It’s interesting how quickly the wind can turn sometimes. While my problems with 5 GHz Wi-Fi, i.e. radar detection and 160 MHz channels seems to have been fixed by cool software upgrades of the AVM devices I use, my first steps into the 6 GHz band with 802.11ax (Wi-Fi 6E) haven’t been as successful as I was hoping.
In practice there are access points and even high end smartphones these days that can be configured to provide Wi-Fi access point functionality (tethering) in the 6 GHz band. For my initial tests, I used a high end smartphone, activated 6 GHz Wi-Fi tethering and then used the network from another smartphone. This worked like a charm.
After this initial test, I expected things to go smoothly, as the 6 GHz band should be less trouble some than the 5 GHz band, as there is to weather radar to detect and circumvent. Hence, less hassle. But while that might be true, there’s another problem: The 6 GHz band has not been approved for Wi-Fi use in all regions of the world, and hence a device needs to make an educated guess in which part of the world it is and activate parts or all of the 6 GHz spectrum when it is in a region in which Wi-Fi in the 6 GHz band has been approved. Unfortunately, the Intel AX211 (Alder Lake-P PCH CNVi Wifi) chip in my notebook seems to have a problem with this and stubbornly refused to cooperate.
Exactly how that decision is made is opaque at best, I couldn’t find any reference on the Internet. My best guess: The Intel Wi-Fi chip looks at the country code in the beacon frames it receives from the Wi-Fi networks around and then accepts this as the current location. But that’s only my guess. However, there seems to be more to it, as the Intel AX211 chip in my notebook refuses to activate the 6 GHz band despite all Wi-Fi networks around broadcasting ‘DE’ or ‘EU’ as location:
martin@m3:~$ sudo iw dev wlp3s0 scan | grep Country
Country: DE Environment: Indoor/Outdoor
Country: DE Environment: Indoor/Outdoor
Country: DE Environment: Indoor/Outdoor
Country: DE Environment: Indoor/Outdoor
Country: DE Environment: Indoor/Outdoor
Country: DE Environment: Indoor/Outdoor
So perhaps this is a Linux kernel issue? For my first tests I used a 5.19 kernel, which I subsequently upgraded to a 6.2.0.32 kernel. Unfortunately this had no effect and all channels in the 6 GHz band were still reported as ‘disabled’:
[...] Frequencies: * 5955 MHz [1] (disabled) * 5975 MHz [5] (disabled) * 5995 MHz [9] (disabled) * 6015 MHz [13] (disabled) [...] * 6755 MHz [161] (disabled) * 6775 MHz [165] (disabled) * 6795 MHz [169] (disabled) * 6815 MHz [173] (disabled) * 6835 MHz [177] (disabled) * 6855 MHz [181] (disabled) * 6875 MHz [185] (disabled) * 6895 MHz [189] (disabled) * 6915 MHz [193] (disabled) * 6935 MHz [197] (disabled) * 6955 MHz [201] (disabled) * 6975 MHz [205] (disabled) * 6995 MHz [209] (disabled) [...]
I also have a Windows 11 partition on that notebook, so I gave it a try here. Same result, my 6 GHz Wi-Fi networks are not detected. I then updated to the latest Intel driver (22.240.0.6), but that also didn’t fix things. How disappointing!
So I’m a bit miffed that the Intel card is so stubborn and refuses to work in the 6 GHz band. Any ideas are appreciated.