[wireless-regdb] Question about 5.8 GHz in E.U.

Maximilian Engelhardt engelhardt at perisens.de
Wed Sep 13 06:55:11 PDT 2017


I sent the patch to add the Frequency range from 5725 to 5875 MHz in Germany 
so I can give you some background on this.
What I'm writing is only valid for Germany, but since it's all based on 
European regulations it's probably very similar in other European countries.

In Germany there are three bands allowed for wireless LAN (WLAN) usage in the 
5 GHz band  [1]:

5150 - 5250 MHz (indoor only)
5250 - 5350 MHz (indoor only)
5470 - 5725 MHz (indoor and outdoor)

However the 5470 - 5725 MHz band is only allowed for fixed outdoor 
installations (this is not stated directly in the legal document but I have 
been told it's interpreted in this way. It's however explicitly stated that 
usage for aircraft communication is not allowed). So for for non-fixed outdoor 
setups none of these 5 GHz bands can be used.

Additionally to the official wireless LAN bands there are short range devices 
(SRD) bands. These are similar to the ISM bands and often share the same 
frequency and power regulations, but unlike the ISM bands which are only 
allowed for industrial, scientific or medical applications the SRD bands can be 
used for data communication.
There exists a frequency range from 5725 - 5875 MHz as SRD band (also an ISM 
band) with a maximum power of 25 mW [2]. While this is not specifically 
regulated for wireless LAN usage, is can be legally transmitted in this band 
following the power restriction. There are also no restrictions to indoor or 
outdoor usage. So this is the only 5GHz band in Germany that can be legally 
used for non-fixed outdoor equipment using wireless LAN.
Power on this band is limited but there may be applications where this is not 
a problem, e.g. if you have line of sight communication or don't need to 
transfer much data.

Because of this I see no reason why this frequency range should be removed 
from the database. It has advantages over the other 5 GHz bands and it can be 
legally used. I would find it annoying not being able to use it while I'm 
legally allowed to and not having another option available.


[1] https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/
[2] https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/

On Freitag, 8. September 2017 00:15:34 CEST Ryan Mounce wrote:
> On 7 September 2017 at 23:33, Mathieu Peyréga <mathieu.peyrega at gmail.com> 
> > Hello,
> > 
> > unfortunately, my wifi skills are not (yet ?) allowing me to track further
> > than what the "iw reg get" command tells me (confirmed by some off the
> > shelf Wifi analyzer sofwares).
> > Do you have pointers/tutorial to help me doing that ?
> Try this
> # find interface name
> iw dev
> # perform scan on interface
> iw dev wlan0 scan -u
> This previously dumped the country IE in a nice readable form, however
> it no longer does on my device running LEDE master so you may not have
> any luck depending on how new your distro is.
> Typically for this task I would use monitor mode + Wireshark or my
> favoured (sadly proprietary) WiFi surveying app, however I can only
> provide advise for macOS.
> > Further reading your answer, my guess is that DJI has complied to UNII-3
> > choice. At least on their website Spark spec page, they clearly give the
> > good max power figures and make the difference between FCC and EU areas.
> > 
> > This leads to my concern about why not adding the matching rules in the DB
> > for EU countries that have transposed it into their laws.
> > Is this regulatory DB supposed to strictly reflect the current state of
> > local regulations or doe it also endorse a higher level of
> > "responsability"
> > in order to prevent issues with non complient devices as I understand your
> > fears ?
> The regdb is only used in practice for 802.11 rather than as a
> universal dictionary for radio regulations. My personal opinion is
> that it should first reflect local regulations, and then subsequently
> reflect established industry conventions that are more restrictive. In
> this instance, the industry convention appears to be disabling the
> UNII-3 range in Europe and I happen to agree more for practical
> reasons than any sense of 'responsibility'.
> > Regards
> > 
> > Le 07/09/2017 à 15:44, Ryan Mounce a écrit :
> >> You can see the 'FR' Country Code, can you see the full 802.11d
> >> Country Information IE that is broadcast by the DJI drone?
> >> 
> >> I can see how this situation has come about. In much of the world
> >> including China (DJI) and the USA (DJI's largest international market)
> >> the 'UNII-3' equivalent range is a simple default choice with high
> >> power and outdoor use permitted, with no DFS to worry about.
> >> 
> >> Europe is not so simple. In roughly descending order of device
> >> compatibility.
> >> 
> >> 2.4GHz has power restrictions compared to USA/China, and is polluted
> >> in every country.
> >> UNII-1 is indoor only and should require the user to confirm they are
> >> indoors (for a device like a drone that is likely to be used outdoors,
> >> unlike a home WiFi AP)
> >> UNII-2 adds DFS and TPC restrictions to UNII-1, quite restrictive.
> >> UNII-2E is fairly quiet and allows more generous power, however DFS is
> >> still a consideration and a portable device like a drone would have to
> >> scan for at least 60 seconds before broadcasting in this band.
> >> UNII-3 has the strictest power restrictions of all, and thus the most
> >> limited range.
> >> 
> >> So it seems that DJI have simply ignored this altogether, and are
> >> broadcasting in a poorly supported frequency band in Europe with
> >> either a very weak short range signal or a very strong signal in
> >> violation of regulations. Either way, this is very much their problem
> >> (and unfortunately also their customers').
> > 
> > --
> > tel : +33 (0)6 87 30 83 59
> _______________________________________________
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