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[STDS-802-11-TGAX] CR-MU Cascading

Hello Mark Rison,

I see you have two resubmitted comments with same suggested change as follows, they are not  the first round resubmission, at least more than two times. The following proposed changes were discussed in TGax F2F meeting several times while you were not in the room,  and the group did not think they are clear.

I  think your concern is that the definition of MU cascading in the spec is not clear. I would like to hear your further opinion and other people’s opinion

An MU cascading sequence is a frame exchange sequence between an AP and one or more non-AP STAs carried in an HE MU PPDU in the downlink and HE TB PPDU in the uplink and characterized by the exchange of Control, Data and/or Management frames in both directions. An example of an MU cascading sequence is shown in Figure 26-5 (An example of an MU cascading sequence).

Like CID 24328, you propose to add “In an MU cascading sequence at least one transmission by the AP is a triggering PPDU that contains an Ack or BlockAck frame.” It is not indeed true if we go through the original proposal 15/0841r1 on MU-cascading motion which was passed. In slide 13, it provides an example.

 

CID

Page

Clause

Comment

Proposed Change

24082

361.26

26.5.3

"An MU cascading sequence is a frame exchange sequence between an AP and one or more non-AP STAs carried in an HE MU PPDU in the downlink and HE TB PPDU in the uplink and characterized by the exchange of Control, Data and/or Management frames in both directions."

The key factor of the MU cascading is the exchange of Data and/or Management frames in both directions. Trigger frame that is a Control frame or A-Control that is not a Control frame can be both used to have the STAs transmit HE TB PPDU. And an Ack or a BlockAck frame that is a Control frame may not be transmitted at all if all the soliciting frames have No Ack policy.

Delete "Control, " from the cited sentence.

Add a note as follows, if necessary.

"NOTE - Trigger frames in downlink and Control frames such as Ack or BlockAck frames in downlink and/or uplink may be present accordingly to achieve exchanging Data/Management frames in both directions. A frame that carries a TRS Control subfield may be used instead of a Trigger frame according to the rules specified in 26.5.2 (UL MU operation)"

24328

361.25

26.5.3

"An MU cascading sequence is a frame exchange sequence between an AP and one or more non-AP STAs

carried in an HE MU PPDU in the downlink and HE TB PPDU in the uplink and characterized by the

exchange of Control, Data and/or Management frames in both directions." fails to capture the underlying requirement

After the cited sentence add "In an MU cascading sequence at least one transmission by the AP is a triggering PPDU that contains an Ack or BlockAck frame."

24329

361.25

26.5.3

It is not clear that in an MU cascading sequence there have to be MU PPDUs.  The definition just says "characterized by the

exchange of Control, Data and/or Management frames in both directions" and the only normative requirement is "transmit an A-MPDU to a non-AP STA that includes an Ack or BlockAck frame together

with a triggering frame"

Delete "HE MU PPDU in the downlink and" and delete "MU " in Figure 26-5--An example of an MU cascading sequence

24427

 

26.5.3

[Resubmission of comment withdrawn on D5.0] CID 20732.  The resolution is vague and not responsive to the comment "Re CID 16076: the comment was valid.  The normative requirement is that cascading is defined by the use of "an A-MPDU to a non-AP STA that includes an Ack or BlockAck frame together with a Trigger frame or a frame carrying a TRS Control subfield." (342.33)"

Change the first sentence of the referenced subclause to "An MU cascading sequence is a frame exchange sequence between an AP and a non-AP STA where at least one transmission by the AP is a triggering PPDU that includes an acknowledgment."

 

Best wishes

Ming Gan

 

 

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