[ath9k-devel] spectral scan

[ath9k-devel] spectral scan

[Simone Di Domenico]

Hi All,
I am a newbie of Atheros WiFi chipsets and I am trying to use the spectral
scan feature available on AR9280.
It's working fine, but I would understand in details the type of data
returned from che chipset.
In particular, I would know if the FFT data are related to the received
signal (let me denote with Y) or to the channel estimation (let me denote
with H), also known as CSI.
My doubt arises from the fact that spectral scan does not require to be
connected to any APs to work.

Thanks in advance for any help and suggestions.
BR,

Simone
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[ath9k-devel] spectral scan

[Adrian Chadd]

hi,

it should be Y.


-a


On 7 November 2016 at 03:34, Simone Di Domenico
<simone.didomenico90@gmail.com> wrote:
> Hi All,
> I am a newbie of Atheros WiFi chipsets and I am trying to use the spectral
> scan feature available on AR9280.
> It's working fine, but I would understand in details the type of data
> returned from che chipset.
> In particular, I would know if the FFT data are related to the received
> signal (let me denote with Y) or to the channel estimation (let me denote
> with H), also known as CSI.
> My doubt arises from the fact that spectral scan does not require to be
> connected to any APs to work.
>
> Thanks in advance for any help and suggestions.
> BR,
>
> Simone
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>

[ath9k-devel] Spectral Scan

[Adrian Chadd]

Hi,

The NIC is either receiving frames or doing spectral scan. It can't
unfortunately do both.


-a


On 23 July 2014 13:34, mahaveer gupta <mgupta1616@gmail.com> wrote:
> Thanks for the answer. Indeed, we thought similar to what you suggest but
> realized that the actual packets still need to be decoded to be able to
> match the spectral samples with decoded packets (by matching the hardware
> timestamp values). Hence this was a little tricky.
>
> If we use a 40Mhz scan on a 20MHz transmission, how would it be possible to
> distinguish the spectral samples corresponding to 20MHz packets and those
> corresponding to background noise.
>
> RSSI could be a weak discriminator.
>
>
> On Wed, Jul 23, 2014 at 2:50 PM, Kamran Nishat <kamran.nishat@gmail.com>
> wrote:
>>
>> hi
>> yes this is the expected behaviour. one can only get spectral scans for
>> things cannot be decoded as valid packets by HW. One way to receive scans
>> for packets is to scan on 40MHz channel while sending traffic  on a 20Mhz
>> sub channel.
>>
>> kamran
>>
>>
>> On Thu, Jul 24, 2014 at 12:29 AM, mahaveer gupta <mgupta1616@gmail.com>
>> wrote:
>>>
>>> Hello,
>>>
>>> We have been able to use the spectral scan feature successfully -
>>> http://wireless.kernel.org/en/users/Drivers/ath9k/spectral_scan
>>>
>>> However, samples are being skipped while the device is receiving packets.
>>> The spectral samples we see correspond to background noise while no packet
>>> is being received.
>>>
>>> Wondering if this behavior is expected and if yes, kindly let me know if
>>> you have a suggestion to change that. We would like to see the spectral
>>> samples corresponding to successfully decoded packets. We tried all three
>>> modes without any success so far.
>>>
>>> We are using AR 9271 Chipset with the usual firmware.
>>>
>>> --
>>> Thanks,
>>> M
>>>
>>> _______________________________________________
>>> ath9k-devel mailing list
>>> ath9k-devel at lists.ath9k.org
>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>
>>
>
>
>
> --
> Thanks,
> M
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>

[ath9k-devel] Spectral Scan

[mahaveer gupta]

Thanks for the answer. Indeed, we thought similar to what you suggest but
realized that the actual packets still need to be decoded to be able to
match the spectral samples with decoded packets (by matching the hardware
timestamp values). Hence this was a little tricky.

If we use a 40Mhz scan on a 20MHz transmission, how would it be possible to
distinguish the spectral samples corresponding to 20MHz packets and those
corresponding to background noise.

RSSI could be a weak discriminator.


On Wed, Jul 23, 2014 at 2:50 PM, Kamran Nishat <kamran.nishat@gmail.com>
wrote:

> hi
> yes this is the expected behaviour. one can only get spectral scans for
> things cannot be decoded as valid packets by HW. One way to receive scans
> for packets is to scan on 40MHz channel while sending traffic  on a 20Mhz
> sub channel.
>
> kamran
>
>
> On Thu, Jul 24, 2014 at 12:29 AM, mahaveer gupta <mgupta1616@gmail.com>
> wrote:
>
>> Hello,
>>
>> We have been able to use the spectral scan feature successfully -
>> http://wireless.kernel.org/en/users/Drivers/ath9k/spectral_scan
>>
>> However, samples are being skipped while the device is receiving packets.
>> The spectral samples we see correspond to background noise while no packet
>> is being received.
>>
>> Wondering if this behavior is expected and if yes, kindly let me know if
>> you have a suggestion to change that. We would like to see the spectral
>> samples corresponding to successfully decoded packets. We tried all three
>> modes without any success so far.
>>
>> We are using AR 9271 Chipset with the usual firmware.
>>
>> --
>> Thanks,
>> M
>>
>> _______________________________________________
>> ath9k-devel mailing list
>> ath9k-devel at lists.ath9k.org
>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>
>>
>


-- 
Thanks,
M
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[ath9k-devel] Spectral Scan

[Kamran Nishat]

hi
yes this is the expected behaviour. one can only get spectral scans for
things cannot be decoded as valid packets by HW. One way to receive scans
for packets is to scan on 40MHz channel while sending traffic  on a 20Mhz
sub channel.

kamran


On Thu, Jul 24, 2014 at 12:29 AM, mahaveer gupta <mgupta1616@gmail.com>
wrote:

> Hello,
>
> We have been able to use the spectral scan feature successfully -
> http://wireless.kernel.org/en/users/Drivers/ath9k/spectral_scan
>
> However, samples are being skipped while the device is receiving packets.
> The spectral samples we see correspond to background noise while no packet
> is being received.
>
> Wondering if this behavior is expected and if yes, kindly let me know if
> you have a suggestion to change that. We would like to see the spectral
> samples corresponding to successfully decoded packets. We tried all three
> modes without any success so far.
>
> We are using AR 9271 Chipset with the usual firmware.
>
> --
> Thanks,
> M
>
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>
>
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[ath9k-devel] Spectral Scan

[mahaveer gupta]

Hello,

We have been able to use the spectral scan feature successfully -
http://wireless.kernel.org/en/users/Drivers/ath9k/spectral_scan

However, samples are being skipped while the device is receiving packets.
The spectral samples we see correspond to background noise while no packet
is being received.

Wondering if this behavior is expected and if yes, kindly let me know if
you have a suggestion to change that. We would like to see the spectral
samples corresponding to successfully decoded packets. We tried all three
modes without any success so far.

We are using AR 9271 Chipset with the usual firmware.

-- 
Thanks,
M
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