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Hi, Carlos,
Sorry for my late response. Please find my answer to your questions in the below email. I hope the replies can answer your questions.
I look forward to hearing from you.
Regards!
Xiaoming.
Hi Carlos
Thank you for your following questions although we did not have chance to discuss it face to face last week.
I am on personal leave this week, I will try to get back to you on your questions ASAP next week. Sorry for my slow response.
Regards
Xiaoming
Sent from my iPhone
Hello Xiaoming,
First of all, let me apologize for not being able to attend last week’s F2F mtg. That said, I have been reviewing 11-13/0433r1 and have a few questions if you don’t mind:
1)
Slide 11 seems to imply that association, RSNA, etc., has to be redone every time a channel split takes place. Do you expect that once a channel split is done, that it would be long-lived?
[Reply]: In principal, the channel split is similar to the operation of channel switch. There is no need to redo association, RSNA, etc when a channel split takes place.
2)
A follow up question to question (1) above is whether you also expect to have usages of a small channel that are short-lived. In other words, a pair of devices may always rely on the large channel for control and management information
(e.g., BTI, A-BFT, ATI), and only switch to using a small channel when data transmission during the DTI is needed.
a.
The main advantages of doing this include:
i.
Complexity is much lower, since there is no need to have back-to-back NPs (which can be quite complex to implement), distributed synchronization, increased overhead due to additional BHI over each small channel, etc.
ii. There is no need to require association, RSNA, etc., once a channel split is done. In other words, this would still rely on the same PCP and PBSS.
b.
Has this been considered? Do you believe this would be simpler and should be supported by 11aj devices?
[Reply]: Yes, this has been considered. Based on my understanding, these are two different methods. The method you mentioned here can only offer 2 logical channels over Chinese 59-64GHz bands.
The proposed method in 11-13/0433r1 can offer at least three independent logical channels over Chinese 59-64GHz bands. To support at least 3 logical channel has been specified in the functional requirement of 802.11aj. Regarding the complexity of the proposed
method, only PCP/AP needs to handle NPs. Non-PCP/non-AP STAs in small band channel does not need to know NPs. From overall network perspective, I agree with that there is an increased overhead due to the additional BHI. However, I think this increment of the
overhead is minimal.
3)
Upon a decision to split a channel, how does a non-PCP/non-AP STA that was not the one issuing the Channel Split Request frame decide to which small channel to switch to?
[Reply]: PCP/AP 1 will inform non-PCP/non-AP STA that was not the one issuing the Channel Split Request frame to switch to a small band (i.e., channel 5, for example as shown in slide 11)
through a Channel Switch Announcement element contained in DMG Beacon/Announce frames.
4)
Has any work been done to look at whether the BF done for a large channel is valid in a small channel? In other words, does a pair of STAs have to re-do BF and potentially hold to sets of BF weights for the large and small channel?
[Reply]: In principal, for the channel switch from a large band channel to a small band channel, it will follow the similar way of the channel switch as described in 802.11ad specification. That
is to say, there is only one set of BF weight for a pari of STAs to hold.
5)
Assuming that the typical length of a BI on a large channel is 100ms, do you have any estimation on the length of a SBBI?
[Reply]: In slide 11, the length of Virtual BI (VBI) is the same as the length of BI on a large band channel. For illustration purpose in slide 11, it is shown that the length of VBI is the multiple
integers of the length of SBBI. However, the length of VBI can also be equal to the length of a SBBI. In your example, the typical length of a BI on a large band channel is 100ms, the typical length of a SBBI can also be 100ms.
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