Arch Linux

wgnm

Member

Registered: 2013-02-02

Posts: 10

Ignoring TX power level limit dictated by AP

Hi,

I have problems with the wireless connection in my university ("eduroam").
Connecting works fine but after that the connection is unstable and occasionally breaks down. I highly assume that is caused by the tx power level "suggestion" send from the AP after connecting.

dmesg says:

...
[552843.118111] wlan0: Limiting TX power to 5 dBm as advertised by a0:cf:5b:XX:XX:XX

and I can confirm this with

$ iwconfig
...
Bit Rate=54 Mb/s   Tx-Power=5 dBm
...

Yes, 5dbm! With 30+ wireless stations around. Those admins here are nuts.

And I haven't found a why to circumvent this 5dbm limit. With

$ iw wlan0 set txpower limit 400

going down to 4dbm (or 3 etc.) works. But everything higher than 500 is simply ignored. Without AP connection the power level is back at (default) 20dbm. But

iw wlan0 set txpower fixed 2000

is ignored and after connecting its back at 5 dbm again.

I found this patch, but it's not in the kernel yet: https://patchwork.kernel.org/patch/7775551/

So does somebody know of any solution here? Thanks.

My card is a Broadcom is a BCM43227. I tried drivers brcm80211,  b43 and broadcom-wl. All of them work, all have the same connection problems.

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,324

Re: Ignoring TX power level limit dictated by AP

And to hell with everyone else trying to use it.

---

Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

wgnm

Member

Registered: 2013-02-02

Posts: 10

Re: Ignoring TX power level limit dictated by AP

And to hell with everyone else trying to use it.

Ehh, thanks for trying to help me...

It's not like I want to jamm and block access for everyone else. But I think raising the 5dbm limit to, say, 12 dbm is probably enough to have a decent connection like everybody else. It makes no sense if I can't even download a 15mb file while at the same time other clients are just ignoring the tx power limit.

And there are other APs which are sending a power limit of 17 in the same area...