On Wed, Jul 22, 2015 at 3:40 PM, Chen-Yu Tsai <wens at csie.org> wrote: > 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". Sorry, this part applies to the US rules, not part of this patch. > 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
