On Monday, October 24, 2016 4:38:36 PM CEST Johannes Berg wrote:
> On Mon, 2016-10-24 at 16:36 +0200, Simon Wunderlich wrote:
> > On Monday, October 24, 2016 4:16:02 PM CEST Johannes Berg wrote:
> > > On Mon, 2016-10-24 at 15:42 +0200, Simon Wunderlich wrote:
> > > > Otherwise, it would be pretty much impossible to perform CSAs to
> > > > another DFS channel.
> > >
> > > I was told that to do that you'd need another NIC that's pre-
> > > CAC'ing another channel.
> >
> > Here is the portion from ETSI 301 893 v1.8.1 [1] (the most recent one
> > to my knowledege), section 4.7.1.4 which describes operation from
> >
> > master devices (Access Points):
> > [...]
>
> Yeah I'm pretty sure there are differences in ETSI vs. FCC. Perhaps the
> information I was told about was for FCC. But perhaps it's all just
> completely wrong :)
I think I've found the right specification [1] for FCC. They doesn't state so
explicitly that it is allowed, but I don't see any remark that this behaviour
is forbidden, either. The important section is 5.1.1 Master devices in 905462
D02 UNII DFS Compliance Procedures New Rules v02, which is pretty similar to
ETSI. They say:
<snip>
a)
The Master Device will use DFS in order to detect Radar Waveforms with
received signal strength above the DFS Detection Threshold in the 5250 - 5350
MHz and 5470 - 5725 MHz bands. DFS is not required in the 5150 - 5250 MHz or
5725 - 5825 MHz bands.
b)
Before initiating a network on a Channel, the Master Device will perform a
Channel Availability Check for a specified time duration (Channel Availability
Check Time) to ensure that there is no radar system operating on the
Channel, using DFS described under subsection a) above.
c) The Master Device initiates a U-NII network by transmitting control
signals that will enable other U-NII devices to Associate with the Master
Device.
d)
During normal operation, the Master Device will monitor the Channel
(In-Service Monitoring) to ensure that there is no radar system operating on
the Channel, using DFS described under a).
e)
If the Master Device has detected a Radar Waveform during In-Service
Monitoring as described under d), the Operating Channel of the U-
NII network is no longer an Available Channel. The Master Device will
instruct all associated Client Device(s) to stop transmitting on this
Channel within the Channel Move Time. The transmissions during the
Channel Move Time will be limited to the Channel Closing Transmission
Time.
</snap>
Again, no explicit "on installation" here, but there is also nothing saying
that we can not check/operate on other channels in the meantime. (NOTE: going
off-channel while operating is a different topic).
Cheers,
Simon
[1] https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?
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