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Re: [STDS-802-11-TGBN] Agenda time request



Hi Dmitry,

 

Thank you for sharing this presentation prior to its scheduled presentation, it certainly needs more than 15 minutes read to be digested.

I have some comments which I am sharing here, as question time is limited in the meetings.

 

  1. How do you explain that no-repetition gives the best results in the 99th percentile even in the presence of hidden nodes? Maybe the simulation did not manage to produce collisions between hidden nodes to them significant (or maybe they are not significant for some reason)? Simplistically thinking, if we have only 2 non-AP STAs and they are hidden one to another, the DS is similar to a CTS-to-self which is not effective, so repetition by the AP should greatly help in such cases.
  2. An non-AP STA can experience a transmit failure due to many different reasons. I think it is important to limits STAs access to using DS, as it can be easily abused but not result in improvements. E.g. the non-AP STA transmits the PPDU using a PHY rate which does not have sufficient SNR to be received by the AP.
  3. Are you assuming that the non-AP STAs do not know what the LL traffic characteristics are and therefore this is the reason they use EDCA? I would imagine that the problem you are trying to solve would not have been created if the AP knew the traffic characteristics of the LL traffic and used one of the existing mechanisms available to service the UL (e.g. OFDMA, R-TWT).
  4. One of the existing features in 802.11, the ability to modify and advertise updated EDCA parameters can be used to mitigate the collisions experienced when the number of STAs in a BSS increases significantly. This is something I have not seen (in my limited time I have been participating in 802.11) being discussed/promoted, but I think it can be used to avoid/mitigate the collisions issue. It tries to solve the same issue by applying the opposite technique, basically increases the space of available backoff values so that collisions are reduced.
  5. If we were to adopt DS, I think we would need to introduce something to allow differentiating between the different existing LL priorities (AC_VO, AC_VI, a UP which has been promoted using Intra-Access Category Priority element, etc), otherwise we risk is compromising relevant priorities. A similar issue arises when STAs start experiencing reduced medium time due to other STAs start using the DS – an effect seen in the DL latency increasing is some simulation scenarios.
  6. Not directly related to your presentation, but I think we are reaching the point that the APs and the non-AP STAs have a number of opinions to select from to try and address the latency issue, so we are risking different devices even within the same BSS trying to use a different mechanism at the same time, in a way that the sum result is not positive. Perhaps we need to start thinking about a framework which will use the capabilities (and maybe preferences) of the devices and some authority/rules which decide which mechanism(s) is(/are) going to be used in order to provide the best results for the user. Is this something you have considered?

 

Kind regards,

Michail

 

From: Akhmetov, Dmitry <Dmitry.Akhmetov@xxxxxxxxx>
Sent: 11 March 2024 23:43
To: STDS-802-11-TGBN@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGBN] Agenda time request

 

Dear all,

 

There is a contribution 2126r1 https://mentor.ieee.org/802.11/dcn/23/11-23-2126-01-00bn-low-latency-channel-access-follow-up.pptx

scheduled for presentation tomorrow in PM1 session. The presentation talk about High Priority EDCA.

 

This presentation is pretty large (30+ slides).  Given announcement made by Alfred, the time for each presentation (as well as for  Q&A) will be limited , I’d like to ask people interested in low latency, channel access and preemption topics to review it beforehand.

 

Dmitry

 

From: Alfred Asterjadhi <asterjadhi@xxxxxxxxx>
Sent: Sunday, March 10, 2024 3:41 PM
To: Akhmetov, Dmitry <Dmitry.Akhmetov@xxxxxxxxx>
Subject: Re: [STDS-802-11-TGBN] Agenda time request

 

Acked with thanks.

 

Regards,


AA

 

On Fri, Mar 8, 2024 at 8:45 AM Akhmetov, Dmitry <Dmitry.Akhmetov@xxxxxxxxx> wrote:

Hi Alfred,

 

Please add the following 2 contributions to the MAC queue

 

11-24-0470-00-00bn-rethinking-latency

11-24-0467-00-00bn-low-latency-channel-access-impact

 

Dmitry

 

 


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--

Alfred Asterjadhi, PhD

IEEE802.11 TGbe/TGbn Chair,

Qualcomm Technologies Inc.

Cell #:    +1 858 263 9445

Office #: +1 858 658 5302


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