[wireless-regdb] [PATCH] wireless-regdb: Update regulatory rules for Taiwan (TW)

[Chen-Yu Tsai]

On Thu, Jul 9, 2015 at 11:15 PM, Seth Forshee
<seth.forshee at canonical.com> wrote:
> On Wed, Jul 08, 2015 at 11:07:20AM +0800, Chen-Yu Tsai wrote:
>> > Thanks. I think there should be a written document about what the
>> > rules should be like, or what is expected:
>> >
>> >   1. WiFi channel boundaries or band boundaries
>> >   2. peak output power or peak power spectral density
>> >
>> > In http://lists.infradead.org/pipermail/wireless-regdb/2015-July/000856.html
>> > you mentioned the software is smart enough to work out how to combine
>> > different bands and what channels to use, so I see no reason to explicitly
>> > chop up contiguous spectrum, unless there are explicit rules forbidding
>> > combined use of bands with different regulatory rules. AFAIK the FCC
>> > only requires one to satisfy all rules when usage crosses band boundaries.
>> >
>> > http://lists.infradead.org/pipermail/wireless-regdb/2015-July/000857.html
>> > also raises a similar question.
>
> I was really commenting about the transmit power updates in your patch.
> I just compared the frequency changes to the documentation you linked to
> and those do look okay to me.

I see.

>> >> I would however consider an update for 5.15-5.25 GHz and 5.6-5.65 GHz
>> >> provided that there's official documentation to substantiate the change.
>> >> I unfortunately cannot read Chinese, so I would need some assistance to
>> >> confirm the documentation.
>> >
>> > I could possibly ask around, though I'm not optimistic. The "official"
>> > documents are just transcripts from NCC hosted Q&A sessions regarding
>> > the latest regulations. Proposals/questions are submitted by vendors,
>> > and the NCC responds and puts together an aggregated transcript.
>>
>> Just got off the phone with the NCC. Their position is, spectrum allocation
>> is not within their purview, but the Ministry of Transportation and
>> Communications. As noted in the patch, they have already opened up the
>> spectrum to U-NII and low power radio usage. What remains is that the
>> NCC revise its testing standards. Until then, their position is that,
>> since their testing standards are modeled after FCC standards, vendors
>> can just test under FCC standards, then convert the reports into LP0002
>> format, and cite the FCC test report.
>>
>> There is no formal English version of the Q&A transcript, at least not
>> until some foreign testing body requests it. The person in charge just
>> asked me to translate it myself...
>
> If you send a patch which updates only the frequencies I would likely
> apply that after allowing a week or so for others to either ack or nack
> it (and running the stuff you linked to through google translate and
> seeing if I could make any sense of the output).

Got it.

> I think the power updates are probably based on a misunderstanding, and
> may not even be completely correct. For the most part after they've been
> converted to EIRP (eirp = 10 * log10(mW)) they don't turn out to be
> substantially different than what we have now. I think the value in
> 5250-5350 MHz is probably incorrect however. Based on my quick skim of
> the document you linked to it should be 50 mW rather than 250. 50 mW
> also roughly matches to the 17 dBm which is in the database today,
> whereas 250 mW is closer to 24 dBm.

Yes. About the first part, it seems dbparse.py converts values in mW
into EIRP anyway. However I don't think EIRT equals "peak power spectral
density".

About the second part, yes the current values match the ones in LP0002.
However as I stated, the regulatory body has explicitly allowed certifying
under the latest FCC rules, which effectively raises the limits from
50 mW to 250 mW.

> My suggestion would be update the frequencies but not the existing
> transmit power limits, unless you discover that any of the power limits
> are definitely incorrect.

I'll split up the patch into 3:

  1. Add the new 5150 - 5250 frequency band, using current LP0002
     limits if any, otherwise FCC limits.

  2. Tweak frequency boundaries for the remaining bands to make
     them contiguous and properly reflect the regulations rather
     than the WiFi channel frequencies.

  3. Update power limits and DFS requirements to latest FCC standards.

Each patch will then explain why and how the regulations changed
along with references, in English if available.

You can then decide on whether to merge all three or just the first
two.


Regards
ChenYu