". Transferring as this is, as far as I can tell, asking for a technical change.
Counter. Insert clarifying statement in Table 7-43j
5845 / 155.09 / 9.16.2 / From line-9 to line-13, there is a description how to do with multiple HTC in an A-MPDU. However, now we have a general rule for it in 9.7a (page-118, line 51~55) that is not included in D2.0. So, the sentence here is not necessary, I think. / Remove "If the HT Control field is included in more than one +HTC frame within the same PPDU, the MRQ field and the MSI field in each +HTC frame shall be set to the same value." / Accept.
5658 / 155.09 / 9.16.2 / "If the HT Control field is included in more than one +HTC frame within the same PPDU, the MRQ field and
the MSI field in each +HTC frame shall be set to the same value."
This is unnecessary given 118.54: "The HT Control field of all MPDUs containing the HT Control field
aggregated in the same A-MPDU shall be set to the same value." / Delete first cited sentence. / See CID 5845.
5391 / 155.15 / 9.16.2 / There is no reason to send MRQ=1 in HTC with a non-sounding PPDU / change "should" to "shall", or add informative text explaining in what condition MRQ is sent in non-sounding PPDU / Counter. Change “should” to “shall” and delete “staggered” in the first bullet.
5660 / 155.55 / 9.16.2 / "On receipt of a +HTC frame with the MRQ field set to 1, the MFB responder initiates computation of the
MCS estimate and associates the result of this computation with the MSI value"
There's something not quite right here when the frame carrying the MRQ is an NDP announcement. / Replace with: "On receipt of a +HTC frame with the MRQ field set to 1, the MFB responder initiates computation of the MCS estimate based on the associated sounding PPDU and labels the result of this computation with the MSI value" / Accept.
5663 / 156.42 / 9.16.2 / "then it should use those matrices reported in Noncompressed Beamforming frame or a Compressed Beamforming frame with recommended MCS which is associated with it"
It is not clear if this is a constraint on the EXPANSION_MAT parameter, or the MCS parameter or both. / Rephrase in terms of TXVECTOR parameters and remove the ambiguity. / Counter. Delete Reword the sentence in question and change the preceding sentence to capture the spirit of the comment. See also resolution of CID 5664.
5664 / 156.47 / 9.16.2 / The inserted text has disturbed the logical order of this subcaluse. In line 41 we stop talking about the responder and talk about subsequent use of the response. Then in line 47 we start talking about the response again. / Move the sentence starting at line 41 into its own para at the end of this subclause. / Counter. Accept in principle. See also resolution of CID 5663.

TGn Editor: in Table 7-43j (Subfields of the HT Extended Capabilities field), in the row labelled “MCS feedback”, modify the third entry in the “Encoding” column as follows:

Set to 3 if the STA can provide MCS Feedback in response to MRQ (either Delayed or Immediate, see 9.16.1), as well as unsolicited MCS Feedback.

TGn Editor: in 9.16.2, page 155, line 9, delete the sentence that begins with “If the HT Control field is included…”.

TGn Editor: in 9.16.2, page 155, line 15, change the sentence and bulleted list as follows:

An MFB requester shouldshall transmit +HTC frames with the MRQ field set to 1 in one of the following two ways:

— within a staggered sounding PPDU, or

— with the NDP Announcement field in the +HTC frame set to 1 and following the +HTC frame by an

NDP transmission.

TGn Editor: in 9.16.2, page 155, change the paragraph that begins on line 55 as follows:

On receipt of a +HTC frame with the MRQ field set to 1, the MFB responder initiates computation of the
MCS estimate and associates the result of this computation with the MSI valuebased on the associated sounding PPDU and labels the result of this computation with the MSI value.

TGn Editor: in 9.16.2, page 156, change the paragraph that begins on line 38 as follows:

If the MCS feedback is to be sent in the same PPDU as a Non-compressed Beamforming frame or a Compressed Beamforming frame, the MFB responder should estimate the recommended MCS under the assumption that the MFB requester will use the steering matrices together with the recommended MCS contained therein. If the beamformer decides to employ Compressed Beamforming or Non-compressed Beamforming, then it should use those matrices reported in Noncompressed Beamforming frame or a Compressed Beamforming frame with recommended MCS which is associated with it.

TGn Editor: in 9.16.2, delete the sentence on page 156, line 41 that begins with “If the beamformer decides…”, and insert the following paragraph at the very end of 9.16.2, after Note 4 on or around page 157:

If a beamformer decides to employ Compressed Beamforming or Non-compressed Beamforming, then it should use the recommended MCS associated with those matrices reported in a Non-compressed Beamforming frame or a Compressed Beamforming frame.

Submissionpage 1Bjorn A. Bjerke, Qualcomm, Inc.