Re: [STDS-802-11-TGBE] Clarification question on 813r0

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Hi Sang,

Thank you for the detailed questions and feedback. Please see inline below.

Regards,

Dibakar

From: SANG GOOK KIM <sanggook.kim@xxxxxxx>
Sent: Wednesday, June 10, 2020 1:40 PM
To: Das, Dibakar <dibakar.das@xxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: RE: Clarification question on 813r0

Hello Dibakar

Thanks for sharing the contribution and your thought for the questions from Rojan below.

I have a few more my understanding:

Based on your contribution, it seems that P2P transmission is initiated by AP. Is it correct? [Yes.] On the other hand, STA may initiate P2P transmission by requesting the permission to AP. If so, can your contribution address that?
Even though, you are focusing on data transmission aspect, it is important for AP to know the intention for P2P transmission from STA(s) with that capability. Otherwise, the resource(s) may be wasted.

[I interpret questions 1 and 2 as whether we also allow the P2P STA to request an AP to be allocated, followed by TF+P2P exchange as shown in the slides. If so, this is related to the question #3 from Rojan. We feel its not critical to define new signaling in spec for this purpose as such signaling already exists in spec (e.g., TSPEC) or that some AP implementations can estimate the need based on internal algorithms.

However, if the group feels strongly about it, we can also consider a simple signaling for non-AP STA to indicate presence of P2P traffic to an AP. As a simple example, we can consider a solution similar to 11-20-463r3 (the SP for which the group passed unanimously today) where a new TID value was used in QoS Control field to signal the presence of P2P traffic. We can also consider other even simpler solutions.]

Peer STA may not know the channel between it and other STA for P2P transmission. In slide 6, there is a designation for “ Data from peer STA to other peer”. Can this include the frame exchanges for channel estimation?

[Yes, this was just an example. The intention is to allow any frame exchange subject to individual peer’s capabilities. Btw please note that we are not defining the capability exchange between the P2P STAs as that could be proprietary.]

I am supportive of this concept, but we need further solid thought for missing parts.

[Thanks for the support of the concept. It seems to me based on both yours and Rojan’s comments the main missing part is about signaling P2P traffic to the AP. Hopefully we now have a complete picture about the whole concept and scope of the solution-space. We can discuss more offline.]

Best regards,

Sang

From: Das, Dibakar [mailto:dibakar.das@xxxxxxxxx]
Sent: Wednesday, June 10, 2020 9:23 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] Clarification question on 813r0

Hi Rojan,

Thank you for reviewing the document and the valuable feedback. Please see my response inline below.

Regards,

Dibakar

From: rojan.chitrakar@xxxxxxxxxxxxxxxx <rojan.chitrakar@xxxxxxxxxxxxxxxx>
Sent: Tuesday, June 9, 2020 6:43 PM
To: Das, Dibakar <dibakar.das@xxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: RE: Clarification question on 813r0

Hi Dibakar,

Thanks for sharing. Few questions:

1) Slide 6: Why is the TBD response frame from peer STA required? Doesn’t the subsequent Data frame suffice? Why is this different from the case of TB PPDUs?

[DD: We were thinking of (a) having a clear signaling to the AP about whether the allocation is going to be used and (b) maintain the 11ax TB operation principle where STA responds in SIFS time to the triggering AP. The mechanism may also work without the Ack part in which case the AP can recover after PIFS if it does not detect energy in medium but that may not be as clean. If there is a huge objection, we can take this part out in next revision until we have more discussion offline.]

2) Slide 6: can you elaborate the sentence “Peer STA uses the allocation for any purpose including peer-to-peer communication.”? E.g. can the allocation be used for uplink transmissions to the AP? I think this will complicate the procedure since now the AP is unsure what to expect.

[DD: We were thinking that the purpose of the TF was simply to grant resource to the peer STA and note that the peer STA is free to transmit any type of frame in that time. Clearly, this does not work if peer STA transmits HE/EHT TB PPDU to AP but works if the peer simply transmits regular SU packets to the AP. However, since the focus of this submission is P2P communication, I agree to remove this text in next revision.]

3) The contribution doesn’t address the issue of how the AP knows when to share the TXOP for the peer STAs. In fact how is the AP even aware of the existence of P2P STAs in the BSS? E.g. TDLP setup frames are transparent to the AP since they are encapsulated in Data frames. Also, BSR reports will likely need special consideration for P2P traffic, right?

[DD: We were trying to focus on just the main feature of frame exchange and did not bring the other discussions here. However, we think only the following are needed beyond whats captured in the slides:

Basic capability exchange: during association, STA and AP discover each others’ TB P2P capability. We perhaps do not need to say anything about how the P2P STAs find each other as that can be a proprietary or non-IEEE protocol.
Dynamic resource-request: In general, something equivalent to BSR may be all we need. This can be as simple as using a frame whose QoS Ctrl field has TID > 7 or a new A-Ctrl field at worst. However, we don’t think this is very critical since the usage of BSR is optional in 11ax as well. The AP may as well have an internal scheduling algorithm that allocates resource to P2P STA by observing history of past transmissions without defining new signaling in the spec. There are also other existing things in spec, such as TSPEC with Direction subfield set to “01”, that can be used by some implementations to signal P2P traffic.]

I am supportive of the use case but I think it is important to address #3 as well before we can decide whether this is really as simple as portraited.

[DD: Thank you for the support on the use-case. Please let us know if issue #3 is addressed.]

Regards,

Rojan

Hi Dibakar,

Thanks for sharing. Few questions:

1) Slide 6: Why is the TBD response frame from peer STA required? Doesn’t the subsequent Data frame suffice? Why is this different from the case of TB PPDUs?

I am supportive of the use case but I think it is important to address #3 as well before we can decide whether this is really as simple as portraited.

Regards,

Rojan

From: Das, Dibakar <dibakar.das@xxxxxxxxx>
Sent: Wednesday, June 10, 2020 2:20 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] Clarification question on 813r0

Hi Stephane and others,

We also think that the Triggered P2P is a very useful feature for supporting P2P applications and improving the overall QoS performance of the BSS in 11be. In order to achieve this in Release 1 without significant spec additions and delaying the timeline, we have uploaded a presentation 11-20-871r1 proposing very simple Trigger based P2P operation. Overall, our thoughts seem to be aligned with what Stephane has. The main features are following:

Limit scope of trigger based P2P for just the cases where the peer STA is associated to triggering AP (slide 5). This is then similar to TDLS use-cases.
To simplify AP’s channel access mechanism, allocate either the entire TXOP to a P2P STA or the rest of the TXOP to a peer STA.

Please review offline and share your views.

Regards,

Dibakar

From: BARON Stephane <Stephane.BARON@xxxxxxxxxxxx>
Sent: Thursday, May 28, 2020 10:48 AM
To: Das, Dibakar <dibakar.das@xxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: RE: Clarification question on 813r0

Hi Dibakar,

I see your point, and I agree not to limit the mechanism to the cascading.

I also clarify that at least in R1, the scheduled station is associated to the AP (even if its peer is potentially outside of the BSS)

So I propose to amend my SP text as follow.

“Do you support that 11be defines a procedure for an AP to share a part of the obtained TXOP for peer-to-peer (STA-to-STA) frame exchanges by signaling an RU for P2P communication in a trigger frame, the “UL Length” field specifying the allocated time for the peer to peer communication, and the RU being allocated to a non-AP STA associated to the AP?

Note: The trigger frame may be included in a cascading sequence.”

Best regards.

Stéphane.

From: Das, Dibakar <dibakar.das@xxxxxxxxx>
Sent: jeudi 28 mai 2020 16:17
To: BARON Stephane <Stephane.BARON@xxxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: RE: Clarification question on 813r0

Hi Stephane,

Thank you for providing the clarification below on the cascade sequence.

At a high-level, we are supportive of this overall simplified sequence for R1 as it requires minimal change in spec while significantly improving medium efficiency and potentially reducing peak latency. Based on the discussion below though we suggest revising the SP text to allow both cascade and non-cascade sequence.

Preferably we will like to remove reference to the Cascade sequence altogether since its more of an implementation choice at AP. We can perhaps instead focus on limiting the scope of the triggered P2P in R1 (e.g., limit only to associated peer STA,…). What do you think ?

Regards,

Dibakar

From: BARON Stephane <Stephane.BARON@xxxxxxxxxxxx>
Sent: Thursday, May 28, 2020 2:51 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] Clarification question on 813r0

Hi Ross,

Thank you for your question.

I think this up to the AP to include the TF triggering with a P2P RU in a cascading sequence or not.

So yes, a simplified sequence as you mention is possible.

However, I think that including a TF for P2P transmission in a cascading sequence provides additional benefits:

The AP have more flexibility to share a TxOp for UL, DL, or P2P.
By using additional information like a “More TF” information, a P2P station can avoid immediate ack from its peer (and then save multiple SIFS overhead) if it is confident that another opportunity will come later in the same TxOp (for instance another time slot allocated to the other peer).

So, to me, the TF triggering a P2P transmission can be in or out of the scope of a cascading sequence, but have more benefits in a cascading sequence.

Best regards.

Stéphane.

From: Yujian (Ross Yu) <ross.yujian@xxxxxxxxxx>
Sent: mardi 26 mai 2020 03:10
To: BARON Stephane <Stephane.BARON@xxxxxxxxxxxx>
Cc: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Clarification question on 813r0

Hi Stephane,

Thanks for preparing the contribution. Could you clarify if the whole (not part of) TXOP can be shared to the triggered P2P transmission or not? In other words, does it have to be combined with MU cascading sequence in slide 4? How about a simple procedure like this?

PS: I usually attend PHY calls, so may not have the chance to ask questions after your presentation. That’s why I send the clarification question here in advance. Thanks.

regards

于健 Ross Yu

Huawei Technologies

发件人: BARON Stephane [mailto:Stephane.BARON@xxxxxxxxxxxx]
发送时间: 2020年5月26日 2:55
收件人: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-11-TGBE] TGbe Conf Calls [May-July 2020]: Call For Submissions

Hi Alfred,

Can you please add the following contribution to the list:

11-20/0813r0 : triggered p2p transmissions follow up (Stephane Baron, Canon), MAC : Medium Access

Best regards.

Stéphane.

From: Alfred Asterjadhi <asterjadhi@xxxxxxxxx>
Sent: dimanche 10 mai 2020 20:14
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGBE] TGbe Conf Calls [May-July 2020]: Call For Submissions

Hello all,

This is a call for submissions for the upcoming teleconference calls meeting.

Please let me know if you have any items to be added to the agenda by sending me an e-mail with a request using the format below:

- DCN-Presentation Title (Author, Affiliation), Topic

Also please ensure that the presentation is uploaded at least one week prior to the conference call as I will include the links to the presentations in the Submission's list. If the contribution is not uploaded by that time then it may not be included in the list.

PS - There is no need to send an additional request for contributions that are already present in the conf call queue as they will be imported by default to the Back-Logged Submission's List.

Best Regards,

Alfred

Alfred Asterjadhi, PhD

IEEE802.11 TGbe Chair,

Qualcomm Technologies Inc.

asterjadhi@xxxxxxxxx

aasterja@xxxxxxxxxxxxxxxx

Cell #: +1 858 263 9445

Office #: +1 858 658 5302

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