Initial automatic channel selection implementation

Helmut Schaa helmut.schaa at
Wed May 25 00:24:32 EDT 2011

Am Dienstag, 24. Mai 2011 schrieb Pavel Roskin:
> On 05/24/2011 12:44 PM, Cristian Ionescu-Idbohrn wrote:
> > On Tue, 24 May 2011, Pavel Roskin wrote:
> >>
> >> Speaking of channels, I think only some channels should be eligible for
> >> automatic selection (that would be 1, 6 and 11 in the 2.4 GHz range).
> >
> > May I ask what the rationale behind that may be?
> That's a safe distance between channels.  That's why channels 1, 6 and 
> 11 are used more often than others.
> Our algorithm make select, say, channel 3.  That may be the most quiet 
> channel at the moment.  We may use absolutely the best algorithm to 
> determine that.  However, it is likely that APs operating on channels 1 
> and 6 would eventually appear in vicinity, and out AP would interfere 
> with both of them instead of just one of them.
> Using a car analogy, consider channels 1, 6 and 11 like lanes on a 
> highway.  Using other channels would be like driving between lanes.  It 
> may seem safe, but only in absence of other traffic.
> It's possible that the list of autoselectable channels could be country 
> specific.  I would hate to add complexity to CRDA.  Hopefully we could 
> device a simple algorithm to find the autoselectable channels based on 
> the CRDA data.

Why not use a channel list as input to the algorithm (in whatever form).
Hence, it would work for all channels (if the user wishes to do so) but it
can be limited to a list of preferred channels (1,6,11).


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