[wireless-regdb] Updates for the regulatory rules for Bulgaria
seth.forshee at canonical.com
Thu Apr 21 09:34:10 PDT 2016
On Thu, Apr 21, 2016 at 07:12:53PM +0300, Petko Bordjukov wrote:
> On Thu, 21 Apr 2016 17:07:21 +0300,
> Seth Forshee wrote:
> > This is almost certainly because these frequencies require transmit
> > power control. We drop the TX power limits by half (i.e. 3 dB) when TPC
> > is required on account of not supporting TPC.
> I was under the impression that the underlying kernel infrastructure had support
> for TPC. What I am observing is that hostapd automatically includes the Power
> Constraint IE in beacons sent out on any channel with DFS enabled. The default
> transmit power reduction is 3dBm.
> This means that the TX power of any clients would be limited to 3dBm below the
> TX power of the AP even though it's not required.
> Would there be any merit in providing additional information regarding the TX
> power and the target average TX power reduction for the system when TPC is
I'm frankly not certain about the status of kernel support, but my
impression was that some drivers might have some level of TPC support
but that it's not universal. I really haven't been keeping track of it
However, even if there is universal TPC support in the kernel we still
lack any way to encode the TPC requirement for a given rule in the
database or inform the kernel about it.
> > > WAS/RLANs 5150-5250 MHz
> > > 200 mW maximum mean e.i.r.p.
> > > 10 mW/MHz maximum spectral density of the mean e.i.r.p.
> > If this range doesn't require TPC then it could be bumped up to 200 mW
> > (23 dBm).
> Yes, the CRC's list explicitly states that TPC is required in the 5250-5350 MHz
> and 5470-5725 MHz bands and there's no further comments on the 5150-5250 MHz
> band. EN 301 893 has the notes below for the 5150-5250 MHz band that could have
> lead to the 3 dBm drop though, maybe linked to the AUTO-BW flag?
> > NOTE 1: The applicable limit is 20 dBm, except for transmissions whose nominal
> > bandwidth falls completely within the band 5 150 MHz to 5 250 MHz, in which
> > case the applicable limit is 23 dBm.
> > NOTE 2: The applicable limit is 7 dBm/MHz, except for transmissions whose
> > nominal bandwidth falls completely within the band 5 150 MHz to 5 250 MHz, in
> > which case the applicable limit is 10 dBm/MHz.
It shouldn't be required for the AUTO-BW flag, so based on everything
I'm seeing here 23 dBm seems fine.
> I changed the TX power values to mW to be consistent with what is stated in the
> CRC's list. I'll resubmit the patch with the values in dBm and with the 3 dBm
> drop for the 5250-5350 MHz and 5470-5725 MHz bands.
Great, thanks. I think you should be fine to bump up the 5150-5250 MHz
rule by 3 dBm as well. If someone knows a reason it shouldn't be raised
they can let us know.
More information about the wireless-regdb