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Message-ID: <a4cb97fc-de32-4d15-47a5-a7ad26bd32ab@gorani.run>
Date:   Thu, 7 Oct 2021 04:18:01 +0900
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Subject: Re: [PATCH] wireless-regdb: Update regulatory rules for South Korea
 (KR)
To:     Seth Forshee <sforshee@kernel.org>
Cc:     wireless-regdb@lists.infradead.org, linux-wireless@vger.kernel.org
References: <20210929172728.7512-1-mans0n@gorani.run>
 <YV2tukujds7PodAf@ubuntu-x1>
From:   Sungbo Eo <mans0n@gorani.run>
In-Reply-To: <YV2tukujds7PodAf@ubuntu-x1>
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On 2021-10-06 23:07, Seth Forshee wrote:
> On Thu, Sep 30, 2021 at 02:27:28AM +0900, Sungbo Eo wrote:
>> This patch is based on MSIT Public Notification 2020-113 ("Unlicensed Radio
>> Equipment Established Without Notice"), officially announced on 2021-01-06.
>>
>> Extend the last 5 GHz frequency range to 5850 MHz.
>>
>> WiFi 6E is now allowed with the following restrictions:
>> * Indoor: the full 1.2 GHz range, up to 160 MHz bandwidth and 250mW EIRP
>> * Outdoor: the lower 500 MHz range, up to 160 MHz bandwidth and 25mW EIRP
>> Here only the former entry is added.
>>
>> And also update the regulatory source links.
>>
>> Signed-off-by: Sungbo Eo <mans0n@gorani.run>
>> ---
>> I have two questions.
>>
>> The regulation has one more restriction:
>>    The TX power should not exceed 2.5 mW/MHz
>>    when the frequency range includes the whole or a part of 5230-5250 MHz
>>    and the bandwidth is equal to or less than 40 MHz.
>> That leads to the followings:
>>    5230-5250 @ 20 -> 17 dBm
>>    5210-5250 @ 40 -> 20 dBm
>>    5170-5250 @ 80 -> 23 dBm
>> Is it possible to add this rule without lowering the TX power for 80 MHz bandwidth?
> 
> I've tried to look at the documents, but much of the information appears
> to be in images where machine translation doesn't work, and I haven't
> been able to find English versions.

Oops, sorry. I should have prepared it in more convertible format.
There's no English version of it, but at least I could find a HWP 
document file [1] that contains regular tables instead of images. (The 
URL is from the "attached files" tab in the source link.)

You can open it with a dedicated viewer [2] or an online viewer [3]. But 
those free viewers do not offer conversion to DOC or HTML. (It seems the 
dedicated one has "print to PDF" feature, though.)

I also tried an online convert tool but it failed due to the long 
processing time... I can send you converted versions myself if you prefer.

[1] https://www.law.go.kr/LSW//flDownload.do?flSeq=93728653
[2] https://www.hancom.com/cs_center/csDownload.do
[3] https://hwp.polarisoffice.com/

> 
> Taking the above at face value, I actually get slightly lower EIRP
> values for a PSD of 2.5 mW/MHz (EIRP = PSD + 10 * log(bandwidth)): 16
> dBm for 20 MHz and 19 dBm for 40 MHz.

I thought log(2.5) equals 0.4? We also have 2.5 mW/MHz * 40 MHz = 100 mW.

> We don't currently have any way to
> express PSD limits in the database nor a way to express different power
> limits for different bandwidths, so it's not possible to comply with the
> PSD limits for 20/40 MHz without also lowering the EIRP for 80 MHz.

Too bad. :( I'll prepare v2 soon.

> 
>> And do we need AUTO-BW for 6E channels? I thought it is for merging adjacent frequency ranges.
> 
> That is correct. Since there are no adjacent rules, AUTO-BW doesn't make
> sense.

Okay, thanks!

Regards,
Sungbo

> 
> Thanks,
> Seth
>