RE: Proposal for an S1G header for radiotap

Hi Johannes and Richard,

As to Aggregation related to A-MPDU, from 802.11ah -2016 spec it can be seen the field is defined in SIG-2 of SIG field of S1G_SHORT preamble, SIG-A2 of SIG-A field of S1G_LONG preamble, and SIG-2 of SIG field of S1G_1M preamble.

If looking at 802.11-2016 and Draft P802.11ax_D3.3 specs, the same field is defined only in HT-SIG, but not in VHT-SIG-A and VHT-SIG-B, and not in HE-SIG-A.

From the spec perspective regarding the Aggregation field, 802.11ah is different from 802.11n/ac/ax.

As you pointed out, Richard, if the existing field can be reused it might need some changes. If defining a new one, the existing one probably also needs to be handled. 

What would you suggest is the best way to tackle it?


Thanks,
Ray


-----Original Message-----
From: [email protected] [mailto:[email protected]] 
Sent: Friday, February 01, 2019 2:04 PM
To: 'Richard Sharpe' <[email protected]>; 'Johannes Berg' <[email protected]>
Cc: [email protected]; Ray Wang <[email protected]>; Tasheng Lin <[email protected]>
Subject: RE: Proposal for an S1G header for radiotap

Hi Johannes and Richard,

Thank you for your work and great comments.

For the S-MPDU issue, S-MPDU is same as VHT single MPDU in 802.11ac.
If there's pre-defined field for VHT single MPDU, we could use that.

For the S1G NDP issue, I found that there's PHDR_802_11_SOUNDING_PSDU for "0-length PSDU" field. That sounding PSDU means NDP sounding frame, I guess.
So I think we could add S1G NDP frames under "0-length PSDU" field.

--
Best,
Aaron J. Lee

-----Original Message-----
From: Richard Sharpe <[email protected]>
Sent: Friday, February 1, 2019 10:35 AM
To: Johannes Berg <[email protected]>
Cc: [email protected]; Aaron J. Lee <[email protected]>; Ray Wang <[email protected]>; [email protected]
Subject: Re: Proposal for an S1G header for radiotap

On Fri, Feb 1, 2019 at 3:33 AM Johannes Berg <[email protected]> wrote:
>
> Hi Richard,
>
> > Attached is a git format-patch patch that contains a proposal for an S1G header.
> >
> > This proposal was created by Aaron Lee and underwent a couple of 
> > rounds of modifications among the WFA folks.
> >
> > All I have done here is to transcribe it to the format required by 
> > the documentation web site. Hopefully I have not changed any intent.
>
> Thanks for doing this! :)
>
> > Below is some feedback from Johannes about the proposal so he does 
> > not have to retype it along with some comments from me.
>
> :-)
>
> Some *additional* feedback below - please do check my previous note 
> about aggregation handling, this is very unclear to me.

I will look at the other comments separately, but I think Aggegration relates to A-MPDU if I am reading section 9.7 of 802.11ah-2016 correctly.

In which case, we already have an A-MPDU header but we might need some changes. Perhaps the WFA folks or Aaron can comment on this/

--
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)(传说杜康是酒的发明者)