Reduce tx power

Reduce tx power

[Giuseppe Siracusano]

Hi to all

Is it possible to set the trasmission power to a value  lower than 1 mW
(0 dBm) ? If the answer is no, why.  Is there a  phyisical limit in the
chip or is just a driver limit?

I'm trying to simulate a large wireless mesh network using machines that
are close toghether, so now every machine has the complete "visibility"
of the network. My goal is to limit the visibility to only a subset of
nodes. I can not move the machines, and the drivers that I'm using are
ath5k.

Bye

Giuseppe Siracusano

Re: Reduce tx power

[James Cameron]

I don't know about ath5k, but in usb8388 firmware (libertas driver)
there is a blinding table, into which MAC addresses were inserted, so
that the firmware would simulate test conditions.

Without a blinding table, sometimes nodes with minimal transmit power,
distance, and shielding, could still be reached.  RF sometimes works
better than you want.

-- 
James Cameron
http://quozl.linux.org.au/

Re: Reduce tx power

[Bob Copeland]

On Thu, Feb 06, 2014 at 07:40:14AM +1100, James Cameron wrote:
> I don't know about ath5k, but in usb8388 firmware (libertas driver)
> there is a blinding table, into which MAC addresses were inserted, so
> that the firmware would simulate test conditions.

At least in the mac80211 11s mesh implementation (and thus available
with ath5k), the equivalent is plink block, which restricts peering
between neighbors:

 $ iw mesh0 station set <MAC address> plink_action block

-- 
Bob Copeland %% www.bobcopeland.com

Re: Reduce tx power

[Giuseppe Siracusano]

Thanks to all for the replies!!

In the previous mail I'forgot to say that I've already implemented a solution based on mac filtering,
but in this case the same wireless channel would be shared among different "virtual" visibility scopes 
and the emulation is less realistic.

I'd like to compare this solution to a second one where the nodes do not share the same channel, 
and then chose the one that fits my experiment's requisites.

bye

Giuseppe Siracusano