New indoor 5 GHz channels

In the USA a few new channels are now allowed for use. 169 and 173 are in the regulatory database but marked as "INDOOR-ONLY" or "restricted". How would I configure the router to know it is indoors and use these channels?

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You wouldn't, you'd just pick the channels. As long as you're running a version with an updated wireless-regdb, they should work as intended [by the FCC].

:spiral_notepad: -

  • Now...has the regdb been updated? :thinking:
  • Also, I recall when Channel 13 was allowed indoors, I never recall seeing it listed on devices... :confused:
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iw reg get
phy#0
country US: DFS-FCC
...
        (5150 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
        (5250 - 5350 @ 80), (N/A, 24), (0 ms), DFS, AUTO-BW
        (5470 - 5730 @ 160), (N/A, 24), (0 ms), DFS
        (5730 - 5850 @ 80), (N/A, 30), (N/A), AUTO-BW
        (5850 - 5895 @ 40), (N/A, 27), (N/A), NO-OUTDOOR, AUTO-BW, PASSIVE-SCAN
...

5850 to 5895 would be channels 169 and 173.

iwinfo wlan0 freqlist
...
  5.785 GHz (Channel 157)
  5.805 GHz (Channel 161)
* 5.825 GHz (Channel 165)
  5.845 GHz (Channel 169) [restricted]
  5.865 GHz (Channel 173) [restricted]

If I use a configuration that works as VHT20 on channel 165, then change the channel to 173, this error occurs:

Sat Apr  8 21:15:14 2023 daemon.notice netifd: radio5 (15581): Command failed: ubus call hostapd config_add {"iface":"wlan0", "config":"/var/run/hostapd-phy0.conf"} (Invalid argument)
Sat Apr  8 21:15:14 2023 daemon.notice netifd: radio5 (15581): Usage: ubus [<options>] <command> [arguments...]

This is ath10k hardware (Nanobeam AC Gen 2) and 22.03.3.

I was trying to get my access point to work on channel 165 (at 80Mhz) too and, yeah, turns out, while regdb has been updated, it is still impossible:

# iw phy1 reg get
phy#1
country US: DFS-FCC
<...>
	(5730 - 5850 @ 80), (N/A, 30), (N/A), AUTO-BW
	(5850 - 5895 @ 40), (N/A, 27), (N/A), NO-OUTDOOR, AUTO-BW, PASSIVE-SCAN
<...>

All channels above 165 are “passive-scan”, but, more importantly, in the actual db they are marked NO-IR, which means that the device is not allowed to be the first one to start radiating (before it sees someone else transmit on this frequency). Naturally, you cannot run an AP in this mode.

The discussion of the corresponding patch explains that this was done intentionally since “the regulations forbid active scans” and NO-IR was the only way to comply with it, given the current implementation in the Kernel:

So we would not be able to operate an OpenWrt or other Linux-based AP,
while other vendors would be allowed to do this? How is this
acceptable? How does this help in liberating the band?

We're allowing clients which use the rules in the db to connect to APs
in the band. We may be able to get APs supported later on by getting
changes to break up passive-scan and no-IR. But with what we have to
work with right now, and based on my interpretation of the rules, I
think this is the best we can do currently.


Also, possibly unrelated, but haven’t seen this mentioned anywhere, so:

One suspicious thing I noticed was that when I looked at my AP from another device (iw dev <...> scan), I was seeing:

Country: US    Environment: Indoor/Outdoor

It turns out, there is an undocumented configuration option that allows you to choose the environment:

# uci set wireless.radio1.country3=0x49
# uci commit wireless

(0x49 is a magic constant from hostapd docs meaning “indoor”)

And voila:

Country: US    Environment: Indoor only

I am not sure if this setting matters at all, but just something to keep in mind for when we are eventually able to get past the NO-IR roadblock.

By the way, another thing to keep in mind:

According to the FCC definitions (from the page linked in the regdb):

Indoor Access Point. For the purpose of this subpart, an access point that operates in the 5.850-5.895 GHz or the 5.925-7.125 GHz band, is supplied power from a wired connection, has an integrated antenna, is not battery powered, and does not have a weatherized enclosure. Indoor access point devices must bear the following statement in a conspicuous location on the device and in the user's manual: FCC regulations restrict operation of this device to indoor use only.

(emphasis mine)

If my AP satisfies the listed criteria, but does not have “FCC regulations restrict operation of this device to indoor use only” on it, is it still an indoor access point? My reading of this is “it is indoor ⇒ has the statement”, therefore no statement (none of mine have it) ⇒ not an indoor AP.

I mean, will the FCC come after everyone using these channels to check if their device has that text on its case and in the manual? I doubt it, but, still, technically...

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Either:

  • The manufacturer failed to perform their duty required under law
  • It's a foreign device; or
  • As I believe, that's a new regulation and your device is likely older (e.g. some ath9k devices allowed/displayed an option to force a pre-2009 setting as I recall, they may have been manufactured after such rule, but the ath9k chip existed before)