[Ns-developers] GSoC 2009 - Minstrel rate control algorithm

[Ruben Merz]

Hi Luciano,

Comments below,

On 3/31/09 4:32 PM, Luciano Jerez Chaves wrote:
> Hi Ruben,
>
> On Mon, Mar 30, 2009 at 17:36, Ruben Merz<ruben at net.t-labs.tu-berlin.de>  wrote:
>> Hi Luciano
>>
>> On 3/30/09 5:16 AM, Luciano Jerez Chaves wrote:
>>> Hi Ns-developers,
>>>
>>> My name is Luciano and I am a MSc Computer Science student at
>>> University of Campinas, Brazil.
>>>
>>> I'm working with Rate Adaptation solutions to wireless networks in
>>> my master's thesis and I'm interested in participating in Google
>>> Summer of Code this year.
>>>
>>> I've been looking for an idea in ns-3 wiki page and I found a interesting
>>> project to implement Minstrel rate control algorithm in ns-3.
>>>
>>> I believe it would be very motivating and helpful to me, since I'm
>>> evaluating my proposed algorithm based on simulations in ns-2.
>>> I've implemented two other different rate adaptations solutions in
>>> ns-2, using the dei802mr (develop by Nicola Baldo, and his team,
>>> at DEI) to compare my algorithm with.
>> Do you plan to also port these algorithms in ns-3?
>
> The algorithms that I implemented in ns-2 are the AARF (an extension
> of the original ARF), CARA, and my own solution, that I didn't finish
> yet.
>
> The initial idea was to port CARA and AARF to ns-3 in order to fairly
> compare my solution with all available implementations, but I figured
> out that the AARF is already implemented on it. Although, we still
> have CARA, and there are other solutions in the literature that could
> be incorporated into the ns-3 as far as possible.
>
>>> I think that a good implementation in ns-3 will contribute to my
>>> project and to many other people.
>>>
>>> I am still not familiar with the ns-3 code, but I figured out that
>>> there many others rate control algorithms implemented on it.
>>> I have good knowledge in C++ programming and about rate
>>> control in wireless networks. I'm currently studding the Minstrel
>>> algorithm, and I think that will be possible to successfully implement
>>> it in ns-3 during the GSoc program.
>> The rate control algorithms are all in src/devices/wifi. You can also go in
>> the example directory and grep for calls to SetRemoteStationManager.
>
> Looking in the suggested directory and in some rate control solutions
> there, it doesn't seem very difficult to implement a new rate control
> algorithm, since the code structure is well defined.

Good to hear. But what I'd like to hear from you is a more detailed plan 
than what you describe below. Minstrel has several components. There are 
(1) gathering the statistics for all the links (2) the moving average 
algorithm (3) the retry chain algorithm and (4) the rate lookaround 
algorithm.

How would you tackle those issues? For instance, gathering the 
statistics for all the links is something that might be of interest for 
the other rate control algorithms? So, it might be interesting to get a 
more general solution. The retry chain concept is something that is more 
related to the underlying hardware than the rate control algorithm in 
itself.

> I believe that it's possible to implement the Minstrel algorithms in
> something like five weeks or so.

As I said above, try to come up with a more detailed plan.

> Since the Minstrel solution is based solely in statistical measured
> performance with minimum of assumptions, the coding difficulty is
> linked to create a data structure that will be used by the algorithm
> (a table to store values for each destiny) and to obtain, from the

Typically, I'm not sure that a simple table would be the most efficient 
way. I'd rather advise a hash table or some tree structure.

I think you should also look into the linux kernel code that implements 
Minstrel: http://lxr.linux.no/linux+v2.6.29/net/mac80211/rc80211_minstrel.c

> simulated code, the performance metrics evaluated.
>
> After that, with the experience obtained with ns-3 programming, the
> code style, simulator structure and many other things, it will be
> possible to introduce other solutions.

Let's see. Before moving to other solutions, I'd like to see some 
validation and testing done. I don't know yet how, but this should be 
planned.

Once it's sure that the code performs reasonably well, I'll be happy to 
see some other rate control algorithm implemented.

>>> I would like a feedback about these project, and any suggestion
>>> that may arise. I would be happy with a mentor' contact.
>> Let me know if you have questions.
>
> I'm looking forward to hearing from you in order to improve my GSoC application.

Well, don't forget to submit you proposal on the gsoc website.

Best
Ruben

>> Best
>> Ruben
>>
>>> Best regards,
>>>
>>> --
>>> Luciano J. Chaves
>>> MSc Computer Science Student
>>> University of Campinas
>> --
>> Ruben Merz                   Deutsche Telekom Laboratories
>> http://www.net.t-labs.tu-berlin.de/people/ruben_merz.shtml
>>
>
> Regards
>
> --
> Luciano J. Chaves
> MSc Computer Science Student
> University of Campinas