[ath9k-devel] Low speeds when AP is very close to stations.

[ath9k-devel] Low speeds when AP is very close to stations.

[Ben Greear]

I put two ath9k (AR9300) nics in one machine, with
6 antenna poking out, and had one NIC be the AP
for the other.

It works, but I'm seeing lots of CRC errors and station-to-station throughput
is only about 5Mbps (one sending to the other).

I tried setting xmit power lower (to 4, for instance), but that
doesn't change the behaviour much.

Any suggestions for other tricks that might make this work
better?

Here's the lspci info for my adapters:

03:00.0 Network controller: Atheros Communications Inc. AR9300 Wireless LAN adaptor (rev 01)
04:00.0 Network controller: Atheros Communications Inc. AR9300 Wireless LAN adaptor (rev 01)

Thanks,
Ben

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

[ath9k-devel] Low speeds when AP is very close to stations.

[Ben Greear]

On 03/07/2012 01:17 PM, Ben Greear wrote:
> I put two ath9k (AR9300) nics in one machine, with
> 6 antenna poking out, and had one NIC be the AP
> for the other.

I was using TCP before on 3.3.0-rc5+...
I upgraded to 3.3.0-rc6+, and saw around 10Mbps performance.
I tried 3.0.23 and saw around 19Mbps.

And, I tried UDP on the 3.3.0-rc6+ and it runs a full
20Mbps with a few drops.  I still see lots of RX-CRC and
some RX-Frame errors reported by the NIC
(as seen in /debug/ieee80211/wiphy0/ath9k/recv),
but maybe things aren't as bad as they first appeared.

The stations are still bouncing around in their rate
control algorithm..typically under 200Mbps (NIC should
support up to 450Mbps), however.

The signal stays at around -12, and noise seems a constant -88.

Thanks,
Ben

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

[ath9k-devel] Low speeds when AP is very close to stations.

[Adrian Chadd]

On 7 March 2012 13:17, Ben Greear <greearb@candelatech.com> wrote:
> I put two ath9k (AR9300) nics in one machine, with
> 6 antenna poking out, and had one NIC be the AP
> for the other.

How far apart are there?

> It works, but I'm seeing lots of CRC errors and station-to-station throughput
> is only about 5Mbps (one sending to the other).


> I tried setting xmit power lower (to 4, for instance), but that
> doesn't change the behaviour much.

Well, that's still going to be quite powerful. Can you try setting it to 1 or 2?

I wonder what RX attenuation setting(s) are being used. An RSSI of ~22
is quite strong. It doesn't -seem- strong enough to cause big issues
though.

Hm, what about setting tx/rx chainmask to 1 on both sides?


adrian

[ath9k-devel] Low speeds when AP is very close to stations.

[Ben Greear]

On 03/07/2012 05:00 PM, Adrian Chadd wrote:
> On 7 March 2012 13:17, Ben Greear<greearb@candelatech.com>  wrote:
>> I put two ath9k (AR9300) nics in one machine, with
>> 6 antenna poking out, and had one NIC be the AP
>> for the other.
>
> How far apart are there?

Well, here's a picture:

http://www.candelatech.com/images/systems/lf0310-back-lo-72dpi.jpg

3 antenna on that pci faceplate are to NIC A, and the right
antenna and ones connected to the case are to NIC B.

>> It works, but I'm seeing lots of CRC errors and station-to-station throughput
>> is only about 5Mbps (one sending to the other).
>
>
>> I tried setting xmit power lower (to 4, for instance), but that
>> doesn't change the behaviour much.
>
> Well, that's still going to be quite powerful. Can you try setting it to 1 or 2?

Sure, will do that tomorrow.

> I wonder what RX attenuation setting(s) are being used. An RSSI of ~22
> is quite strong. It doesn't -seem- strong enough to cause big issues
> though.

How do I figure this out?

> Hm, what about setting tx/rx chainmask to 1 on both sides?

I'm not sure how to do this either..will poke around tomorrow.

Thanks,
Ben


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