Hello Jonghoe,
Thank you very much for your detailed comments on Motion 14. We have been discussing this topic for several months, and I really appreciate your feedback and inputs.
While I understand your intention here, I suggest we focus on Motion 14 itself and do not mix different topics together. The key idea of Motion 14 is straightforward and simple,
which basically says we shall not have any Beacon transmissions in the mmWave link. Technical reasons for doing so are clearly specified in DCN1619r0 and have been reviewed and discussed in TGbq. However, the two suggested notes below are mixing other topics
that are irrelevant to this motion, some of which are still being discussed in the group. Personally, I prefer to separate them from this motion and therefore do not think it is appropriate to add either of them.
Let’s focus on your suggested note texts first.
- Note a says “This motion does not preclude the transmission of a frame by IMMW AP…”. Motion 14 text clearly says we are
only disallowing a specific frame in the mmWave link, which is Beacon frame. It does not talk about any other frames. So, this Motion has nothing to do any other frames that may be transmitted in the mmWave link. In this sense, I don’t see where “the transmission
of a frame by IMMW AP” is coming from given that you are using a generic wording “a frame” here.
- Note b says “This motion prevents unassociated non-AP IMMW STA from discovering an IMMW AP on the mmW channel and measuring
link quality.” Beacon frame is indeed a method of discovery, but as you also correctly said in your email, we have not concluded on “no probe request/response frame” yet. So, disallowing Beacon frame transmission in mmWave band does prevent the in-band discovery
via the Beacon frame, but saying this motion completely prevents unassociated non-AP IMMW STA from discovering an IMMW AP on the mmWave channel is technically wrong and not part of Motion 14 itself. If you really want to clarify the impact of this motion on
in-band discovery here, the correct statement should be “This motion prevents unassociated non-AP IMMW STA from discovering an IMMW AP on the mmW channel and measuring link quality
through Beacon frame.”
Let’s then talk more about your technical points.
- Based on my previous discussions with you, your main technical point is that you would like to define a
configurable semi-persistent frame transmitted by the IMMW AP in the mmWave link that is primarily used for
beam discovery. So, this frame is not necessarily always transmitted, but if it is transmitted, it can be configured to semi-persistent. The main function for this frame is for initial beamforming in the mmWave link. As I have
explained multiple times, I don’t think it is appropriate to call a configurable semi-persistent frame that is mainly used for initial Beamforming the Beacon frame, which instead, is always transmitted in a periodic manner and is mainly used for discovery
and BSS management. If you would like to propose such a frame for 11bq, you are welcome to bring a separate proposal and a separate SP specifically for this “Beam Discovery frame” (you can call it whatever you prefer), and it is up to the TG to decide whether
we need such a frame or not.
- You were also asking if we do not have a Beacon frame, how we can carry the AP identifier and TSF information for the
IMWW AP. I have responded to you that both of these can be addressed in the sub-7 GHz. For example, the TSF offset between the mmWave link and the sub-7.25 GHz links can be included in the Multi-link element, which is already enabled in the MLO framework defined
in 11be. Several other contributions also share the same view with mine, including DCN1126, DCN431.
Because of the preceding considerations, I prefer to keep Motion 14 text as it is and do not add any additional notes. However, I am open for more discussion with the group and
will be glad to hear more opinions when running Motion 14 tomorrow at PM1 session.
Thanks again for all the discussions.
Best,
Cheng
From: jh89.koo@xxxxxxxxxxx <jh89.koo@xxxxxxxxxxx>
Sent: Wednesday, January 14, 2026 5:14 PM
To: Chen, Cheng <cheng.chen@xxxxxxxxx>; STDS-802-11-TGBQ@xxxxxxxxxxxxxxxxx
Subject: Suggestion for adding a note to Motion 14
Hi Cheng,
Regarding Motion 14 scheduled for Thursday PM1, I would like to request the addition of a note for technical clarification on the intention behind Motion 14 and its impact on the overall design.
Motion 14(MAC): Move to add the following text to the 11bq SFD:
- There is no Beacon frame transmitted in the mmWave ink by an IMMW AP
To clarify the technical scope after approving this motion, I suggest adding one of the two notes below, which are mutually exclusive, depending on your perspective.
- Note a: This motion does not preclude the transmission of a frame by IMMW AP to enable an un associated non-AP IMMW STA to discover the IMMW AP on the mmW channel and measure
link quality.
- Note b: This motion prevents unassociated non-AP IMMW STA from discovering an IMMW AP on the mmW channel and measuring link quality.
If you wish to close the door on this issue, please add Note b (even though we haven't agreed on 'no probe request/response frame').
If you prefer to keep it open, Note a can be helpful.
I would suggest adding Note a.
The intention behind this is to confirm whether you agree with the potential impact of this motion, particularly focusing on disabling beam discovery and reachability checks for unassociated non-AP IMMW STAs.
Additionally, it would be greatly appreciated if you could share your thoughts on whether this should remain a limitation of TGbq devices due to a simple technical scope/design, or if you are open to defining a mechanism to provide a supplemental
method for beam discovery/reachability checks that can be utilized by both unassociated and associated non-AP STAs.
Please note that I understand the need to keep the IMMW design as simple as possible, prioritizing cost reduction over performance.
Thus, I generally agree that transmitting beacons over mmW is redundant and unnecessary.
However, I have a concern about losing the functionality for an unassociated non-AP STA MLD to accurately assess mmW reachability.
Sub-7 GHz signal-based reachability checks are not stable or accurate.
In certain cases, it is useful for an unassociated non-AP IMMW STA to verify the presence of a communicable IMMW AP in the vicinity before deciding to use the mmW link and performing ML setup.
If we eliminate all in-band discovery mechanisms, the non-AP MLD would have to perform ML setup via the sub-7 GHz link and then proceed with beam establishment to locate a communicable IMMW AP.
This issue becomes more problematic when there are multiple candidate AP MLDs discovered via the sub-7 GHz band, especially if the non-AP MLD aims to associate with the best AP MLD affiliated with the IMMW AP providing optimal service.
Conducting an exhaustive search to identify the best option imposes a significant burden and overhead on the non-AP MLD.
Furthermore, relying solely on sub-7 GHz signal quality to assess mmW link quality is inaccurate.
Regards,
Jonghoe Koo
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