Re: Questions on direct-cabling 3x3 MIMO systems (ath9k)

[Ben Greear <greearb@candelatech.com>]

On 10/04/2012 03:36 PM, Julian Calaby wrote:
> Hi Ben,
>
> On Fri, Oct 5, 2012 at 4:49 AM, Ben Greear <greearb@candelatech.com> wrote:
>> I finally got my 3-attenuator system up and running,
>> and I'm starting to do some tests.
>>
>> AP and Station are running 3.5.5+, ath9k ar9380 NICs.
>> Channel 157, HT40, no encryption.
>>
>> One question right away:  Should I expect decent performance
>> if I directly cable 2 wifi NICs, where one is acting as AP and
>> the other as station?  I'm cabling ch0 to ch0, ch1 to ch1, ch2 to ch2.
>
> Going off on a tangent: arguably it shouldn't matter which channel on
> the AP card is connected to which channel on the STA card. I wonder
> what results you'd get if you cabled them in each combination and
> tested the throughput keeping the other variables the same. I also
> wonder what impact it would have on the throughput if you started
> disconnecting the cables.

I doubt it matters either....just seemed sane to start with something
I could easily keep track of in my head :)

I had really shitty performance when I had only one cable connected
to the station, but I think it is probably related to rate-control,
which seems too aggressive.  When I force things to slower speeds
it works fine.  I'm starting to look into that now.

I hope to eventually produce big pretty graphs reporting signal, rx-rate,
etc over various attenuations...but still got a ways to go first!

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com