regards
于健 Ross Yu
Sent from Great Huawei Mate 40 Pro
Ross,
Thanks for the email. Looks like we did not have time to discuss this today. I agree OFDMA does not depend on B0.
Since as you pointed out that maximum allowed number of LTFs for multiuser transmissions is either 4 or 8 (with 16 reserved for R2), then if we just delete the sentence “If B0 is set to 0 then B3 and B4 are both reserved.” Then those two bits indicate the maximum number of supported LTFs for multiuser transmission (either 4 or 8).
Regards,
Steve
From: Yujian (Ross Yu) <ross.yujian@xxxxxxxxxx>
Sent: Monday, May 10, 2021 3:45 PM
To: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: 答复: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Hi all,
Rxing extra LTF for OFDMA case is mandatory in 11be, so it doesn’t rely on B0. B3-B4 is used to indicate if extra LTF is initial number of LTFs based on beamformee NSTS (at least be able to cover MU-MIMO) or 8 in 11ax, 11be can do similar.
Ross Jian Yu 于健
Huawei Technologies
发件人: Steve Shellhammer [mailto:sshellha@xxxxxxxxxxxxxxxx]
发送时间: 2021年5月11日 6:09
收件人:
STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Srinath,
The original two motions are listed below. These two motions were merged into a single capability field. That may be an issue. We can discuss on the call coming up.
Maybe it can be solved by making B3B4 reserved for non-OFDMA when B0 is 0, and set as needed for OFDMA.
Regards,
Steve
--------------------
The allowed values of maximum NLTF receive capability for multiple-user transmission are 4, 8, and 16.
- NOTE 1 – This capability is for both OFDMA and non-OFDMA MU-MIMO transmission.
- NOTE 2 – The value of maximum NLTF = 16 is available in R2.
[Motion 141, #SP261, [3] and [52]]
802.11be agrees that
- the number of EHT-LTF in NDP transmissions can be larger than the initial number of EHT-LTF determined by Nss;
- the support of extra LTF in NDP is optional for beamformee;
- the same capability fields for non-OFDMA data transmission to multiple users applies to NDP:
- The support of extra LTF is claimed by the capability bit of “Extra LTFs support for non-OFDMA PPDU”;
- The supported maximum number of EHT-LTFs in NDP is claimed by the capability field of “maximum number of LTFs supported for non-OFDMA data transmission to multiple users and NDP”.
[Motion 142, #SP296, [53] and [54]]
From: Srinath Sundaravaradhan <srinath.sundar@xxxxxxxxx>
Sent: Monday, May 10, 2021 1:48 PM
To: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>
Cc: TGBE <STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx>
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Hi Steve,
If B3-B4 also covers OFDMA, can it truly be reserved if B0=0?
Thanks,
-Srinath
On Mon, May 10, 2021 at 1:35 PM Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx> wrote:
Posted 755r2, with these changes.
Regards,
Steve
From: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>
Sent: Monday, May 10, 2021 1:13 PM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Xiaogang,
Yes, for B0=0, we should make B1B2 and B3B4 reserved.
I will post a revision in a bit.
Regards,
Steve
From: Chen, Xiaogang C <xiaogang.c.chen@xxxxxxxxx>
Sent: Monday, May 10, 2021 1:01 PM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Hi Wook Bong,
A counter example is a non-AP STA support maximum 2SS, so it can support up to 2 LTF SU reception. If we don’t have the capability to indicate whether that STA support extra LTF, then AP can chose to use 2 LTF (1 extra) to send 1ss. The intension of this capability is for a non-AP STA that has already optimized channel estimation and don’t need the extra LTF. For those STA the capability can save some LTF durations.
Hi Steve, Youhan
If B0 = 0, B3B4 set to reserved make sense.
B1B2 will also be set to reserved if B0 = 0?
BRs,
Xiaogang.
From: Wook Bong Lee <wookbong.lee@xxxxxxxxxxx>
Sent: Monday, May 10, 2021 12:32 PM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Hi Youhan, Xiaogang and Steve,
Do we need to mention whether a device is supporting extra LTF or not?
Can we just have how many LTFs it can process for SU?
If it is matching with its Nss value, then the device is not supporting extra LTF.
Best regards,
Wook Bong Lee
From: Steve Shellhammer [mailto:sshellha@xxxxxxxxxxxxxxxx]
Sent: Monday, May 10, 2021 12:28 PM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Youhan and Xiaogang,
Xiaogang, thanks for bringing up this point.
If B0 is zero, then Extra LTFs are not supported. So setting B3-B4 to 0, which is used to indicate a max of 4 LTFs, is not correct.
I agree with Youhan, that making those bit Reserved is correct.
If we do that, the B3-B4 does not have any impact on the number of supported LTFs, which I believe fixes the issue brought up by Xiaogang.
Xiaogang, do you agree that making them reserved solves this issue?
Regards,
Steve
From: Youhan Kim <youhank@xxxxxxxxxxxxxxxx>
Sent: Monday, May 10, 2021 11:43 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
How about “If B0 is set to 0 then B3 and B4 are both reserved”?
Thanks.
Youhan
From: Chen, Xiaogang C <xiaogang.c.chen@xxxxxxxxx>
Sent: Monday, May 10, 2021 11:36 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Sorry Steve, one more question regarding the B3B4 setting. If non-AP STA doesn’t support extra LTF, the text below means it can only support up to 4 LTF in sounding / MUMIMO and OFDMA? e.g. If AP has 8 antennas this STA can even not be fully sounded because it only receive up to 4 LTF (B0 = 0)? If that’s the correct understanding, I think we need to decouple B0 and B3,B4.
If B0 is set to 0 then B3 and B4 are both set to 0.
BRs,
Xiaogang.
From: Chen, Xiaogang C <xiaogang.c.chen@xxxxxxxxx>
Sent: Monday, May 10, 2021 10:57 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Hi Steve,
Regarding the text below, if a non-AP STA is capable of receive 2 SS and don’t support extra LTF reception (B0 = 0), then B1B2 set to 0 means it can still receive 4 LTF in single user transmission. So AP can still transmit 4 LTF where 2 out of the 4 LTF are extra. I guess it’s not a correct interpretation right?
If B0 is set to 0 then B1 and B2 are both set to 0.
BRs,
Xiaogang.
From: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>
Sent: Monday, May 10, 2021 9:41 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGBE] EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Ross,
You bring up a good point. I have revised the document (now 755r1), and dropped the text on “non-OFDMA” in the description of bits B3-B4.
Thanks for reminding me of that motion.
Regards,
Steve
From: Yujian (Ross Yu) <ross.yujian@xxxxxxxxxx>
Sent: Friday, May 7, 2021 6:51 PM
To: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: 答复: EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Hi Steve,
Then how about the OFDMA case?
We have the following motion:
The allowed values of maximum NLTF receive capability for multiple-user transmission are 4, 8, and 16.
- NOTE 1 – This capability is for both OFDMA and non-OFDMA MU-MIMO transmission.
- NOTE 2 – The value of maximum NLTF = 16 is available in R2.
[Motion 141, #SP261, [3] and [52]]
regards
于健 Ross Jian Yu
Huawei Technologies
发件人: Steve Shellhammer [mailto:sshellha@xxxxxxxxxxxxxxxx]
发送时间: 2021年5月8日 2:50
收件人: Yujian (Ross Yu) <ross.yujian@xxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: RE: EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
Hi Ross,
It is my understanding that this Extra LTF PHY Capability is for the non-OFDMA mode. As you can see B0 indicates support for this feature, where it is clear that it is for the non-OFDMA case. That is why we are providing clarifying text.
The main point of the edits is to clarify this is a receiver capability, which was unclear in the original text.
I hope this addresses your comment.
Regards,
Steve
From: Yujian (Ross Yu) <ross.yujian@xxxxxxxxxx>
Sent: Thursday, May 6, 2021 11:33 PM
To: Steve Shellhammer <sshellha@xxxxxxxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: 答复: EHT PHY Agenda Item - PDT Clarification Extra LTF PHY Capability
CAUTION: This email originated from outside of the organization.
Hi Steve,
B3-B4 previously covers OFDMA case, which is the case in 11ax. For OFDMA case, it indicates 8 or same as Beamformee NSTS capability.
regards
于健 Ross Jian Yu
Huawei Technologies
发件人: Steve Shellhammer [mailto:sshellha@xxxxxxxxxxxxxxxx]
发送时间: 2021年5月1日 7:42
收件人: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: [STDS-802-11-TGBE] EHT PHY Agenda Item
Alfred, Sigurd, and Tianyu,
Please add the following PDT to the PHY Agenda,
· Doc 11-21/755r0, PDT Clarification Extra LTF PHY Capability
Thanks,
Steve
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