Subject: [manet] /proc/net/wireless

From: "[email-masked]" <[email-masked]>
Date: Tue, 22 Apr 2003 16:47:34 +0200

Hi all
- Can anyone tell me what mean 'link', 'level' and 'noise' in 
/proc/net/wireless and if I can calculate the SNR from the 
informations in /proc/net/wireless(noise level) and from 
iwconfig(Txpower).
- is it possible to convert 'noise' and 'level' in db
thank you 

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From: David Young <[email-masked]>
Date: Tue, 22 Apr 2003 12:29:42 -0500

> informations in /proc/net/wireless(noise level) and from 

  I believe that level & noise are only meaningful in an infrastructure
  network, where they tell the received signal strength and an average
  noise level of packets received from the AP. I recommend that you
  read the driver source to find out for certain. Also, search the Prism
  "knowledge base" at Intersil for questions and answers regarding signal
  & noise measurements.

  The Tx power control that the hostap driver gives is misleading and
  wrong. There is no reliable relationship between dBm and CR31 settings.
  A proper power control should use a feedback loop such as the Prism MAC
  firmware does. See <http://www.intersil.com/data/an/AN1037.pdf>.
  AN1037 was my guide for a NetBSD power control; see
  <http://lists.bawug.org/pipermail/bsd-wireless/2003-March/000061.html>.

> - is it possible to convert 'noise' and 'level' in db

  Prism chips provide signal & noise indications with every received
  packet. Register 0xFC46 tells the constant to substract from the signal
  and noise indications to approximate dBm, but manufacturers may not
  reliably calibrate that register. RID 0xFC46 may also be the constant
  to subtract from the indications in /proc.

Dave

-- 
David Young             OJC Technologies
[email-masked]      Urbana, IL * (217) 278-3933
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From: "Roberto Aldunate" <[email-masked]>
Date: Tue, 22 Apr 2003 15:46:21 -0400 (Pacific SA Standard Time)

For some cards, I think that level & noise are meaningful not only in
infrastructure mode , but also in ad-hoc mode. In particular, I've used such
information using a Cisco aironet 340 receiving SS (link, noise and level)
from a Compaq WL110 card, the embedded one in the toshiba e740 and a Socket
(the ones used in HP Jornada) (all of them running on ad hoc mode).

regards, 

roberto.

-------Original Message-------

From: David Young
Date: Tuesday, April 22, 2003 2:40:57 PM
To: manet
Subject: Re: [manet] /proc/net/wireless

Dave

.