[Make-wifi-fast] Fwd: [ath9k-devel] Bayesian rate control

[Dave Taht]

---------- Forwarded message ----------
From: Thomas Hühn <thomas at inet.tu-berlin.de>
Date: Tue, Oct 25, 2016 at 12:31 PM
Subject: Re: [ath9k-devel] Bayesian rate control
To: Björn Smedman <bjorn at openias.org>
Cc: ath9k-devel at lists.ath9k.org, linux-wireless ???
<linux-wireless at vger.kernel.org>



On 23 Oct 2016, at 15:57, Björn Smedman <bjorn at openias.org> wrote:

Hi all,

I've been thinking about rate control a bit lately. I've written up
some of my thoughts in a blog post
(http://www.openias.org/bayesian-wifi-rate-control), but very briefly
put I'd like to build a rate control algorithm based on Bayesian
statistical inference, possibly by modeling the rate control problem
as a "multi-armed bandit" problem and/or using Thompson sampling.

A couple of questions for the list:

1. Is there anybody else out there thinking along similar lines?

I'd very much like to find collaborators interested in working on
this. It could serve as a pretty nice masters thesis problem, for
example.

2. What would be the best hardware/software stack to base this work on?

I'm thinking the best driver for rate control experimentation would be
ath9k, right? If so then a TP-Link TL-WA901ND router (apparently based
on Qualcomm QCA956x SOC) with OpenWrt, and a TP-Link TL-WDN4800 PCIe
card (apparently based on Atheros AR9380 with PCI ID 168c:0030) for my
desktop sounds like a good combo, no? But would I have to run a custom
kernel on my desktop then (or can I somehow get by with an Ubuntu
standard kernel)?

Any other thoughts or pointers are also more than welcome.

Many thanks,

Björn Smedman
_______________________________________________
ath9k-devel mailing list
ath9k-devel at lists.ath9k.org
https://lists.ath9k.org/mailman/listinfo/ath9k-devel

Hi Bjoern,

Nice to have someone remembering me on a one year idea I have roughly
implemented but never got the paper ready :)
My comments are inline:

On 23 Oct 2016, at 15:57, Björn Smedman <bjorn at openias.org> wrote:

Hi all,

I've been thinking about rate control a bit lately. I've written up
some of my thoughts in a blog post
(http://www.openias.org/bayesian-wifi-rate-control), but very briefly
put I'd like to build a rate control algorithm based on Bayesian
statistical inference, possibly by modeling the rate control problem
as a "multi-armed bandit” problem and/or using Thompson sampling.


While I have designed and implemented Minstrel-Blues in ath5k and
mac80211 and digged into the rate control code, I observed several
parts that I would like to do differently as is seems there is room
for an improvement. Over time I started to look around for a proper
mathematical view on rate control and found the multi-armed-bandit
problem a very promising way to solve such a WiFi resource allocation
problem.
The two major publications that I used as motivation/guideline and my
proof of concept implementation:

https://people.kth.se/~alepro/pdf/infocom2014.pdf

jmlr.org/proceedings/papers/v23/agrawal12/agrawal12.pdf

Thompson Sampling is straight forward to understand/implement and to
apply to the rate problem as dynamic exploration vs. exploitation.
I have not played with the optimal solution by Gittins Index or the
UBC alternatives.
So I started detouring from power control and changed Minstrel’
Sampling to follow the Thompsons approach.
Each rate is a bandit with a changing value of expected reward and a
variance. And in each round the algo draws a random number from each
bandits beta distribution and play the one with the highest reward.
I had to solve certain computational issues. The major I just remember
while typing this email was that Thompson uses the Beta distribution.
And
in order to calculate the rate (rate bandit) with the most reward I
had to find a fast way of calculation a reverse Beta CDF that runs in
kernel space, so on intergers no floats… that was not an easy one.
The first tests were promising in terms of performance, but I focussed
on finishing tpc first and than come back to my rate control ideas …
so maybe it is the right time now :)

I have to look up my patch set of Thompson based Minstrel rate
control…by the end of the week I find the time.
… all my current rate control changes and WiFi work I do have on my
github repo: www.github.com/thuehn


A couple of questions for the list:

1. Is there anybody else out there thinking along similar lines?

I'd very much like to find collaborators interested in working on
this. It could serve as a pretty nice masters thesis problem, for
example.


As I am a postdoc at TU Berlin, I would like to collaborate with you.
So I would prefer to write a joint publication as paper .. in an open
fashion on github o share latex .. what do you think?
Are you working in academia or what kind of collaboration do you have in mind ?


2. What would be the best hardware/software stack to base this work on?

I'm thinking the best driver for rate control experimentation would be
ath9k, right?


As this is currently the most open and advanced driver to use with
mac80211 rate control, yes I would go for it.

If so then a TP-Link TL-WA901ND router (apparently based
on Qualcomm QCA956x SOC) with OpenWrt, and a TP-Link TL-WDN4800 PCIe
card (apparently based on Atheros AR9380 with PCI ID 168c:0030) for my
desktop sounds like a good combo, no? But would I have to run a custom
kernel on my desktop then (or can I somehow get by with an Ubuntu
standard kernel)?


My students and me do our daily linux wifi development under Linux
Lede trunk, PCengines APU with ath9k Atheros radios.


Any other thoughts or pointers are also more than welcome.


Greetings from Berlin
Thomas


Many thanks,

Björn Smedman
_______________________________________________
ath9k-devel mailing list
ath9k-devel at lists.ath9k.org
https://lists.ath9k.org/mailman/listinfo/ath9k-devel



_______________________________________________
ath9k-devel mailing list
ath9k-devel at lists.ath9k.org
https://lists.ath9k.org/mailman/listinfo/ath9k-devel



-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org