Re: Fwd: Cannot achieve throughput higher than 460Mbps using CT firmware and 3x3 ath10k

[Ben Greear <greearb@candelatech.com>]

On 05/07/2015 09:04 AM, richard mayers wrote:
> If you mean orthogonal between receiver and transmitter I already
> tried and same results.
> 
> I also tried to lower the transmission power from 30dbm to 18, 6, 12..
> but nothing changed.


Assuming you have 3 antenna on each system.  Put two vertical on both AP and
station.  Put third horizontal (say, pointing east) on each system.  Make sure
the units are turned such that the east antenna on the two sysetms
are parallel with each other.

You might then try changing one of the verticals to be a bit offset as well
(maybe 45 deg from vertical, matching orientation with peer device).

Finally, you need to move to the country and test on a farm with all household
appliances powered off and no other house within 1/2 mile.  Make sure there are no
airports or other radar towers within 50 miles.  Then, maybe you will have clean
environment :)

You can also buy a $20,000 isolation chamber, which will help a bit.

On the cheap end, old metal filing cabinets provide a bit of isolation, and
inside a refrigerator might help as well.  I would be curious if being inside a turned-off
microwave also helped, in case someone has done such tests!

All that said, even in isolation chambers we see funky throughput on ath10k,
especially in 3.17 and newer kernels (our old hacked-upon 3.14 kernel seems
to work the most reliable for throughput, but I don't yet know why that is the case,
I suspect buffer-bloat related patches in newer kernels is causing issues on bulk
throughput tests, though mostly we see these problems with tcp traffic, not UDP).

Thanks,
Ben


> 
> Thanks,
> Richard
> 
> 2015-05-07 16:19 GMT+02:00 Ben Greear <greearb@candelatech.com>:
>> You tried your antenna at different orientations?  Seems they work better
>> when they are somewhat orthogonal to each other.
>>
>> Thanks,
>> Ben
>>
>>
>>
>> On 05/07/2015 12:52 AM, richard mayers wrote:
>>>
>>> ---------- Forwarded message ----------
>>> From: richard mayers <richard.mayers92@gmail.com>
>>> Date: 2015-05-07 9:51 GMT+02:00
>>> Subject: Re: Cannot achieve throughput higher than 460Mbps using CT
>>> firmware and 3x3 ath10k
>>> To: Michal Kazior <michal.kazior@tieto.com>
>>>
>>>
>>> Hi,
>>>
>>> Yes, with only one spatial stream I can use MCS9 and I get 290Mbps
>>> more or less, then with 2 spatial streams I can also use MCS 8, but as
>>> I said with 3 streams  I only get a "good throughput" with  MC6.
>>>
>>> Richard
>>>
>>> 2015-05-07 7:47 GMT+02:00 Michal Kazior <michal.kazior@tieto.com>:
>>>>
>>>> On 6 May 2015 at 17:01, richard mayers <richard.mayers92@gmail.com>
>>>> wrote:
>>>>>
>>>>> Hi all,
>>>>>
>>>>> The maximum throughput I get with the following set up is around
>>>>> 460-470Mbits/s when using MCS 6, 80MHz channel and 3 spatial streams.
>>>>> However, when I try MCS 7, the throughput drops to 200Mbits/s, and
>>>>> when I use 8 or 9 it goes to 0. The signal level is -11dBm which I
>>>>> guess is quite good.
>>>>
>>>>
>>>> Hmm.. From my experience too strong signal can degrade performance
>>>> with qca988x. You could try reducing it via `iw`. You could also try
>>>> checking if using only 2 spatial streams also yields problems with
>>>> MCS8 and MCS9.
>>>>
>>>> Antenna themselves might be the problem as well. Strong signal doesn't
>>>> mean good signal quality. If your antenna connector is damaged or
>>>> antenna is of poor quality you might end up not being able to use
>>>> highest MCS rates.
>>>>
>>>>
>>>> Michał
>>>
>>>
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>>>
>>
>> --
>> Ben Greear <greearb@candelatech.com>
>> Candela Technologies Inc  http://www.candelatech.com
> 


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


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