From: Simonas Kazlauskas <iwd.lists.linux.dev@kazlauskas.me>
To: Denis Kenzior <denkenz@gmail.com>
Cc: James Prestwood <prestwoj@gmail.com>, iwd@lists.linux.dev
Subject: Re: Is the data rate estimation for 5GHz channels overly pessimistic?
Date: Tue, 24 Oct 2023 18:19:24 +0300 [thread overview]
Message-ID: <oo6afd4ygkvv47vthzqlvklqnm3gecjkkvhttrxlrmrqqb643t@6dzpfsigq6j6> (raw)
In-Reply-To: <3d2c3d76-e08c-4d71-8a72-7193dd51cbfc@gmail.com>
Denis Kenzior wrote:
>On 10/24/23 07:32, James Prestwood wrote:
>>So you could set:
>>[Rank].LowSignalRateThreshold=-90
>>
>>Any RSSI between -82 and -90 would use -82 for the rank calculation.
>>No idea how this would play out in practice, but its at least simple
>>and not tied to any given hardware.
>
>No, I was more thinking about:
>/* Added to the rssi value prior to looking up in the ht_vht_he_base_rssi */
>SensitivityFudgeFactor=4
>/* Width penalty */
>SensitivityWidthPenalty=0 (3 today)
>/* NSS penalty */
>SensitivityNSSPenalty=3
>/* Same as SensitivityFudgeFactor, but for HE */
>SensitivityHEFudgeFactor=10
My main worry then would be finding good defaults for these values. Ultimately,
unless `iwd` ends up in a place where people install it and get a great
experience in anything that involves ranking (roaming, initial association,
etc.), the WiFi experience on Linux may have a hard time shaking off its stigma.
If many has to modify some config variables to get a good experience, the
experience will continue staying subpar for the large majority still. Although
having the knobs will at least enable a minority to extract a reasonably good
experience.
What worries me in parituclar here is that if we tune these defaults too high
(i.e. estimate rate better than it might end up being in practice) then we might
end up associating with the AP that is too far away/weak to provide a
serviceable connection.
I wonder if there’s any place in here for some dynamic component that would
monitor how the NSS, MCS and other bandwidth affecting parameters behave for a
given SSID/BSSID/etc. as the RSSI varies, and transparently learn these
parameters throughout a… session (is that a term?) That way even if the
estimation for the very first association is too pessimistic, `iwd` can do
better when it needs to estimate again for e.g. a romaing decision or a new
association after a sleep.
With such a scheme in place “training” IWD would also be pretty easy to explain
to the users (walk around the area with your device connected to the network) if
they encountered problems with a particular AP.
S.
next prev parent reply other threads:[~2023-10-24 15:19 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-14 9:23 Is the data rate estimation for 5GHz channels overly pessimistic? Simonas Kazlauskas
2023-10-14 16:02 ` James Prestwood
2023-10-14 17:36 ` Denis Kenzior
2023-10-14 17:45 ` Simonas Kazlauskas
2023-10-14 18:07 ` Denis Kenzior
2023-10-15 19:40 ` Simonas Kazlauskas
2023-10-16 11:35 ` James Prestwood
2023-10-16 12:38 ` James Prestwood
2023-10-16 19:12 ` Denis Kenzior
2023-10-16 20:20 ` Simonas Kazlauskas
2023-10-21 23:23 ` Simonas Kazlauskas
2023-10-22 20:14 ` Denis Kenzior
2023-10-24 12:32 ` James Prestwood
2023-10-24 14:26 ` Denis Kenzior
2023-10-24 15:06 ` James Prestwood
2023-10-24 15:32 ` Denis Kenzior
2023-10-24 15:40 ` James Prestwood
2023-10-24 15:19 ` Simonas Kazlauskas [this message]
2023-10-24 15:29 ` Denis Kenzior
2023-10-16 18:36 ` Denis Kenzior
2023-10-14 17:42 ` Simonas Kazlauskas
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