Re: [Madwifi-devel] Survey: What are you using MadWifi for, and why?

On Wed, Nov 18, 2009 at 3:05 PM, Jouni Malinen <[email protected]> wrote:
> On Wed, Nov 18, 2009 at 02:08:16PM -0800, Luis R. Rodriguez wrote:
>> Are you aware of any regulatory rules which prohibit narrower
>> channels? It just seems odd.
>
> I don't remember any rules that would explicitly do that, but there may
> be some implicit limitations due to the slower TX rate. I don't know
> whether this would hit anywhere, but at least quarter width channel with
> 1 Mbps TX rate and maximum frame length might get pretty close to some
> maximum TX-without-sensing limits. Though, that is less likely to be an
> issue on 5 GHz band due to 6 Mbps minimum TX rate even at quarter
> channels could be fast enough. There could also be some rules that state
> the minimum TX rate, so there could potentially be need to change
> supported rate sets and/or fragmentation threshold in some corner cases.
>
> Actually, even with 6/4 Mbps TX rate, the channel sensing rule in Japan
> (carrier sense every 4 ms) (if that rule is still valid.. haven't
> really checked), we could hit the limit with maximum frame length.

Thanks for the details, we'll poke our regulatory guys just to confirm.

  Luis

------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day 
trial. Simplify your report design, integration and deployment - and focus on 
what you do best, core application coding. Discover what's new with
Crystal Reports now.  http://p.sf.net/sfu/bobj-july